Dr. Quack distortion problem and low signal output

[chemman]

I built the Dr. Quack with the layout on GGG. Printed trace from GGG (geofex circuit) and used values amz posted on GGG.

I get good signal past the LED after the opamp but very distorted. Using 2.2M in feedback loop. Also the effect needs tons of signal and boost to get any sound. using 5mm RED Leds without matching them.

One side of the opamp is -4.55 V and the other 1.5. Using 2n5457 and 2n3094 and voltages seem fine for these. Tried Tlo72 and RC4558 chips.

However, when i switch the Normal/Bass switch there is a Huge volume drop and the second transistor voltage goes to Zero. I get lots of sound in only one setting no matter what I do. The position that gives sound has a quack funk tone but kind of poppy and noisey. With less gain on the guitar the signal cuts off fast. Hitting strings hard gives spikes of sounds goining through the unit.

Was wondering what is goin on .

Thanks,
Chemman

[chemman]

In one switch setting the volume and quack is fine. When I switch to the Bass? setting it crackles and the sounds dies out. On the good setting there is no voltage on the 2n3904. When I switch to the non-working side a 6 V forms on the Collector. The area that seems to be a problem is the 0.005uF cap section. There is only low noise distortion on the output in that setting. In addition the LED stops being responsive to the signal applied in the bad switch setting but probing around seems to make the LED reconduct and the signal dies again slowly.
While playing in the GOOD switch setting and quickly switching to the bad side the signal hangs on and with constant strumming a small signal comes through. Stop strumming and Voltage forms on the collector and no signal strength can get sound and LED is unresponsive.

I have checked all caps and they seem fine. In one switch setting the 10uF Right after the 2n5457 gain stage has a charge (~4V) but when the switch is turned it goes to 0 V. The Faulty connection sends the signal from the sensitivity control to the 0.005uF cap area.
No solder bridges or bad connections after 3 checks.   

Has anyone built the PCB layout from GGG and had this problem?

Thanks and I will continue to debug this thing..
Good side is one position works and it sounds cool.

Chemman

[Mark Hammer]

The Q/Quack is one of those designs that attempted to get something for next to nothing.  More specifically, E-H found that a switch could easily provide another filter topography and response type.  Personally, I find the "bass" setting far more usable than the other setting, largely because the filter seems to "hang" too long at the extreme end of the sweep in the other setting.  It doesn't sound bad, it just tends to interfere with the pacing of a great many tunes.  If you plan to include variable decay that can bring the swept filter back down to earth quickly, then I suppose it is worth retaining.  But if your intent is to have a largely stock unit, my own vote is for ditching the second filter mode for now and letting time resolve the problem with the 2nd mode.

Of course, that depends on which mode is the one working.  Your note suggests it is the mode I treat as problematic that is the working one.