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Post by montanaamper on Mar 13, 2006 1:23:45 GMT -5
I purchased a Crate GHX-1200H on ebay it arrived with a problem. It has two channels one clean one distortion. The clean channel is quite but the distortion chanel has a high pitch/ hum noise when only on 2 turing it up past that is usless as the noise is horrid. I think it may be AC noise and the transformer does look discolored like it has over heated. But the clean channel works perfectly so I'm not sure if that is the problem. Does anyone know were to find amp transformers? Specifically for a 120 watt crate amp head. Or have a suggestion as to what could be the problem and how to fix it? Thanks.
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Post by UnklMickey on Mar 13, 2006 9:58:28 GMT -5
...the transformer does look discolored like it has over heated. But the clean channel works perfectly so I'm not sure if that is the problem. .... i think your reasoning on the clean channel is on target. the transformer is probably not the problem. it seems like the problem is in the distortion channel only. without a schematic, i wouldn't be able to even guess where to start. unk |
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Post by sumgai on Mar 13, 2006 19:24:40 GMT -5
monty,
What you described is a common sign of a microphonic tube. Do this: swap the first two of the smaller tubes in the lineup - they should be either 12AX7's or a 7025.'s Power up the amp - the noise should now be in the clean channel, and the distortion channel should be OK.
Am I correct?
sumgai
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Post by UnklMickey on Mar 13, 2006 19:48:46 GMT -5
sumgai,
check your messages.
unk
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Post by sumgai on Mar 15, 2006 20:33:07 GMT -5
D'oh!!
It's solid state. I somehow saw the word "transformer", and I was instantly catapulted into the tube world.
And no, the landing was not soft..... someone had the kindness to give me a gentle wake up call, but I still have this sickly red-faced, embarrased feeling.
How do I make up for this?
sheepish sumgai
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