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Old 14th August 2002, 08:46 AM   #1
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Question Aleph P current sources?

Hi all,
Can I use in Aleph P current sources with
bipolar transistors (i have a lot of them)?
Will this change the sound performance?
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Old 14th August 2002, 01:48 PM   #2
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Hi Stefan,

yes you can. Wouldn´t know why not. As for sound differences it´s not so difficult to try both isn´t it.

I assume you´ll have to buy more fets than you need anyway

william
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Old 15th August 2002, 08:47 PM   #3
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For all I know they will sound better.
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Old 16th August 2002, 08:46 AM   #4
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Thanks, mr. Pass!
I'll try and if all is OK I'll post schematics here.
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Old 16th August 2002, 10:30 PM   #5
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Default Simplified schematic - how will work?

Here is simplified schematics for Aleph P
with bipolar current sources.
I still didn't made it and I need your opinions.
Do you think this will work well?
Attached Images
File Type: gif aleph_p_m.gif (11.4 KB, 691 views)
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Old 17th August 2002, 09:50 PM   #6
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Your input source is going to see some DC, so you might
consider caps for that. Also, some nice caps across the
Zeners will take out some noise. Maybe a few hundred
ohms in series with the transistor bases to keep them
from loading down the reference when they saturate.
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Old 17th August 2002, 10:04 PM   #7
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How would it affects the circuit if feedback resistors R11 and R14 would be removed? I mean, is there a way to get rid off the input coupling caps?
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Old 19th August 2002, 06:50 AM   #8
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I think that it's too dificult to make in this circuit.
In all cases input capacitors are simplest and safest way.
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Old 19th August 2002, 06:58 AM   #9
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Quote:
Originally posted by Peter Daniel
How would it affects the circuit if feedback resistors R11 and R14 would be removed? I mean, is there a way to get rid off the input coupling caps?
I would try connecting R11 *after* C2, and R14 *after* C3. That would give you AC feedback only, but I would expect the circuit to auto-equillibrate with the input gates drifting to ground. Mr. Pass?

Jan Didden
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Old 19th August 2002, 08:03 PM   #10
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The Gates have to be held at a positive potential or
the gain Mosfets will shut down, so some kind of DC
bias for them is required, or use a negative supply
rail instead of ground for your negative current
sources.
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