Dr Boogey help needed please

[pakrat]

Hello all,

First of all, this is a great community here with a lot of great, smart people.Thank you for all of the time you spend helping us! I have built a few pedals before, and always found my answers here when they didn't work. That is, until now.....
I recently built gaussmarkov's version of the Dr Boogey and have reached a dead end. Any help in troubleshooting this thing would be greatly appreciated.
Here is the link to the schematic and layout: http://gaussmarkov.net/wordpress/circuits/dr-boogey/
This was built using all original values the layout called for.
One thing worth mentioning, is that the DC jack I originally installed was shorted the first time I fired this up (it was grounded to the huge pot i used for the mids). I noticed it when the battery was hot when I took it off..... since I get sound on the input, I'm not too sure if this affected the circuit.

Here is what I have done so far to try and debug....

I have checked for cold solder joints, even to the point of reflowing just about everything to be safe.
I also checked all pos and neg points on electro caps and there is 8+ volts on pos side and 0v on the neg sides.
I have biased the jfet drains to nearly 4.5v for a starting point.
Double checked all resistor values.
Used a razor to clean between any possible bridges.
Swapped out all jfets.

When the effect is engaged, there is no sound at all on output. I have used an audio probe on this and found that Q1 has sound on all 3 legs, but for some reason on R5, there is sound on the left side of the resistor, but not on the right side (closest to Q2). I have already replaced this resistor and nothing changed. There is no sound anywhere on the board after that.

Battery voltage is 9.15v. The voltage on the 9v in on the pcb is 9.13v, ground is 0.00.

Q1

D 4.56
S 0.45
G 0.00

Q2

D4.47
S0.49
G 0.49

D3

D4.57
S0.48
G0.00

Q4

D 4.56
S 0.68
G 0.68

I have been trying to figure this out for days now, and I almost feel like I need to start over. So if anyone has the time to help me get this going, I would really appreciate it! And thanks to gaussmarkov for the great site and giving me the bug to get into building pedals in the first place.

[PRR]

C18 shorted.

[pakrat]

Wow Paul, good call.... you were right! Having the same issue now up to R11, signal stops on the right side closest to Q4. I just checked for a short on C19 and it's ok. Can you please tell me how you knew there was a short on C18? I feel stupid now, but thanks for responding!

[Govmnt_Lacky]

Short between Q4 Source and Gate??

[PRR]

> how you knew

> on R5, there is sound on the left side of the resistor, but not on the right side (closest to Q2).
> Q2 S 0.49 G 0.49

The R5 observation says the right side of R5 is audio-shorted to ground.

Q2 Gate should be zero volts DC; instead it is same-as Q2 Source.

So there is a short from R5-right to audio ground, apparent dead-short G-S then the largish 1uFd cap to ground.

The DC observation rules out short in C5. (Gate would be at zero.)

JFET shorted G-S, but that's fairly unlikely.

C18 short matches observations.

PCB shorted in this area..... I pointed to C18 figuring if you stared at that area, you might see if it was C18 or PCB/blobs.

Use the same thinking on your new problem.

BTW: C18 looks pretty useless to me. I'd cut it right out.

[pakrat]

Paul, you definitely know your stuff. I'm just starting out so I have so much more to learn. This is my 3rd pedal so far since I started only last month, and I'm glad there is people like you around to help.
Govmnt, you were right, short between S and G... an error in my pcb etch made it look like it should have been like that. Thanks!!
Thanks to both of you guys for helping me on this, the pedal works now and sounds damn close to my Recto! Now for the tweaking...

[Govmnt_Lacky]

Good to hear. For the biasing, I recomend setting Q1-Q4 Drains to 4.5V and tweak each one to ear.

Good Luck 

[pakrat]

Thanks man, I did start at 4.5 and worked up to 6 just to see. I just A/B it live with the other guitarist in my band. He is using a real Dual Rectifier, and I went into the clean chan of a peavey valveking. This thing is really does come close to the sound of a real recto, but only at low vols from what I see. Some of my pots are acting weird, like... not at all, or mid really sounds like presence ... etc..., so I need to recheck the wiring and get all of that working to really test it, but so far it's definitely a nice sounding pedal! I think everyone should have one of these things.......