D1 with high transconductance FET?

[ak4396]

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]

Perhaps you should try it and see.

😎

 

[ak4396]

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

 

[h_a]

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]

How about power D1 as current source amplifier?

 

[Nelson Pass]

The usual: high transconductance with low capacitances

Actually, the circuit is pretty tolerant of capacitance.

😎

 

[h_a]

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]

this might be of Interest http://www.diyaudio.com/forums/digital-line-level/154866-new-take-classic-pass-labs-d1-ess-dac.html
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]

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