Teahead
Member
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- 1,375
I have a 2006 Cornell 18/20 Plexi Combo... link
A great sounding amplifier indeed, but so damn choosy about the first position preamp tube! I'm not saying it only sounds good with certain valves, far from it, the amp sounds great, if a little different, with both NOS and current production.
The problem seems to be with any tubes that are even slightly microphonic. I can use tubes in the PI position of the Plexi, or anywhere in my AC30, that cause lots of problems when used in v1 of the Plexi. These problems are usually odd noises like whines or crackles.
My question is, are all 18w Marshall type amps so choosy about the first tube? If so, why? Is it something to do with the amp having more gain than my Vox? I've been told short plate nos ECC83s would help, any opinions there?
Thanks.
A great sounding amplifier indeed, but so damn choosy about the first position preamp tube! I'm not saying it only sounds good with certain valves, far from it, the amp sounds great, if a little different, with both NOS and current production.
The problem seems to be with any tubes that are even slightly microphonic. I can use tubes in the PI position of the Plexi, or anywhere in my AC30, that cause lots of problems when used in v1 of the Plexi. These problems are usually odd noises like whines or crackles.
My question is, are all 18w Marshall type amps so choosy about the first tube? If so, why? Is it something to do with the amp having more gain than my Vox? I've been told short plate nos ECC83s would help, any opinions there?
Thanks.