Voltage check question...

[trantor5]

Hi Folks - new Bottleheader here, just finished building my first crack. Resistance checks all pass. Voltages looked good aside from 5,7 and 9 which were off (measuring ~147ohm for all three above) from the manuals range of 90v - 115V. Does this look right? Both tubes light up but havent tried plugging in headphones yet - thought i would double check.
full voltage test numbers:
1 - 56
2 - 162.9
3 - 0.05
4 - 163.8
5 - 147.7
6 - 0
7 - 147.7
8 - 0
9 - 146
10 - 0

thanks!~

 

[trantor5]

alright couldn't wait. Plugged in the headphones and...beautiful music! all good so far. sounds absolutely amazing! Thank you Doc and team - the instructions were super easy to follow. here is a view of it in action... cheers!

 

[Paul Birkeland]

You HAVE NOT passed your voltage checks and SHOULD NOT listen to or use your amp.  Continued use of your amp like this is very likely to damage the amp and/or headphones.

Again, your amp did not pass the voltage checks.  It is not working. 

 

[trantor5]

yikes. thanks Paul - stopped immediately and rechecking everything today..... any thoughts on where I would focus the troubleshooting?

 

[Paul Birkeland]

Do both halves of the 12AU7 glow?  Do both socket LEDs glow? (If they don't, don't mess with them just yet)

 

[trantor5]

Both halves of the 12AU7 glow, both leds light up as well. Checked all solder connections and rectifier directions - looked ok. then let the tubes warm up for a few minutes this time (had not done this for the previous voltage check) and rechecked voltage - looks better now:
1- 82.2
2 - 171.5
3 - 0.03
4 - 171.1
5 - 88.6
6 - 0.04
7 - 106.9
8 - 0.00
9 - 110.3
10 - 0.03

 

[Paul Birkeland]

That's a working set of voltages.  If you did nothing between your last voltage check and getting this set of voltages, you have at least one loose connection in the amplifier that you need to address.

I know this is not a tube warm up issue because you had ~140V DC at terminals 7 and 9, which means the 6080 was all the way warmed up, and that takes a lot longer than the 12AU7 does.

 

[trantor5]

Thanks Paul - will try to hunt it down. I appreciate the help!