D1 with high transconductance FET?

ak4396 · 5th March 2010, 03:14 PM

Hi,

Did some body tried a high transconductance FET like the IRF3205 (gfs = 44S) in the I/V stage. The IRF 510 sounds also better than the 610.
The 3205 have much more input capacitance. But I think this is not a problem in that kind of circuit.

Is it?

AK4396

Nelson Pass · 5th March 2010, 06:05 PM

Perhaps you should try it and see.

ak4396 · 19th March 2010, 02:53 PM

Hi,

I did some listening tests the 510 is still my favorite! The 3205 is not so bad maybe one step with the 610.

I have the 540 and 540N on my list.

I want to try some other parts.
What are the good values I have to look for?
Maybe low Vgs?

Thanks

h_a · 19th March 2010, 04:12 PM

The usual: high transconductance with low capacitances - but these keep coming together so it's as always a compromise

Low vgs and low rds-on are of no real interest.

Have fun, Hannes

Ipanema · 19th March 2010, 05:42 PM

How about power D1 as current source amplifier?

Nelson Pass · 19th March 2010, 07:06 PM

Quote:

Originally Posted by h_a

The usual: high transconductance with low capacitances

Actually, the circuit is pretty tolerant of capacitance.

h_a · 20th March 2010, 07:51 AM

Good to know! I thought the DAC in the D1 is current driving the fets, so the little output current may be happy to see lowish capacitances.

Have fun, Hannes

samoloko · 22nd March 2010, 12:57 PM

this might be of Interest A New Take on the Classic Pass Labs D1 with an ESS Dac
It Is Interesting that guy has excluded In final development the buffer stage

would anyone be nice and explain the purpose of 2,7 nF caps - what type Is best here, can I use 2,2 mkt

thanks

samoloko · 29th April 2010, 06:42 AM

any updates
Is irf510 still your winner
did you replace only I/V FET or both
are you using original schematic
what Is your out cap

5th March 2010, 03:14 PM	#1
ak4396 diyAudio Member Join Date: Feb 2008	D1 with high transconductance FET? Hi, Did some body tried a high transconductance FET like the IRF3205 (gfs = 44S) in the I/V stage. The IRF 510 sounds also better than the 610. The 3205 have much more input capacitance. But I think this is not a problem in that kind of circuit. Is it? AK4396

19th March 2010, 02:53 PM	#3
ak4396 diyAudio Member Join Date: Feb 2008	listening tests Hi, I did some listening tests the 510 is still my favorite! The 3205 is not so bad maybe one step with the 610. I have the 540 and 540N on my list. I want to try some other parts. What are the good values I have to look for? Maybe low Vgs? Thanks

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5th March 2010, 06:05 PM	#2
Nelson Pass The one and only Join Date: Mar 2001	Perhaps you should try it and see.

19th March 2010, 04:12 PM	#4
h_a diyAudio Member Join Date: Sep 2006 Location: Graz, Austria	The usual: high transconductance with low capacitances - but these keep coming together so it's as always a compromise Low vgs and low rds-on are of no real interest. Have fun, Hannes

19th March 2010, 05:42 PM	#5
Ipanema diyAudio Member Join Date: Jun 2004 Location: KL	How about power D1 as current source amplifier?

20th March 2010, 07:51 AM	#7
h_a diyAudio Member Join Date: Sep 2006 Location: Graz, Austria	Good to know! I thought the DAC in the D1 is current driving the fets, so the little output current may be happy to see lowish capacitances. Have fun, Hannes

22nd March 2010, 12:57 PM	#8
samoloko diyAudio Member Join Date: Jun 2006	this might be of Interest A New Take on the Classic Pass Labs D1 with an ESS Dac It Is Interesting that guy has excluded In final development the buffer stage would anyone be nice and explain the purpose of 2,7 nF caps - what type Is best here, can I use 2,2 mkt thanks

29th April 2010, 06:42 AM	#9
samoloko diyAudio Member Join Date: Jun 2006	any updates Is irf510 still your winner did you replace only I/V FET or both are you using original schematic what Is your out cap

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