Terminal 1 measures high in voltage test [resolved]

Universe Man · 1794

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Offline Paul Birkeland

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Reply #15 on: August 16, 2021, 01:24:15 PM
Can you see any printing on the tube?  I think you may have accidentally gotten a 12AT7.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Universe Man

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Reply #16 on: August 16, 2021, 02:32:28 PM
Can you see any printing on the tube?  I think you may have accidentally gotten a 12AT7.
I can make out a 6679, online it says that’s a 12at7. Problem solved(ish)! I guess the question now is what to do about it…

Regardless of if I’m getting a replacement 12au7, is it safe now to finally use with my hd6xx? I see that it’s higher output, but the headphones are fairly high impedance.



Offline Universe Man

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Reply #17 on: August 16, 2021, 02:56:49 PM
Can you see any printing on the tube?  I think you may have accidentally gotten a 12AT7.
Also, do the voltage readings seem good considering it’s a 12at7?



Offline Paul Birkeland

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Reply #18 on: August 16, 2021, 06:23:04 PM
You definitely can't use a 12AT7 in the amp.  You can contact replacementparts(at)bottlehead(dot)com to let them know you got a 12AT7 by mistake.  Including a link to this thread is a nice idea, along with your name and mailing address. 

The voltages at terminals 1 and 5 would be about what I would expect for a 12AT7. 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Universe Man

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Reply #19 on: August 16, 2021, 06:40:58 PM
You definitely can't use a 12AT7 in the amp.  You can contact replacementparts(at)bottlehead(dot)com to let them know you got a 12AT7 by mistake.  Including a link to this thread is a nice idea, along with your name and mailing address. 

The voltages at terminals 1 and 5 would be about what I would expect for a 12AT7.
Ok, I will take care of that.
Thank you for helping.