Build Your Own Clone Message Board

I'm getting no sound when in Envelope filter mode. In Manual mode, the guitar tone is weak and slightly distorted. I do get the appropriate sweep of the filter if I turn the knob, so that part of the circuit seems to be working.

Before I start taking pictures, I have a few questions:

I initially insterted the op amp chip in backwards. I powered up the pedal before I realized this. Is it possible to damage the chip this way? I also bent up the pins a bit removing it. I got them all back in place, and they are seated in the socket correctly, but I'm also wondering how fragile the chip is to this type of abuse?

Also, while doing the initial soldering, I noticed a "fizz" sound as I soldered the 10n capacitor that sits by the Attack knob. I had the soldering gun on a little longer than usual, as it wasn't heating as easily as usual. I'm hoping that was just the sound of some of the plastic that was a little far down the leads melting, but could I have fried this capacitor? How would I check? There is not continuity between the leads, so I didn't short it, at least.

I did some preliminary looking around, and checking of basic continutiy of the signal path through the switch and onto the board, and everything looks pretty good. The soldering went really well, so I'm surprized and disappointed to be having issues (this is my second build, so I hoped I would nail it this time). If the above issues are not likely problems, and ideas for where to start looking? I'll post pics if need be.

Thanks!

Here's some more troubleshooting information/questions:

I decided to check all the resistors with a meter, to make sure I didn't just mix a couple up. Most of them checked out, however, there is a group of 5 22k resistors just to the right of the 13600 chip with all wrong values. They are all red red black red brown, but the meter says each is either around 9k or 13k. Is there anything in the circuit that would cause the resistance across their leads to be less than their rated resistance, or do I just have a whole batch of bad 22k resistors? There is one or 2 of these elsewhere that test correctly and another one or two with the same low readings.

Some resistors can't be tested in the circuit, so if you get off values, don't be alarmed. On those, check the bands, which it sounds like you did.

As far as the filter circuit itself goes.....someone else is gonna have to jump in here.

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Problem solved - one way or another, the op-amp got trashed. I'm assuming it was my own fault.

I picked upa a TL082 Dual BiFET Op Amp from Radio Shack, and the pedal works fine now. Is there any point to tracking down the "correct" Op Amp? This one seems to work fine, but being new to all this, I'm not sure what effects different Op Amps would have in this circuit. I'm guessing that since I'm not using the op amp for distortion, as long as I have low noise I'm pretty much good - is this right?

Yup - pretty much right.

If you use your manual filter control and it seems a bit abrupt I recommend you check out - http://www.buildyourownclone.com/board/viewtopic.php?f=12&t=34270

Pins 4 & 8 of a dual op-amp are the ground and +Vcc (+9V) connections respectively. When you install the chip backwards you reverse these connections which in turn fries the op-amp.

The TL082 will work fine as a replacement for the 4558 chip.

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"It’s your soldering."