Chauffeur OD squealing

G

Grazza

Active member
Just finished another build and I have plugged it in to see how it goes and it's not good!
Chauffeur passes sound when not on but high pitched squeal when on. I've never experienced this before. I love some input on how to trouble shoot this one.
 

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ok, done that. Now its a little more like really loud white noise than a squeal, but still there. Components were all tested other than the IC's. I don't know how to test them. I can try swapping them out?
 
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These charge pump are a source of squeal sometimes. Sometimes they are fakes, sometimes they are defective and sometimes weird interacting with other parts like buffers or other charge pumps happen.
 
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Grazza said:
ok, done that. Now its a little more like really loud white noise than a squeal, but still there. Components were all tested other than the IC's. I don't know how to test them. I can try swapping them out?
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Do you have guitar signal thru, or just noise?
Put the lid/baseplate on the enclosure when testing?
 
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Are the transistors firmly seated? The sockets are handy but sometimes I find that the outer legs don't seem to lock in.

I would attempt flipping the charge pump to see if it has any effect.

Also this isn't touching on your stomp writing is it?
 

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I get sound through when off, but nothing when on. I will check the sockets, they are handy but I'm starting to be suspicious of them a bit lately. I have looked at the stomp switch a couple of times, it is close but I'm pretty sure there is no contact. I don't generally put the back on til I am sure it works, just one more things to unscrew if it doesn't, should I have it on?
 
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The charge pumps are from tayda, I thought they would be legit, don't often use those ones though. Will the 1044 work in this circuit? I think I have some lying around
 
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Grazza said:
The charge pumps are from tayda, I thought they would be legit, don't often use those ones though. Will the 1044 work in this circuit? I think I have some lying around
Click to expand...
Out of hundreds of ICs I've purchased from Tayda I think I've only had one batch of bad chips and they noticed it before I did. It could be luck of the draw and you got one bad one. Either way it's something to try since some chips can be noisier than others.
 
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Ive found them to be fairly reliable too. I do have one more 7660 charge pump, bought at the same time though, but I'll swap it out anyway. I've had a bad run with pedals lately I've built heaps with no problems at all, but the last four have all needed troubleshooting
 
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Tried the charge pump upside down and no sound at all. Tried the only other 7660 I have and the high pitched noise was present but I also got sound through and you can notice a difference when pots are turned. When you touch the charge pump it alters the noise.
 
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Audio probe through the gain stages
Obviously, if there is no audio early on, you can stop.
Since there's no audio on the transistors, there's no reason to socket them. Only socket if you may be auditioning different transistors.
Solder them in, just move fast and give them time to cool between legs.
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Also, make sure you don't plug in to the out jack. Easy to do when the pedal is upside down....
 
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I'll start probing. I use the sockets on transistors because I have been duped before by fake transistors and felt like it was easier to sort out if they were socketed. I don't particularly love the sockets. They saved me on the xc phase build I've been troubleshooting though.
 
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I have no audio on any of those postions. Interstingly, the screeching does not exist anymore, but there is no sound when the effect is turned on. It's been in the box this whole time, hoping it would be an easy fix. I will endeaver to pull it out and test it out of the box and re-flow all solder joints. pehaps it is shorting out on something. Thanks for your help so far and stand by.
Cheers
 
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Ok, effect works when out side the box. Nothing real obvious as to why it doesnt work in side the box. If anyone is out there reading this thread, is the DC jack to close to that top transistor and charge pump? Or is something just shorting when its in the box?
 
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