Don't worry, neither mosfet will give your dac any problem. As clearly explained by Papa himself here, measured effective input capacitance of IRFP240 is ~75pf when used as source follower. Hence, choosing IRFP240 for a 2W output is perfectly valid.
how's that ?
I'm always getting everything backwards
no gain , so no Miller pain ........ though Payton's Flying Choke Circus is funny ...... before first morning coffee
MoFo as Headphone Amp.
I connected my 55ohm OB-1's to the MoFo. Again, driven with the Aksa-Lender pre. Holy smokes, this amp can really kick it up on headphones! Very quiet, silent when no music playing. I calculate that it is capable of driving 1.8W rms into a 50ohm load if needed. The sound is very very good on a headphone. Even complex and loud speed metal sounds great.
I connected my 55ohm OB-1's to the MoFo. Again, driven with the Aksa-Lender pre. Holy smokes, this amp can really kick it up on headphones! Very quiet, silent when no music playing. I calculate that it is capable of driving 1.8W rms into a 50ohm load if needed. The sound is very very good on a headphone. Even complex and loud speed metal sounds great.
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any benefit to reference input and output ground to +V like in this buffer ?
OTA - One Transistor Amplifier
OTA - One Transistor Amplifier
I just tested the MELF resistor version of my preamp tonight and see that it can drive 51Vpp with still a nice profile and 0.013%THD. So this could be used to drive a Super MoFo with high Vcc, big beefy MOSFETs, and a huge heatsink (or water cooling) to 41Wrms. 
With 59V Vcc, the preamp is doing a nice job with 51.4Vpp:
With 59V Vcc, the preamp is doing a nice job with 51.4Vpp:
10K as gate stoppers ............ well , that even goes before my dislike of ECC83 for signals greater than mic level
hope that's mistake of person drawing that schematic ... though I've seen even bigger stupidities in HiEnd gadgets
...... and - after some searching through my files , I see same 10K value on 3 different versions/sources of same schm
what to say more ....
hope that's mistake of person drawing that schematic ... though I've seen even bigger stupidities in HiEnd gadgets
...... and - after some searching through my files , I see same 10K value on 3 different versions/sources of same schm
what to say more ....
Since the subject of gate stoppers has come up, I have a question about R2, 221 ohms. When I build tube amps I would normally use a carbon composition resistor which is non-inductive as grid stopper on a tube. Since I am not knowledgeable about transistors, is a metal film or carbon film ok on the gate of a mosfet?
ray
ray
the engineer commented the same error on other brand amplifiers
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On some locations in a circuit it makes a measurable (and possibly audible difference). I would not have believed it until I searched for the culprit that made H3 climb higher than H2 on my amp. In the critical feedback resistor, a carbon film vs metal thick film reduced H3 relative to H2. It’s not about thermal effects because I made a series parallel out of same metal thick film and effect is intrinsic to the material.
Initial discovery:
http://www.diyaudio.com/forums/anal...ender-preamp-40vpp-output-13.html#post5247095
Study of whether thermal or intrinsic effect:
http://www.diyaudio.com/forums/anal...ender-preamp-40vpp-output-19.html#post5251105
But for gate stoppers probably not a difference. However, I always use carbon film if given a choice where it’s not critical to have ppm stability of metal thin film.