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Barber Gain Changer Haaaalp

Started by fixxe, May 12, 2014, 12:42:36 PM

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fixxe

It's me...again ::)
http://www.barberelectronics.com/Gain_Changer_service_schematic.pdf
How can it be that I get a signal with an audioprobe on the input, but not on the other side of 56n, but instead crackling??
When I bypass 56n with a wire I get the same crackling...
I already reflowed the connections on the board and went through some vero gabs with a box cutter to eliminate possible shortcuts.
Bypass is working. I only get audio on the input rail. I connected Pin2 of the Volume pot to the upper right pin of the footswitch (madbean standard wiring), I hope this is right.
And I'm not too sure if i put the IC in the right direction.

midwayfair

Could be lots of things. No way to tell what went wrong just looking at the layout. We need voltages at least, pictures of both sides of the board (this is especially important on vero), and preferably a link to the schematic that layout is based on.

Please then reformat your top post according to the tech help rules.

fixxe


fixxe


fixxe


fixxe


oldhousescott

I hate to say it, but it looks like you made your board upside down (front/back). The drawings of the veroboard both with and without components are showing the top/component side of the board, not the trace side, even though the traces are displayed. Kind of confusing I know. Your trace cuts should be the flipped version of the bottom drawing, then stuff and solder the components and wiring connections exactly as shown in the top drawing.

fixxe

#7
Quote from: oldhousescott on May 12, 2014, 03:24:52 PM
I hate to say it, but it looks like you made your board upside down (front/back). The drawings of the veroboard both with and without components are showing the top/component side of the board, not the trace side, even though the traces are displayed. Kind of confusing I know. Your trace cuts should be the flipped version of the bottom drawing, then stuff and solder the components and wiring connections exactly as shown in the top drawing.

Are you sure? My traces are where they need to be I think :/
Looking at the copper side, my diodes are in the upper left corner, with 2 pairs of diodes divided by a cut, for example.

GermanCdn

Oldhousescott is right, you've laid it out backwards.  In IVIark's layouts, you're looking at the component side in all views, so you have to reverse the layout when you're cutting your trace (i.e. if a cut is four holes in from the left of the board on the components side, it is cut in four holes from the right on the trace side).  Your components layout should match on the non trace side.
The only known cure in the world for GAS is death.  That's my story, and I'm sticking to it.

fixxe


fixxe

#10
Didn't I do everything backwards, so it should be fine?
The layout goes In, then through 56n, then 3 spaces, then through 470K (with 2 cuts underneath it) to the third rail form below.
Mine does the same...

oldhousescott

The problem is the opamp. Its pins are flipped from where they should be for your board to work. You could clip out the opamp socket and solder the opamp directly to the trace side. You wouldn't be able to ever swap the chip, but hopefully, you'd never need to.

fixxe

Quote from: oldhousescott on May 12, 2014, 05:35:48 PM
The problem is the opamp. Its pins are flipped from where they should be for your board to work. You could clip out the opamp socket and solder the opamp directly to the trace side. You wouldn't be able to ever swap the chip, but hopefully, you'd never need to.

I just came to the same conclusion  ;D
Thanks, now it's working. The gain switch seems to give a huge amount of volume though. But maybe it's supposed to be this way?