Orange Squeezer OSQ Trouble

[hendrix2489]

Here is the checklist to fill out:
1.What does it do, not do, and sound like? IT SOUNDS LIKE IT HAS A LITTLE GAIN BUT MOSTLY CLEAN WITH NO NOTICEABLE COMPRESSION WHEN THE EFFECT IS ON, WITH EFFECT OFF IT SOUNDS PERFECT
2.Name of the circuit = ORANGE SQUEEZER/OSQ COMPRESSION
3.Source of the circuit (URL of schematic or project) =http://www.generalguitargadgets.com/pdf/ggg_osq_sc.pdf
4.Any modifications to the circuit? Y or N    NO
5.Any parts substitutions? If yes, list them.
6.Positive ground to negative ground conversion? Y or N         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? =>  9.2V

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 =1V
S =1.5V
D =9V

Q2
G=.6V
S=1V
D=1V

IC1 (or U1)
P1=8.4V
P2=8.4V
P3=0V
P4=0V
P5=3V
P6=4.7V
P7=4.7V
P8=8.8V

[hendrix2489]

basically i get i perfect bypass but when i stomp on there is no compression

[Guitarmatt818]

The voltages on Q1 look a little bit low compared to mine. The trimmer at R7 sets the supply voltage for it and requires a bit of "tuning". The easiest way is to just turn it (R7) all the way down (very little sound) and slowly increase while playing. There should be a distinct change in the amount of compression as you turn it up. You can dial in the sound that you prefer, though there is a fairly limited range of "compressed" sound. I've set mine to get the max compression. Here's the readings from Q1 on mine:

G=1.4v
S=2.0v
D=9.4v

These voltages are with 2N5457s, I found that the voltages were quite different with MPF102s.

Peace, Matt

[hendrix2489]

i tried tuning  the trim pot.  Right now i have the external volume on 10 and the trim pot a little clockwise then the factory setting and the output is the same as bypassed.  It does NoT sound compressed.  i tried turning more clockwise but then i lose ouput.

[Guitarmatt818]

The compression is subtle, but noticeable, and with the volume pot full up it should be quite a bit louder than bypassed. A few of suggestions:

1. Double check the orientation of the polarized caps, JFETs, and the diode, ect... (you may have already done this)

2. Double check the value of the 10k trim pot (R7) with a meter, it should range from 0 ohms to 10kohms. A mislabled 1k or 5k pot could produce the results you are experiencing.

3. With the volume full up, slowly sweep the trim pot through its full range to see if you can find the "sweet spot" (do this while playing hard - light strumming wont sound compressed)

Hope this helps, Peace, Matt

[hendrix2489]

checked and still nothing

[hendrix2489]

i think both my transistors are a little low on the source.