Dynacomp on BB doesn't sound right

[Ben Lyman]

I have stripped it off the breadboard and started over 3 times now with the same result, harsh distortion and gating of the signal. I also measured each resistor with the DMM as I replaced them on the board and double checked the schematics, both muzique and geofex.
With the Sens knob all the way up I can't get any signal once I let the gate close (about 2 to 3 seconds) If I turn the Sens knob back down and strum lightly nothing happens until I hit the strings hard, then distortion and sustain but not the squishy compression that I am familiar with. I don't have a lot of experience with IC chips so I measured the volts the same as the transistors, DMM- on ground and poking each part with DMM+
I used 2n5088 for all 5 transistors and a CA3080E that I got cheap on eBay sent from China.
Here's the schematic I used and the voltages I measured, the trim pot and sensitivity knob affects some readings as indicated. Also note the minus .05 at Q4B
http://www.muzique.com/schem/dynacomp.gif 

IC
2  3.91 to 3.93
3  3.91 to 3.93
4  0
5  .06
6  7.41
7  9.5

Q1
C  9.5
B  1.36
E  1.78

Q2
C  9.4
B  .05
E  .02

Q3
C  .96
B  .16
E  0

Q4
C  .96
B  -.05
E  0

Q5
C  9.51
B  .97
E  .06 to .68

[anotherjim]

Don't like the high voltage on 3080 pin 6. What volts is Vr? The 150k on pin 6, check that is to Vr.

[ElectricDruid]

I don't know whether 2N5088 is a good replacement for the 2N3904. The '3904 is a medium gain transistor, hFe = 60-300, but the '5088 is a high gain transistor, hFe = 300-900+.

So you've put a transistor in which has as its minimum gain the maximum gain for the transistor specified. I don't know if this is a problem in this circuit, but if you've got "harsh distortion" it sounds like it could be.

HTH,
Tom

[Ben Lyman]

Don't like the high voltage on 3080 pin 6. What volts is Vr? The 150k on pin 6, check that is to Vr.

Thanks Jim, hadn't even thought to check the V at VR. It is 3.47v and I checked the resistor at 148k, its hooked up right and IC pin6 is 7.41v.
Could this mean bogus CA3080?
Next step is probably try lower gain transistors.

I don't know whether 2N5088 is a good replacement for the 2N3904. The '3904 is a medium gain transistor, hFe = 60-300, but the '5088 is a high gain transistor, hFe = 300-900+.

Thanks Tom, I suppose that will be my next step, everything I've read says 5088 swill work in a Dynacomp but I got these from China too, 100 pcs. for $3 free ship! So far, they have all worked fine as booster pedals, OD, Dist, Fuzz, etc. Maybe comp is a different story? If I could only replace 1, 2, 3, or 4 of my 2n5088's, is there any obvious ones that should be the first to go? It seems to me Q5 might be the most likely suspect but I really don't know what I'm doing here   Calling RG, special request:
The Technology of The Dyna Comp! 

[Kipper4]

How come if pin6 and q2 base are tied your getting differant voltages at both Ben?

[Ben Lyman]

How come if pin6 and q2 base are tied your getting differant voltages at both Ben?

Thanks Rich, gave me something to think about and experiment. Results are baffling me and probably not a good thing.
Last night I had been playing guitar thru it, then unplugged and started taking readings in the order as listed above. IC6 did read 7.41v but by the time I got to Q2B it read .05v   
I measured both these parts just now at .05v, then plugged guitar in and remeasured both parts at 7.4v as soon as I strummed, then unplugged and both parts dropped and hung steady around 2.0v perhaps even lowering as I type this.
Bad IC? Bad tranny? Bad breadboard? I dunno but guitar signal affects volts at that point.
btw, I just decided to measure IC pins 1 and 8 in case it gives a clue, they are not connected to anything, pin 1 is .06v and pin 8 is 8.76v. 

[anotherjim]

How come if pin6 and q2 base are tied your getting differant voltages at both Ben?

Good catch.
Use DMM on resistance and check they really are connected.
You could do with a signal generator Ben. Bases of Q3&4 won't do anything unless a signal is present. That's awkward to see if you keep having to strum the guitar.

[Ben Lyman]

Thanks Jim, I don't know if you got a chance to read my last post, maybe I'm too wordy. Anyway, I was saying they are indeed connected and the volts go up and down in unison when I plug my guitar into it. The discrepancy came from the brief amount of time that lapsed in between taking the two measurements.
A sig gen and an Oscope would be cool if I knew what to do with them, I'm sure I will reach that point someday soon.

[Kipper4]

Ben a super simple project and very useful as a testing tool is the Quick and Dirty signal generator.
Well worth the perf.
I bagged an old c.r.oscope on eBay. I bought for the right price far before I understood it's capabilitys. 30bucks.
I'll see if I can find the q and d.

[Ben Lyman]

Thanks Rich. and thanks everyone, I'm gonna scrap this one for now and move on to something simpler like a green ringer maybe. I don't have all the parts on hand for any other comps and the only pedals I need to complete my rig are an octave fuzz and comp. I have an old crybaby to compliment my humble array of diy TB, OD, Dist & Fuzz, so after I add the octave fuzz and comp, maaayyybe I will tackle my own diy wahwah. Never been much of a modulator guy but who knows, maybe that too someday...

[Ben Lyman]

Gotta revive this one for a couple seconds.. hehe

I got it working! First try with a CA3080 from Small Bear, fired right up and sounds exactly like it should.. I have a Keeley, so ya this CA3080 from Small Bear is the real thing.

Just to be sure I dug out the old eBay stash of "CA3080" chips and tried each one in place of the SBE chip... nasty distortion or nothing at all.

Lesson learned

[thermionix]

Seems like every "Dynacomp not working" thread leads to the same issue.  Glad you got it figured out!

[Kipper4]

I guess you like it then Ben?
Haha told you so......

[Ben Lyman]

Ya, I have been waiting for the opportunity to prove my suspicions. I sold my only Really Cheap Comp and thought it's about time I revisited the Dynacomp to find out for sure if I got bunk chips from eBay. I love the Really Cheap, it's super quiet even with a distortion pedal and my Keeley is kinda noisy but I'm gonna go ahead and try my hand at the Dynacomp anyway.

Rich, you did say I was gonna love it, that was a long time ago!