Question for Randy & other electrical smarty type peoples

Help!I'maRock!

Mediocringly Derivative
One of the hazards of playing in hourly rehearsal studios in Manhattan is you get to play through a lot of roached out amps. You booked your rehearsal for the same time and day as you did last week, but today you're stuck in room 3 instead of playing through the cool shit in room 10. This is much of the reason I went to a pedal based distortion. Because I should be able to get a workable clean tone out of any amp and then add dirt from there.

One amp I play through regularly is a Bogner Shiva. This particular Bogner absolutely hates my tremolo pedal, a bantam box Catalinbread Valcoder. (There's a new Valcoder coming out this Spring. Mine is the old one.) When I turn the effect on, there's a large pop, the volume completely drops out, and everything goes to shit. Turn it off, no problem.

Now the many of you would say, "well, just don't use tremolo". This smiley is for you: :annoyed:

I had solved the problem by using my Z-Vex Super Duper at the end of my signal chain as an always on buffer. However, now I'm using the Super Duper to drive my new Skreddy Hybrid Fuzz Driver.

I brought my Ernie Ball MVP volume pedal to the last rehearsal in that room. For whatever reason, the buffer did not have the same effect.

Why would one pedal work and another not? Both send the signal through their circuit, and buffer the amp from the rest of the signal chain. Is there really that big a difference? Additionally, if i were to take a Boss pedal, say my LS-2 (which I'm not using in this project) and put it at the end, leaving it in that always on function, how would it's buffer be different?

Your thoughts greatly appreciated.
 
I found the schematics and had to think a bit about this.

http://music-electronics-forum.com/t36145/

Preamp

http://spinoo.free.fr/sloclone/Shiva preamp.png

Poweramp

http://spinoo.free.fr/sloclone/Shiva power amp.png

The strange part about this amp are the Opto Couplers in the circuit. In seems that they are using it for low noise switches hence when you use your tremolo, the opto's are working against the signal when it drops because of your tremolo, the opto's low noise switch kicks on. Those Opto's just cannot keep up with the tremolo therefore the issues you are experiencing cannot be fixed unless you use another amp or turn the tremolo off.
 
I found the schematics and had to think a bit about this.

http://music-electronics-forum.com/t36145/

Preamp

http://spinoo.free.fr/sloclone/Shiva preamp.png

Poweramp

http://spinoo.free.fr/sloclone/Shiva power amp.png

The strange part about this amp are the Opto Couplers in the circuit. In seems that they are using it for low noise switches hence when you use your tremolo, the opto's are working against the signal when it drops because of your tremolo, the opto's low noise switch kicks on. Those Opto's just cannot keep up with the tremolo therefore the issues you are experiencing cannot be fixed unless you use another amp or turn the tremolo off.

Wow! Thanks, Randy!

That explains why it doesn't like tremolo. But why does the SHO circuit eliminate the issue while the active buffered volume pedal circuit doesn't?
 
I suspect that the buffer in your volume pedal is prepot so when you lower your volume, the opto follows like the tremolo. Buffers only help to reduce line losses or help with impedance mismatch's. Volume pedals are vampires at tone and volume unless buffer equipped. Unsure about why the SHO doesn't. Could be floor noise that is unaudible to the human ear.
 
I suspect that the buffer in your volume pedal is prepot so when you lower your volume, the opto follows like the tremolo. Buffers only help to reduce line losses or help with impedance mismatch's. Volume pedals are vampires at tone and volume unless buffer equipped. Unsure about why the SHO doesn't. Could be floor noise that is unaudible to the human ear.

Who knows. I was hoping the buffered volume pedal would do the trick, but oh well. I'm going to try my BOSS LS-2 next time and see what happens. As always, thanks for your help. :thu:
 
Bypass-Looper-einfach.jpg


My question is this: I ordered most of the stuff I was missing for this passive loop, but forgot the two resisters for the led and the out socket. What would be the best values for those? Could I do without the one on the output? Sorry, the website didn't have a partslist or schem out there. Weird for them, but still.
 
It's been quite some time since I played through this amp again, but I played through it tonight in rehearsal. I went to show Smurfco the problem as expressed in the OP and the amp sounded just fine with the tremolo pedal and no buffer. Which is weird, because it was such a terrible issue before. It's been more than 6 months since we were in this room, so my guess is the amp was overhauled. It actually sounded great tonight.

I actually keep my Channel 2 on the board because of inconsistent amps like this one. It's weird how turning it on can solve most "popping" problems with amps, regardless of why the pop is there. Though now I may chance it...
 
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