Harbinger One - Vintage/Modern switch pop

[MAO]

I'm getting a noticeable pop the 1st couple uses of the Vintage/Modern switch. Same pop regardless of the starting position of the switch.

I had also been getting a pop with the Chorus/Vibrato switch, but adding a 10u cap between Volume pot lug 2 and the output seems to have solved that one.

I also added a 1M pulldown resistor at the input right on the stomp switch.

The stomp switch and Chorus/Vibrato switches are quiet. The vintage/modern is still popping.

Looks like skeeter had this same pop http://www.madbeanpedals.com/forum/index.php?topic=21836.15

Does anyone know the solution?

[midwayfair]

Put a pulldown on lug 2B of the vintage/modern switch.

Remove the resistor you added to the stomp switch. It's not doing anything helpful (just reducing your input impedance in modern) because the pop comes from DC leakage across C29 and/or C1.

There should not have been any DC on the volume pot (which is already its own pull-down resistor), and adding the capacitor would not normally be a way to fix that problem. It's not hurting anything but you may have a problem elsewhere. What else do you have in line with the effect while you're testing?

[MAO]

Thanks Jon,

Nothing else inline, just Les Paul, Harbinger, Amp.

I've since tried a 1M pulldown on lugs, 2B, 3B, and 3A, one lug at a time.  No improvement. But I did this with alligator clips.

As for the 10u at the output, I was also getting a pop with the Chorus/Vibrato switch, I assumed C5 and/or C6 was leaking. That pop went away after adding the 10u. I can easily short across that capacitor and see if the pop returns on the C/V switch.

And sorry, I didn't mention that the guy who owns this Harbinger (which I did build for him) had plugged in a 9v AC output adapter rather than DC, which I'm assuming is what shorted out the D6 zener. After replacing the zener, there was no other noise or hum and the pedal sounds fine otherwise...other than this switch pop. But maybe the AC voltage damaged some other caps or components?

Thing is, he doesn't recall there being any switch pops prior, but isn't positive either.

And last, the pop is less loud every time the V/M switch is toggled, but always loudest the 1st couple times after power is applied.   

I'll remove the Stomp SW resistor as you mentioned and solder in the 1M pulldown on 2B and report back. 

[MAO]

Improvement, I removed the said resistor and soldered a 1M from Switch 2B to ground.

It seems like the pop is now just a faint click. And the faint click is there no matter how many times I toggle the switch so I'm assuming I'm hearing the switch contacts. But it's livable, plus I don't see the need to use that toggle once it's set.

In fact, if I build another I'll probably just go with a hard wired modern mode as their is a slight volume drop in vintage mode. I don't really hear any mojo in vintage mode.   

Another thing I found, after adding the resistor I had some additional noise. Sounded like a loose connection. I tapped on a few caps and all were very noisy, then tapped on Q10 and had some wild feedback. I re-flowed the solder on that socket and then soldered Q10 to the socket. (Didn't want to risk damaging the pcb) I also soldered all the other transistors to their sockets to be sure no others were loose.

Seems like it is fine now.

I'll test it some more tomorrow and report back.   

[MAO]

Worked well, now there is just a faint click - if at all.

Thanks Jon and skeeter.

[skeeter]

Good to hear you solved the problem, I used a 2.2m resister , I cant remember where I read that value but it works ,a light mechanical click is better than a loud pop ,