Edit:
Here are a few mods if you want to use it on bass. Some say stock is best, others say to uses these substitutions. As always, YMMV.
• Swap the output cap from 4.7µ to 1µ (between the 390k and 1.5k resistors, below the IC)
• Swap bleeder cap from 4.7µ to 10µ (cap connected to the 1N34 diode)
• Reduce the feedback resistor from 220k to 200k (between Q2 and the IC)
Here are a few mods if you want to use it on bass. Some say stock is best, others say to uses these substitutions. As always, YMMV.
• Swap the output cap from 4.7µ to 1µ (between the 390k and 1.5k resistors, below the IC)
• Swap bleeder cap from 4.7µ to 10µ (cap connected to the 1N34 diode)
• Reduce the feedback resistor from 220k to 200k (between Q2 and the IC)
external bias pot A or B?
ReplyDeleteA B10k is what I used I think.
Deletethanks.
DeleteWhat is the difference between a-pots, b-pots and c-pots. Can't find that info. (or didn't look properly)
DeleteThey represent the pot taper. A=logarithmic/audio, B=linear, C=reverse log.
DeleteThanks for the quick reply. Maybe you could add this to the General Layout Notes in the pot wiring section. That's where I was looking for this info first.
DeleteAnyway - great site with lots of interesting stuff. Looking forward to buuilding something based on your designs.
is it possible to replace 1n34a with 5458 or something else?
ReplyDeleteYou can try it, but I would stick with a germanium diode there.
DeleteOut is from level pot (pin 2) ?
ReplyDeleteYup
DeleteThank you, now I have absolutely all the information needed for this project.
DeleteI was going to ask this :-)
Deletemaybe you could add this info to the pic
This comment has been removed by the author.
ReplyDeleteVerified by me! =) Thanks
ReplyDeletewould j201 transistors work for this layout
ReplyDeletePossibly. They'll need to be matched though.
Deletemine didnt work and i have no clue why =/
ReplyDeleteif the admin let me, i can post a link to pictures of the board for some help
its the 4th that i build and dint work =(
Feel free to post pics. Does it not pass signal at all? Have you gone through it with an audio probe? Did you match the JFETs?
DeleteMine isn't working properly. Opamp part is ok - clean sound, but compression works strange. When I hit a big chord attack works acceptable but release pumps up and down for 3-4 times until the level gets normal. Is there a reciept? Please help.
ReplyDeleteThis comment has been removed by the author.
ReplyDelete
ReplyDeleteThere is a problem with the pedal's power when I turned on the unstabilized unit, The pedal began to fade strongly, but if I connect a 9 volt battery it works fine. I added a stabilizer straight to the power supply. Is there any way to change the circuit so as not to redo the power supply? thank
DeleteI'm sorry I wrote using the Internet translator, I hope I clearly explained the problem
Hello, I would like to do one of these for an acoustic guitar, what do you think would be a better idea? 1-do it as to use it with bass, or 2-have a splitter prior to the compressor and be able to mix the dry signal with the compressed one? Thank you
ReplyDeleteHello everyone. Finished this and sounds great but when I turn the trimmer to clockwise it begins ticking. Why?
ReplyDeleteIf you mean the trimmer itself, that's normal for a multi-turn trimpot when it reaches either end of its value. You can keep rotating but the value won't change because it's maxed (or min'ed) out.
DeleteI want to try this one but I don´t know if 2N5458 could work instead 2N5457 / same datasheet /
ReplyDelete5457 Vgs off = 2.5V
5458 Vgs off = 3.5V
Maybe satting the bias / B5k and B10K pots.
Does it could work this way?
thank you
Done... ...2N5458 / 10k TRIM / NO NEED TO SET Q2 BIAS - JUST Q1. SAME as GGG DOC:
DeleteQ1s = 4.0 V
Q2s = 2.6 V
GREAT SOUND