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Post by tennjed on Apr 18, 2009 6:05:27 GMT -7
In another thread on the RxJr forum I described a problem I'm having. The amp had not been used for about a month and had worked fine at that time. However, when powered on earlier this week no sound came from the amplifier. Volume controls, connections, and fuses were checked and were ok.
After powering on the two EL84 tubes have a dim glow. The rectifier has a dimmer almost imperceptible "glow". The two 12AX7 and the EF86 do not exhibit any indication that they are on.
When I described this to my Z dealer yesterday he said it sounded like the amp need re-tubing.
Now I'm a noob on amps having been an acoustic player exclusively. But it seems odd to me that all the tubes would fail simultaneously.
Is it a common or relatively common occurrence that all the amp's tubes could fail at the same time?
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Post by zdogma on Apr 18, 2009 15:19:13 GMT -7
Seems pretty odd to me. Probably a dead rectifier.
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Post by foxx on Apr 19, 2009 9:41:37 GMT -7
When my 5ar4 rectifier failed it caused the fuses to blow, no other problems with other tubes. That was with my Mazerati.
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Post by zdogma on Apr 19, 2009 10:12:53 GMT -7
When my 5ar4 rectifier failed it caused the fuses to blow, no other problems with other tubes. That was with my Mazerati. Yeah, I agree that's usually what happens, I wonder if this one is marginal and not supplying adequate power.
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Post by tennjed on Apr 22, 2009 9:40:20 GMT -7
Thanks to zdogma and foxx on the rectifier possibility.
There was a very faint "glow" equivalent to about 1 pixel from the rectifier. If it was "on" it couldn't have been doing much.
The amp has been taken to the dealer to have their amp guy look at it. Will make sure to ask them to take close look at the recitifier before anything else.
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Post by tennjed on May 4, 2009 15:51:39 GMT -7
It turns out the recitifier was marginal and not supplying adequate power.
Also the 12AX7 in V1 was frosted.
Perhaps the failed tube in V1 contributed to the "silent' amp?
Anyway... it is no longer silent. ;D
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Post by zdogma on May 4, 2009 19:03:43 GMT -7
It turns out the recitifier was marginal and not supplying adequate power. Also the 12AX7 in V1 was frosted. Perhaps the failed tube in V1 contributed to the "silent' amp? Anyway... it is no longer silent. ;D Great. I have frequent failures with new production rectifiers. The Mullards last pretty well.
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