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Old 26th April 2013, 03:20 PM   #531
tinitus is offline tinitus  Europe
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yeah, life is great, and could so much more fun, if only...
well, I can't help you with that, sorry
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Old 28th April 2013, 12:59 PM   #532
shanx is offline shanx  Canada
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On JMFahey's comments, I agree with all that he said. I still scratch my head when looking at the EVH 5150 amp! For a lot of reasons, maybe subjective but ''meltdown'' overdrive in the preamps on many later model tube amps is a bit tiring on my ears.

Tinitus, I would suggest again that for a bass pre, that a simple fet gain stage with attenuator then emitter follower out (to drive loads/passive filters etc) should be more than enough.
Building simpler, well constructed circuits IMHO are going to sound quite good, an ideal probably lost at Mesa engineering (and many many others) but an ideal of which many are followers of here on this forum. Simpler doesn't mean ''easier'', as JM pointed out with fets, you need to get the source biasing/drain current and gain right. Fets aren't plug and play.
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Old 28th April 2013, 01:03 PM   #533
tinitus is offline tinitus  Europe
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now working on a very nice distortion 'machine'

hey, Im not going to use any of these curcuits for very long...
but man, not long ago I didnt even know the words emitter, drain...or whatever
that is if its of any use to me at all
I guess only if its possible to learn from mistakes

but will soon leave this crap, and build other properly designed curcuits ...and thats a promise
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Old 28th April 2013, 02:15 PM   #534
shanx is offline shanx  Canada
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That's the point Tinitus, keep trying stuff, and ''mistakes'' are lessons learned. If you take some valuable knowledge away from it, great. Have fun! Better to try this stuff on low voltages when you are starting, If you blow a fet or 2 no big deal. But mistakes with high voltage tubes can be dangerous and harmful. An underrated cap or resistor can not only damage the circuit..but the builder as well. YOu need to know theory and foremost follow safe practices before starting on that.
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Old 29th April 2013, 11:39 AM   #535
tinitus is offline tinitus  Europe
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my BC547 buffer works now...no distortion machine this time, sorry
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Old 29th April 2013, 11:58 AM   #536
shanx is offline shanx  Canada
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Nice work!!
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Old 29th April 2013, 12:14 PM   #537
tinitus is offline tinitus  Europe
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thanks
I was a bit unsure whether I really needed a buffer at all
the jfet preamp seemed to work ok without
though it still had some issues with overdrive distortion

but with the buffer, no overdrive .... just gets insanely loud, and stays clean
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Old 29th April 2013, 12:15 PM   #538
AndrewT is offline AndrewT  Scotland
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Tin,
have you forgotten to show us the "other" biasing resistor that is not isolated by omitting the input capacitor.
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Old 29th April 2013, 12:25 PM   #539
tinitus is offline tinitus  Europe
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complete preamp

still waiting for the new attenuator
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Old 29th April 2013, 12:27 PM   #540
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Quote:
Originally Posted by AndrewT View Post
Tin,
have you forgotten to show us the "other" biasing resistor that is not isolated by omitting the input capacitor.
It's certainly biased FAR too high
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