Aleph P current sources?

stefan · 14th August 2002, 08:46 AM

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?

wuffwaff · 14th August 2002, 01:48 PM

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

Nelson Pass · 15th August 2002, 08:47 PM

For all I know they will sound better.

stefan · 16th August 2002, 08:46 AM

Thanks, mr. Pass!
I'll try and if all is OK I'll post schematics here.

stefan · 16th August 2002, 10:30 PM

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?

Nelson Pass · 17th August 2002, 09:50 PM

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.

Peter Daniel · 17th August 2002, 10:04 PM

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?

stefan · 19th August 2002, 06:50 AM

I think that it's too dificult to make in this circuit.
In all cases input capacitors are simplest and safest way.

janneman · 19th August 2002, 06:58 AM

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

Nelson Pass · 19th August 2002, 08:03 PM

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.

14th August 2002, 08:46 AM	#1
stefan diyAudio Member Join Date: Aug 2002 Location: Bulgaria	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?

14th August 2002, 01:48 PM	#2
wuffwaff diyAudio Member Join Date: Aug 2001 Location: Ingolstadt Germany	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 __________________ een ooievaar is geen konijn want zijn oren zijn te klein!

17th August 2002, 10:04 PM	#7
Peter Daniel diyAudio Member Join Date: Jul 2002 Location: Toronto, Canada	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? __________________ www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC

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15th August 2002, 08:47 PM	#3
Nelson Pass The one and only Join Date: Mar 2001	For all I know they will sound better.

16th August 2002, 08:46 AM	#4
stefan diyAudio Member Join Date: Aug 2002 Location: Bulgaria	Thanks, mr. Pass! I'll try and if all is OK I'll post schematics here.

17th August 2002, 09:50 PM	#6
Nelson Pass The one and only Join Date: Mar 2001	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.

19th August 2002, 06:50 AM	#8
stefan diyAudio Member Join Date: Aug 2002 Location: Bulgaria	I think that it's too dificult to make in this circuit. In all cases input capacitors are simplest and safest way.

19th August 2002, 08:03 PM	#10
Nelson Pass The one and only Join Date: Mar 2001	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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