The TrotskyDrive

[dano12]

I had the opportunity today to get some listening tests with a pedal-junkie friend. He was quite enthralled with it. We both noticed that with single coils it can be a bit bright but is pretty much perfect with humbuckers. To make up for this, I've added a switchable small 6.8n cap to ground that gently eases up a bit on the treble side. The rev 1.02 schematic below shows this.



I've also finished a test layout and hope to get it built on this layout tonight:



Yep, all schematics, layouts etc. are done in Visio. Thanks for all the feedback!

[KerryF]

Im about to throw one together on breadboard.  I will post my results.

Kerry

[KerryF]

Ok, I just finished breadboarding it and doing a very short test (Fingers are in pain from long jam session.  .  I will test more tomarrow but its pretty cool.

I used a 2N4401 transistor which works, dont know how much different from the other choices it is.  I will try 2N5088s/2N5089s/whatever tomarrow.  The switch for the diodes is cool.  Cant exactly tell what the different tonal qualities are, but it kindof sounds like the difference when I turn my Valve Junior from Pentode to Triode operation.

Kerry

[Meanderthal]

 Ya may also wanna try lower gain trannys... this one's designed around a low gainer... 2N4401 is more in the neighborhood of 2N3904- medium gain, all purpose. 5088 and 5089 are higher gain than those.
Which might be interesting(or even great), but probably won't capture the intended Trotsky tone... heh.

Really, the high gain trannys would be more or less going back to Electra territory...

Fingers are in pain from long jam session

Pain is the sensation of weakness leaving the body.(a marine cliche') You'll be a stronger player for having put yourself through that.

[markm]

Ya may also wanna try lower gain trannys... this one's designed around a low gainer... 2N4401 is more in the neighborhood of 2N3904- medium gain, all purpose. 5088 and 5089 are higher gain than those.
Which might be interesting(or even great), but probably won't capture the intended Trotsky tone... heh.

Really, the high gain trannys would be more or less going back to Electra territory...

I'll bet 2N2222's would be right at home in this circuit, or 2N3440's.
Metal can mojo!

[Dragonfly]

Ya may also wanna try lower gain trannys... this one's designed around a low gainer... 2N4401 is more in the neighborhood of 2N3904- medium gain, all purpose. 5088 and 5089 are higher gain than those.
Which might be interesting(or even great), but probably won't capture the intended Trotsky tone... heh.

Really, the high gain trannys would be more or less going back to Electra territory...

I'll bet 2N2222's would be right at home in this circuit, or 2N3440's.
Metal can mojo!

I keep saying this, but I'll repeat it again

2N3903's ...yes, 2N3903's are great sounding, low HFE (usually 90-125 or so) transistors...and they're DIRT CHEAP !!!

They'd probably sound fantastic in this circuit.

AC

[MartyMart]

+1 on the 2N3903's they work just as well as 2369's and are half the price !!
Nice work Dano 

MM.

[Mark Hammer]

Um, should I assume the Trotsky reference is related to "icepick through the forehead" tones?

[dano12]

Um, should I assume the Trotsky reference is related to "icepick through the forehead" tones?

Yes, an unfortunate allusion. However, I think the Trotsky name is fitting for an overdrive--I've reserved Stalin for a fuzz that is brutal and oppressive.

[Mark Hammer]

 

I suppose that the "Chamberlain" would be a fuzz that has immediate sag in response to any sort of pick attack?

[KerryF]

Thanks for the transistor ideas everyone.  I will try a metal can 2N2222 later!  I used my 2N3904 in one of my projects.  If I could just remember which, I could get it out to test 

[dano12]

I suppose that the "Chamberlain" would be a fuzz that has immediate sag in response to any sort of pick attack?

We have two coffee pots at work, one for wicked strong brew, the other for whatever lightweight stuff the other folks make.

To avoid accidentally pouring a cup of the weak stuff in the early AM, I put pictures on each pot. Ghengis Khan is on the good stuff, Chamberlain is on the weak

Sounds like a good description of a Chamberlain pedal.

Next up, Il Duce Fuzz! Swaggers around your board until the other stompboxes revolt and string it up by its power cord.

[Meanderthal]

 LOL! You guys crack me up!

[dano12]

Here's the latest 1.02 PDF for the Trotsky. I've included the latest layout and also a wiring diagram. Man, I'm loving this one--so simple to build and yet it sounds so good.

http://www.beavisaudio.com/Projects/TrotskyDrive/BAR_Trotsky_102.pdf

[MartyMart]

That's a great project Dano, but you should turn the "R" around in Trotsky 

MM

[dano12]

That's a great project Dano, but you should turn the "R" around in Trotsky 

MM

Yeah, I tried that but the output went out of phase.

[Ben N]

Trotsky, Stalin, Chamberlain, Ghengis... GOD, i LOVE THIS PLACE!

I imagine that on some other boards an awareness of history is knowing the names of last year's contestants on American Idol. Here we've projected historical personas onto stompboxes and coffeepots, just for fun. It sure makes fiddling with transistors and opamps more interesting when the people who do it are, well, more interesting.

BTW, just to keep things on topic, the circuit looks really cool (and easy, can't forget that) and I look forward to trying it. Have you tried other diode combinations with it?

Ben

[vortex]

Hey Dano, I am curious about the gain pot arrangement. Can you tell us what the usable range of the pot is?

Thanks comrade!

[dano12]

Hey Dano, I am curious about the gain pot arrangement. Can you tell us what the usable range of the pot is?

Thanks comrade!

Pretty much the whole rotation is usable. I ran out of b50ks and used a b100k on one of them and it still seemed usuable, but with a lot more travel.

[ambulancevoice]

anyone thought of trying a metal can 2n3053?