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Old 5th March 2010, 03:14 PM   #1
ak4396 is offline ak4396  Germany
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Default 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
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Old 5th March 2010, 06:05 PM   #2
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Perhaps you should try it and see.

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Old 19th March 2010, 02:53 PM   #3
ak4396 is offline ak4396  Germany
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Default 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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Old 19th March 2010, 04:12 PM   #4
h_a is offline h_a  Europe
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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
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Old 19th March 2010, 05:42 PM   #5
Ipanema is offline Ipanema  Malaysia
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How about power D1 as current source amplifier?
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Old 19th March 2010, 07:06 PM   #6
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Quote:
Originally Posted by h_a View Post
The usual: high transconductance with low capacitances
Actually, the circuit is pretty tolerant of capacitance.

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Old 20th March 2010, 07:51 AM   #7
h_a is offline h_a  Europe
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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
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Old 22nd March 2010, 12:57 PM   #8
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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
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Old 29th April 2010, 06:42 AM   #9
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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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