Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: FS on January 31, 2011, 04:57:30 AM
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Hello,
I am new here, and I am a newbie to DIY audio as well...:-)))
I am turning to you guys for help with my Crack build. The resistance check of the circuit was OK. When I put in the tubes and switched it on, only the 6080 would glow, the 12AU7 would not. My first assumption was that maybe the tube does not have to show a visible glow. Therefore, I proceeded to the voltage checks and got the following voltages:
Terminal Voltage expected Voltage measured
1 90 0
2 170 0
3 0 0
4 170 0
5 90 0
6 0 0
7 100 53
8 0 0
9 100 55
10 0 0
11 0 0
12 0 0
13 170 155
14 0 0
15 185 166
20 0 0
21 206 175
A1 90 0
A2 0 0
A3 1.5 0.14
A4 0 0
A5 0 0
A6 90 0
A7 0 0
A8 1.5 0.14
A9 0 0
B1 90 0
B2 170 137
B3 100 55
B4 90 0.1 - 0.3 (fluctuating)
B5 170 157
B6 100 56
B7 0 0
B8 0 0
I would appreciate any help with this as I have re-checked all wires and they seem OK to me. Should the 12AU7 exhibit a noticeable glow? Could that tube be broken?
Thanks very much in advance.
Falko
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Falko,
You have a PM to keep me from embarrissing myself on an amp I don't have the schematic for.
12AU7s don't glow much. Try a dark room.
Your incoming B+ (high voltage) on the 6080 is low. It is nonexistent on the 12AU7.
More later, less sooner.
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Hello Crack-aficionados,
I would like to close this thread as my headphone amp is working now, thanks to the great help that I received from Grainger, one of the tireless and selfless volunteer support specialists in this forum...:-)))
And I just wanted to repeat my sincere thanks to Grainger for the immediate response to my question and all the help with troubleshooting my Crack build.
His willingness to help and to share his expertise made this a really easy ride for me...Thanks also to the Bottlehead team for the nice kit, which was spot on for a DIY newbie...:-)))
Now I am off to more listening....
Have a great evening!
Falko