diyAudio

diyAudio (http://www.diyaudio.com/forums/)
-   Tubes / Valves (http://www.diyaudio.com/forums/tubes-valves/)
-   -   Playing with hybrid amp: SRPP + MOSFET (http://www.diyaudio.com/forums/tubes-valves/202549-playing-hybrid-amp-srpp-mosfet.html)

siliconray 15th December 2011 07:32 AM

Playing with hybrid amp: SRPP + MOSFET
 
Just finished a new audio amp. It's my first hybrid design. 6N8P is used as preamplifier. 2 IRFP240 forms class A output stage. I had built more than 15 amplifiers in the past 3 years but this is the most favorite one. Althought it has 0.27% THD (1KHz, 1W, 8Ohm), much higher than the JLH amplifier (0.03%) I designed a few weeks before, but it sound sweet, and the background is dead silent. .

http://gallery.siliconray.com/var/al...G?m=1323936676

http://gallery.siliconray.com/var/re...G?m=1323936678

http://gallery.siliconray.com/var/re...g?m=1323936680

Jeffrey689 15th December 2011 07:55 AM

interesting, can you post the circuit? do you have plan to sell kits on your website?

DF96 15th December 2011 10:20 AM

Why SRPP? Unless correctly designed and loaded it can have high distortion, as you find.

Yarpen 15th December 2011 12:32 PM

It's look nice ! Can you post the schematic etc?

siliconray 15th December 2011 12:38 PM

The MOSFET has 1300pf Cg so it needs low output impedance to drive, especially when the freq is high. SRPP because the output impedance is low. I think the distortion is acceptable for a hybrid amp. I believe 50% of the distortion is cause by the mosfet. It's a design without global feedback.

Quote:

Originally Posted by DF96 (Post 2821449)
Why SRPP? Unless correctly designed and loaded it can have high distortion, as you find.


Skorpio 15th December 2011 12:42 PM

I would suggest to use the valve for both channels and load the anodes with CCS (DN2540 cascode). Then use the low impedance output, you will get an Ro of 200-500 Ohm and good drive for the MOS-FET input...

I have done this with a 12BH7A and DN2540 CCS to drive a F4 design without the JFET input...

siliconray 15th December 2011 01:09 PM

schematic
 
1 Attachment(s)
Sure! here it is..Modified slightly from the beta version after testing.
Quote:

Originally Posted by Yarpen (Post 2821609)
It's look nice ! Can you post the schematic etc?


Ken Newton 15th December 2011 01:23 PM

Quote:

Originally Posted by siliconray (Post 2821657)
Sure! here it is..Modified slightly from the beta version after testing.

Perhaps I'm missing something, but that schematic doesn't appear to go to your hybrid amplifier.

Cassiel 15th December 2011 04:21 PM

Schematic?

boontiam 15th December 2011 06:04 PM

Schematic and sound this one. Tank.


All times are GMT. The time now is 03:35 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio


Content Relevant URLs by vBSEO 3.3.2