Half 12AU7 doesnt work, maybe.

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Faber
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Posts: 7
Joined: 01 Mar 2016, 10:03

Post by Faber »

Hi all!
Is it possible that only half of a tube doenst work?

The tube is a new JJ ECC82 running at 12V. The heaters are connected in series, pin 9 unconnected. Both sides light up.

I was building my circuit and with the first triode (1-2-3) as first gain stage was all ok, with the signal coming out and all.
When I connected the second triode (6-7-8) as second gain stage nothing happened.

I rechecked wiring and all but to be sure I've rebuild the circuit using the second triode as first gain stage. Nothing.

It's still on breadboard and if I move the jumper wires from 6-7-8 and connect them to 1-2-3 the gain stage is working.
For more info:
plateR: 100k
catR: 680R
GridLeakR: 1M

Thanks all.
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User avatar
Faber
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Posts: 7
Joined: 01 Mar 2016, 10:03

Post by Faber »

Edit: if I disconnect pin8 while always using 6-7-8 triode, signal goes through, but not amplified. If I connect pin 8 it's muted.
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