microphonics in ODS preamp section

[lpplayer]

I have a Ceria Tone none HRM in for repair issues. There is a GREAT deal of noise, and microphonics from the first preamp tube. I have ran thru the basic drill of tests such as using a know good tube that is very quite. when any stray (hand test) at the front controls by volume and switchs as well at the tube it gets crazy. I can see many reasons in the design with grid loads and switching. anyway can someone tell me if this is the norm for this type of amp

Thanks

[sonicmojo]

I've had a Ceriatone Bluesmaster HRM and (partial Ceriatone parts) OTS 183 model which follow a similar design pattern. I haven't experienced the type of issue you are describing with either noise or microphonics of this sort. Pics would help so we could see if there is anything obvious.

[lpplayer]

I found the issue. Who ever built it used poly type caps in the switch area, with all the AC's floating as they do in this amp switched out to disc and problem solved. Thanks guys

[cornel moldovan]

Do you think that HAD covered with goop that part of the b oard accidentally? You can identify the source of the microfonic noise using the hammer test...take a drumstick as you hold a pencil in your hand and kick the preamp 's caps one by one until you find the source of noise... may be even the first tube in the chain..SELMER amps had a special type of noval tube socket with rubber suspension for the first stage to avoid the mechanical vibrations transmitted thru the chassis ...usually ceramic disc caps are microphonic..my experience in high gain overdrives tells me this.

[lpplayer]

Well this one was a NON HRM, I think they call it a bluesmaster ? the sorce was again the cluster of caps/ resistors at the switch on front. The poly cap was amping the A/C from the volume control back to tube. In 32 years of doing this I had never seen one of these kit amps