Dirtbag Troubles

[tenwatt]

It's all fabbed up.  I set the trimmers and pots for biasing and hooked it up for testing and got a signal.  I started probing after disconnecting my output.  I started by probing the "In" pad and have a strong signal.  I  probed the "Out" pad and it was a little weaker.  Turned the "Level" clockwise and the output was more faint.  All the way counter-clockwise produces the loudest output.  So there's the first problem.

Next I probed pin #3 of IC4...nothing.

I then probed pin #3 of IC5...nothing.

Any ideas?  

[madbean]

Check the following pins for signal strength and let us know what you find:

IC1: pin1 and pin7
IC2: pin7
IC6: pin7

Which version are you building?

[Scruffie]

3005 or 3205 version?

Done the correct mods to work with the version you're building?

All ICs properly socketed?

What are your voltages on all the ICs? Especially the BBDs & 4047.

Have you actually tried to bias the BBDs, if they're not biased you wont get an output.

Edit:Bean Beat me there.

[tenwatt]

REALLY weird gremlin.  I walked away from it, came back, and now it's working fine other than biasing adjustments.  I'm going to bed now and will mess with it later.

I'm building the 3205.

[tenwatt]

I'm having trouble getting the biasing set well.  I got bias 1 to sound pretty clean but I couldn't get all the distortion out of bias 2.  I got it as clean as I could but it still sounds pretty distorted.  I would guess it's between 1 and two o'clock.  

Also, when I turn the "Delay" and "Feedback" pots it starts oscillating EARLY in it's turn.  Maybe around a ¼ of a turn on the "Feedback" pot.

Any tips?    

[LaceSensor]

I'm having trouble getting the biasing set well.  I got bias 1 to sound pretty clean but I couldn't get all the distortion out of bias 2.  I got it as clean as I could but it still sounds pretty distorted.  I would guess it's between 1 and two o'clock.  

Also, when I turn the "Delay" and "Feedback" pots it starts oscillating EARLY in it's turn.  Maybe around a ¼ of a turn on the "Feedback" pot.

Any tips?    

I could be wrong but the gain trimmers set the feedback onset. you need to incrementally adjust them from zero with the feedback control all the way up.

With regards the BIasing, are you starting with everything set up as per the BOM instructions?

are you working with an audio probe and probing the suggested pins?

[tenwatt]

I could be wrong but the gain trimmers set the feedback onset. you need to incrementally adjust them from zero with the feedback control all the way up.

With regards the BIasing, are you starting with everything set up as per the BOM instructions?

are you working with an audio probe and probing the suggested pins?

I'll mess with the gain trimmers some more tonight but the answer is "yes" to the rest of your questions.

[LaceSensor]

balance is in the noon position?

cant say I really know what I am talking about but this might help when I come to try mine, hopefully this evening

[tenwatt]

balance is in the noon position?

Yupper doo.

[Scruffie]

Gain 1 & Bias 2 will be highly interactive, this is a flaw in the design so keep playing with that.

Did you remember to make R11 & 12 47k in the Compander?

Once that's sorted adjust Gain 2 to stop run away repeats.

[tenwatt]

Gain 1 & Bias 2 will be highly interactive, this is a flaw in the design so keep playing with that.

Did you remember to make R11 & 12 47k in the Compander?

Once that's sorted adjust Gain 2 to stop run away repeats.

R11 and R12 are, indeed, 47k.  I'll mess with the trimmers some more and report back.

[tenwatt]

I wish I knew how to use an oscilloscope.  I just learned that there is one here at work I could use.  

[tenwatt]

Okay...when I sweep through the bias pots while probing the #3 pins (as described) it always sounds like there is a little bit of a fuzz.  It goes from a LOT to a LITTLE but it NEVER sounds clean. 

It seems to be working well other than the fuzz sound.

[gtr2]

How are you testing.  Guitar (type?), sine wave? etc...

[tenwatt]

How are you testing.  Guitar (type?), sine wave? etc...

PRS Custom 24 (humbuckers).