MOSFET Amplifier IRFP240/IRFP9240

[apexaudio]

Originally Posted by mathez

what instead for irfp240/irfp9240?out of stock here

2sj200/2sk1529

[Tube Pro]

Thanks Mile...

[udhay_cit]

Hi, anybody interested in my PCB work for HV350.2 without the Toshiba transistors. I replaced all the 2SA/2SC series Toshiba transistors with available 2N series. I cont find the Toshiba transistors in my city so i cont comment the performance difference b/w the original apex design and my design.

Just now i finished the design work so i didn't tested that.......

I will post my pictures after the testing now find the attachment ......

Thanks Mile

Regards
Udhay

[apexaudio]

Originally Posted by udhay_cit

Hi, anybody interested in my PCB work for HV350.2 without the Toshiba transistors. I replaced all the 2SA/2SC series Toshiba transistors with available 2N series. I cont find the Toshiba transistors in my city so i cont comment the performance difference b/w the original apex design and my design.

Just now i finished the design work so i didn't tested that.......

I will post my pictures after the testing now find the attachment ......

Thanks Mile

Regards
Udhay

Thanks for share your pcb design,
Regards

[apexaudio]

Originally Posted by udhay_cit

Hi, anybody interested in my PCB work for HV350.2 without the Toshiba transistors. I replaced all the 2SA/2SC series Toshiba transistors with available 2N series. I cont find the Toshiba transistors in my city so i cont comment the performance difference b/w the original apex design and my design.

Just now i finished the design work so i didn't tested that.......

I will post my pictures after the testing now find the attachment ......

Thanks Mile

Regards
Udhay

On your pcb track from emiter of BC546 (clip indicator) to -75V missing.
Regards

[apexaudio]

Originally Posted by homemodder

Hi Apex, i dont think your vas is unusal, its a cfp, I use it in alot of my amps, what is unsual is the your temp compensatiom circuit, Im still guesing how it could work.
The thought has come to mind that the cfp transistor that gets mounted on the heatsink has something to do with it but Id have to build it to see the exact effect.

Yes CFP in VAS give temp compensation to the amp, but when amp is hot this circuit reduce bias to almost half of adjusted current: 200mA to 120mA per MOSFET, that is the reason to add Vbe multyplayers with one transistor on heatsink and other not, there is no problem with underbiased. Temp compensation without underbiased can be made with LED in emiter of Vbe multyplayer like in my DC Servo Mosfet Amp.
Temp stability of this amp in usual home aplication is satisfacted, and underbiasing with full power in PA aplication reduce disipation.
Any version of this amp work great, and build it to see effect.

[najjachi]

Hi Apex. Is the heatsink with dimension 300x190.5x56 mm enough for the stereo version of the APEX350.2 amplifier?

Regards.

[apexaudio]

Originally Posted by najjachi

Hi Apex. Is the heatsink with dimension 300x190.5x56 mm enough for the stereo version of the APEX350.2 amplifier?

Regards.

Yes this heatsink is enough for stereo (see post #246), only for PA you need to add fan cooler,
Regards

[najjachi]

thanks!

[apexaudio]

Heatsinks from post #246 are made of recicled aluminium by melt, and have only half wait compare to industrial.