No sound in either channel (resolved)

Jimb0 · 2235

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Offline Jimb0

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on: January 25, 2020, 09:48:36 AM
Just finished building a Crack with Speedball. Voltages checked out okay but I am not getting any sound. I tried using both my laptop and desktop.

« Last Edit: February 07, 2020, 04:37:25 AM by Jimb0 »



Offline Jimb0

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Reply #1 on: January 25, 2020, 10:09:02 AM
N/m it's my Modi Multibit that stopped working.



Offline Jimb0

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Reply #2 on: January 25, 2020, 10:25:04 AM
Actually yes there is something wrong with the sound. It's very low and I can't get the volume to go up.



Offline Jimb0

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Reply #3 on: January 25, 2020, 10:32:01 AM
ok so i'm getting 1.7v at OB and OA




Offline Paul Birkeland

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Reply #4 on: January 25, 2020, 03:06:01 PM
At which OA/OB, the big board or the small board?  Are both tubes glowing?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Jimb0

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Reply #5 on: January 25, 2020, 06:08:20 PM
Yes both tubes are glowing and OA and OB on the big board

LED's light up on the small board and the two at the bottom but not on the big board
« Last Edit: January 25, 2020, 07:44:06 PM by Jimb0 »



Offline Paul Birkeland

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Reply #6 on: January 26, 2020, 06:40:07 AM
What DC resistance do you get between OA and OB and ground on the big board?  As always build photos can help too.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Jimb0

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Reply #7 on: January 26, 2020, 02:04:46 PM
OB and OA reading infinity. Ground is reading 40 ohms.

Pics
https://imgur.com/a/eYBPLEj



Offline Paul Birkeland

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Reply #8 on: January 26, 2020, 02:51:15 PM
If you pop each wire out of the big board, you can take it all the way out of the amp, then just temporarily solder the 3K resistors onto the end of those wires.  It would be helpful to know if the amp works under those conditions.  Also, are the voltages on the small boards OK?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Jimb0

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Reply #9 on: January 27, 2020, 07:35:50 AM
I no longer have any 3K resistors to test it, is there another way? I'll recheck the voltages soon



Offline Paul Birkeland

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Reply #10 on: January 27, 2020, 07:40:19 AM
I would obtain a pair of 3K resistors so that you know if the amp is otherwise working without the big Speedball board.  This is what I would do if I had your amp on the bench for repair.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Jimb0

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Reply #11 on: January 27, 2020, 08:27:08 AM
Will do PB



Offline Jimb0

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Reply #12 on: January 27, 2020, 08:52:13 AM
Do I need the 22.1 KR ½W resistors as well?



Offline Jimb0

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Reply #13 on: January 27, 2020, 09:11:12 AM
OA and OB on the small board is 72v

OA and OB on the big board is 2v

B+ is at 217 on the big board



Offline Paul Birkeland

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Reply #14 on: January 27, 2020, 10:40:27 AM
You can leave the small board in and just tack the 3K resistors onto the wires poking up that would hold the big board.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man