foxx tone machine--thin fuzz?

[Stratomaster]

Hello,
  A while back I asked for help on the layout of a Foxx Tone Machine clone.  Thanks to JDSleep's PCBs, it is now done.  I mainly wanted something to replace my Dano-French Toast (as well as a nice project for myself).  I noticed that the fuzz on the clone is thin and trebly compared to the dano.  The gain of the pedal is also very low.  It doesn't have that distinct fuzz tone that I was so used to--that bassy, overwhelming sound.  I do not have a multimeter to give exact readings, but do any of you have an idea as to what might be wrong?  Also, there is a slight volume drop when I kick on the octave.  Thanks in advance.  Even with the problems, not bad for a first build--if I do say so myself.
-OMJ

[Doug_H]

Before you do anything else, get a multimeter. You won't get far debugging without it.

Doug

[Wild Zebra]

I built the tone machine using JD Sleeps layout and I can verify its right.  As in the afformentioned post multimeter will help the cats around here help you out.  There must be something wrong because my tone machine is over-the-top fuzz and when you switch on the octave, watch out.

[Stratomaster]

Before you do anything else, get a multimeter. You won't get far debugging without it.

Doug

Got one... now what?  Any and all help is appreciated.  Thanks.
-OMJ

[Ben N]

I haven't played it in a while, but my recollection of the sound of my FT is that it is rather thin and trebly, if intense and "over the top", as well.

Ben

[Fret Wire]

Before you do anything else, get a multimeter. You won't get far debugging without it.
Doug

Got one... now what?  Any and all help is appreciated.  Thanks.
-OMJ

It'd help out (and go faster) if you follow this debugging guide and then post the voltages and results.
http://diystompboxes.com/sboxforum/viewtopic.php?t=29816

[Stratomaster]

If I understood this meter correctly, I'm supposed to set it to volts, double digit & 2 decimal places.  Red probe goes on battery positive connection on the board and the black probe goes on each pin of the transistors, collector base and emitter.  I've done this and the numbers are FUBAR.  Compared to the suggested ones on JDSleep's site, there are hardly any similarities.  I'm thinking this is meter user error.  Help please.
-OMJ

::EDIT::
Sorry, re-read and saw that I'm a complete moron.  Be back in a few with the voltages.

[Stratomaster]

Q1
C = 3.53
B = .59
E = .06

Q2
C= 6.85
B= 3.53
E= 2.96

Q3
C= 7.65
B= .75
E= .20

Q4
C= 8.16
B= .72
E= .21

D1 --octave switch off
A (anode, the non-band end) = 0.00
K (cathode, the banded end) = 0.00

D2 --octave switch off
A = 4.75
K = 4.33

D1 --octave switch on
A = 3.32
K = 2.91

D2 --octave switch on
A = 3.35
K = 2.91

D3 --octave both on and off
A = 0.00
K = 0.00

D4 --octave both on and off
A = 0.00
K = 0.00

battery: 9.58


I'm no genius, but I think something's wrong with d3&d4.  Any ideas?

[Doug_H]

I've never built one so I hope someone who has chimes in with some voltage measurements.

But it looks like something may be wrong with Q4. The collector voltage of ~8v seems too high. The <1v base voltages seem too low too, I would normally expect 1-2v there but I might be wrong. It just may bias up that way for all I know.

I would expect approx 1/2 battery voltage on D2 (a or k, roughly) when the octave is off and roughly 1/3 when it is on.

Doug

[Stratomaster]

The <1 voltages are ok according to JDSleep's given measurements.  Thanks for the response though.  Anyone else have any ideas?  I don't want to be sitting here with a weak sounding pedal that I'm not going to use. Thanks.
-OMJ

[Hal]

not even looking at the schematic, but d3 and 4 could be clipping diodes - in the mV range, increasing with signal.

[Fret Wire]

The voltages are kinda off, but still close enough to rule out the transistor pinout being wrong. Something minor is dragging this pedal down. I've never built this ckt, so I don't know it's little quirks. So time to try some basics.

1. Whip out the magnifying glass and check all the solder joints for cold joints and bridged traces, by either solder or copper. Really check good around the trannies. Even the simple octive switch could be a cold joint.

2. Double ckeck all the offboard connections. Make sure pots are wired right, and you got your jack tips, sleeves, and ring all straight. Check the main switch.

3. Double check the polarity orientation on all those damn 10uf caps. And double check all the cap and resistor values to make sure they are right. (like 47k instead of 4k7). Make sure all your diode anodes and cathodes are oriented the right way. If just one cap or diode was backward, it's enough to throw off the ckt.

Usually when a pedal works, but is very weak, it's something small that throws the whole thing off. Every time it gets annoying, walk away for awhile. When you come back fresh, you'll find something you missed before.

[Stratomaster]

It honestly looks like everything is hooked up and soldered just fine.  I'll give it another go and resolder everything.  I'll print out another layout of the circuit and see if there are any major bridges/shorts.  As of right now, it still sounds weak.  I'll be back with more info and seeking more help.  Thanks, Fret Wire.
-OMJ

[Stratomaster]

I've resoldered everything there was to resolder.  I found a cold ground joint, but that's about it.  After fixing that, I reconnected and tested.  No change.  I thought about what one person said in a previous post to something similar about Q1 being "the key".  I changed that particular transistor, and now it sounds more like it's supposed to sound.  It's still not as heavy or bassy as the dano is, but it's at least an improvement.  I didn't test the other transistors before putting them in, but the one I popped in tested at around 220/230.  Any suggestions on which one to change to finish this off, or should I just solder in some sockets and go nuts experimenting?  Thanks in advance.
-OMJ

PS.  I really like the way it sounds right now.  I just wish it had a little more dirt.  Is there any way I can solder a 22k resistor in series with the fuzz pot to get more dirt?  If there is, can anyone hold my hand through it?  I wouldn't know which lug to solder to from which point on the board.  Thanks again.

[Stratomaster]

bump