Colorsound Tremolo problem

[skrunk]

I've been building a Colorsound Tremolo on vero and keep running into the same problem.
I'm using this vero as my reference (vintage 3 tranny version):



as well as this schematic (4 tranny version, the same as above except it uses a darlington pair instead of the MPSA13):



right now I've got the 3 tranny version on my bench.
I've triple checked everything, made several different veros (of both version), continuity checks, audio probe etc.

here's my voltages (using 9.7v power supply:

Q1
c 2.7v
b 2.4v
e 1.8v

Q2
c 0v
b 0v
e 0v

Q3
c 3.6v
b 1.1v
e 0v

clearly a problem with Q2.

I get a signal going through the circuit, but no modulation.
I've breadboarded it and it works fine, but every time I translate it to vero I get the same problem, even using different layouts.
I've tried different trannys, reversing pinouts, different pots, checked all part values, but no joy.
right now I've got a 2N5088 in Q1 and Q2 and an MPSA13 in Q3.
everything else is stock values.

it's really baffling me, especially as it's fine on the breadboard but every different vero I make has the same problem: getting a signal but no modulation.
when I check for voltages at Q3, (black probe to ground, red to Q3 B and C) I can hear the effect working when the probe touches the tranny legs.

someone here had a similar problem, but wasn't sure how it started working when they boxed it up:
http://www.diystompboxes.com/smfforum/index.php?topic=63442.0

which led me to think it might have been a grounding issue.
I've tried grounding it every which way, but no luck.
I've not boxed it up yet, but am testing the vero with test leads.

anyone got any idea what's going on here or had a similar problem?
I'm at my wits end here!

[deadastronaut]

http://www.diystompboxes.com/smfforum/index.php?topic=84089.0


 so you built it before then?..


this guy reckons q1 and q2 should be reversed....(at the bottom)...then it worked.

http://www.diystompboxes.com/smfforum/index.php?topic=67579.msg539268#msg539268

hope it helps...i thought it may be something like that if it worked fine on breadboard....

[LucifersTrip]

this guy reckons q1 and q2 should be reversed....(at the bottom)...then it worked.

skrunk himself actually wrote: "Also, the pinouts for Q1 and Q2 should be reversered for that vero, which I did."

http://www.diystompboxes.com/smfforum/index.php?topic=84089.msg699892#msg699892

[LucifersTrip]

it's really baffling me, especially as it's fine on the breadboard but every different vero I make has the same problem: getting a signal but no modulation.

if taking you're own advice (switching pinouts for Q1 and Q2) doesn't work, the obvious solution (since it works on breadboard) would be to perf  instead of vero

[skrunk]

http://www.diystompboxes.com/smfforum/index.php?topic=84089.0


 so you built it before then?..


this guy reckons q1 and q2 should be reversed....(at the bottom)...then it worked.

http://www.diystompboxes.com/smfforum/index.php?topic=67579.msg539268#msg539268

hope it helps...i thought it may be something like that if it worked fine on breadboard....

thanks guys,
yes I built one for my ex a couple of years ago which worked, which is really annoying!
the only notes I took were to reverse the pinout of Q1 and Q2 on the above vero.
but this doesn't work this time, I've tried every which way I can.
also, on the breadboard, reversing the pinout on these two works both ways, but sounds better the 'correct' way.

as I said, I've tried several different vero layouts, all of which give me the same problem,
which lead me to think its not a problem of a misplaced part or solder bridge, things like that.

perf could be an idea, but I can't see why it shouldn't work on vero.
I've put a LPB-1 boost on the end of this one too, could that be interfering with the voltage of Q2 in some way?
again, it works fine with the added boost section on the breadboard.
all the voltages check out everywhere on the vero, except at Q2 which is just 0v on all 3 legs.
with the audio probe, I get a signal everywhere I would expect too, it's just not modulating, except when I touch the legs of Q3 with the DMM for some reason.
it's like somehow the voltage just isn't getting to Q2.
I don't know what else I can try.
I'll keep at it