super hard on- stuck on full

[Bricksnbeatles]

Hey everybody, I'll be brief. I built a sho clone. I wired it up and after testing it I find that the volume knob does nothing... It gives plenty of boost, so it's essentially acting as full up regardless of how much the knob is turned. Any suggestions as to which connection could be causing the problem? i used this diagram

[mojokorn]

Sounds like you're operating in saturation.  This would most likely come from the Vs not being high enough.  Maybe the G3 pot is wired wrong.  Honestly, I always struggle a bit analyzing board layouts, I do well with schematics.  If you can post a schemo, I'm glad to have a closer look.

[J0K3RX]

If it lasts for more than 4 hours call your doctor, immediately!

[mth5044]

And that SHO on full blast is not fooling around. Hope your ears are alright! triple check your pot wiring

[mojokorn]

Also, not sure how Gain 1-3 are connected to the ckt based on this diagram.  The schemo would show it.

[Bricksnbeatles]

Sounds like you're operating in saturation.  This would most likely come from the Vs not being high enough.  Maybe the G3 pot is wired wrong.  Honestly, I always struggle a bit analyzing board layouts, I do well with schematics.  If you can post a schemo, I'm glad to have a closer look.

I don't quite understand what you mean by operating in saturation, but if you mean that the amp is already at the point of saturation, then that isn't the case, I tested it out with my ac 30 with the preamp level at 1 and the master at 3 so it wasn't at breakup. I'm sure that it's the pot bc it's supposed to crackle when you turn the knob and that didn't happen either, so the pot isn't doing anything.

And that SHO on full blast is not fooling around. Hope your ears are alright! triple check your pot wiring

I double and triple checked all the wiring and it all looked good, but I'll reflow the connections for the pot to try

Also, not sure how Gain 1-3 are connected to the ckt based on this diagram.  The schemo would show it.

gain 1 goes to lug 1, lug 1 bridges to lug 2 and then lug 3 goes to gain 3

[mojokorn]

Is the circuit always operating with distortion?  If so, that's saturation of the transistor (assuming it's a JFET).  Make sure your testing it with a clean sound on the amp, so any effect you hear is coming from the circuit.  Schemo?

[PRR]

> volume knob does nothing

Volume (optional on that diagram!) or Gain??

If Volume, you didn't tie the bottom (lug 1) to ground.

Or you did, but the joint is bad.

Or the pot is cracked inside.

[Bricksnbeatles]

> volume knob does nothing

Volume (optional on that diagram!) or Gain??

If Volume, you didn't tie the bottom (lug 1) to ground.

Or you did, but the joint is bad.

Or the pot is cracked inside.

I meant gain, I didn't even think about the confusion I may have caused (on my pedal I'm labeling it as volume because it's a boost pedal so yeah, I meant gain tho. Glad I could clear that up. I'll take gut shots tomorrow evening.

[PRR]

If the Gain knob don't work, there's a short across the pot.

As Gain pot 3 and BS170 Source should go to each other and *nothing* else, that's a small area to inspect.

[mojokorn]

"gain 1 goes to lug 1, lug 1 bridges to lug 2 and then lug 3 goes to gain 3"

Ah, I think I see the issue...

Lug 1 to Lug 3 is the full resistance of the pot.  Lug 2 is the wiper.  Hence, Lug 2 and Lug 1 (or Lug 2 and Lug 3) need to connected in the ckt.  Try putting the wire from Lug 2 on Lug 3 and remove Lug 3 altogether.

[mojokorn]

If the gain operates backwards, then use lug 1 and 3 instead.

[bloxstompboxes]

If it lasts for more than 4 hours call your doctor, immediately!

I have to admit that post was not lost on me JOK3RX, lol.

[garcho]

"gain 1 goes to lug 1, lug 1 bridges to lug 2 and then lug 3 goes to gain 3"

Ah, I think I see the issue...

Lug 1 to Lug 3 is the full resistance of the pot.  Lug 2 is the wiper.  Hence, Lug 2 and Lug 1 (or Lug 2 and Lug 3) need to connected in the ckt.

not positive, but I'm fairly sure he means that lug 1 and 2 are soldered together, rendering the potentiometer a variable resistor, which makes sense if it's 'gain' control. double check that those two lugs are indeed soldered together, or the variable resistor won't be variable.

maybe just bad wiring? it's (not) shocking how many different problems can result from near-microscopic wiring mistakes, meandering whiskers, cold joints, etc. i hate vero/strip board for many reasons but one of them is how easy it is to bridge traces after cutting them. maybe gain 1 & 2 aren't sitting at 0V. maybe the trace on the bottom isn't cut 100%.

buy a cheap multimeter if you think you might build another pedal or two.

[mojokorn]

"not positive, but I'm fairly sure he means that lug 1 and 2 are soldered together, rendering the potentiometer a variable resistor"

Yes, true.  Ignore my previous post.  It was a bit late last night... that's my story and I'm sticking to it 

[mojokorn]

Is it me, or is the black wire just below Gain 1/2 connection shunting the 5k1 resistor?  Maybe, I'm reading it wrong.

[duck_arse]

just you. there's a cut under the long 100k.

[stallik]

Provided the cuts have been made (correctly). Forgive me if this is obvious but the red squares on the vero layout indicate that the track has to be cut at that point.

[mojokorn]

Provided the cuts have been made (correctly). Forgive me if this is obvious but the red squares on the vero layout indicate that the track has to be cut at that point.

Thanks for the clarification.

[Bricksnbeatles]

ok so it was just a little thread of metal on the lug on the pot was shorting out against the enclosure, but now I'm running into another problem, its super loud at 0, then it drops down near unity almost instantly later, so the pot is wired backwards, i switched the wires around but then the pot does nothing, so i went back to how it was and it works, but the taper is all wonky and backwards. I've wired many pedals with no problem, so i don't know why one of the simplest circuits I've done yet is giving me issues...