Trotsky Debug

kurtlives · July 08, 2008, 01:41:02 PM

I somehow screwed this simple circuit up.

Schem: http://www.beavisaudio.com/Projects/TrotskyDrive/Schematic_1_14.gif
Layout: http://www.aronnelson.com/gallery/main.php/v/DRAGONFLY-LAYOUTS_0/album17/trotsky+pcb.gif.html

Bypass works and LED lights up when on. Thing is when the effect is on I get signal but it is the exact same as my bypassed signal. I thought maybe there were solder bridges on the bypass switch but no.

2N2222
C 8.14V (Gain knob fully CCW)
B 6.62V
E 7.61V

Thanks...

O also I recently bought a bunch of stereo jacks...I bought 12A instead of the usual 12B from Switchcraft. The LED can be turned on by pressing the bypass switch when no lead is in the input jack. Does this mean my battery is constantly draining?

kurtlives · July 09, 2008, 12:01:34 AM

Found a few small problems... I no get a extremely low output and a fuzz tone.

I used my audio probe and found I got sound at the effect output (volume pot lug 2). Does this mean anything?

Q1 (gain knob fully CCW)
C 6.86V
B 0.86V
E o.28V

raycroft · July 09, 2008, 12:03:20 AM

I wish I could help you. I love Dano's stuff- I just got done building the Trotsky 2 days ago- my first successful from-scratch build ( I built the Rocket from scratch- it's being peiced out for parts- the FKR was my second, and I haven't debugged it yet- it took 2 days to make and when I fired it up and it wasn't working right, I just set it aside). Anyway- mine worked as soon as I plugged it up; and sounds great. i used a 2n3904. If you need some pics or something, I can work that out, or some voltages or whatever. I did take some voltages - but it was w/ power off, no plug in the input- I got B .58 E .03 C 1.1. Sorry not much help, let me know if I can be more.

As far as jacks go- I don't know the diff between the A or the B- as long as you've got it hooked up to the "-" on your battery ( don't know any other way) it should be off when there's nothing plugged in- but, it sound's like it ain't, if you can power it up w/ the switch.

kurtlives · July 09, 2008, 12:06:10 AM

Hey Ray glad yours is working... How does it sound?

Do you think you could get me voltages with input lead in and effect on with gain fully CCW.

Thanks

raycroft · July 09, 2008, 06:58:55 AM

It sounds great, very fuzzy and nasty sounding. I'll post a clip when I get home today- also I can post those voltages for ya.

raycroft · July 09, 2008, 09:11:27 AM

I measured again, gain maxed and circuit on : B 0.55 E 0.76 C .01.

raycroft · July 09, 2008, 10:10:27 AM

some pics .

I'll post the vid later today, after it has processed (?)

raycroft · July 09, 2008, 10:15:11 AM

vid http://www.youtube.com/watch?v=eqF4v9H6BOw

kurtlives · July 09, 2008, 12:28:18 PM

Haha great video...!

You could try some 1N914 in the clipping section for a bit less gain and less fuzz.

Damn I wanna get mine workin.

railhead · July 09, 2008, 01:16:34 PM

I'm going to have to build this again. When I built mine, it sounded like total crapola with hardly any gain at all.

raycroft · July 09, 2008, 01:59:02 PM

"less gain and less fuzz" ?!!? What are you talking about? I want MORE of those two!!!

kurtlives · July 09, 2008, 02:03:35 PM

To each his own...I hate the sound of germanium diodes clipping really hard.

raycroft · July 09, 2008, 02:32:07 PM

yeah, I haven't heard it enough to know the difference. I plan on finding out, though! I'm currently in the process of de-bugging a GGG BMP. Must...... have..... distortion.....

morpha2 · July 09, 2008, 02:34:47 PM

I'm currently taking a 2nd pass at the Trotsky. My 1st try had much the same problem that you're describing. Were you able to correctly determine the pins on the 2N2222?

DWBH · July 09, 2008, 02:40:01 PM

Quote from: railhead on July 09, 2008, 01:16:34 PM
I'm going to have to build this again. When I built mine, it sounded like total crapola with hardly any gain at all.

I think the main problem you, me, and some other fellas have faced is caused by the transistor. Dano designed this pedal around a "special" Russian transistor. And although many other transistors are electronically compatible with that trannie, they aren't sound compatible, if you know what I mean.

raycroft · July 09, 2008, 02:43:09 PM

i personally used the 2n3904. had to bend the pins to make it go where they were supposed to.

kurtlives · July 09, 2008, 02:45:09 PM

Quote from: morpha2 on July 09, 2008, 02:34:47 PM
I'm currently taking a 2nd pass at the Trotsky. My 1st try had much the same problem that you're describing. Were you able to correctly determine the pins on the 2N2222?

Ya I could...I used my DMM to help me. Mine is a 2N2222A

I am going to try a 2N3904 now.

kurtlives · July 09, 2008, 02:59:09 PM

2N3904 gain maxed

C 2.27V
B 0.7V
E 0.08V

deaconque · July 10, 2008, 06:43:27 PM

you guys might want to try building an Electra dist. it's what the trotsky was based off of and isn't tuned to work with such an obscure transistor. if you're looking for a lot of gain then this one might not be for you, though. it sounds great but it's more of a nice crunch than a high gain dist/fuzz.

ayayay! · July 11, 2008, 09:44:55 AM

I briefly built this on a breadboard but barely remember it. I want to build it into a pedal this weekend. I plan on putting a trimmer in place of the 680ohm bias resistor. My money would be on that for your guys problems. Try a trimpot there and see if you can find a sweeter spot.

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Trotsky Debug