L5 Preamp issues

[Timko]

After getting past my regulator issues with my L5 preamp, I have 2 other things that have come up.

1.  Channel 1 is super weak.  If I dime every control, it just gets above unity volume.  If I compare that to Channel 2, which stars to break up just short of 12, there's a massive volume difference.  I think I most likely fried IC2 or something.  I'll have some voltage readings later this evening, but if someone has voltages written down I would be very interested in them.

2.  I'm not quite sure what the compressor/limitor is supposed to do.  The light just barely lights up when the knob is turned all the way to the left.  Futhermore, there doesn't seem like a lot is happening with it.  When I set up the pedal, I never got a reading of 1.17 on the output pad (it was around 0.2), so maybe I'm doing something wrong there?  Or maybe (like before) I did something to IC11, IC12, or the 2 transistors around that part of the circuit.  Again, I'll reply back with voltages later tonight, but if someone has them, I would love to have some comparison.

I think these are small problems overall, and once they're resolved, this build will be golden.  So far, Channel 2 sounds huge!

[Timko]

Here's the DC off of IC2:

-15.29
0
4.3m
-15.3
-15.29
39m
14.91
0

I ran my multimeter around some of the other ICs, and every pin seems to be either -15V, 15V, or 0.  I even tried hooking up to my testing rig to run a signal through the pedal.  No luck there.  Perhaps I did fry my ICs in my regulator snafu?

[gordo]

You DID socket these buggers didn't you?  Timko?

If you did, then just the switcheroo but why do I feel like I'm preaching to the choir :-)

I had this problem initially and I'll be dipped if I can remember what I did.  I think it may have been tied to the LED issue and having to leave a ground off one of the switch boards?  Follow the thread about the LED that was around a few days ago and see if that helps.

I'm trying to finish my second build of the L5.  I socketed the IC's on the first one, and all the IC's and trannies on this one.

[Timko]

Yeah, it's all socketed.  With that much stuff I was sure something wouldn't go right.  I had the same LED issue, but I resolved that by connecting the channel board to the ground next to the LED pad on the main board.

I'm going to try to switch them, but I need to grab some more LM741's for the first channel and some more CA3080's for the compressor.  Those aren't components I have extras of unfortunately .  I wanted to see if anyone's voltage readings looked different than mine though.

[BrianS]

I thought mine was all good, boxed it up and I'm getting zero out of channel 2 now.  I am getting ready to start probing so I will send you what I get off of Ic 2 just to give you something (good/bad) to reference.

[BrianS]

Well I am getting sound out of Channel 2 now but it's not at unity with Channel 1 and it sounds real bad.  I still need to set the trimmers but I'm not sure that would cause the volume drop. So I have some issues some where in there.  Anyway here's what I got off of IC2
1 -15.06
2 0
3 0
4 -15.09
5- 15.06
6 0
7 -14.61
8 0

[Timko]

Well I am getting sound out of Channel 2 now but it's not at unity with Channel 1 and it sounds real bad.  I still need to set the trimmers but I'm not sure that would cause the volume drop. So I have some issues some where in there.  Anyway here's what I got off of IC2
1 -15.06
2 0
3 0
4 -15.09
5- 15.06
6 0
7 -14.61
8 0

Well darn.  Back to the drawing board, because IC2 is basically the same as what I got.