Thread: Mike and Scott
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Scott Dorsey Scott Dorsey is offline
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Default Mike and Scott

gray_wolf wrote:
If you were designing a solid state guitar preamp for guitar, pedal steel and
fiddle for the cleanest possible sound what would be the maximum signal input
you would design for. I built some amps Using j-fets.My first stage would handle
1.0 Vrms, with a gain of 10.


That's probably enough. My tendency would be to crank the source voltage up
a little more so you can deal with a little more voltage swing. Somebody
will plug some crazy thing in there... two or three volts would be a good
thing to aim for and your front end won't be any more noisy if you move the
bias point up a little.

This worked well but I, later on, upped the power amp to 240 watts and felt I
could use a bit more front end gain and eliminate the master gain control for
low noise studio work.


That's a crazy amount of power. Yeah, back in the seventies people had crazy
backlines like that but these days I think it's more fashionable (and better
sounding) to have small amps and mike them into the PA.

It really doesn't matter much. I'll be 80 in February and will most likely never
build anything again. Still I like to think about what I could have done better.
:-) My gut tells me a +- 24 volt front end would be a start.


My feeling is that you can never have too much headroom, and if you don't have
high voltage rails you can always stick a couple 10M resistors into a pad on
the front end. Do it right and you get a higher impedance seen by the pickup
for free in the bargain. You get a little more noise but you have to balance
that.

Don't give up! Build something! Even if it's just a pad!
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."