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Post by monotone on Dec 30, 2006 14:29:26 GMT -7
Howdy folks! I have a question that might end up in the "duh" folder but bare with me. As I was playing my 6545 and I felt the sound was getting worse after a while, a good few minutes of playing. So I checked the tubes if something obvious would appear. I softly tapped on the tubes to check for microphonics (with volume and gain turned up) - this is the 65 side - and the V1 tube was a whole lot noisier than the others. In fact, no other tube made noise at all. So "aha!" goes me and changes the tube (and throws the old one to trash bin, only to pick up again...). But I checked the other one as well and it has the same noise, same as every other tube I try. I had a few TADs, JJs and Sovteks lying around, no fancy NOS stuff. Having switched the tubes around I feel the problem went away but the microphonics are still there in V1. I've had the amp at home for a while so I haven't had a chance to play at normal volume levels. So, finally, my question - is this characteristic of the V1 tube position (it being the first gain stage) or is it a symptom of something else?
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Post by skydog958 on Dec 30, 2006 15:18:27 GMT -7
Just as a suggestion, you should post this in the Tube or Ask the Experts section, Myles can answer it for ya!
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Post by rhythmeister on Dec 31, 2006 14:18:49 GMT -7
I think the tube in V1 will always show the way your test shows because it is the gain stage pre-amp tube.
Interesting that you note the sound getting worse over time. My 6545 does this...but only when it is placed on top of the speaker cab. I'm convinced the vibration from the speakers causes the deterioration of the sound. When I put the head anywhere else, the problem goes away. There's definitely nothing wrong with my tubes as I've now replaced them all and cycled through both new and NOS tubes in all positions.
Cheers, B
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