This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.
Today's layout is the EQD Plumes. It's based on the Tube Screamer but with a load of tweaks, including the usual BJT buffers replaced with op amp buffers, selectable clipping, and a charge pump to provide a bipolar supply. Should fit nicely in a 1590B.
yeah, i noticed it the other day and was going to mention it but i see that you corrected it now. by the way,i built it and it works perfect so you can VERIFY it.
Cutoff frequency of the first gain stage is a bit weird. If my calculator is right it's 1.59khz and that is far from tube screamer type of sound. Does this mean that only frequencies above 1.59khz will get full boost or am I getting something wrong?
I have a Plumes on hand to compare to my build using this schematic and it is way brighter than the Plumes. To get them to sound similar I need to turn the Plumes tone all the way up and the and this builds tone almost all the way down. Any suggestions on fixing this?
Any suggestion on how to mod it for use with (5 string) bass guitar? Would changing C2 with an upper-value cap suffice? (If I am not wrong C2 seems wo work as a hi-pass filter in combination with R5). Should I also increase values of input/output caps? -thanks in advance-
The general rule of thumb for making a circuit more bass friendly is increasing the cap values in the audio path by 10x. For example, use a 330n instead of the 33n for the input cap.
I would probably start by replacing C1 and C6 with 1uF caps, C4 with anything from 1 to 10uF (negative side to R4), C5 to 470nF, C8 and 9 with 10uFs (negative sides towards the Volume pot). After that if there's still a bit too much treble (which I kinda doubt there would be) you could increase C3 and C7 to 470pF or 1nF. Sockets are your friends here.
Did anyone ever figure out exactly what is ideal for more/better bass? I have the actual EQD pedal and really like it but would love to do the cap switch to get make it a little better for bass.
C4 and R4 combines to make a high pass filter that cuts anything below 338Hz (using 100nF and 4.7k respectively). Since the low b string is ~30Hz and the low e string is ~40Hz you should increase C4 and/or R4 to lower the cut off. Either 56Kohm or 20uF should do it. Or you could try both 10Kohm and 1uF together.
See section 1.4.3 here: https://www.electrosmash.com/tube-screamer-analysis
It works but too trebly and I can hear the full distorted and compressed sound slightly in the background. Even when gain is almost down to zero. What cap do you think needs to be changed?
Hey, Dave told me that replacing the 47nF under the tone pot should fix that too. Made it a bit chunky and fixed the bright issue. I found 220n-330n fixed it. 470 was too much for me.
When you said the 47nf cap, you were meaning the 470 nf after mug 2 of the tone pot ? Replacing the 470nf by 220nf makes the pedal less bright ? Thanks.
I'm currently simulating this circuit in LTSpice. It's the first pedal I'm building. I didn't notice anything wrong with the tones I'm getting out of the simulation, but the volume levels I'm getting are louder than expected. Does anyone know the output voltages that should be expected for this one?
I found a similar ploblem: the schematic is working but the output level is exagerate. With a 1kHz test tone and the gain pot setted to the minimum (tone and level full open) the AC gain is roughly 30. The gain control almost immediately undergoes to clip (let's say among the 8 and 9 o'clock depending upon the diode switch position) Values of R6 and gain pot are not convincing to me. Anyone has the same impression? Best Regards :)
Thanks, I went with the 2 4.7 Ms in Series, we'll see if it works. What is the purpose of that resistor and why is it such a large value? I've never seen a resistor in that spot going to ground before.
Sorry for the newbie question, but can anyone tell me what purpose is being served by C12 and SJ1 in the schematic? I don't see them in the layout anywhere, nor do I see them on pedalPCB's schematic.
I have a high pitched squeal that changes pitch depending on the gain pot. Someone in madbean forums said that putting a phase shifting buffer in front cures it. Can someone confirm it? Thanks! :D
Hi Rahul! I just commented on your post on the fb page for diy pedal builders lol. Yeah the noise on my build is gone whenever I put a boss pedal in front of it so I tried the phase inverting buffer trick. It did remove the high pitch hum but there is still a low pitched hum past 12 oclock of the gain. I will try rebuilding this but if it’s the same, I might just use 500k for the gain pot
Verified with LMC7660IN. However, had to scratch my head about very low output until I brought in the lovely EFL tester and like in 30 seconds spotted broken level pot. Replaced with 500K Log and it worked just fine. Especially like how the bass sounds @ minimum gain with no clipping involved. Thanks for the great build and your work!
While the build is hot, an update: I got rid of hi freq hiss by replacing LMC7660IN with 7660s cpaz as mentioned above. No distraction anymore regardless of Tone pot position.
Thanks a lot for posting!
ReplyDeleteCan you provide the schematic?
Thanks in advance
i'd like to see it too.
Deleteduckduckgo is your friend, go to pedalpcb
Deleteis it possible to use lt1054 for the charge pump?
ReplyDeleteYes, doesn't connect pin 1.
DeleteThanks I'll try that
ReplyDeleteOne of diodes 4148 is inverted.
ReplyDeleteThis comment has been removed by the author.
DeleteI fixed it. That's why they're correct now. lol
Deleteyeah, i noticed it the other day and was going to mention it but i see that you corrected it now. by the way,i built it and it works perfect so you can VERIFY it.
DeleteCool. Thanks John!
DeleteCutoff frequency of the first gain stage is a bit weird. If my calculator is right it's 1.59khz and that is far from tube screamer type of sound. Does this mean that only frequencies above 1.59khz will get full boost or am I getting something wrong?
ReplyDeleteI have a Plumes on hand to compare to my build using this schematic and it is way brighter than the Plumes. To get them to sound similar I need to turn the Plumes tone all the way up and the and this builds tone almost all the way down. Any suggestions on fixing this?
ReplyDeleteand my build is brighter than the plumes
Delete1K should be 4.7K
ReplyDeleteHow do I add a 3rd diode on mode one?
ReplyDeleteAny suggestion on how to mod it for use with (5 string) bass guitar? Would changing C2 with an upper-value cap suffice? (If I am not wrong C2 seems wo work as a hi-pass filter in combination with R5). Should I also increase values of input/output caps? -thanks in advance-
ReplyDeleteThe general rule of thumb for making a circuit more bass friendly is increasing the cap values in the audio path by 10x. For example, use a 330n instead of the 33n for the input cap.
DeleteIncreas every Cap Value in the audio path or is swaping C1 enough?
DeleteThanks!
@EffectsLayouts by audio path, do you mean that bottom row on the schematic, so C1, 2, 8, 9, and 10? Or also the ones up top?
DeleteI would probably start by replacing C1 and C6 with 1uF caps, C4 with anything from 1 to 10uF (negative side to R4), C5 to 470nF, C8 and 9 with 10uFs (negative sides towards the Volume pot). After that if there's still a bit too much treble (which I kinda doubt there would be) you could increase C3 and C7 to 470pF or 1nF. Sockets are your friends here.
DeleteDid anyone ever figure out exactly what is ideal for more/better bass? I have the actual EQD pedal and really like it but would love to do the cap switch to get make it a little better for bass.
DeleteC4 and R4 combines to make a high pass filter that cuts anything below 338Hz (using 100nF and 4.7k respectively). Since the low b string is ~30Hz and the low e string is ~40Hz you should increase C4 and/or R4 to lower the cut off. Either 56Kohm or 20uF should do it. Or you could try both 10Kohm and 1uF together.
DeleteSee section 1.4.3 here: https://www.electrosmash.com/tube-screamer-analysis
An alternative for type w for tone. Here in Argentina you can't even find it, jajaja. Thanks for the hard working.
ReplyDelete@Effects Layouts The two 56pF, I only have 68pF available. If use them instead will there be a huge difference in sound?
ReplyDeleteNot a huge difference, no. You probably wouldn't be able to really hear any difference at all...
Delete#Effects Layouts, can I use TC1044 as direct swap for the MAX1044 here?
Delete@Effects Layouts, can I use TC1044 as direct swap for the MAX1044 here?
ReplyDeleteShould be ok.
DeleteIt works but too trebly and I can hear the full distorted and compressed sound slightly in the background. Even when gain is almost down to zero. What cap do you think needs to be changed?
DeleteI have similar problem.
DeleteThanks for posting this! Built mine though and it's quite bright which I saw someone else who had that issue--any advice on fixing that?
ReplyDeleteMine too. It’s too bright and I noticed that it’s too loud. @Effects Layouts any advice on what to change?
DeleteSolved! R4 here should be 4.7k instead of 1k. (Between 100n and ground) https://forum.pedalpcb.com/threads/greengage-overdrive-too-bright.1490/
DeleteHey, Dave told me that replacing the 47nF under the tone pot should fix that too. Made it a bit chunky and fixed the bright issue. I found 220n-330n fixed it. 470 was too much for me.
ReplyDeletei confirm,220n ok
DeleteWhen you said the 47nf cap, you were meaning the 470 nf after mug 2 of the tone pot ?
DeleteReplacing the 470nf by 220nf makes the pedal less bright ?
Thanks.
Or maybe the 47nf going to ground I guess.
DeleteI'm currently simulating this circuit in LTSpice. It's the first pedal I'm building. I didn't notice anything wrong with the tones I'm getting out of the simulation, but the volume levels I'm getting are louder than expected. Does anyone know the output voltages that should be expected for this one?
ReplyDeleteThis comment has been removed by the author.
DeleteI found a similar ploblem: the schematic is working but the output level is exagerate. With a 1kHz test tone and the gain pot setted to the minimum (tone and level full open) the AC gain is roughly 30. The gain control almost immediately undergoes to clip (let's say among the 8 and 9 o'clock depending upon the diode switch position)
DeleteValues of R6 and gain pot are not convincing to me.
Anyone has the same impression?
Best Regards :)
Does E3 need to be 10M or can I possibly use 4.7M?
ReplyDeleteR3 Sorry.
DeleteYou can try it—I think it will work with that. Or you can try 2, 4.7M resistors in series to make an (almost) 10M resistor.
DeleteThanks, I went with the 2 4.7 Ms in Series, we'll see if it works. What is the purpose of that resistor and why is it such a large value? I've never seen a resistor in that spot going to ground before.
DeleteIt's to bias the input of the opamp. Usually a resistor like that is like 1M, but EQD must have found some mojo in using a 10M there.
DeleteCool, thanks!
DeleteCan 1uf electrolytics be used instead of the box/poly ones? How should they connect, if so?
ReplyDeleteYou could with C8 and C9. Negative sides connecting to the Level pot. C2 though probably needs to stay non-polarized.
DeleteSorry for the newbie question, but can anyone tell me what purpose is being served by C12 and SJ1 in the schematic? I don't see them in the layout anywhere, nor do I see them on pedalPCB's schematic.
ReplyDeleteC12 is extra power filtering I added mostly out of habit. It's apparently not necessary in this circuit. Just ignore SJ1
DeleteHi, just about to build this but few things I'm seeing conflicting info on...
ReplyDeleteThe LEDs here are asymmetric, but Earthquakers description of the mode is symmetrical LEDs?
Is R4 def 4.7K and not 1K as in the schematic? Read a few times now that 1ks incorrect.
Can i use 7660cpa instead of 1044.?
ReplyDeleteVerified with 7660cpa
ReplyDeleteThere i a high pitch back ground noise like whistleing
But it might go away after i box it..im not sure though
I have a high pitched squeal that changes pitch depending on the gain pot. Someone in madbean forums said that putting a phase shifting buffer in front cures it. Can someone confirm it? Thanks! :D
ReplyDeleteI have the same problem? Did u solve the problem?
DeleteHi Rahul! I just commented on your post on the fb page for diy pedal builders lol. Yeah the noise on my build is gone whenever I put a boss pedal in front of it so I tried the phase inverting buffer trick. It did remove the high pitch hum but there is still a low pitched hum past 12 oclock of the gain. I will try rebuilding this but if it’s the same, I might just use 500k for the gain pot
DeleteI came to know tht my problem was 7660cpa where 7660s is needed
DeleteVerified with LMC7660IN. However, had to scratch my head about very low output until I brought in the lovely EFL tester and like in 30 seconds spotted broken level pot. Replaced with 500K Log and it worked just fine. Especially like how the bass sounds @ minimum gain with no clipping involved. Thanks for the great build and your work!
ReplyDeleteWhile the build is hot, an update:
DeleteI got rid of hi freq hiss by replacing LMC7660IN with 7660s cpaz as mentioned above. No distraction anymore regardless of Tone pot position.
A 10M resistor?!?
ReplyDeleteSomebody over at EQD needs to CALM DOWN.
What is Tone w20K? Is like a C tipe pot?
ReplyDelete