Super-it FET question

[Bob]

Dose anybody here know which fet to use to replace the ones ia a Super-it
tube preamp. The old ones are noisey.

 

[Tim Schwartz]

Bob,

Do you mean that they are inherently noisy, and you would like to find
a lower noise part, or that they are defective and you need to replace
them? In either case posting what the original ones are would be
helpful to those of us who don't have a schematic diagram of the
Super-it, and (hopefully) get you a better answer to your question!

Have a great holiday,
Tim Schwartz
Bristol Electronics

P.S. (and again I don't know your product) are you sure its the FET's,
and not the power supply or tubes that are causing the noise?

 

[Asimov]

"Bob" bravely wrote to "All" (24 Dec 04 02:18:42)
--- on the heady topic of "Super-it FET question"

Bo> From: "Bob" <[email protected]>

Bo> Dose anybody here know which fet to use to replace the ones ia a
Bo> Super-it tube preamp. The old ones are noisey.

Fets tend to be noisier than transistors when used with medium
resistance signal sources because they are very high input impedance
devices and are better suited to voltage amplification instead of
current, like with transistors.

I haven't seen your circuit before but be aware that it might not
easily retrofit with a different fet type as these tend to be very
different from one another, unlike transistors. In any case, try
posting the generic part numbers and see if anyone can help you out.

A*s*i*m*o*v

.... I remember the 6SN7...