Orange Compressor with serious issues

[Asan]

Hey guys, I'm attempting to build an Orange Squeezer pedal that isn't really doing what it is supposed to.  I'll be upfront and say that this is my first guitar pedal build but that I've worked in a Computer/TV repair shop for a couple years now so I figured I'd give it a shot.  I've got this pedal built on a breadboard setup so I could make sure it worked before I went any further.  Instead of 1/4" jacks I've got the input and output wires hooked in with alligator clips just for the simplicity(Don't know if this is "technically" wrong or not).  BTW, This is my first post in this forum so if it's to formal or it's missing something necessary to analyze then please let me know.  I'm sure I probably just made some sort of silly mistake but none of my friends no enough to help out so I figure the people here are plenty smart enough to help me put.  Thanks in advance for your help!!!

1.What does it do, not do, and sound like?
It does have signal going all the way through, but it has a very high gain distortion sound which is probably related to the fact that I can't turn the volume over 1/10 on the pot with out it sounding over driven.  Also, the 10k bias pot crackles on one end and that's when it started smoking.  I unplugged the battery and checking the pots resistance and it still read 10k with it all the way open so I've still got it hooked up.  I need help figuring out the distortion, and the shorting out pot, too.


2.Name of the circuit =
Dan Armstrong Orange Squeezer

3.Source of the circuit (URL of schematic or project) =
http://www.generalguitargadgets.com/pdf/ggg_osq_sc_original.pdf
It's the one off of GGG that they say is the original Dan Armstrong schematic

4.Any modifications to the circuit? Y or N
No

5.Any parts substitutions? If yes, list them.
There are a couple of resistor values that I had to put 2 resistors in series to equal up to(Is this ok?), instead of 1/4" jacks the in/out are direct wired, and that's all I can think of that's different

6.Positive ground to negative ground conversion? Y or N
No Conversion

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?
9.07v

Now insert the battery into the clip. If your effect is wired so that a plug must be in the input or output jack to turn the battery power on, insert one end of a cord into that jack. Connect the negative/black meter lead to signal ground by clipping the negative/black lead to the outer sleeve of the input or output jack, whichever does not have a plug in it. With the negative lead on signal ground, measure the following:

Voltage at the circuit board end of the red battery lead = 9.05v
Voltage at the circuit board end of the black battery lead =0.00v

Now, using the original schematic as a reference for which part is which (that is, which transistor is Q1, Q2, etc. and which IC is IC1, IC2, C1, and so on) measure and list the voltage on each pin of every transistor and IC. Just keep the black lead on ground, and touch the pointed end of the red probe to each one in turn. Report the voltages as follows:

Q1
G = 8.27v
S = 8.28v
D = 9.04v

Q2
G= 0.04v
S= 8.27v
D= 0.00v

IC1 (or U1)
P1= 0.00v
P2= 4.93v
P3= 0.00v
P4= 0.00v
P5= 0.00v
P6= 0.00v
P7= 0.00v
P8= 9.03v

[arma61]

Hi

looking at the voltages here
http://www.generalguitargadgets.com/pdf/ggg_osq_instruct.pdf?phpMyAdmin=4a28f86a515b7883e7bc35a68d4e7b6d


it looks like your ones are far away to be ok.
Probably you've a short somewhere on the board. ( I usually have, on a breadboard, two resistors' legs touching, as I never cut them short!)

Cheers
Armando

[jkokura]

Did you try wiring in the jacks? How is the circuit grounding if not through the input jack? Try that and see if it works better.

[Asan]

The guitar is wired in via a cable that has 1 end cut off so that the positive wire is hooked in where it should be and the negative wire is plugged into the common ground.  Same goes for the cable that goes out to the amp.

As for the resistors that might be touching I'll go back and take a look at that this afternoon and get back with the findings.  Thanks for the suggestions!

[Asan]

OK so I got the Orange Squeezer mostly working...I think.

First problem:  It doesn't seem or sound like the "bias" pot does anything on my build.  I read other threads and people talked about how if you don't get the bias just right then there won't be any sound  If it's to far off in a certain direction.  On mine, If you have it all the way counter clockwise or all the way clockwise then they sound identical...and so does every point in between.

Second problem:  I'm using the typical guitar with just the bridge humbucker on for testing.  When the volume on the guitar is at half the pedal sounds good.  Once you hit 3/4 then if you strum even remotely hard then the sound clips, but fingerpicking sounds great.  At full volume on the guitar, the pedal constantly clips.  Is this pretty much how it is supposed to work?  Thanks again for helping me out guys!!!

[jkokura]

nope, that's not how mine works.

Jacob

[Asan]

Ok, I've triple checked how the transistors are hooked up and the distortion problem is fixed now but the bias trim still has no direct effect on the sound.  Any thoughts guys?

[PRR]

Short C3, short C7.

In this mode, Q2 should radically reduce the signal coming in through the 82K resistor.

If that isn't so, suspect undiscovered mis-wire, or mis-reading the FET pinout.

If you get the FET sucking signal, un-short C3. Trim R7 to zero resistance. Confirm the FET still sucks signal. (If not, R7 has a problem.)

When R7=zero sucks signal, increase R7 until the signal is hardly sucked at all. That's approximately "normal bias". Mark this point! It may have to be fine trimmed when we un-short C7, and for best-sound, but will always be very nearly this setting.

Put R7 back to short for another test.

Un-short C7. Measure the DC voltage across C7 while you play real loud. It should bop up to +plus+ 2V or 3V. If not, follow your R11 D1 C7 R12 path for mistakes. You should also get 2V bops at Q2 Gate.

Finally: 2N5457 "can" have cutoff voltage of 6V, which can't happen in this plan with a 9V supply. I think a 6V cutoff would be rare, but it can happen. Also if you have used a different part-number FET, it may not be close to workable. With C3 shorted, measure the voltage on top of R5. If it is more than maybe 3V, the FETs are unsuitable.