[aphex944]

Just had my 5% efficient MOSFET(IRF510) zero-feedback amplifier built by a friend. Uses Black Gate output coupling, polycarbonate input coupling, and audio-grade Muse cap for power supply bypass.

Simply put, it sounds better than anything I've heard for headphones, and runs extremely hot

Very clear in detail, but also very mellow. Kind of a mix of tube sweetness and solid state detail.

Here are some pictures:

 

[morsel]

Woohoo, Aphex! I've always been a die hard MOSFET fan. Care to show us a schematic?

 

[Budgie]

I love mine too. I see you went with a switch mode power supply. I was going to give that a try with my next one,so I am glad to hear you like yours. Let us know how it sounds after the caps burn in.
A schematic would be great, if you can post one.

 

[was ist los?]

I too would like to see a schematic. I'm tempted to build a Mosfet based amp these days.

 

[aphex944]

Here's the schematic, we'll call this one the SolAmp(Sol Headphone Amp):

 

[morsel]

Very similar to the Szekeres:

 

[PeterR]

This one is a common source and has voltage gain, the Szekeres is a source follower.

 

[ECM]

how do you determine gain for an amp like this?

 

[Tomo]

Hi,

You should probably use bigger heatsinks. The original Szekeres amp draws less than 100mA/ch, but it gets too hot to touch with 5W heatsinks. Your amp draws like 600mA/ch according to your schematics. Right?

Ic = 625mA = 5V / 8ohms
Vs = 0.5V = 0.625A * 0.82ohms

Hey, you can calculate your Vgs from there, lol.

Just one thing I remember from my EE class, but common source amp is dependent on load impedance. (I don't remember HOW it was dependent ... sorry)

Tomo

P.S. I do more circuit calculation after graduation ... I guess I was skipping too many homework sets. ...