Switchable Hi-Z input impedance, how ? - Page 48 - diyAudio
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Old 9th March 2013, 08:38 AM   #471
tinitus is offline tinitus  Europe
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this variations sounds 'promising'... different... and feet tickling
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Old 23rd March 2013, 08:48 PM   #472
tinitus is offline tinitus  Europe
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this version is better, and works ok, for the moment
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Old 7th April 2013, 12:19 PM   #473
shanx is offline shanx  Canada
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Hi tinitus, looking at the blend balance control and wondering if you consider to add some signal filtering at that stage? Maybe look at rolling off some of the real low frequency to the mid tweeter stage, and cutting some high freq to woofer stage. Not sure if you plan to have EQ past the first two or not, so just suggestion..
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Old 7th April 2013, 01:44 PM   #474
tinitus is offline tinitus  Europe
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hello shanx
been quite happy playing though the latest shown version

but removing a hifi preamp/buffer for other purpos have shown that its time to work on that buffer output

I am now driving my poweramps directly with just a single jfet boz
no gain control or any other att
only the bass guitar onboard att pot
the gain is excessive I can barely touch it..its pretty exstreme
and its only with passive pickups
needless to say, a bit noisy too

so Im now working on a simple BJT buffer with a single BC547
just to try it

looking at another alternative 'angle'
it also shows that I can easily drive a 3way active crossover with a simple jfet

hopefully soon will work on the curcuits I got from Juma
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Old 7th April 2013, 07:46 PM   #475
tinitus is offline tinitus  Europe
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Quote:
so Im now working on a simple BJT buffer with a single BC547
just to try it
wow, I have a working power supply
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Old 8th April 2013, 02:28 AM   #476
shanx is offline shanx  Canada
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I am glad you like playing through it. Sometimes better to have without tone circuit, depending on your preference of course. I am still working on my jfet preamp, and agree that for bass you could easily overdrive the stages..but which for guitar is not necessarily a bad thing! But I am still trying some simple tone shaping methods with interesting results. Good luck on the BJT build and keep us posted.
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Old 12th April 2013, 04:08 PM   #477
tinitus is offline tinitus  Europe
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Quote:
Originally Posted by shanx View Post
Good luck on the BJT build and keep us posted.
it works but distorted
I suppose bias is too low
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Old 13th April 2013, 06:38 AM   #478
tinitus is offline tinitus  Europe
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but was expected....

could it be too low base turn-on voltage
and maybe I need to 'isolate' the input att pot

on the positive side...noise is much lower with the buffer
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Old 13th April 2013, 12:55 PM   #479
tinitus is offline tinitus  Europe
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small adjustments
and now with 100K 'pots'

wow, what a change
no audible distortion
straight clean sound
plays fast


but now I got a little trafo humm in the speakers
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Old 14th April 2013, 07:19 PM   #480
tinitus is offline tinitus  Europe
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humm is annoying
trying a 4mH air core
takes the snerring
but there still a very deep humm

next project
a 'rail splitter'
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