Caesar Chorus low volume

[LukasCabrio]

Hi guys,
I'm new to this forum and hope to find some help around here for my Caesar Chorus build.
To tell the whole story:
1. First I had no sound when pedal engaged & and no LED, bypass was ok - resoldered everything without any progress on the signal, LEDs started working
2. I did my first real audio probing and found the problem = a stupid solder bridge between IC2 and R37 or something *idk but
3. Now I have a signal going through and all the knobs have en effect on it (except the sine/triangle switch) but the volume is really low.
Is there any idea which could help me? For tomorrow I wanted to take on some advices from another thread posted by jeffwhitfield regarding the IC voltages.
Thanks!

 

[gheorge77]

I'm reupping this thread because I have the same issue. I get a chorus effect but the volume drops almost 50% with the effect engaged. I changed all of the ics with no change. Haven't tried the 2N5088s yet. Looking for other ideas...

 

[carlinb17]

Images are helpful in helping identify issues, a picture is worth a thousand words....

 

[gheorge77]

Coming back around to this project and I still have no idea what is causing this volume drop. Here's some photos, thanks in advance!

 

[Robert]

Is the clean/dry volume low if you turn the Blend control all the way down?

 

[gheorge77]

Is the clean/dry volume low if you turn the Blend control all the way down?

Yes it is. There is a noticeable level drop once it is turned on.

 

[gheorge77]

Just bumping this again to see if anyone has any thoughts. Changing ICs had no impact. Id say it's close to a 50% volume drop when the effect is on, regardless of where the blend knob is. Moving the trimpot had no impact on the volume. I'm guessing there's a misplaced component in there but I can't see anything. I dont have an audio probe to test. Does anyone have a link for a simple one?

 

[KR Sound]

Here you go:

Misc > Audio Probe : DIY Fever – Building my own guitars, amps and pedals

[DIY Fever] Audio Probe - very simple contraption that helps with debugging audio circuits

diy-fever.com

 

[gheorge77]

Yes thanks! Found it right after I posted that question. Seems like the volume drop occurs at the blend pot and at R35-R37. Tried swapping out those resistors but no change. My vref was consistent throughout the pedal at around 6.4v. I guess the next step is swapping out the blend pot? I'm out of other ideas.

 

[KR Sound]

Worth a shot! Defective or wrong pots have definitely been issues before.

 

[gheorge77]

Worth a shot! Defective or wrong pots have definitely been issues before.

No dice again. This has been the only pedal I'd say I haven't been able to crack in the close 50 pedals I've built. Really frustrating.

 

[KR Sound]

Damn, that sucks. I'd go downstream from there and verify 100% that all the components are the correct values to rule that out.

 

[gheorge77]

Damn, that sucks. I'd go downstream from there and verify 100% that all the components are the correct values to rule that out.

I'm tempted to just take all of those later components out and repopulate all of them. I've verified that it's not the ICs, the transistors, and the pots. Such a weird build for me.

 

[KR Sound]

If it’s any help, here’s a pic of mine I built last year. They’re full size so you can zoom in and compare.

 

[KR Sound]

This should be 6n8 and not 68n

 

[gheorge77]

This should be 6n8 and not 68n

View attachment 73235

Holy moly, that was it! I feel rather dumb for missing it. Thanks so much! Sounds awesome now.

 

[KR Sound]

Holy moly, that was it! I feel rather dumb for missing it. Thanks so much! Sounds awesome now.

Awesome. It was the first thing I looked at when I was comparing mine!