One LED out, audio only on R channel (passed resistor/voltage checks) [resolved]

[Crackawaka]

Hi all,

I finally got around to building my Crack! I'm an experienced builder, having built several amps and countless cables so far. Resistance check passed, voltage too (although see below for values), both tubes light up (both halves of the 12UA7 and the 6080 are lit). After discovering the issue, went back and checked all joints (I solder with a magnifier AND wear glasses, lol). Voltage:

1: 82
2: 167.9
3:0
4: 167.9
5: 152.5
6: 0
7: 105.9
8: 0
9: 151.8
10: 0

I'm attaching a picture of the socket in case that's helpful. Thanks in advance for any assistance! The R channel sounds great, can't wait to hear the L!  ;D

 

[Paul Birkeland]

Can you carefully measure the voltage at A2 and A3?

-PB

 

[Crackawaka]

Can you carefully measure the voltage at A2 and A3?

Yessir!

A2: 0
A3: 12.12

Thank you!

 

[Paul Birkeland]

The LED at A3 is open.  You can wire a jumper in between A8 and A3 to get up and running, or replace that LED.

 

[Crackawaka]

The LED at A3 is open.  You can wire a jumper in between A8 and A3 to get up and running, or replace that LED.

I'll try jumping them, but question: Would it be okay to go from the functional LED's lead, close to A8, or does it need to be soldered right on the terminal (it's a tight space there already).

EDIT: Also, if that works, does that degrade the quality of sound (if it works, am I getting any degradation of sound and should probably look to replace the LED down the line?)

 

[Paul Birkeland]

It doesn't degrade the quality of the amp.  Trying to solder a wire to the lead of the working LED may damage that LED.

 

[Crackawaka]

That did it! Thank you for the help!! It's sounding FANTASTIC! I'm going to live with it for a couple of weeks before building the Speedball kit for it!