English Channel Worked for 10 Seconds... Help?

[Chris in Idaho]

First of all hello from North Idaho!

I'm a newb.  I have worked as an electrician for a few years and I'm familiar with wires and basic electrical principals but I don't claim to know the theory behind all of the electronic components and circuits.  So far I have built a Blues Breaker clone and a BSIAB2 both from GGG kits and they worked first try. 
I bought an "English Channel" kit from OLcircuits and put it together yesterday.  I powered it with a 9v adapter, adjusted the trimmers so the top leg of the transistors measured as close to 4.5v as possible, closed it up, plugged in the guitar and amp and... nothing.  I then opened it back up and compared it with the layout and found that I had the "in" and "out" from the board connected backwards to the 3pdt switch.  I fixed that, plugged it all back in, hit the stomp switch and was rewarded with thick voxy heaven.  I flipped my Les Paul to the bridge pickup and just as I hit the first D chord in "You Wreck Me" the sound cut out.  It played just the very first attack of the chord and stopped.  So I opened it back up and looked to make sure nothing was pinched or broken or shorted to the enclosure etc and everything looked fine.  I laid the guitar down and kept the strings ringing while gently prodding the board/wires around to get things to move (hoping to find a loose connection).  The sound cut in and out and when I could hear sound it was a garbly farty decaying sound like when a 9v battery is dead.  Sometimes it would work for a few seconds on end while the strings were ringing but whenever I hit them again the attack of the notes made the sound cut completely out. 

Since then I have looked carefully over all of my wiring and can't find any obvious bad connections or shorts.  When in bypass mode the bypass signal comes across just fine.  I'm beginning to wonder about the transistors?  Is there a way I can check to see if the J201's are damaged or faulty somehow?  Is there anything obvious I'm overlooking?  Thanks.

I read the "Debugging post instructions" so here is the info:

Here is the checklist to fill out:

1.What does it do, not do, and sound like?
The LED lights up and I get intermittent sound and the sound is noisy and farty.

2.Name of the circuit =  English Channel

3.Source of the circuit (URL of schematic or project) = http://www.olcircuits.com/olc_englishchannel.html and http://www.runoffgroove.com/englishchannel.html

4.Any modifications to the circuit?    NO

5.Any parts substitutions? If yes, list them.   NO

6.Positive ground to negative ground conversion? NO

7.Turn your meter on, set it to the 10V or 20V scale. Remove the battery from the battery clip. Probe the battery terminals with the meter leads before putting it in the clip. What is the out of circuit battery voltage? =>  I get 9.5V from my adapter (not a battery)

For the rest of the voltages I'll have to check tomorrow after work (bedtime here) but I did check the "top leg" of each transistor again as per the instructions and they were still exactly what they were initially, as close to 4.5v as I could get them.  I'll check thoroughly tomorrow and post up every voltage I can find.

Thanks very much!  That ten seconds that it worked already has me hooked on this pedal so I can't wait to get it going.  I'm also very excited about all of the learning that I'm going to do on this forum.  I can't believe I hadn't found this before!

Thanks,
Chris

[jimbanzini]

check all of your solder joints.

[Chris in Idaho]

check all of your solder joints.

Thanks.  I went over all of them again and each looks clean and solid as far as I can tell.

Voltages:
Q1:
4.78
0.23
0.0

Q2
4.61
0.22
0.0

Q3   (no trimmer feeding Q3)
9.53
4.63
0.0

Q4
5.23
0.25
0.0

Q5
5.73
0.02
0.0

Hmm... I don't know what any of this means but Q5 sure seems to be lower than the rest on the middle leg...  Does that mean anything?

There are no diodes or ICs to measure so I went on to the electrolytic caps.  They all have a small (.1-.2) positive voltage on the positive side and zero voltage on the negative side... except for one which had zero volts on both sides.  This one is fed from the middle leg of Q5...

Can anybody tell me if any of this means anything and what I should do next?

Thanks,
Chris

[jimbanzini]

resolder that cap and probably Q5.  you have a bad joint somewhere.

[Chris in Idaho]

Well, I re-flowed Q5 and the Cap and as I was mounting everything back into the box I just happened to notice something I missed the last ten times 

First of all these are the pots that came with the kit and they look to me like they're more suited to solder to a PCB, not wires.  Anyway, on the right hand lug you can barely see one strand of the hookup wire straying away and touching the body of the pot.  After snipping that guy out the pedal is working!

Well, it squeals if I turn any of the pots (except bass and cut) up past 1/2 but I can worry about that later.  It's functioning and it sounds good!

http://im1.shutterfly.com/media/47a1dd02b3127ccefcfb3746853700000030O02Qct2TNm4ZA9vPhQ/cC/f%3D0/ps%3D50/r%3D0/rx%3D720/ry%3D480/

[Scruffie]

Well, I re-flowed Q5 and the Cap and as I was mounting everything back into the box I just happened to notice something I missed the last ten times  

First of all these are the pots that came with the kit and they look to me like they're more suited to solder to a PCB, not wires.  Anyway, on the right hand lug you can barely see one strand of the hookup wire straying away and touching the body of the pot.  After snipping that guy out the pedal is working!

Well, it squeals if I turn any of the pots (except bass and cut) up past 1/2 but I can worry about that later.  It's functioning and it sounds good!

http://im1.shutterfly.com/media/47a1dd02b3127ccefcfb3746853700000030O02Qct2TNm4ZA9vPhQ/cC/f%3D0/ps%3D50/r%3D0/rx%3D720/ry%3D480/

Squeel can be tuned out with biasing, 4.5V isn't a Must, it's a Starting Point, Go through and tune by ear.

But Congratulations 

[jamiefbolton]

you can try an MPF102 for Q1 and Q2. less gain. less squeal.

[Chris in Idaho]

Thanks guys.  Wierd... I played around with it some more today and didn't get it to squeal...   I think I do want to try a MPF102 though just to lower the gain.  I turn the gain pot all the way down and just start bringing it up to where the sound begins and it's already just a bit too much for me.  If I pick really lightly it's clean and sparkly beautiful but if I play with my 'normal' pick attack it's already to dirty.  I can nail all the early U2 tones just by digging in with the gain set as low as possible.  I'm completely blown away by how wonderfully dynamic the pedal is (it's really incredible) but I need just a bit more headroom.  Would putting a MPF102 in the first position help with this?  What about changing the gain pot value or perhaps a related resistor?

Thanks!