DIYstompboxes.com

As mentioned in this thread (http://www.diystompboxes.com/smfforum/index.php?topic=79012.20), I might do a double-sided layout for the Gristleizer and get some PCBs made up. The purpose of this thread is to find out how many people are interested, how many everybody wants, and the particulars of the design.

yea/nay:

Board-mounted pots?
Board-mounted rotary?
Quad opamp for the LFO/dual for audio sound good to everybody?
Any additions to the circuit (We'll have a leftover opamp in the quad...)?
Is there a particular box everybody wants to design around?

Just so I don't let anybody down, this is still an exploratory thing. If there's not enough interest, the boards won't be made, so don't get our hopes up just yet.

Quote from: Taylor on September 16, 2009, 05:19:45 AM
Any additions to the circuit (We'll have a leftover opamp in the quad...)?

A noise circuit for a random function?

Quote from: Dan N on September 16, 2009, 06:42:50 AM

Quote from: Taylor on September 16, 2009, 05:19:45 AM
Any additions to the circuit (We'll have a leftover opamp in the quad...)?

A noise circuit for a random function?

That's a good thought.

However, I think I'd like to see an oscillator--not sure if you can whip up a decent one with a single opamp, but...it would definitely make the unit useful as a rhythm instrument as well, and I could see myself doing some cool stuff with it.

Either way, I'd be in for one at least.

oh--and nay on board-mounted controls for me--it would take up so much extra space that it wouldn't be worth it to those of us who like more unique controls layouts.

I'd probably keep making them in 1790s, just because it makes for a very clean build when finished, but I'd love to see the board designed to fit in a BB enclosure. That gives everyone more options.

Also--I'd like to see the power supply mounted on the same board. That would save some serious space. Just a simple 9v-->+/-9v using a charge pump :)

I would be in for 3 of 4 boards as previously stated.

As for the board mounted pots and rotary switch that might be a nice option to have.  Although it does handcuff you in regards to box/drilling template.

Either way, board mounted or not, I'd be in.

I'm flexible and would go with whatever the hive mind wants. I'd also be in for one or two.

What kind of price range are we talking? Under or around $20?

I'd be in for one; I vote 'no' on board-mounted pots and 'yes' on onboard powersupply section!

- Strategy

I don't like board-mounted pots, if the case is drilled wrong there will be stress on the solder joints.

Quote from: Strategy on September 16, 2009, 01:44:19 PM
I'd be in for one; I vote 'no' on board-mounted pots and 'yes' on onboard powersupply section!

Took the words right out of my mouth.  :)

Quote from: Dan N on September 16, 2009, 06:42:50 AM

Quote from: Taylor on September 16, 2009, 05:19:45 AM
Any additions to the circuit (We'll have a leftover opamp in the quad...)?

A noise circuit for a random function?

I think implementing sample and hold, and a noise generator to drive it would add at least a couple more opamps, a FET and a couple of transistors, plus some passive components. It would be an interesting addition though, and you could even use the existing LFO for a sample source for the S/H, giving cool stepped waveforms - which can sound very sequencery.

i'm in for a board

Price will depend entirely on how many we get. I understand it's kind of circular, since the interest depends on the price, but the price depends on the interest... hmm.

Re: power supply, yes I would do onboard power supply with a charge pump.

Board mounted pots: it's possible to do them without making the board larger. Since you need pads for the wires anyway, I'll try to do them. If it does end up making the board larger, I'll scrap it. You won't be forced to use them if you want another control layout.

S+H is probably a little more than I have time to whip up right now. A simple oscillator is probably doable with an opamp and a resistor. Won't have multiple waveshapes or anything, though.

LM324n + a single for the lfo would probably achieve the higher fidelity and eliminate ticking. The only reason I was looking to use alternatives to the 741 was due to the fact I often swap around FX pedals on my board and use them in recording sessions for other instruments and FX sends. I dunno if the 741s would be good or bad in those situations since I've never personally had experience with this effect. Sometimes that low-fi sound is just what I'm looking for. I ordered a board from the same guy that made them for the original build report here, and I'll post my build report as well when I'm done. I'llsocket all 5 of them, and play around with different combinations and share my results with everyone here.

I'd be interested. Yes on modern chip choices/layout, on-board power supply. No to board mounting pots. I don't know if any mods to the board would really be required (LDR?), but whenever I see an LFO, I would like to also see LFO out and control in jacks.

Thanks Taylor, really good of you to take this on.

I'd like four, please.  Not so keen on hard-mounted pots, but not worried if the consensus says yes to them.  On board power supply if poss.  Other mods - not bothered, just so long as it works.....I don't feel like you should have to invest any extra time......

I'd take one board (maybe two if the price was low enough).  For the mounted pots question, why not run pads for either mounting them or not?  This may make a larger board, but people will have the option.

Ry

Seems nobody wants board-mounted pots, so I won't bother. Kind of surprised people aren't into this; the absolute worst part of this hobby to me is off board wiring. But that's fine, I don't even know if I'll build one of these, so I'd rather make the board the way everyone else wants it than for myself.

You can just as easily solder a wire to a pad where a pot should go.  Have it both ways.  (Not interested in buying a board, just a general comment.)

Quote from: earthtonesaudio on September 17, 2009, 01:54:53 PM
You can just as easily solder a wire to a pad where a pot should go.  Have it both ways.  (Not interested in buying a board, just a general comment.)

Absolutely. My only concern here is that we've been talking about ways to reduce PCB size--board-mounted pots will increase the footprint. Other than that, I'm indifferent to it--I even like board-mounted pots :)

Taylor, you might find additional takers for this pcb over at electro-music, even though it can be tricky to juggle the headcounts between multiple forums. Even though the Gristleizer could be approximated with several modular synth modules, the standalone itself is sort of a synth-DIY heritage item, being associated with Throbbing Gristle and all. I'd say you'll be able to lower the cost of the pcbs if you get some takers over there, just a thought.

- STrategy

Quote from: Strategy on September 17, 2009, 02:05:41 PM
Taylor, you might find additional takers for this pcb over at electro-music, even though it can be tricky to juggle the headcounts between multiple forums. Even though the Gristleizer could be approximated with several modular synth modules, the standalone itself is sort of a synth-DIY heritage item, being associated with Throbbing Gristle and all. I'd say you'll be able to lower the cost of the pcbs if you get some takers over there, just a thought.

- STrategy

That's a good idea, I'll try that.

I would be interested in one like in his nice build report.
That was a nice looking board.

John Lyons made that. I'm sure he'd make another.

completely curious about this

where does one land on the ettique/moral/douche bagerie scale if one were to make and sell a few these

Quote from: Taylor on September 18, 2009, 12:34:19 AM
John Lyons made that. I'm sure he'd make another.

Huh? I made it.

My bad, bluesdevil. I misread Josh's post - John did the powder coating, my eyes mixed it up. Sorry about that, don't mean to take your business away.

Ha, no problem. Just funny to see John automatically get lip service from you guys.... even for my work.
     

Well, again, it wasn't so much PCB=John in my mind, as the fact that in Josh's build, the phrases "john did the" and "PCB etch" are mere millimeters apart. I'm a scooch dyslexic. Apologies.

Quote from: big bustle on September 18, 2009, 03:09:31 AM
completely curious about this

where does one land on the ettique/moral/douche bagerie scale if one were to make and sell a few these

I pretty much assumed people would do this. I can't think of any other reason why these guys would be wanting 4 of the PCBs. As with all stompbox ethics, you can pretty much decide how you feel. You didn't design the circuit. You didn't do the layout. But the same is true for lots of commercial effects. You're not going to be taking food out of anyone's mouth, except the others who plan to sell them. Maybe you could kick me a couple extra bucks when you sell one for doing the free layout, if you felt like it. A guy called Roy Gwinn did the original design in the 70s, if he's still around, and if you felt really compelled, you could try getting his blessing. But the truth is that other people will make and sell them and nothing will come of it.

Quote from: Taylor on September 18, 2009, 04:21:17 AM

Quote from: big bustle on September 18, 2009, 03:09:31 AM
completely curious about this

where does one land on the ettique/moral/douche bagerie scale if one were to make and sell a few these

I pretty much assumed people would do this. I can't think of any other reason why these guys would be wanting 4 of the PCBs. As with all stompbox ethics, you can pretty much decide how you feel.

In the case of behaving like a gentleman I feel it is important to ask the creators if this is ok. Glad you're down with it. I wonder if Chris Carter should be asked as well.

Quote from: Taylor on September 18, 2009, 04:21:17 AM

You didn't design the circuit. You didn't do the layout. But the same is true for lots of commercial effects. You're not going to be taking food out of anyone's mouth, except the others who plan to sell them. Maybe you could kick me a couple extra bucks when you sell one for doing the free layout, if you felt like it.

How about links to buy PCBs from you for folks that want to make their own?

Quote from: Taylor on September 18, 2009, 04:21:17 AM
A guy called Roy Gwinn did the original design in the 70s, if he's still around, and if you felt really compelled, you could try getting his blessing. But the truth is that other people will make and sell them and nothing will come of it.

one more question. off the top of your head, ball park figure for the parts not including pcb or enclosure? i'm guessing $40 +/- $10. am i close?

For info.....

Roy Gwinn's original PE article here:
http://rubidium.dyndns.org/cag/pdf/gep.pdf (http://rubidium.dyndns.org/cag/pdf/gep.pdf)

Gristleizer on TG website here:
http://www.throbbing-gristle.com/tg/gristleizer.html (http://www.throbbing-gristle.com/tg/gristleizer.html)

New 'official' Gristleizers here:
http://www.smashingguitarsasheville.com/products (http://www.smashingguitarsasheville.com/products)

Smashing Guitars also have a PCB available - I think it's $50, but I've also seen it listed at $30.


Sorry, I may have jumped the gun a bit, but I've contacted Roy to get his blessing for our efforts. Or otherwise.

I'd be in for 1 or 2 boards, thanks.

Quote from: Taylor on September 18, 2009, 04:21:17 AM

Quote from: big bustle on September 18, 2009, 03:09:31 AM
completely curious about this

where does one land on the ettique/moral/douche bagerie scale if one were to make and sell a few these

I pretty much assumed people would do this. I can't think of any other reason why these guys would be wanting 4 of the PCBs. As with all stompbox ethics, you can pretty much decide how you feel. You didn't design the circuit. You didn't do the layout. But the same is true for lots of commercial effects. You're not going to be taking food out of anyone's mouth, except the others who plan to sell them. Maybe you could kick me a couple extra bucks when you sell one for doing the free layout, if you felt like it. A guy called Roy Gwinn did the original design in the 70s, if he's still around, and if you felt really compelled, you could try getting his blessing. But the truth is that other people will make and sell them and nothing will come of it.

I cant speak for anyone else, but I was personally planning on giving a couple of these that I made away.  I've been fortunate to rub shoulders with some talented guys, and it's always nice to give them a new tool for their arsenal.

yes, i too would be in for a few or couple depending on price. i probably will end up giving them away  to my friends if i build more than one of these.

I might be in for one or two (in case I screw it up on the first go).

I'll make the layout and figure out the costs at various quantities, and let you guys know.

I got a reply from Roy, saying he has a "2009" design using more modern components and a new filter.  Apparently he is a forum member, but has never posted, and will give this thread a once over and maybe post something for us.

Taylor, do you think it might be worth holding off for a few days?

Sure, I'm in no rush personally. I probably won't be building one of these anyway, as I'm pretty set on this kind of effect. I'm really just doing this as a small way of giving back to this great forum, from which I've learned so much, and for all the effects I've made for myself using other people's layouts.

Quote from: markeebee on September 18, 2009, 07:20:41 PM
I got a reply from Roy, saying he has a "2009" design using more modern components and a new filter.  Apparently he is a forum member, but has never posted, and will give this thread a once over and maybe post something for us.

Taylor, do you think it might be worth holding off for a few days?

That's awesome! I know we'd love to see an update to the circuit :)

I got here, eventually.

Part of the reason why this design works is the really lo-fi FET section. There'll be lots of second harmonic, and to have that nonlinearity in the impedance to ground in a multipath filter will cause all sorts of artifacts. When I designed it, this crudeness could be put down to inexperience. I should have put half of Vds on the gate, but I didn't know about that then.

Endangered Audio in North Carolina are sending me one of the Gristleizers they've made. They tweaked it a bit, putting on the known improvements of an external BIAS control, and a LED following the LFO. There was some ticking trouble, which I've always believed was down to layout, but they've done their own fix for that.

I shall have a good old poke around with that and see what the distortions are.


Roy Gwinn

Thanks Roy, let us know how the EA box fares.  Maybe you could then post us some tweaks for the "definitive 2009 Gristelizer"?

Taylor - that ok with you?

Yeah, we'll see what comes out of this. My original reason for doing this was to squeeze down the ICs to one quad and one dual opamp. Roy, do you think using the 741s is an indispensable aspect of the sound? I'd be happy to do a redesigned board if there could be some major changes, but if the whole thing depends on the 741s, perhaps the currently-available single-sided board is perfectly adequate?

what quad chip would you be using ? a TL074 ?  I imagine, given the tolerance of 741's back in the 70s, just about anything will work or sound the same.

Hi, I'm in for one board, I'd be interested in the new chip design and tweaks if we get some info through on that. Don't care about the pots PCB mount or Pads. On-board power a "must have".

Anybody pick up on Dan N's comment "No! Don't run the audio in the same chip as the lfo! I speak from experience."
Something we should be worried about?

@Taylor, whats this free cad for mac? + Thanks for taking time to do this for the rest of us

can someone chime in with what this does "in a nutshell"?  I may be interested.

There is a link to the original thread at the beginning of this thread, there are sound clips and a build report there, if thats what you were looking for.

Quote from: Skruffyhound on September 23, 2009, 05:09:08 PM
There is a link to the original thread at the beginning of this thread, there are sound clips and a build report there, if thats what you were looking for.

i looked through all that.  nothing with guitar was demonstrated and it all sounded like synth-oscillation and such.

I was hoping this was like an LFO-Filter or something

Quote from: aziltz on September 23, 2009, 05:20:39 PM

Quote from: Skruffyhound on September 23, 2009, 05:09:08 PM
There is a link to the original thread at the beginning of this thread, there are sound clips and a build report there, if thats what you were looking for.

i looked through all that.  nothing with guitar was demonstrated and it all sounded like synth-oscillation and such.

I was hoping this was like an LFO-Filter or something

You sure you looked through all that? I recorded the clip with my Telecaster>Tube preamp>sound card.

An LFO filter is half of it. The other half is a radical tremolo.

sorry i meant that i looked through the commercial version by EA or whoever

Quote from: aziltz on September 23, 2009, 05:31:40 PM
sorry i meant that i looked through the commercial version by EA or whoever

Ah, then you need to check out the thread that started this one: http://www.diystompboxes.com/smfforum/index.php?topic=79078.0 (http://www.diystompboxes.com/smfforum/index.php?topic=79078.0)

Quote from: Rectangular on September 23, 2009, 02:55:38 PM
what quad chip would you be using ? a TL074 ?  I imagine, given the tolerance of 741's back in the 70s, just about anything will work or sound the same.

I'd lay it out for the generic quad opamp pinout. TL074 is my goto quad opamp, but the LM324 and probably others have the same pinout, so people can experiment if they want. Thanks for your comment, it's what I assumed, but I wasn't sure.

Quote from: Skruffyhound on September 23, 2009, 04:35:18 PM
Hi, I'm in for one board, I'd be interested in the new chip design and tweaks if we get some info through on that. Don't care about the pots PCB mount or Pads. On-board power a "must have".

Anybody pick up on Dan N's comment "No! Don't run the audio in the same chip as the lfo! I speak from experience."
Something we should be worried about?

@Taylor, whats this free cad for mac? + Thanks for taking time to do this for the rest of us

Yes, I did hear this and responded that I would put the LFO+waveshaper in a quad, and the audio opamps in a dual, so they'd be separate. There's still the matter of "ticking LFO" to deal with, and I'll read up a bit on that. I know about not having right angle traces, but I'm not sure what other tricks there are to avoid this. Do you guys need a blinking LED? It's my understanding that having a rate LED can create ticking.

The free CAD for Mac is called Osmond. I haven't done anything with it yet, but it looks good, and is the only free CAD for Mac I've found, so it's certainly better than nothing at all.

http://pages.swcp.com/~jchavez/osmond.html

Taylor, did you read the comment on the gaussmarkov project page regarding the rate LED? If not, you should check it out. I get no LED noise using a transistor to switch the ground of the rate LED. It's crude, but simple, and it works.

No, I didn't see that until now. I hadn't read the comments.

"From IC1 pin 6 I have another
transistor rigged as a follower with a LED plus load in its collector to +9V and its emitter grounded. 6k8 between its base and IC1 pin 6. This gives a flashing indication of the rate. Crude but maybe useful."

I'll implement that.

Another way to help prevent LFO ticking is to use a capacitor to ground on the LFO out.  This will make a square pulse a little less square, but will also reduce the ticking, as will using a low power opamp.

Roughly what value of cap would you recommend?

Quote from: Taylor on September 23, 2009, 02:39:09 PM
My original reason for doing this was to squeeze down the ICs to one quad and one dual opamp.

My experience has been that I get more compact and orderly layouts with better signal flow by using only duals, not quads. In my mind this is because the two outputs of the dual are on the same end of the package, while the quad has outputs in all four corners. Sometimes it doesn't matter, but the extra freedom of being able to point the outputs all in the same direction has generally more than made up for the price of two more power pins. And  in this case, the extra package may provide some signal isolation.

You might want to think about it.

Quote from: Taylor on September 23, 2009, 10:40:09 PM
Roughly what value of cap would you recommend?

I think I used something like a 10uF electrolytic, though I am not positive on that.

Quote from: Ripthorn on September 23, 2009, 10:34:44 PM
This will make a square pulse a little less square

This would concern me if it's possible to detect it audibly--if you implement this cap, please make sure to add a note mentioning that it's optional, and what effects it might have.

The square wave LFO shape is one of the most useful parts of the circuit, and if you lose that all-on/all-off ability, it would detract from the purpose of the effect, IME.

The LFO should have very minimal ticking, if at all, if the layout is done right. Mine ticks just a little at the most extreme bias setting, but it's barely noticeable.

Anyway...like I said...the OPTION to add that cap is a good idea, just make sure to note it.

Good idea, it should be jumberable if people want to.

Quote from: Taylor on September 24, 2009, 01:45:46 PM
Good idea, it should be jumberable if people want to.

I think you could just leave it out, since it goes to ground.

...in other news, I'm generally of the mind that everything should be jumberable. I recently jumbered over to the store to buy some turnips.

RG is probably onto something with regards to using duals instead of quad+dual. quad stuff can get messy fast.

maybe its just me, but I'm not thinking about this projects in terms of nice, clean, high fidelity audio. its the gristleizer. plus, its a practical electronics circuit, I imagine you'd have to go out of your way to make it sound wrong, they really DIY-proof their stuff

actually, does anyone on this forum have any Practical Electronics magazines ? I came across some a couple of weeks ago by pure chance, and scooped them up. they're amazing. completely unlike the DIY magazines that were sold around the same time (1950s-1970s) in north america (and usually heavily reliant on Radioshack parts)

Quote from: jacobyjd on September 24, 2009, 01:49:39 PM

Quote from: Taylor on September 24, 2009, 01:45:46 PM
Good idea, it should be jumberable if people want to.

I think you could just leave it out, since it goes to ground.

...in other news, I'm generally of the mind that everything should be jumberable. I recently jumbered over to the store to buy some turnips.

Here in the south, we write our P's upside-down.  :icon_sad:

It occurs to me that "making something jumperable" doesn't really mean anything. Obviously, any part can be jumpered without any special PCB tricks. I really need to learn not to wake up and immediately post on this forum while I'm still half-dreaming. (http://img3.harmony-central.com/acapella/ubb/facepalm.gif)

Beware the jumberwok, my son...

Quote from: jacobyjd on September 24, 2009, 01:49:39 PM

Quote from: Taylor on September 24, 2009, 01:45:46 PM
Good idea, it should be jumberable if people want to.

I think you could just leave it out, since it goes to ground.

...in other news, I'm generally of the mind that everything should be jumberable. I recently jumbered over to the store to buy some turnips.

Sorry for the derail, folks, but I have been chuckling about this all day since Josh drew my attention to my post. I had to put this in my signature, because it's one of the most hilariously dumb posts I've seen, and I don't have to worry about offending the poster.

 :icon_cool:

Does making it jumberable have anything to do with jumberlaya?

You know, this might get my New Orleanian card revoked, but I think I've eaten jumberlaya maybe once in my life.

Quote from: Taylor on September 24, 2009, 10:23:09 PM
You know, this might get my New Orleanian card revoked, but I think I've eaten jumberlaya maybe once in my life.

It's delicious.

less chit-chat

more gristleizer designing blease !!!

Does anyone have any good suggestions for the rotary switch via Mouser? I found one on Mouser for around $4.30. Part #  105-14573
I want the Non-shorting contacts version, correct?

Quote from: jacobyjd on September 24, 2009, 11:42:42 PM

Quote from: Taylor on September 24, 2009, 10:23:09 PM
You know, this might get my New Orleanian card revoked, but I think I've eaten jumberlaya maybe once in my life.

It's delicious.

Don't you mean qelicious?

Quote from: Ripthorn on September 25, 2009, 03:57:33 PM

Quote from: jacobyjd on September 24, 2009, 11:42:42 PM

Quote from: Taylor on September 24, 2009, 10:23:09 PM
You know, this might get my New Orleanian card revoked, but I think I've eaten jumberlaya maybe once in my life.

It's delicious.

Don't you mean qelicious?

I don't live in the south  :icon_cool:

Less talkey, more designey!

One thought I had was that expression outputs would be nice. Say, for speed.

You could just wire the expression outs as switched jacks so that the on-board knob is used unless there is a cable plugged in to the expression pedal jack.

So I've just heard from Markeebee that Roy's new design will involve an AVR micro doing the LFO. He'll release the code and sell programmed chips, but it seemed to me that this might kind of miss what a lot of people like about the Gristelizer, which is the low-tech design with all its peculiarities.

What does everybody think? Should we do the board using the new AVR design or make a board for the original, albeit with updated opamps? We don't know a timetable for the new design, but if we go with the Gaussmarkov schematic, I'll start the layout in the next day or so.

Quote from: Taylor on October 01, 2009, 02:14:23 PM
So I've just heard from Markeebee that Roy's new design will involve an AVR micro doing the LFO. He'll release the code and sell programmed chips, but it seemed to me that this might kind of miss what a lot of people like about the Gristelizer, which is the low-tech design with all its peculiarities.

What does everybody think? Should we do the board using the new AVR design or make a board for the original, albeit with updated opamps? We don't know a timetable for the new design, but if we go with the Gaussmarkov schematic, I'll start the layout in the next day or so.

How about this for an idea: Put together the standard LFO section on the board, but add points where the AVR chip could added to the LFO input, so once the new design comes out, it won't be hard to just leave the analog LFO unpopulated, then put the AVR on a daughterboard. That gives both options, and you probably won't be talking much more space. Better yet, leave some spaces for standoff holes to mount the daughterboard straight to the main PCB.

Just an idea :)

*edit* Hah--now I fixed it, so anyone who reads your comment will just think you're crazy!  :icon_biggrin:

Quote from: jacobyjd on October 01, 2009, 02:19:44 PM

Quote from: Taylor on October 01, 2009, 02:14:23 PM
So I've just heard from Markeebee that Roy's new design will involve an AVR micro doing the LFO. He'll release the code and sell programmed chips, but it seemed to me that this might kind of miss what a lot of people like about the Gristelizer, which is the low-tech design with all its peculiarities.

What does everybody think? Should we do the board using the new AVR design or make a board for the original, albeit with updated opamps? We don't know a timetable for the new design, but if we go with the Gaussmarkov schematic, I'll start the layout in the next day or so.

How about this for an idea: Put together the standard LFO section on the board, but add points where the AVR chip could added to the LFO input, so once the new design comes out, it won't be hard to just leave the analog LFO unpopulated, then put the AVR on a daughterboard. That gives both options, and you probably won't be talking much more space. Better pet, leave some spaces for standoff holes to mount the daughterboard straight to the main PCB.

Just an idea :)

So do you write your "y"s like that in Indiana? :icon_biggrin:\

In all seriousness, I like this idea.  Maybe the builder could put in a switch to switch between them. You could label it Hi/Lo Tech.

throwing an AVR in seems to defeat the whole purpose of using an handful of cheap opamps to get a nice noisey little effects box.  it also limits the people than can participate or build their own, because when someone digs up this thread in 4 years and wants to build one, they'll have to track down a avr, burner, and the code.  it just seems like a layer of obfuscation.  opamps are future proof (knock on wood)

Hmm, very true. The future-proof thing hadn't occurred to me, although it does somewhat apply to the PCB as well - if someone wants to build this using the layout I'm doing, and I'm dead or in prison, they won't be able to get the PCB.

I'm currently leaning towards just doing the layout with opamps as originally planned, but I'd still be interested in hearing opposing views.

Opamps. Hasn't Roy got some more input on the lo-tech design?

I like Josh's idea

It's a good one, but I'm not really sure how to implement it until we see how the AVR LFO turns out. That's not the kind of stuff I have much knowledge about, so what exactly would be needed to interface them? I could just put a pad at the gate of the JFET - would that do the job? And standoff holes for the daughterboard.

I want to believe that it would basically be an 'internal' CV input, so yeah...I mean, you're just running an LFO to the same place from two different sources. The goal would be to make them switchable...probably something like an ON-ON-ON so you could have one, the other, or both in parallel.

When set up like that on the board, it wouldn't be hard to wire it up for just one or the other, with no switch.

I just add that I'm interested in one if the cost's reasonable.

maybe I'll just perfboard one, skip the pcb

Taking too long for you?

I'll probably have the layout done this week.

I'm not really sure how big this is going to end up, but what do you guys think about $12 per PCB? I'm trying to get to a price point where I can afford to do all the packing and mailing and taking orders (selling parts recently has taught me that this part takes up a lot of time). Does that seem reasonable? The one at Smashing Guitars is $47... I'll probably charge more for non-board members, but I would like to cut a decent deal for everybody here.

Ill take a couple. :)

I think $12 is more than fair.

$12 is great

you're not taking too long. I think the AVR stuff just turned me off :)

Well, the PCB will still be for the opamp LFO. It will just be compatible with a possible AVR LFO if such a thing surfaces down the road. So nothing has changed from the original idea of the PCB.

At $12, I'd definitely be in for two.

*hand poised over the Paypal "send money" button

1 for me please :icon_biggrin:

Sounds awesome!  I'd still be in for 2-3.

Thank you!

I'm still in, I'd take 2 at that price.

I'm in for one.

Yeah, $12 is very reasonable. I'd get one!

I could be persuaded, at that price. Might even stretch to two. I know, last of the big spenders  ::).

I just reconfigg'd my pedalboard...I pulled my tremolo in favor of the Gristleizer and placed it before my distortion/booster section. Wow. Talk about useful.

Anyone who is on the fence better just go for it. You'll be glad you did.

I'm still in for at least one

might even do two @ $12 each ... my bass player would probably find it useful

I'm thinkin' blue solder mask... What do you guys think about that? Blue boards are my favorite. Or maybe black.

Quote from: Taylor on October 10, 2009, 04:07:41 PM
I'm thinkin' blue solder mask... What do you guys think about that? Blue boards are my favorite. Or maybe black.

The one bluesdevil etched for me is black...it's badass.

Black would be cool!

What chips are you going to use for your design Taylor?

Specific Vactrol or home-rolled?

Anything else that's specific to the build?

I'll be making a parts order soon ... figure I should get these things.

Hell, if you've got a bill of materials already, it would be great to see it.

thanks

It's a quad and a dual opamp. So TL072 or 4558 should be fine for the dual. TL074 or LM324 for the quad. MAX1044 for the bipolar power supply.

There's no vactrol in this project, it uses a JFET to control amplitude/filtering. The JFET is a 2n3819.

The spec'ed diodes are 1n34A, which are available at Mouser, but Roy said that any diode should do, so if you have hundreds of 1n4148/1n914 as I do, they should work and are cheaper.

The parts list will be pretty much the same as this, barring the above notes:

http://gaussmarkov.net/layouts/gristle/gristle-parts.txt

awesome dude

thx

does the jfet need to be a 2n3819 or will others work ?

According to Gaussmarkov, any JFET should work:

http://gaussmarkov.net/wordpress/circuits/gristleizer/

But, this guy says the opposite:

http://www.thelongafternoon.com/?p=437

So I don't know. I'd spring for the right one, since it's cheap and available.

I don't know who "that guy" is, but I read his blog post on the gristleizer. is he a hobbyist or is he one of these guys thats manufacturing/selling them ?  basically I'm just trying to figure out where his level of understanding is. I seriously doubt that the 2N3819 is the only one that works, I'm guessing his either got the pinout wrong (if he's a beginner) or that he didn't rig up an FET tester and find one that matches the 2n3819.  in either case, I don't see popular electronics releasing a hobby effects pedal schematic if it could only use one transistor on the planet. they were smart guys, they understood that substitution is an essential part of DIY.

Quote from: Taylor on October 10, 2009, 10:40:20 PM
According to Gaussmarkov, any JFET should work:

http://gaussmarkov.net/wordpress/circuits/gristleizer/

But, this guy says the opposite:

http://www.thelongafternoon.com/?p=437

So I don't know. I'd spring for the right one, since it's cheap and available.

agreed

Quote from: Rectangular on October 11, 2009, 04:12:47 AM
I don't know who "that guy" is, but I read his blog post on the gristleizer. is he a hobbyist or is he one of these guys thats manufacturing/selling them ?  basically I'm just trying to figure out where his level of understanding is. I seriously doubt that the 2N3819 is the only one that works, I'm guessing his either got the pinout wrong (if he's a beginner) or that he didn't rig up an FET tester and find one that matches the 2n3819.  in either case, I don't see popular electronics releasing a hobby effects pedal schematic if it could only use one transistor on the planet. they were smart guys, they understood that substitution is an essential part of DIY.

I agree with you, and I don't know who that guy is, somebody just pointed that out to me at another forum. But I don't really think it matters except for people who only buy electronics at Radio Shack (in fact you can be sure that that guy is a noob if he buys all his parts at Radio Shack).

Quote from: Taylor on October 11, 2009, 03:55:42 PM
(in fact you can be sure that that guy is a noob if he buys all his parts at Radio Shack).

true enough ! :D

OK, so the PCB is nearly done. It will fit comfortably in a 1590BB. I still need to implement some of the little additions people have mentioned through this thread. I recently bought RG's book on PCB layout, and I have tried to implement as many of his design rules as I could.

I'm a little unsure of how to implement the bipolar power supply. According to RG's page (http://www.geofex.com/circuits/+9_to_-9.htm), using the stock charge pump schematic from the datasheet will lead to switching noise if using stereo jack switching for the battery. He suggests an alternate way to to do this, but I have to admit that I'm confused by it. The audio input signal goes on the sleeve of the input jack?  ??? That doesn't make sense to me, and I'm not sure how to separate audio and power ground.

Josh, it looks to me like you used the stereo switching schematic for your power supply (I can see the 2 resistors and one transistor on your daughterboard) but it doesn't look like you're using stereo jacks.

Anyone have some thoughts on this?

Quote from: Taylor on October 12, 2009, 02:46:17 PM
Josh, it looks to me like you used the stereo switching schematic for your power supply (I can see the 2 resistors and one transistor on your daughterboard) but it doesn't look like you're using stereo jacks.

Anyone have some thoughts on this?

Personally, I don't use batteries in my DIY effects. Those extra parts you're seeing are actually the components needed for the flashing rate LED. :)

RG's charge pump stereo switching schematic works well (it uses a transistor to switch the ground). I'd say you should incorporate it, but make sure it's laid out in such a way that it could be ignored if a battery is not used. The power supply gets MUCH simpler without the jack-switching circuitry (basically the IC and 2 caps).

+1

I don't use batteries either

Yeah, I don't use batteries either, but I figured a lot of people would want to have that ability. I'm trying to facilitate the needs of as many people as I can here - kind of a juggling act.

Ok, so on to the flashing LED. Here's the idea:

Quote from: Taylor on September 23, 2009, 10:07:48 PM
No, I didn't see that until now. I hadn't read the comments.

"From IC1 pin 6 I have another
transistor rigged as a follower with a LED plus load in its collector to +9V and its emitter grounded. 6k8 between its base and IC1 pin 6. This gives a flashing indication of the rate. Crude but maybe useful."

I'll implement that.

I drew a schem of what I think this means:

(http://img101.imageshack.us/img101/9657/ledflash.jpg)

So this should be an NPN transistor, right? Like 2n3904? Do I have the idea right?

Yupper. I used a 2n5088, but any normal NPN should be ok. I placed mine close to the power supply for my final setup. However, I had no ticking problems whatsoever when testing it with long leads on my breadboard.

Yeah, the same device is used on Ricks "Vibracaster" for a rate LED, he's got a 47k on the ground leg as well, but maybe thats just peculiar to that circuit.

Nice picture

Quote from: Skruffyhound on October 13, 2009, 04:14:49 PM
Yeah, the same device is used on Ricks "Vibracaster" for a rate LED, he's got a 47k on the ground leg as well, but maybe thats just peculiar to that circuit.

Nice picture

It never totally cured the ticking though, so I ended up not using it.  :icon_cry:


EDIT: ......but then again, that was before I used a 3.3uF cap to reduce the ticking in the circuit, so maybe it should work in the Vibracaster now - hmmm need to try it now! BTW, I 'stole' that little device from a Roland 100m Modular synthesiser schematic, so it's certainly not a unique approach.

Sorry for silence - I've been away. I half thought I might get thread replies in email, but no.

Opamps - 741's are old hat. There are much better modern opamps, as people have said.  I'd use duals. TL082 would do in a +/-9 environment (and that's pretty old now too). LM6132 I'm fond of these days. Rail-to-rail, fast, low power. Not as cheap as some, but if you're just making a few of something it doesn't matter much what it costs. Time is money too.

Given new opamps I'd get the input impedance up to 1M or more. Also there are places where the 100nF coupling caps form an HPF that rolls off too high. They need rooting out. Also in the LFO the integrator capacitor could be reduced by an order of magnitude, which reduces ticking currents. Just increase the resistor driving the integrator by the same factor.

Any old FET WILL do. I use J112 or J113 these days. But remember that the Vgs(off) is all over the shop with JFETs, even within the same batch. Use the bias control to get round this variation. J112, for example, is somewhere between 1 and 5 volts. Such precision and repeatability!

A LED to mirror the LFO is good, like Chris Carter added. A LED to show effect in/out is also good. Millenium Bypass is the answer to that. A cracking design!

I started the 2009 reissue in Feb this year thinking I'd just revamp it for modern stuff. Op-amps on a single 9V rail would be much cleaner than two batteries or switching negative converters. But, as with many things I start, it grew into more than I'd expected. It is now sufficiently different to justify having both. I redid the filter with three bandpass sections because I've been playing around with voice formants. It sounds really nice on rock organ/gritty Hammond tones. The deal with the LFO is that I think the original is a bit of a bugger to play along with. You have to let it take the lead on timing. You follow it, it doesn't follow you. What I wanted was an LFO with sync from an envelope follower. And that led me into AVR because I've got most of the software components written already for another project. All the waveshaping stuff and that cumbersome rotary switch get subsumed into software.

You're right - it does need to be future-proofed. The object code as a free download on the web in several places at the least. I'm not going to put the source code out there - that's my job and I need to earn money out of it.

I'm not ready to publish on the 2009 reissue anyway, so don't hold your breath. Full steam ahead on the PCB's I would say - and could I have one or two please? I'll build it up and pot comments.

I'm STILL waiting for a Gristleizer from Endangered Audio. Ho Hum.


Roy

Thanks for the comments Roy. I'm not really sure what to do to change the input impedance, is this just a matter of changing the resistor to ground at the input?

I will of course send you some PCBs when they're complete.

Yes, it's just component value changes, so no need to change the PCB. Same with the choice of op-amps.

Roy

Jacobyjd ,

did you use a DP4W switch as per gaussmarkov's design?

where did you get it from?

I've never worked with a rotary switch before.

thx

Quote from: Derringer on October 14, 2009, 09:34:29 AM
Jacobyjd ,

did you use a DP4W switch as per gaussmarkov's design?

where did you get it from?

I've never worked with a rotary switch before.

thx

I actually used a 2p6t switch, so I have 2 unused positions. however, you can get a 3p4t switches pretty readily--you'll just leave 1 pole unused.

what happens to the signal when you turn the switch to an unused position?

Did you jumper the unused positions to default back to the nearest connection?

Derringer, I'll post links to the right parts when I'm done with the PCB, with a Mouser part number, and when available, a Small Bear number for people who prefer to buy from SB.

The rotary switches have a special washer with a little tab that allows you to set the switch for only as many positions as you need. I think setting the switch to an unused lug would disconnect the LFO from the FET.

cool thanks

I found the DP6T switch at SB ...  the ones at Mouser are actually more expensive

Quote from: Derringer on October 14, 2009, 12:54:18 PM
what happens to the signal when you turn the switch to an unused position?

Did you jumper the unused positions to default back to the nearest connection?

Unused positions just disconnect the LFO :) No harm done, no real change to the signal.

Thought you guys might like a sneak peak.

(http://img200.imageshack.us/img200/6468/gristlepcbtraces.tif)
(http://img527.imageshack.us/img527/5286/gristlepcbsilk.tif)

It's not quite done, need to fix some pads that are a little too big and overlapping each other, add the pads for the 2 switches, and just go over it more to make sure everything's right.

Overall I think it's coming out pretty well. It's only 3.2" x 2.2" (RG's recommended board size for fitting into BB enclosures). It allows for board mounting of the 4 things I think most people would want to board-mount, but also has spots for trimpots for everything that's a trim in the original. I designed it for a specific trim pot type, which I will give you guys the part number for, but I also added pads that should accept the other common trimpot size. Of course, you don't need to board-mount anything if you don't want to, and the board isn't any bigger than it needs to be to accommodate  the onboard pots.

I have integrated the flashing LED, the optional LFO cap for de-ticking, and the charge pump to derive -9v from a single-sided supply.

One thing I wanted to do but couldn't is make the pot pads more universal. They are setup for Alpha's 16mm pots, which I think are the most common pc mount pots for pedals (again, I'll post part numbers for these). I wanted to allow for the tiny little green ones ala ZVex, but I just couldn't fit the pads in there and still have the pads big enough to solder onto. As much as I want this to be as universal as possible, I don't want to sacrifice ease of soldering just to allow for lots of obscure parts.

Let me know what you think.

It looks good--any plans for ground planes?

Yeah, I was thinking about it. Just need to figure out how to do it. This program I'm using is very powerful, but I just started learning it recently.

Ok, the board is done. I'll be ordering a prototype, which will take a few weeks to get, and if it's good, I'll order the full run. Once those are in, I'll start taking orders. So I guess that means it'll be around a month and a half before I can start sending boards out.

I have implemented the ground pour, btw. It wasn't possible to do an entire layer of ground plane, since this is only a 2-layer board, but I think it should do the job reasonably well.

Good job. Let us know when you are ready for some cash, and don't sell yourself short on the postage. I'll go ahead and order the few parts I'm missing. Put me down for 2 boards. Thanks :icon_biggrin:

Yup, say the word and my Paypal finger is ready.

This is gonna make for a nice holiday gift to myself. Keep us posted on the details.

Sounds fantastic, Taylor--thanks for your work on this! I know there are a bunch of us who appreciate it!

I'm ready to pick up at least one. I kind of want to experiment with a second though...I could see some cool stuff happening with parallel processing/multiple LFOs with these things.

I can probably only afford one, but Portland is crazy for noise music, I know that I probably have friends who would jump at the chance to have me build them a musical device of Throbbing Gristle lineage/pedigree/relation.

It's noise band heaven over here in Cascadia for sure, the weirder and more custom the FX the better, for most good local bands.

- Strategy

I may be interested in one or two of these...  I've checked the thread, and maybe I'm missing it by trying to skim through 7 pages quickly, but any idea of a cost estimate?

Quote from: mr.adambeck on October 30, 2009, 01:55:54 PM
I may be interested in one or two of these...  I've checked the thread, and maybe I'm missing it by trying to skim through 7 pages quickly, but any idea of a cost estimate?

I'm pretty sure $12 is the current estimate :)

Yep.

Just came across the Gristleizer build report thread, decided I wanted to build one, then found this thread. Perfect. I'm definitely down for two if they're in the $12 range.

Dan

Got the proto board, building it tonight...

awesome


thanks for the update

Gristleizertastic!

OK, guys, the Gristleizer is built up and works perfectly as far as I can tell. As Josh mentioned, there is some slight ticking when using really extreme bias settings, but pretty unobjectionable in my opinion.

One question for you: the way I currently have the flashing LED, it would have to be in addition to an on/off LED. That's how I think Josh has his. Is that a problem? I could probably figure out a way to turn the flashing LED on and off with bypass, but I'm hesitant to mess with the PCB right before ordering a big batch of them. I actually think having the flashing LED on all the time is helpful, but I don't know what everyone else thinks.

I need to change a couple things on the silkscreen layer, but other than that I think we're ready to go on the big order.

BTW, this thing is extremely versatile for a relatively simple circuit. Besides the multi-shape trem and VCF, the LFO gets up into audio speeds for nice ring mod/filter ring mod madness. There are also plenty of lofi, distorted sounds to be had (I had heard fears that updating the opamps would kill all the craziness - not something you need to worry about).

I have no problem with the flashing LED being in addition to the bypass indicator, in fact, I prefer it. Do you want to start taking orders now?

Well, I guess so, but keep in mind that it will probably be about 2 weeks before I can start sending out PCBs.

For some reason the PCB house sent me 2 instead of just 1, so I do have one PCB available right now. If anyone wants one right now, you can have it, but it's green (the final ones will be black). $12 plus shipping.

Re: flashing LED-- I don't think you should change the board for this reason. It'd be easy to mod how the LEDs work to whatever your preference is.


Taylor, sorry if you already mentioned this, but what are the rough dimensions of the board again?

Also, I'm definitely in for 2 boards as soon as you start taking payments...lol...I want another one in a non-stompbox format to keep around for synth stuff, and I want to put together a 3rd one so I can do terrible things to it.  :icon_twisted:

The more I use my first one, the more I love it. I may fiddle around with pot values as well on the new ones--maybe with some fixed resistors--I know currently I'd rather have more usable travel on my bias pot...

I believe it's 3.3" x 2.1". Fits comfortably in a 1590BB.

Yeah, my bias pot has a very narrow area of usability, but I used a log pot instead of linear, so I figured it was because of that. Maybe a reverse log pot would be ideal here.

Put me down for one. When do you want to start taking payments?

Well, if you want a green one you can have it right now. Otherwise, It's probably best to wait until the PCBs are in my hands. There's a hurricane headed this way, so who knows if I'll be around in a couple of weeks?  :icon_wink:

BTW, the optional cap to stop ticking works well. It didn't seem to have a huge impact on the choppiness of the square wave, but a slight difference. It would be easy to make this switchable if you want maximum tweakability.

Quote from: Taylor on November 08, 2009, 09:20:10 PM
I believe it's 3.3" x 2.1". Fits comfortably in a 1590BB.

Yeah, my bias pot has a very narrow area of usability, but I used a log pot instead of linear, so I figured it was because of that. Maybe a reverse log pot would be ideal here.

Yeah, either that or a fixed resistor + lower pot value. Either/or should work.

Ok, I'm going to make the big order unless anyone has any last thoughts...

Quote from: Taylor on November 09, 2009, 03:40:05 PM
Ok, I'm going to make the big order unless anyone has any last thoughts...

(http://www.homevideos.com/freezeframes2/KindergardenCop16.jpeg)

DOO IT NAOW!!!

First things first, Taylor: Get your ass someplace high and dry, and don't solder anything for the next day or so, ok?

Yeah, be safe. Looking forward to your next post....

Good job, 2 for me please. As I said a few pages up, let me know how and when with the cash, and I'm in Denmark so + European post and while you are at it add on the price of a beer/smoke/few of your favorite caps on me. Kudos for getting this done.

Two for me plz

I'll grab two.

Me two :)

Like I said earlier in this thread, I'm in for two.  8)

Two for me!
- Strategy

is/are there CV output jack(s), for example with the LFO? If not then I'll try to initiate a mod...not my forte but willing to try, this would be an ideal modulation source for other pedals/synth stuff

- Strategy

Quote from: Strategy on November 10, 2009, 02:46:32 PM
is/are there CV output jack(s), for example with the LFO? If not then I'll try to initiate a mod...not my forte but willing to try, this would be an ideal modulation source for other pedals/synth stuff

- Strategy

That's why I want 2 :)

I don't really need CV ins or outs, since I won't be interfacing it with other effects or a synth, but I'm thinking of adding other LFO options--maybe an additional one to allow LFO 1 to modulate LFO 2. or whatever.

There's no dedicated LFO out, but the optional "de-tick" cap is attached to the LFO, so you could take the LFO from that pad. I suppose that point could also be a CV in. The wiper of the depth pot is also a spot from which you could take the LFO.

This is what I meant "any last thoughts" yesterday, but unfortunately I've already placed the order, so no mods can be done to the PCB. Still, the pads for the speed and depth pots can be used with some additional wiring to provide CV insert points for modulating everything. All the pots are voltage dividers rather than variable resistors, so that makes adding CV fairly simple.

I haven't played around with modular kind of stuff in a while, but some interesting things often come from modulating an LFO with itself, so you could, for example, pipe the LFO into its own speed pot maybe?

definitely, Taylor.

I'm not really speaking in terms of mods to the OCB--in fact, I think any changes to it would have been too much. Things like CV ins and outs can be added as daughter boards or by other methods--it IS cool that there are several pads that, if left unused, could serve as insert points--that's beyond most PCBs. However, if you add too much, it becomes a pain for the person who wants to build it stock...and it leads to BUMS. :-P

Is that an acronym, or do you just mean HOMELESS PEOPLE?

I think it's an RG-coined term. Blind Urge to Mod Syndrome.

Put me down for 1.

Thanks,
~David

i typically prefer to build things stock, but where there's an easy opportunity (like the ones you mention- that is great, pretty much all that's needed) to bring an LFO to the front panel, I like to- a nice thing to have extra of in a jiffy. The multiple wave shapes will be great.

Generally I'm pretty timid about mods and would rather just get a pedal up and running without doing a chop job on it. The idea of getting something up to speed and then potentially ruining it with a bad hack makes me cringe. Bringing internal CVs to a front panel jack seems like some low impact (non pcb altering) goodness.

- Strategy

Me want one too, yes!!!

I'd like two please.

Sorry, originally I said four (first page) but times are tough.  So just two, please.

I'm still in for three. 

Thanks!

As before, I'm in for one.

noob here, spotted you rpost over on electro-music forum, and i'd be up for a board to build  :)
cheers!

Ok, thanks for the interest everybody. The boards should be in hand in about a week and a half I'd guess. At that point I'll have instructions on how to place orders, and I'll post all the necessary build info.

Quote from: Taylor on November 14, 2009, 03:41:15 PM
Ok, thanks for the interest everybody. The boards should be in hand in about a week and a half I'd guess. At that point I'll have instructions on how to place orders, and I'll post all the necessary build info.

Taylor,

Thanks again for doing all of this. Seriously. It was a lot of fun putting my first one together, and I can't wait to see how my next two turn out. The improvements you made and the amount of work you put into a project for the sole purpose of distributing it to the community is something that everyone who gets a board should value. I'll be looking forward to getting mine :)

Well, I don't know that anything I did was that significant. I still consider myself a noob with electronics, so I enjoy any chance to get a deeper understanding of things. Digging into circuits to do layouts really is helping me to understand things better.

For example, I wasn't really familiar with the Gristleizer before doing this. Doing the layout, I discovered that this is a very smart, efficient design. Very few parts for what it does.

I'd be up for doing another of these board designs if anybody can think of another circuit that could benefit from a double-sided layout.

Quote from: Taylor on November 14, 2009, 10:11:29 PM
Well, I don't know that anything I did was that significant. I still consider myself a noob with electronics, so I enjoy any chance to get a deeper understanding of things. Digging into circuits to do layouts really is helping me to understand things better.

For example, I wasn't really familiar with the Gristleizer before doing this. Doing the layout, I discovered that this is a very smart, efficient design. Very few parts for what it does.

I'd be up for doing another of these board designs if anybody can think of another circuit that could benefit from a double-sided layout.

Correction:" You WERE a noob. Now you're a guru.  :icon_mrgreen: Y'know what they say in medicine: See one, do one, teach one.

Quote from: Taylor on November 14, 2009, 10:11:29 PM
I'd be up for doing another of these board designs if anybody can think of another circuit that could benefit from a double-sided layout.

One project that I've noticed is missing from the DIY universe is the Mu-tron Octave Divider. If you search in the forum, there have been more or less stalled attempts with a lot of hand-drawn materials. I can't remember what the questions or stopping points were that prevented people from proceeding with a layout. It is also absent from the web's DIY world in general. I don't believe there are any effort-stopping obsolete parts or anything involved.

I do have an electronic version of the schematics and service document but I don't feel I yet have the capabilities to create a layout. It's open to debate whether this is a good candidate project. In favor is that Mu-tron designs are sick, and this pedal sounds amazing. "Con" arguments would be that there's a ton of neat, easy octave projects already out there, like the original CMOS type octave designs on this forum, etc.

Just thought I'd mention that one as an obvious "never/seldom been done circuit- has no current layout" pedal.

- Strategy

EDIT: PS, I don't know if the layout needs to be a double-sided, manufactured PCB per se, but a layout of any sort would be popular.

Quote from: Ben N on November 15, 2009, 11:30:18 AM
Correction:" You WERE a noob. Now you're a guru.  :icon_mrgreen: Y'know what they say in medicine: See one, do one, teach one.

Hmm, well, don't know about that, but I do appreciate the kind words!  :)

Quote from: Strategy on November 15, 2009, 11:36:04 AM
One project that I've noticed is missing from the DIY universe is the Mu-tron Octave Divider. If you search in the forum, there have been more or less stalled attempts with a lot of hand-drawn materials. I can't remember what the questions or stopping points were that prevented people from proceeding with a layout. It is also absent from the web's DIY world in general. I don't believe there are any effort-stopping obsolete parts or anything involved.

I do have an electronic version of the schematics and service document but I don't feel I yet have the capabilities to create a layout. It's open to debate whether this is a good candidate project. In favor is that Mu-tron designs are sick, and this pedal sounds amazing. "Con" arguments would be that there's a ton of neat, easy octave projects already out there, like the original CMOS type octave designs on this forum, etc.

I'll check into that.

Let me know if you want me to email the Octave Divider pdf I have. I can't remember if it came from experimentalistsanonymous or somewhere else, people forward me Mu-tron related things from time to time knowing I'm a fan...

It's often mentioned as a bass player's octave pedal, if that makes it any more appealing!  :)

- Strategy

I'll put one more idea, maybe more ambitious, has maybe been done: pull the Korg MS-20 pitch to voltage converter and make it a seed circuit for a guitar synth project. I know it's not the best pitch to voltage conversion, but it's so fun and one of the coolest things about the synth. I often run guitar and bass into it to play the synth. It has difficulties, but it's part of the fun.

could there be 'demand' in the forum community for something based around this? is it already out there?

- Strategy

Quote from: Strategy on November 15, 2009, 02:43:23 PM
I'll put one more idea, maybe more ambitious, has maybe been done: pull the Korg MS-20 pitch to voltage converter and make it a seed circuit for a guitar synth project. I know it's not the best pitch to voltage conversion, but it's so fun and one of the coolest things about the synth. I often run guitar and bass into it to play the synth. It has difficulties, but it's part of the fun.

could there be 'demand' in the forum community for something based around this? is it already out there?

- Strategy

I would second this suggestion.  the MS-20's pitch-to-voltage converter is very unique, and is probably the second most important module that synth (the first being it's sallen-key filters, which have already been cloned to death).  I have not seen any major DIY effort to clone this module, save for perhaps Juergen Haible's MS-20 clone. I just checked my schematics, it uses a crazy 4-gang pot, and another 3-gang pot. so those would have to be sourced, or a workaround would have to be found.  a lot of people buy MS-20s just for the weird pitch-to-CV effects that synth generates.   

That particular pitch to voltage converter is also the centerpiece of Korg's X911 analog guitar synthesizer, which itself is pretty rare and expensive.  just in case any of you were questioning how applicable the circuit was to guitar effects usage.

Quote from: Rectangular on November 15, 2009, 03:59:06 PM
save for perhaps Juergen Haible's MS-20 clone. I just checked my schematics, it uses a crazy 4-gang pot, and another 3-gang pot. so those would have to be sourced, or a workaround would have to be found.  a lot of people buy MS-20s just for the weird pitch-to-CV effects that synth generates.   

A quick email or electro-music.com PM to Juergen Haible might reveal clues about how to either substitute or source the unusual pots, I'm sure he'd be happy to share insight about that.

- Strategy

The pitch-to-voltage might be a bit too much. Doing these PCB orders, there needs to be a reasonable amount of interest in order to get good prices on the boards.

That circuit has around 12 opamps, which seem to be picky about what type (i.e., can't just put them all in quad packages because there are several different types). A hex inverter chip, plus trannies and passives, and the aforementioned quad and triple pots, which are generally quite pricy. I could possibly do it, but the boards would be more expensive because of the expected low interest.

Quote from: Taylor on November 16, 2009, 01:29:46 AM
The pitch-to-voltage might be a bit too much. Doing these PCB orders, there needs to be a reasonable amount of interest in order to get good prices on the boards.

That circuit has around 12 opamps, which seem to be picky about what type (i.e., can't just put them all in quad packages because there are several different types). A hex inverter chip, plus trannies and passives, and the aforementioned quad and triple pots, which are generally quite pricy. I could possibly do it, but the boards would be more expensive because of the expected low interest.

there might be low-to-marginal interest on this forum, but  if the boards were also mentioned/sold on the www.electro-music.com  (http://www.electro-music.com)forums, I'm willing to bet that you'd get a lot of additional orders.

Yeah, you may be right. Modular guys are also a bit more spendy in general...  ;)

I'm surprised that there aren't more 'guitar synth' pedal projects in this forum though. Note the complete lack of microsynth clones, Korg synthepedal, anything that 'synths up' your guitar.
- Strategy

Quote from: Strategy on November 16, 2009, 11:18:33 AM
I'm surprised that there aren't more 'guitar synth' pedal projects in this forum though. Note the complete lack of microsynth clones, Korg synthepedal, anything that 'synths up' your guitar.
- Strategy

I know what you mean--I've been looking at portions of synth schematics with the thought of adapting them to guitar. I'd love to see those two worlds blended more in the DIY community.

However, I think keeping guitar-synth specific projects separate from this one is more favorable, especially since it would be extremely easy to pair the Gristleizer up as an effect to go along with a guitar synth project on a modular basis.

Hi All,

Good to hear it's moving forward. I've not got round to doing the tweaks I mentioned months back, but it really would be just minor things. The design does basically work just the way it is.

I got one from Endangered Audio. Obviously I'm going to have a poke around inside see what they've done. The ticking on square wave has been a problem for some people. The approach EA has taken is to change the square to a clipped triangle, so reducing the slew rate on the edges.

They sent me a stomp box version. The only thing I did to mine was to add two RG Keen-style millenium bypass indicators for the bypass switch (standard stuff) and the VCA/VCF switch, working off the unused terminal of the VCA/VCF stomp switch.

I haven't got anywhere much with the software LFO - too many other projects. But I came across one implemented in a PIC (same as an AVR, only different) by Electric Druid (google electric druid lfo). It doesn't have the sync to audio that started me off down the soft lfo route in the first place, but it's finished and it works, and would make a fine lfo section in a gristleizer.


Roy

Anybody want a green Gristleizer PCB? Special price, $8 plus $2 shipping takes it.

Same layout as the final black ones? I'll take it off your hands. I'll send you a PM.

Dan

Yep, the same, just not black.

I'm writing up the build info on this right now, and for the modding section, I was thinking that the VCF really should have a resonance control. Any thoughts on how to add one here?

Boards should be here in the next couple of days...

 :icon_biggrin:

Quote from: Taylor on November 26, 2009, 12:19:05 AM
I was thinking that the VCF really should have a resonance control. Any thoughts on how to add one here?

That's a very simple VCF, single stage (-6dB/oct?). You could try a 470K pot configured as a variable resistor between the -ve input of IC4 and the output of IC5. Maybe.  :icon_eek:

Ok, guys, the boards are on their way to me, so I'll start taking orders now.

The boards are $12 and shipping is $1.50 for one board, 50 cents for each additional board. I haven't figured out international shipping yet, but if you're outside the US, ask and I'll work it out.

To order, send the money to taylorlivingston at yahoo dot com. Make sure to note in the Paypal notes that this is for Gristleizer boards, and how many you are ordering. Also note your forum name and your real name, please.

I've made a wiring diagram, BOM, and tweaking/modding notes, and I will upload them as soon as Aron ok's my gallery account. All the part values are marked on board, so you should be able to build it without looking at any notes, except for the switch wiring. I'll also include a big image of the silkscreen layer for anybody with trouble reading small text.

If anybody has the ability to assemble multi-page PDFs and would like to put these docs together in a single file, that would be great.

I'll post a picture of the boards when they get here (should be tomorrow or the next day I'd guess... dang Thanksgiving holding up the mail).

Yeeeeeeeeeeeeeeeeeeee haaaaaaaaaaaaaaaa!!!!!!!!!

Thanks Taylor, you are a prince.

On behalf of myself and your many other admirers over here, please could you conjure up a price for sending to the UK?  Sorry to add to the workload  :icon_redface:

Hmm, let's say $2.00 for one board and 50 cents for each additional one to Europe.

I received Taylor's green PCB yesterday, and it looks really good. Well laid out, easy-to-read silk screen layer, etc. Highly recommended.

Taylor, just a note -- the envelope arrived with a small manila envelope clipped to it, with a note from the postman saying there was an additional $0.20 postage due and that I should leave the money in that little envelope. That's interesting, I'd never encountered that before -- I thought they just didn't deliver it if it had insufficient postage. Anyway, just wanted to let you know now in case you need to adjust your shipping charges for the black boards.

I haven't had a chance to build this yet, but I did just finish a Gristlizer with a home-etched gaussmarkov 5x741 board, and it sounds great. I'm getting LFO ticking with my home-etched board, so I'm curious if there will be any difference with this one, or if it's just a symptom of my lackluster enclosure wiring skills. I suspect the latter.

Dan

Once this Thursday rolls around, you'll be seeing my order :) Well done, Taylor.

Thanks again Taylor, payment sent today.

~David

I just paypal'd you for 2 boards. Thanks!

I'll be paying for 2 boards tomorrow, 26 dollars 50 cents to Europe right? Good Job :icon_mrgreen:

Payment sent (1). Thx, Taylor.

Payment sent for two boards. Thank you!!!

Paypalled for two. This shall be the cornerstone of my forthcoming Throbbing Gristle cover band, "Pulsating Tissue". Just kidding, but I am stoked about the boards!!!

- Strategy

Ha! I wonder why you don't see tribute bands to people like TG. Would be funny to see the industrial equivalent of this guy (http://www.diystompboxes.com/smfforum/index.php?topic=75017.msg651595#msg651595).

Here's the build info as it stands currently. (http://www.aronnelson.com/gallery/main.php/v/Taylor/) If you guys want to look it over, and see if there are any typos or things that aren't clear, that would be a big help. Also let me know if you think of important information that I left out. I've asked gaussmarkov if we can put his schematic in the PDF, but haven't heard back.

A bunch of the Analogue Heaven list dudes in Seattle had a killer Kraftwerk cover band, analog/modular everything...

- Strategy

Paid for two.

Thanks a lot Taylor, I hope to return the favour sometime.

Hooray for an awesome new project!

I too have forwarded a payment for my boards.

Thanks again.

I've payed for two. Thank you :icon_mrgreen:

Payment sent. Thanks!

paid for two.

thanks again!

There was a question about adding a resonance control to the filter.

It's not that kind of filter. The classic synth filter is a four pole low pass, with four coincident real poles. If you put feedback round it, the poles spread out to make it more bandpass. This one is a 'multifeedback' filter, which is already bandpass. It's not particularly sharp, and the Q varies with frequency. Its main virtue is the very simple circuit.

You might be interested to learn where I got the idea for the filter.

http://c73.student.utwente.nl/sjoerd/audio/leesvoer/pdf/Basic%20Active%20Filter%20Circards.pdf

Sheet 8 is the one. I'd just bought this pack of circuits, and it ignited my teenage brain with all sorts of possibilities. The DPDT switch to reconfigure between this VCF and a VCA is all my own work. That and putting a FET in to take the place of the variable resistor. But those cards were quite inspirational.


Roy Gwinn

Interesting.

Mine sounds like a phaser with the resonance cranked way up--the only thing I would really change about it would be to lower the range of it a bit.

However, one thing I noted when playing around with it is that if you roll off the depth, the 'dry' filtered signal is pretty much set at the lowest range of the 'wet' filter. This improves it, but a deeper sweep would be nice. I might jigger around with the caps on one of the new ones I build.

Hmm, interesting. I always want to add more controls to anything I build, so some way to change the sound of the filter would be nice. Maybe a rotary to select some different caps would be a cool mod?

Once people start building these and coming up with tweaks I will be adding them to the PDF. I think I'll also start a new thread for building and modding, because I find these long threads to be difficult to navigate, and people end up not reading the earlier posts and asking the same questions over and over.

Not a bad idea at all to vary the caps. I'd make the steps approx an octave apart. 6n8 is where it is now, perhaps add 15n (one octave down) and 33n (two octaves down), and try 3n3 (one octave up).

I wouldn't switch it though. For the cost of the switch, you might as well build multiple parallel VCF circuits, and mix the outputs. That allows for the possibility of running more than one bandpass at the same time, which can sound really nice. You'd need to match the FETs so they track together.

Roy Gwinn

Roy, you should probably stop posting good ideas. :-P

LOL  :icon_biggrin:

My order is in for 2 :)

And so, the Gristleizer boards (mostly black, a few green) went forth from Nawlins to conquer the Earth!

Hey guys, that moment is here:

(http://img27.imageshack.us/img27/228/gristleizerpcbimage.jpg)

Sorry for the junky scan, I don't have a camera at the moment. The boards are here. Ordering info is here (http://www.diystompboxes.com/smfforum/index.php?topic=80658.msg667424#msg667424).

All the boards ordered so far will probably ship tomorrow. Thanks guys! Looking forward to seeing your completed Gristleizers.

Looks like I underestimated shipping charges.

Shipping will be $2.00 for one board and 50 cents for each additional board within the US.

$4.00 for one board and 50 cents for each additional board to the UK and Europe.

All others please contact me for a shipping quote.

Just to clarify, anybody who's already paid is fine. Since it was my fault for underestimating shipping at first, no one who already paid is expected to pay the updated shipping charge. It only applies to future orders.

http://www.aronnelson.com/gallery/main.php/v/Taylor/

The PDF has been updated. Let me know if you see anything that needs further attention.

Just ordered my parts for this and have roped my bandmate into building this with me (his 3rd pedal!)

With any luck we'll be gristleizing our audio by the end of the year!  :icon_twisted:

- Strategy

Got 'em today. Boards look great and labeled to boot! Thanks.

Got mine, too. Looks great! Can't wait to build it. Thanks again.

You should have all received the email about the updated PDF, but if not, the LED is labeled backwards on the PCB and the original PDF. The mistake is now fixed on the updated PDF.

http://www.aronnelson.com/gallery/main.php/v/Taylor/

And the first build report is in, I figured we could make that the thread for all your building questions, comments, pictures, etc. so we don't end up with a 30-page thread here.

http://www.diystompboxes.com/smfforum/index.php?topic=80976.0