Anybody build their Gristleizer yet, comments on it?

[oldschoolanalog]

Hey Aston,
Just finished mine. Same ticky problem as you have. I tried a few things and this seems to have promise:
Take a fairly large electrolytic cap; I tried 330uf; and touch it to pins 4 & 11 of the TL074 (I used a 33174). Take care to mind correct polarity and not to short anything.
In initial tests this seemed to eliminate the ticking. This was done at low volume without any input signal, so obviously more testing needs to be done.
I got this idea from here:
http://sound.westhost.com/dwopa.htm
The bypassing section. Figure B.
More testing tomm. when I don't have to have things at a whisper volume...
Hope some of this helps.
Dave
PS: There has to be a less "brute force" way to do this, but this is a start.

[Skruffyhound]

Thanks Dave, I already tried the cap trick on pins 4 and 11, but with only a 100uF, I'll try again.
Flo and J.C. gave some interesting advice in this thread
http://www.diystompboxes.com/smfforum/index.php?topic=69638.40
But in order to decouple more it seems like I'll have to break the quad up, I don't understand this circuit well enough to be able to say what the different sections of the quad are doing so I can see if I need a double and a single or 3 singles.
Hopefully there will be a much more elegant solution
I'll post back if the cap has the desired effect. Thanks

[Skruffyhound]

Ok I tried the 330 cap without success, I guess I will bend pins 4 and 11 of the 74 up and try to implement that design you linked to on ESP.

[oldschoolanalog]

Just tried mine at a "normal" (fairly loud ) volume. The ticking is barely noticeable. You really have to turn things up and listen carefully to hear it. I'll check out some of the ideas in the thread you mentioned (Thanks!) and report back later.
Have you tried any other op amps in place of the 074? Maybe try something w/lower current consumption; LM324, TL064, MC33174, etc.
Nice little effect. BTW, I got a much better response using a C100k for the bias pot.
More later...

[Skruffyhound]

Yeah I think the low power consumption quad is the way to go, unfortunately the only other quad I have at the moment is a RC4136N, which apart from the different pinout is (if I am looking the right place in the datasheet) higher consumption.
You used the MC33174  so if it's got to be ordered I'll go with what is working
Great to hear there is a solution. The bias pot is also interesting to get a confirmation on, but again I only have a 50k or 500k in stock , perhaps I'll try the 500k for the sake of experimentation.
Do you know if two dual Opamps are generally higher consumption than an equivalent quad, I may try to gerry rig something on the breadboard with two TLO62's and some of the decoupling you linked to.
Thanks for your help, glad you got it sorted out.

[oldschoolanalog]

Don't go ordering MC33174's just yet; they are kind of expensive (traded w/a friend for mine). It was the first low current quad I had handy. That's why I used it. I have some LM324's (nice & inexpensive) somewhere I'll dig out & try later.
Try putting a tapering resistor on the B100k bias pot (you can just clip it on temporarily) to see if you like the "feel" of a C taper pot.
I tried 10k between lugs 2 & 3, IIRC. I liked it, so the change was made.
Check datasheets for current consumption info.
I wouldn't say it's sorted out completely yet. I still think there has to be a less brute force way to do this.

[Skruffyhound]

I tried the 10k on the bias pot, quite different, it will take some getting used to but in some way the effect now seems to need less bias adjustment between channels, so that could be useful.
81 cents is not going to kill me for the quad you used, but I would be interested to hear about the other options as and when you get a chance. Thanks for the help.

[svstee]

Is there a suitable replacement for the 2n3819? I ordered some from Futurlec but they weren't in the package they sent.

[Taylor]

It's mentioned in the PDF:

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

I can't remember for sure now, but I think I used a J113. Make sure you doublecheck the pinout if using something else.

[svstee]

Bummer, I don't have a J113 either. Could a J201 work if I got the pinout right, or should I just wait for the 2n3819?

[Taylor]

I'm afraid I don't know enough about the necessary qualities in a JFET to work properly here. I believe Roy Gwinn said that any JFET will do, so it's worth trying. I think any one will work, but it may have a narrower band of usable sweep or something. Anyway, it won't hurt anything, so you can certainly try.

[svstee]

Well, I just got an email from Futurlec:

Dear Sean

Our apologies for the missing part.    6 of 2N3819s will be resent during today via standard post.


Should you have any further enquiry, please feel free to contact us.

Best Regards
Amp
Futurlec


Might as well just wait, although I was really looking forward to boxing this thing up...

[jacobyjd]

socket that sucker! Don't wait!

Once I (finally) get around to building my 2nd one, I'm going to spend some extra development time with it--one of the things I'll be testing will be the Jfet. I'm going to test a few types, and hopefully yield some results on what other options exist.

[svstee]

Urgh, I HATE socketing transistors. Always falling out and bumping into other stuff, but I might break my rule this one time. Those sound samples you posted are twisting my arm on this.

[jacobyjd]

You could always do the alternative: solder long leads in place of the transistor legs, then run those leads to your breadboard. this allows you to try just about any pinout very easily.

[Strategy]

Mine is mostly built, I should be ready to test it tonite or tomorrow! Sorry, no pics yet.

So far, no issues, really. Again feeling somewhat iffy about my 2P6T rotary switch wiring, these things confuse the heck out of me.

I used 1N4148, not being able to get 1N34's. This should be no problem, correct?

I visited my folks for a couple of days right before the holiday and my dad had a stack of computer switch boxes of various sizes. Two of them are perfect for pedals, they'll be repurposed for the Gristleizers (building mine in tandem with a friend) for that industrial "repurposed" look- should suit this design, given its history! 

- Strategy

[Taylor]

4148 or 914 will be fine instead of the 1n34 (as noted in the PDF). I used 1n914s on mine. I imagine purists might want germanium, though the difference they'd make is likely to be subtle, if extant.

Is the wiring diagram in the PDF not clear enough? The basic idea is this: the pad marked "1" is the pole for one switch. 2, 3, 4, and 5 are the throws for pole 1. Then the pattern starts over: pad 6 is the second pole, and 7, 8, 9, and 10 are the throws. The throws for the 2 switches should be in the same order as the numbering, so pad 2 should be selected at the same time as pad 7, 3 with 8, 4 with 9, and 5 with 10.

Now, there are 2 different rotary switch types I've come across. The Lorlin type (but this one is an Alpha clone):

Http://www.smallbearelec.com/Detail.bok?no=46

and the open type:

Http://www.smallbearelec.com/Detail.bok?no=117

They do not have the same "pinout" I guess you could call it. The closed/Lorlin type has what seems to me an intuitive arangement - the pole is in the center of the 4 contacts that it touches (this is what is shown in my wiring diagram). But the open type has the pole in between throws 1 and 2. You should take your multimeter to the pins to be sure you understand the arrangement of contacts in your particular switch.

Looking forward to seeing those boxes. You know, even after selling quite a few G-izer PCBs, not a single picture has been made of a finished box. (Even by me...  )

[Strategy]

Uh Oh. I did get the "open" type, the second one, that make and model from Smallbear. I'll see what I can learn from my multi meter with this and probably have to resolder...darn. Although, I have some Lorlin 3P4T's which would work in a pinch, but i assume ignoring one of the poles...?

OK, well I'm glad I asked about that. At the risk of sounding like a total noob, where can I find a tutorial about using a multi meter to identify switch pinouts? (if such a thing exists)

Rotary switches so far have really not been my friends in many projects...

- Strategy

[Strategy]

Actually, looking back over my work, I may have done the rotary right. Before I dissassemble that I may power up the module and test it as is to see if I hit the nail on the head (blind luck)

- Strategy

[jacobyjd]

that 3p4t will probably serve you best (meaning you won't have any unused positions on the switch), since the user won't see a difference. An unused pole is no big deal.

I think I want to use a 6t again on my next one, but I want to add some crazy 2nd LFO mojo to it that will use those extra positions.