Paragon Mini suddenly lower output

[JFurgie]

Built this a while ago and until recently it was working perfectly. The other day I noticed that the setting I usually use on my Paragon Mini was much lower and I wasn’t getting unity gain until about 2 o’clock on the level knob where before it was around noon if not a bit lower.
voltage readings on ICs:

IC1
1 4.89v
2 4.89v
3 2.42
4 0v
5 4.70v
6 4.89v
7 4.75v
8 9.55v

IC2
1 4.97v
2 4.97v
3 2.50v
4 0v
5 1.96v
6 7.34v
7 1.32v
8 9.55v

I was under the impression that all pins but 4 (0v) and 8 (about 9v) should be reading around 4.5v So it seems like something is definitely amiss
SW3 is set so 1 is ON and 2 is OFF
SW4 is set so 1 is OFF and 2 is ON

Appreciate any insight

 

[JFurgie]

Bump

 

[Mcknib]

Looks like IC2.2 is the main problem with only a low output at pin 7 and a large input at pin 6 and a low input at 5 which should be VREF

Worth checking your VREF source the voltage divider at R12 and 13 junction albeit you do have it on most pins of the op amps so I'd expect that to be ok

I'd also take voltages with the op amps out of socket before trying another one in IC2

If it worked and you haven't done anything to the circuit then somethings failed, by the looks of it half of IC2

 

[phi1]

Also, what’s going on at the pin 3s is that the pin is at 4.5v, but likely the input impedance of your meter is 1M, so it forms a voltage divider with the 1M resistor from vref and only reads at half the actual voltage. A meter with 10M input impedance would show near 4.5v. (Chuck d bones pointed this out on another thread and this is the same situation).

 

[JFurgie]

Thanks both of you for the info!

I checked the voltage split at R12 and R13 and it seemed like it was working just fine, so then I checked the voltages of the sockets and was getting 0V on pins 1, 2 and 4, about 2.3V on pin 3, about 4.7V on 5, 6, and 7, and then about 9.5V on pin 8 for both chip sockets. I replaced IC2 with a new 4580 and I now get voltages much closer to 4.8V on pins 5 and 7 and on pin 6 I still see a voltage about 7.32V with switch 2 set to 1 off and 2 on. Despite returning the voltages to IC pins 5 and 7 to expected range the low level issue persists and unity gain is still just past 2 o'clock on the volume knob, maybe that's where unity is on this circuit? I've tried using other power supplies and cables to be sure it isn't a problem outside of the pedal and the results were the same so I'm fairly sure its an issue within the pedal somewhere

 

[Mcknib]

Just to be clear your pedal worked fine then you lost output level without doing anything to the circuit does it do the same in all switch positions on both overdrive and distortion

 

[music6000]

Put both dip switches exactly the same for both channels,
You are clipping different diodes or none which will change Gain & Volume structure.
If you notice a big difference between channels at the same settings then you have an issue.
Curious, Your Knob's have not slipped on the shaft giving you a false reading?

 

[JFurgie]

So I've done some further testing and here is what I found: for all these tests all knobs were at 12 o'clock for both channels and I also found that the level between the two sides was the same when switching between them. All dip switches off gives basically unity gain, turning on any of the switches (dip 1 on both channels, dip 2 on both channels, 1 and 2 together on both channels) results in a noticeable level reduciton with unity now around 2 o'clock. I also checked to make sure the knobs hadn't slipped. I'm going to check my wiring as well to make sure it's all good, maybe this is exactly how it's supposed to function, but I could swear it wasn't that noticeable of a volume drop between dip settings before.