Switchable Hi-Z input impedance, how ? - Page 24 - diyAudio
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Old 28th July 2012, 04:18 PM   #231
tinitus is offline tinitus  Europe
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small trafo for the LEDs have now found a new home

and btw, it will have its own mains fuse, so that it dont take out the whole amp in case of errors

which is also part of my point with having both solid state and tube curcuit
should a tube fail, or in need of being replaced, it will still be a fuctional preamp

still need parts for the regulated +/-20V
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Old 29th July 2012, 09:29 AM   #232
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trying to rethink my curcuit/function layout

first, the tone control
I suppose it would optimally have a buffer on both input and output
despite the fact thats it means adding further curcuits
and that its best not to place any att in between

buffers will be placed together with the control knobs
all mounted on a small bord behind the front plate
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Old 29th July 2012, 11:07 AM   #233
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and, thinking about a rotary switch after the first gain stage, with a direct out option
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Old 29th July 2012, 11:19 AM   #234
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problems
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Old 29th July 2012, 01:13 PM   #235
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and a possible new front for the changed layout
good thing Im slow, sometimes
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Old 29th July 2012, 11:33 PM   #236
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3P4T rotary switch
could be I have solved it now

pos 1 is first gain stage direct to output

pos 2 involves the tone control (toggle bypass for fast tone defeat)

pos 3 involves tube stage output

pos 4 input direct to tube stage output
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Old 30th July 2012, 06:42 AM   #237
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Quote:
Originally Posted by tinitus View Post
3P4T rotary switch
could be I have solved it now
shoot, no, not quite so simple
maybe better go back to the one with all bypass toggle switches
or a combination
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Old 30th July 2012, 03:06 PM   #238
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have found a 4PDT toggle switch with ON/ON/ON switching that might give what I want
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Old 31st July 2012, 12:08 AM   #239
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man, thats a tricky one

its a 4P ON/ON/ON
but with jumpers made a DP3T
read that jumpers are external and may be cut to make it 4PDT
I do need at least 3P because of the LEDs
but maybe the last 4th pole could work with leaving one of the jumpers
which would make it a mixed 4PDT/3P3T hybrid, or whatever aint switches just a lot of fun
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Old 31st July 2012, 08:27 AM   #240
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and the 4P switching with both jumpers cut

it gives 3 options
and able to 'create' complicated connections
or in other words, it can do signal in/out switching and bypass at the same time
and still have a free pole for LEDs
now I only need to figure out what is the reality
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