Best mosfet amplifier to build

NMOS

Member
2010-12-11 5:13 pm
Frankfurt
Hi all, i'm an expert audio builder and i'm looking for a very good mosfet amplifier kit or schematics. Power should be not less 200W RMS on 8 Ohms, high current final stadium able to manage very old load.
What do you suggest me ?

Thank you in advance


200R will be a lot of heat, you need big heatsinks

you can use use hexfets, dont use old style lateral mosfets

look for Quasor Mosfet amp or Quasi ACTRK400/600

recommended is to add Class H / TD Rail swichter, the amp running cool with small heatsinks

but you starting from scratch


with Class D you dont start from scratch

you can get Class D 1500W PCB to assemble

with construction Video
 
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I'm not sure Class D sound is good for me. I like Mosfet sound (old style like Hitachi 2SK/2SJ and also Hexfet IRF240 etc...)in AB class circuit.
I have listen one time a class D amp and it doesn't hit me (Ice D amp).
I already have had many Mosfet amp in AB class and they sounds good for me but now i need something more powerful and definitive. I already have a power supply over 1KW with 160,000uF of filtering with out voltage 70-0-70. Is there some one who have schematics and PCB of FET 400 or AV 400 or other similar ?
 
Personally, I find Planer Stripe FETs (singular well) to be very robust even more so than hex-type (plural well). Not to be confused with Trench type FETs which may have higher Gm, they are different in architecture. Trench type are not suitable for analog OPT.
The Stripe FETs work especially well when used in a well designed "Amplified Diode" circuit (Hawksford; Cordell).;)
 
From some of my previous experimentations, Here and here and here and here and here are some posts from some older threads. And this is the latest iteration of this OPS arrangement. I use this amp almost every day, sound is quite amazing. Each channel drives a 6R front speaker (8" Advent tower), parallel with 4R sub/w LP filter (Sound Ordinance 8", 25Hz tuned boxes), and the rear surroud speakers connected to right and left channel outputs. With +/-30V rails, two pair of TO-220 is plenty of power for me, speakers couldn't take much more anyway.:) Actually I don't see using other OPS arrangements, it seems to work so well, and the parts are cheap, OPT are about $1 each.:D.
Also, I found a diagram from awhile back here for the Darlington BJT version showing how the HEC stage interfaces to the VAS using CCS, diamond buffer, current mirror, and bootstrapped rail voltages for the driver/EC stage.
 

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NMOS

Member
2010-12-11 5:13 pm
Frankfurt
have add extension for Legend Quasor

Snubber tp prevent Mosfet Oscilllation

DC Protect Crowbar (the best and reliable speaker protection)

Clip Limiter and Signal + Power LED

Class TD prepared


coming soon

Temperatur controlled Fan Speed, Temperatur, Overcurrent, Short Circuit Protect

Class TD

with external PCB to add with Connector (under Development)
 
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I'm not sure Class D sound is good for me. I like Mosfet sound (old style like Hitachi 2SK/2SJ and also Hexfet IRF240 etc...)in AB class circuit.
I have listen one time a class D amp and it doesn't hit me (Ice D amp).
I already have had many Mosfet amp in AB class and they sounds good for me but now i need something more powerful and definitive. I already have a power supply over 1KW with 160,000uF of filtering with out voltage 70-0-70. Is there some one who have schematics and PCB of FET 400 or AV 400 or other similar ?

You should try pure class A circuitry if you care about good sound and you want to deal with transistors because the electron tubes is a very expensive..hobby!