Switchable Hi-Z input impedance, how ? - Page 58 - diyAudio
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Old 1st May 2013, 07:35 PM   #571
tinitus is offline tinitus  Europe
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Quote:
Originally Posted by Nigel Goodwin View Post
Notice in particular the value of R11 - does it's placement remind you of anything?.
sure
I suppose its there because the curcuit have a bypass switch
needs to be there not to leave the curcuit 'open', and unloaded

yeah, I know Kreuzer's site, and his work, and a some others
I suppose his preamp from 2002 is designed for acoustic bass

anyway, Im not building a preamp...yet
Im only testing my 2SK170 jfets
and those old Motorola BC547 I happen to have too
there really isnt a lot more to it than that

and Im testing how it works with plug in boards
in the end I hope to have one big mother board with power supply lines
and everything else is made of small plug in boards

thats basicly the idea
no need to rush it...the longer it takes, the more fun we have
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Old 1st May 2013, 07:47 PM   #572
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Quote:
Originally Posted by tinitus View Post
yeah, I know Kreuzer's site, and his work, and a some others
I suppose his preamp from 2002 is designed for acoustic bass
Why would you think that?.
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Old 1st May 2013, 08:06 PM   #573
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because they needed it
there were no preamp for acoustic bass at the time
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Old 1st May 2013, 08:25 PM   #574
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btw, need to practice every day
so right I use this dodgy setup
its the 2-channel BJT buffer
and my first single jfet hi-z input
not the best, but ok for now
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Old 2nd May 2013, 06:42 AM   #575
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drawing with new 2-channel att pot, and adjustable bass cut in one channel(just to try it)
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Old 2nd May 2013, 07:40 AM   #576
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but maybe this is m ore like in my 'ballpark'
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Old 2nd May 2013, 08:11 AM   #577
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Quote:
Originally Posted by tinitus View Post
because they needed it
there were no preamp for acoustic bass at the time
No real difference for an acoustic preamp to an electric one (apart from higher input impedance), and there's certainly no reason to assume that preamp was for acoustic, quite the opposite.

If it was intended for acoustic bass it would have said so, yet it quite clearly refers to it as a bass preamp.
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Old 2nd May 2013, 08:15 AM   #578
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Old 2nd May 2013, 08:25 AM   #579
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this looks more like it
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Old 2nd May 2013, 09:29 AM   #580
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...or adjustable cap size
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