Improved EA Tremolo Transistor Pinouts

[caprotesta]

Hello all,

Working on the GGG Improved EA Tremolo build. I've breadboarding the project, and it's not working. I think the trouble lies in the pinouts of the transistors. After reviewing the datasheets and the schematic, here's what I've come up with for what connects to each pin of the transistor (Top view; the pipes indicate the flat side of the transistor, the o's where the pins would be.)

Q1 (2N3904)

     o  |     C. to junction of R4/C2
     o  |     B. to junction of R2/R3/C1
     o  |     E. to R5

Q2 (J201)

     |  o     D. to C3
     |  o     S. to GND
     |  o     G. to R13

Q3 (2N5089)

     |  o     E. to GND
     |  o     B. to junction of R9/C6
     |  o     C. to junction of R8/C4

Q4 (J201)

     o  |     G. to junction of R16/R17
     o  |     S. to junction of C9/R17
     o  |     D. To +9V DC

Sorry about the crude diagrams. I don't have attachment rights, so I had to create something on the fly. I tried to make my breadboard layout as close as possible to how the schematic is laid out. Hence the transistors in different directions.

I've built many pedals successfully before, but this one's giving me fits. What's more annoying to me is that just about everybody says that this is a simple build. I must be missing something very obvious! Please help!

[caprotesta]

Sorry, didn't include link to the schematic:

http://www.generalguitargadgets.com/projects/26-tremolo/142-ea-tremolo

[GGBB]

Q4 (J201)

     o  |     G. to junction of R16/R17
     o  |     S. to junction of C9/R17
     o  |     D. To +9V DC

     o  |     G. to junction of R16/R17

should be junction of C8/R15/R16 - R16 and R17 shouldn't be connected except at ground.

FWIW, the ROG version is a bit simpler - 4 or 5 less components.

[caprotesta]

Thanks, GGBB. I mistyped the information for that pin. On the breadboard it is connected to the junction of C8/R16/R17. That was a transpositional error.

I'll check out the ROG version, but it'd be nice to get this one up and running.

[GGBB]

Then the transistor pinouts are okay I assume.  What exactly "doesn't work?"  No sound or no effect?

[caprotesta]

I've got no sound, but no effect.

[GGBB]

I've got no sound, but no effect.

I assume you mean you've got sound, just no effect.  Did you use non-polar 1uF caps for C5,6,7?  Also, I noticed when I built mine that if the speed was up too high, the caps would not have time to cycle so it was as if there was no effect.  Opposite for depth - too low and no tremolo.

Since you've got sound coming through, the problem is most likely after C13.

Edit:  C3 (not C13)

[caprotesta]

Yes, you are correct: I've got sound, but no effect (sorry, trying to do too many things at once).

The caps are non-polarized film capacitors.

I originally thought that the pots might be set too low/high, so I tested originally with both at the middle point, and then swept each one, keeping the other at its midpoint. No discernible change.

I'll double check the circuit after C3 and make sure that everything is connected properly. It's a relief to know that the transistors are hooked up the right way. I originally thought that one of them might be bad, but I tested them with my multimeter and everything appeared to be above board.

[caprotesta]

Got it to work! In the end, I had a pot wired incorrectly. Now that it's working it sounds great! Thanks to your help, GGBB

[GGBB]

Got it to work! In the end, I had a pot wired incorrectly. Now that it's working it sounds great! Thanks to your help, GGBB

No problem - I love mine too.