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Post by Chris on Apr 10, 2016 13:38:08 GMT
Ok - I've had a ringing noise coming from one of a quad of Black Treasure 6CA7s. I put a multimeter on it then up and downed the bias on that valve which changed the noise coming from it but with a slight ringing still occurring. It seemed to get quieter at lower mV - say 240 up to 320mv then returned at the desired 390mv.
Is the valve knackered? There's no sign of this from any of the others and it's bloody annoying!
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Post by Eduardo Wobblechops on Apr 10, 2016 14:25:35 GMT
Is this from the valve itself or through the speakers?
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Post by Chris on Apr 10, 2016 14:41:55 GMT
From the valve itself
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Post by Eduardo Wobblechops on Apr 10, 2016 15:05:54 GMT
I'd replace to be on the safe side.
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Post by Chris on Apr 10, 2016 15:15:29 GMT
Damn. Thought so.
Don't know what to do then - a new quad is £250! and the other three seem OK.
Cheers Ali!
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Post by Eduardo Wobblechops on Apr 10, 2016 15:21:58 GMT
Yeah a downer.
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Deleted
Deleted Member
Posts: 0
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Post by Deleted on Apr 11, 2016 8:02:16 GMT
Chris - do you have a valve tester? If not, and given the price of a quad I'm more than happy to test them for you. I have an AVO CT160, an AVO Mark 3 and a Taylor 45C. I'm based near Oxford.
Craig
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Post by Chris on Apr 16, 2016 4:32:03 GMT
If you ever read this Craig then yeah,that would be great! Much appreciated.
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Post by Greg on Apr 16, 2016 8:53:59 GMT
Once you get the valves tested, you will be in a position to order a single replacement for the dud one because you will know the measurements that the supplier can use to replace to match the good ones, thus restoring a matched quad at minimum cost.
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Post by Chris on Apr 16, 2016 18:26:04 GMT
Think the problem there Greg will be the fact it's a Chinese supplier,also I'm going to end up with one much newer than the others. I've used the amp with 2 6CA7s and 2 EL34s but that doesn't sit right with me. Sounds good but the look annoys me.
Can see myself selling the three working ones for a good price.
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