"Red Star Drive"
This is so simple stupid I can't believe I didn't try it sooner. Last week I breadboarded a few different fuzzes and drives using some newly acquired Ge trannies and Ge diodes. One of the circuits I did was the Trotsky Drive, I used one SFT353 and two 1n67a – I was amazed at the great sounds coming from such a simple circuit.
It got me thinking how it would sound if I replaced the transistor with a 5672 submini pentode. So I breadboarded it – sounded good, but could be better.
Over the last few days I've played about with the 5672 biasing in an attempt to get more gain from what is essentially a PentaBoost with clipping diodes. I came to the conclusion that it won't deliver any more gain at low voltage. So I started playing about with different combinations of clipping diodes until I stumbled across the perfect pair – a back to back 1n4148 (Si) and 1n67a (Ge).
The result is good IMHO – nice clipping, a good amount of gain, and excellent boost too. This is not a massively saturated gain pedal by any means. I find it nicely gritty and fattening, while preserving the character of the original signal. More bluesy than metal – but sometimes oatcakes go down better than brownies right?
Turn the 'Clip' to minimum and you effectively have a clean boost pedal, turning it up increases the clipping.
I think it should work equally well at 9 volts or 12 volts. I'm a 12 volt guy myself.
So:
Red - influenced by the Trotsky Drive.....
Star - uses a pentode.....
Drive - it's an overdrive.....
Cool name huh?
Soundclip #1 (dry): http://www.aronnelson.com/DIYFiles/up/Red_Star_Drive_Dry.mp3
Soundclip #2 (cab sim): http://www.aronnelson.com/DIYFiles/up/Red_Star_Drive_+_Cab_Sim.mp3
(http://i210.photobucket.com/albums/bb292/frequencycentral/9d8faa06.jpg)
When all the 5672's arrive I'll have to breadboard this one up and compare it to my trotsky.
Rick you are KING OF SUBMINI'S!
Very Nice.
Very nice Rick. Your going to crack up at the PM I sent you before I read this post. Oh well.
Nice little design Rick! ;)
I did something like this in a 10 watt tube amplifier of mine but with a switch to disconnect the diodes.
But with one diode the volume drop was rather big.
So I placed 3 diodes in series on each side.
And also placed a 10K pot in series with that.
The pot works like a kind of blend this way.
Did you also tried multiple diodes in this design?
Nice one Rick. Think all my remaining 5672s have found future homes and might need to look into getting some more!
btw, how do the Raytheon sound compared to the Valvo - any other differences in noise, construction, etc?
Quote from: Jimmy-H on October 09, 2008, 03:56:29 AM
Nice little design Rick! ;)
I did something like this in a 10 watt tube amplifier of mine but with a switch to disconnect the diodes.
But with one diode the volume drop was rather big.
So I placed 3 diodes in series on each side.
And also placed a 10K pot in series with that.
The pot works like a kind of blend this way.
Did you also tried multiple diodes in this design?
I tried a few different diode combinations:
2 x 1n67a - too much of a drop in gain
2 x 1n4148 - not enough crunch
2 x red LED - no crunch
2 x amber LED - no crunch
Some other (unidentified) germaniums I have performed identically to the 1n4148.
What i haven't tried yet is zeners.....
I also played about with some diode warping ideas from the AMZ site, but finally decided that this arrangement was the simplest and the best, added crunch but preserving gain. I don't have every diode type available - it would be interesting to find out how it performs with 1n34a for example. I'm sure there are other multiple diode combinations that would sound good.
Quote from: sweetwilly on October 09, 2008, 04:21:40 AM
Nice one Rick. Think all my remaining 5672s have found future homes and might need to look into getting some more!
btw, how do the Raytheon sound compared to the Valvo - any other differences in noise, construction, etc?
I replaced a Valvo for a Raytheon as soon as they arrived - there doesn't seem much difference. The soundclip was using the Raytheon.
I'm justs in the middle of putting my build together, just waiting for the clearcoat to dry...............I changed a couple of things:
I opted to use a 220 ohm / 1 watt voltage drop resistor instead of the LM317. It's a big fat sausage of a resistor and gets nice and warm! I'm measuring 1.275 volts at pin 3 of the 5672, which is just fine, well within tolerance.
I changed the 'Clip' pot from 47k to 100k. Strangely, the one on my breadboard only needs 47k to get clean boost with the 'Clip' pot turned all the way down, whereas my build is still dirty with a 47K, so I changed it. The only thing I can guess this is due to is slightly different tolerances in the clipping diodes - maybe?
(http://i210.photobucket.com/albums/bb292/frequencycentral/8401b061.jpg)
(http://i210.photobucket.com/albums/bb292/frequencycentral/4a8dfa76.jpg)
That resistor is almost as big as the tube :icon_lol:
Can't wait to see the finished product.
Box of 10 raytheon 5672's finally arrived on my desk this morning, so time to start testing out these designs! ;D
Just a question, but wouldn't a 100K log pot be better as a volume control?
Quote from: asfastasdark on October 12, 2008, 09:44:13 PM
Just a question, but wouldn't a 100K log pot be better as a volume control?
My background is modular synth building, where Lin is used for audio and Log for control voltages. The range seems smooth enough to me. Just do what you're comfortable with!
OK, cool. This might very well be a future build for me. ;)
Really nice layout again Rick!
I'm looking forward to your final result!
I'm convinced that it's a typecal frequencycentral design again. ;)
Great work so far
I made a layout for Version 2, I think it's pretty nice and compact, and I think it's one of my best so far. :) I represented the 5672 by a blue switch. See what you think, and this is completely unverified, of course.
(http://img356.imageshack.us/img356/6419/redstardrivev2jg7.gif)
Quote from: asfastasdark on October 13, 2008, 11:19:56 PM
I made a layout for Version 2, I think it's pretty nice and compact, and I think it's one of my best so far. :) I represented the 5672 by a blue switch. See what you think, and this is completely unverified, of course.
Cool looking layout, I can't see any errors. I should do a layout myself of the build I just finished (I'll post photos of the finished build tonight!) , although I used 'Tripad' board which is not widely available. I could translate it to perf, it's pretty neat because the pots are also on the board, so the off-board wiring is minimal.
I should mention that I use a 10uf electrolytic decouling/smoothing cap on all my builds between +ve and ground. I usually mount it onto the 2.1mm DC input socket.
Also, iif anyone plans to build Version 2 for a 9 volt supply, the 220 ohm / 1 watt resistor should be changed to 150 ohm / 1watt. With only 50 ma current draw it's quite feasible to run this circuit from a 9 volt battery
(http://i210.photobucket.com/albums/bb292/frequencycentral/6f9a0b16.jpg)
(http://i210.photobucket.com/albums/bb292/frequencycentral/f08fbfc8.jpg)
(http://i210.photobucket.com/albums/bb292/frequencycentral/950ec68c.jpg)
(http://i210.photobucket.com/albums/bb292/frequencycentral/f2c8cd45.jpg)
Quote from: asfastasdark on October 13, 2008, 11:19:56 PM
I made a layout for Version 2, I think it's pretty nice and compact, and I think it's one of my best so far. :) I represented the 5672 by a blue switch. See what you think, and this is completely unverified, of course.
Really quickly looking over this...
Out is lug 2.
Clip should be 2 not 3. If it was 3 then the pot would not function as a variable resistor.
Ok, here's an UNVERIFIED layout for stripboard. It's my first time using DIY Layout Creator. It's very close to my finished pedal, just a few changes I made to suit stripboard as opposed to the 'Tripad' board that I prefer. A couple of long jumpers on there, but pretty much everything is on the board including the pots, so off-board wiring is minimal. The red dot on the 5672 should be at H7. I mounted my tube on 'the wrong side of the board' in my build, which worked well for me but was a little fiddly to solder. I would be obliged if someone could check it!
(http://i210.photobucket.com/albums/bb292/frequencycentral/0f19dd80.gif)
A real great build Rick.
It fits with the other pedals you've build.
I like it very much. :icon_wink:
As for the vero layout: I think there's a mistake with D1 and D2.
Now they are connected to the middle lug of P1.
But they have to be connected to the lower lug.
The middle lug and the upper lug should be connected to ground.
You forgot one thing!
Add a pot(100k-500k) between the 1µf cap and ground. That way you can dial in compression from the pentode. I didn't have the idea. It's ripped off of the Blues Preamp from ax84.com. It's usually a linear pot, but I've found that a reverse audio generally works better.
Matt
Thanks Jimmy!
I think practically the layout and the schematic are functionally the same. The way the pot is wired in the layout is how I did my build. I should alter the schematic really - I get confused with pot lug numbers. I can't tell left from right either!
Quote from: morcey2 on October 14, 2008, 04:46:55 PM
You forgot one thing!
Add a pot(100k-500k) between the 1µf cap and ground. That way you can dial in compression from the pentode. I didn't have the idea. It's ripped off of the Blues Preamp from ax84.com. It's usually a linear pot, but I've found that a reverse audio generally works better.
Matt
That sounds interesting......what does it do, how does it sound, and do you think it would work at low voltage? Do I need to breadboard this idea?
Ah now I see!! ;D
It's different compared to the schematic, but it works just the same!
Quote from: frequencycentral on October 14, 2008, 05:04:01 PM
That sounds interesting......what does it do, how does it sound, and do you think it would work at low voltage? Do I need to breadboard this idea?
I've got a couple of amps that use the pentode side of a 6U8 or 6GH8 as the first gain stage that has the 'squish' control in them. It very much changes the feel of the amp and adds quite a bit of compression when it's dialed in all the way. I ended up wiring my pots backwards on both amps so the knob is labeled 'dynamics'.
The summary on what it does is vary the stiffness of the screen voltage. With just the cap from screen to ground, the screen voltages is very stiff which allows the pentode to have it's full range of dynamics. If you remove the cap totally, the screen voltage varies with the signal. The larger the signal, more current the screen pulls which drops voltage through the resistor feeding the screen, the 100k in your schematic. The pot varies the screen stiffness between these to extremes.
'Zoe N Iain' over at ax84 are the ones that originated it over there, so they'll probably give you a much better description than me.
And yes, I think it would work at low voltage. And yes, you need to breadboard it. You may need to drop the value of the cap to get the full range though.
And yes, I need to order me some submini tubes. You've come up with some seriously cool stuff.
Matt
Quote from: morcey2 on October 15, 2008, 09:35:21 AM
Quote from: frequencycentral on October 14, 2008, 05:04:01 PM
That sounds interesting......what does it do, how does it sound, and do you think it would work at low voltage? Do I need to breadboard this idea?
I've got a couple of amps that use the pentode side of a 6U8 or 6GH8 as the first gain stage that has the 'squish' control in them. It very much changes the feel of the amp and adds quite a bit of compression when it's dialed in all the way. I ended up wiring my pots backwards on both amps so the knob is labeled 'dynamics'.
The summary on what it does is vary the stiffness of the screen voltage. With just the cap from screen to ground, the screen voltages is very stiff which allows the pentode to have it's full range of dynamics. If you remove the cap totally, the screen voltage varies with the signal. The larger the signal, more current the screen pulls which drops voltage through the resistor feeding the screen, the 100k in your schematic. The pot varies the screen stiffness between these to extremes.
'Zoe N Iain' over at ax84 are the ones that originated it over there, so they'll probably give you a much better description than me.
And yes, I think it would work at low voltage. And yes, you need to breadboard it. You may need to drop the value of the cap to get the full range though.
And yes, I need to order me some submini tubes. You've come up with some seriously cool stuff.
Matt
Thanks
morcey/yecrom, that's a really interesting concept. I'm going to have to investigate this fully at some stage soon. I guess it will end up in another damned pedal build!
Quote from: frequencycentral on October 15, 2008, 01:31:11 PM
I guess it will end up in another damned pedal build!
TSS TSS TSS TSS :icon_lol:
Quote from: frequencycentral on October 15, 2008, 01:31:11 PM
I guess it will end up in another damned pedal build!
Hate it when that happens!!
Rick,
Have you had a chance to try the squish control on one of these yet?
Matt
Quote from: morcey2 on October 18, 2008, 03:16:17 PM
Rick,
Have you had a chance to try the squish control on one of these yet?
Matt
Haven't tried it yet - though
jasperoosthoek over at the AX84 forum is doing some interesting experiments with the PentaBoost/Red Star Drive, including adding a CCS instead of the anode resistor to get more gain - I suggested 'squish' to him. Hopefully something good will come out of that. I'll get onto it in a while - I've got another project on the breadboard right now though!
I breadboarded a hybrid of Jasper's revision and the MKI this evening and played around with diode combos for a bit. I found 2 1n67a's and a 1 1n4148 to suit. Also changed the input cap to 0.0022 for the hell of it to see if it brightened up with both neck and bridge. Didn't really make a huge difference straight into a USB mixer to my mac. I used the extra PNP transistor stage from the Pentaboost MKII as I don't have all the parts for the full Red Star MKII but still found the results very pleasing. Also tried the squish pot out. Seems to reduce gain a bit from my quick play, but only played around very quickly.
Nice work again Rick and kudos to Jasper at AX84 also.
Jasper Oosthoek over at AX84 has now finalised his redesign of my "Red Star Drive" and has also finished his pedal build. He's christened it "Decibel".
Here's Jasper's soundclip, the song was recorded with a telecaster equivalent for riff #1 and les paul type sound for riff #2 and solo. The clip/texture knob is either at 0% for riff #1 and at 100% for the rest. : http://www.iivault.com/jasper/She%20just%20won't%20listen.mp3
And here's his schematic, the 'Clipping/Texture' pot is a dual-ganged Lin pot, which maintains the volume when increasing the clipping. In my MkI version increasing the clipping caused a decrease in volume.
(http://i210.photobucket.com/albums/bb292/frequencycentral/71ea250d.jpg)
Quote from: frequencycentral on October 24, 2008, 02:35:45 PM
Hi Adriano,
Could I ask you check my vero layout please? I'm asking because a couple of people have PM'd me asking if it's verified, so I'd like to know that another set of eyes other that mine have checked it out. If you could look it over and bump the thread if you think the layout is cool I would be grateful. If you see mistakes please PM me.
Best wishes and thanks,
Rick
Quote from: Renegadrian on October 27, 2008, 04:05:58 PM
I didn't build it but seems ok to my eyes...
So yeah it should work correctly - Adriano
hey guys, hope all are well! does anyone know where i can source the diodes for this pedal? found one at maplin but the second i'm having no luck with! cheers!
Quote from: Jimmy-H on October 28, 2008, 02:13:49 PM
Hi Rick,
Sorry for the delay, but the Vero you made seems OK to me!
But you already have a new version so.......time for a new vero ;D
I've been busy with all kind of stuff...sadly not with effect building!
But keep up with the good stuff you are doing'.
Best wishes to you to!
Question about V2.
I bought up a bunch of those subminis when I saw the thread over at AX84, but ran into some problems getting the 317's. I want to build one, but I don't have any 1 watt resistors. Can I use 1/2 watt resistors?
Quote from: svstee on January 16, 2009, 02:52:00 PM
Question about V2.
I bought up a bunch of those subminis when I saw the thread over at AX84, but ran into some problems getting the 317's. I want to build one, but I don't have any 1 watt resistors. Can I use 1/2 watt resistors?
Hi, nice to see this thread again, I do love the RSD for rhythm work. That 220 ohm/1 watt resistor drops the 12 volts supply down to 1.275 volts (which is the heater requirement). All that voltage that's being dropped has to go somewhere, and is dissipated as HEAT, so thats why the resistor is 1 watt - to handle the heat. If you were to use a 1/2 watt resistor you would risk it burning out, as it would be incapable of handling the dissipated heat. So to be safe you really need a 317 or the specified 220 ohm/1 watt resistor.
I'm not sure if it would be possible to parallel two 440 ohm/ 1/2 watt resistors? That would give you the correct voltage drop, but I don't know if paralleling two 1/2 watts gives a 1 watt. Anyone know?
If you have some 5672 spare you could try my "Murder One" (http://www.diystompboxes.com/smfforum/index.php?topic=73222.0) amp - but hold off for a while as I'm still experimenting with different topologies.
Good luck with your build!
Rick
I've been following your murder 1 thread, it looks awesome, unfortunately I don't have any LM317's or the transformer. Once you get the final setup worked out, I'll get what I need, though.
I thought about two 1/2 watt 440's, but I'm not sure if that would give you 1 watt. I think you just get 1/2 watt 220, I'm not sure, though.
OK, I'm going to use two 1/2 watt 440ohm resistors and hope for the best.
Wish me luck!
Quote from: svstee on January 16, 2009, 04:58:43 PM
OK, I'm going to use two 1/2 watt 440ohm resistors and hope for the best.
Wish me luck!
Good luck! Hope it works out!
It worked out!
Hardly heats up the resistors at all. played hard for 45 minutes and both the tube and the resistors were barely warm. I am running it off 9V, so that may be a factor. Hooked it up to a DIP diode switching array and found out the best combo really is one GE and one Si, although decent, lower gain asymmetrical clipping can be produced with 2 Si on one side and a single Ge on the other. I'll box it up tonight and have it on me board tomorrow!
Thanks for the help and the great circuit!
Hey well done - glad it worked for you!
Check this out:
Quote from: frequencycentral on October 14, 2008, 02:39:00 AM
Also, if anyone plans to build Version 2 for a 9 volt supply, the 220 ohm / 1 watt resistor should be changed to 150 ohm / 1watt. With only 50 ma current draw it's quite feasible to run this circuit from a 9 volt battery
So you are starving the heater a little - shouldn't be a problem, but worth checking the voltage at pin 3 of the 5672. You may want to change to voltage drop resistor. It would be interesting to see if what you've done has any effect on the sound?
.........and post some photos when you're done boxing it up.
Actually, I accidentally used two 220 ohm resistors instead of two 440's... so I'm running at 110 ohms. sounded good, so I didn't bother to fix it.
I'll probably do what i do to 99.9% of my pedals, put it in an unpainted 2$ RACO box.
Less money spent on enclosures=more money for parts=more pedals!
Here come the pics, all mounted to the lid of a RACO box. Easy to wire, but I gave myself way to much extra wire because I wasn't sure it would fit...
(http://s301.photobucket.com/albums/nn71/svsguitarhero/th_redstardrive005.jpg)
(http://s301.photobucket.com/albums/nn71/svsguitarhero/th_redstardrive002.jpg)
(http://s301.photobucket.com/albums/nn71/svsguitarhero/th_redstardrive003.jpg)
I actually boxed her up last night, but I left my camera in my shop and was too lazy to go back and get it.
As for the enclosure, when I first started making pedals, I went to Lowes to look for things that might work as boxes, and found all those awesome RACO boxes. I thought I was the most original thinker ever, built like 10 pedals before I saw how many people had done it before me :icon_rolleyes: oh well, there really is nothing new under the sun.
Couple questions though:
1: how did you chose 1 watt for the resistor? I have two 1/2 watts running (still onny 1/2 watt I think, but I figured it would dissipate heat better) and it barely gets warm.
2: In your other versions you use an LM317. What advantages does it have that the resistor does not? Dealing with the heat sinks semms like a pain to me.
3: Where did you get those heat sinks?
Quote from: svstee on January 17, 2009, 01:45:49 PM
1: how did you chose 1 watt for the resistor? I have two 1/2 watts running (still onny 1/2 watt I think, but I figured it would dissipate heat better) and it barely gets warm.
I chose that resistor based on this equation:
5672 > 1.25 volts / 50 ma heater requirement. Voltage drop from 12 volts required: 10.75 volts.
10.75 volts / 50 ma = 215 (ohms)
10.75 volts x 50 ma = 0.5375 (watts)
So I guess I'm being conservative on the watts.
Quote from: svstee on January 17, 2009, 01:45:49 PM
2: In your other versions you use an LM317. What advantages does it have that the resistor does not? Dealing with the heat sinks semms like a pain to me.
My first build using 5672 was the pentadriver, which uses two of them. I was pretty green about how to drop voltages, and the LM317 seemed the logical way at the time.
Quote from: svstee on January 17, 2009, 01:45:49 PM
3: Where did you get those heat sinks?
Maplin in the UK.
Here's my Pentadriver with two 5672 and the heatsink:
(http://i210.photobucket.com/albums/bb292/frequencycentral/000_0006.jpg)
Your photos are awful by the way! No offence meant! ;)
I took all of them with "Bat. Low" blinking at me. I'll get some decent ones later.
Any idea were I could find heatsinks like that one in the U.S.?
The only advantage of the LM317 really is that whatever voltage you feed into it you get the same voltage out. With a voltage drop resistor out output is (maybe?) proportional to the input voltage.
No idea where to get those heatsinks in the US, sorry!
Cool, thanks!
Looking forward to building your Murder One sometime soon!
Quote from: svstee on January 17, 2009, 02:09:05 PM
Looking forward to building your Murder One sometime soon!
Me too - I think the design stage is finished - I've just got to decide on the enclosure. I would like to build it without it looking like a Zvex ripoff, but that layout is so logical. I'll see what I come up with.
Would running this at 18v be a good experiment? I'm thinking about building a voltage doubler/A-B Box so I can give my tube pedals good headroom without giving me multiple power supply problems and not having a separate unit for A-B switching (for a tuner).
Quote from: svstee on January 24, 2009, 04:03:19 PM
Would running this at 18v be a good experiment? I'm thinking about building a voltage doubler/A-B Box so I can give my tube pedals good headroom without giving me multiple power supply problems and not having a separate unit for A-B switching (for a tuner).
Yeah - that would definately be worth doing! I've tried 5672s with a MAX1044 to increase the voltage - sounds great.
EDIT: Though have a look at the MkII version that Jasper designed - it occurs to me that a higher plate voltage will mean that you will need to change the diode clippers, maybe double them up like Jasper did. The signal will be too high for the MkI diodes to clip otherwise.
I have no doubt that you guys are now sick to the teeth of me and my submini tube obsession! Anyway, I recorded a couple of new soundclips of my Red Star Drive, nothing special playing wise, just trying to show what the pedal can do.
Signal path:
Squier Telecaster Custom (HB) > Red Star Drive > Roland Bolt 60 watt tube combo > Shure SM58 > Event Echo Gina 24 soundcard > Wavelab
The effect is bypassed in the first half of this clip, then the Red Star Drive is stomped set up for (maximum) clean boost: http://www.aronnelson.com/DIYFiles/up/Red_Star_Drive_Boost.mp3
This clip has two parts, with the clip pot set at half and then full: http://www.aronnelson.com/DIYFiles/up/Red_Star_Drive_Clipping.mp3
Man, that sounds exactly like mine, and I'm running it at 9v. I wonder how much difference those 3 watts make. Also wanted to share my thoughs on this pedal, I'm not a huge fan of its clipping for lead work, I think it sounds too compressed. Great for rhythm stuff though, and works great as a booster of other FX.
My .02$.
hi...where can I find 1N67A, mouser doen't have one? ???
or what is substitute for 1N67A?
Thank you
Quote from: criszou on April 07, 2010, 06:15:32 AM
hi...where can I find 1N67A, mouser doen't have one? ???
or what is substitute for 1N67A?
Thank you
Try any Ge diode, In34a should work too.
Just finished to build the MK I of the project and now i understand why there's MKII out there... It doesn't have hard clipping...
Is there any vero version for the MKII?
Thanks
anyone? ???