New high end, high power MOSFET amp

[H._Lecter]

I have been recently thinking of building my own amp that can properly drive my Kappas 9.2i and any other future Infinity's I'm going to own.
I have not much experience with building electronics, besides recapping some old amps and reading a few books a long time ago. But I love playing around with this kind of stuff. So I would like get some input on where to begin.

I want a BIG and powerful amp capable of delivering at least 300 watts at 8 ohm and being stable at 1 ohm. MOSFET or SIT. Also playing first 20-50 watts in class A.

I know this will be expensive and maybe difficult to build, so I'm looking at this as a long term project.

So, where should I begin?
Can I use some of the Firstwatt or Pass schematics?
Have anyone here build a similar amp?

 

[barmanekm]

Sounds like serious project. Big and expensive.
Do you meant it has to be stable ar 1 Ohm, or does it have to deliver enough power as well? What output power do you expect at 1 and 2 Ohms?
Pass circuits are very good starting point for characteristics you have described.
Firstwatt are rather low power, but some of them are quite scalable.
It is not the only way, but very reasonable for your case.

 

[stocktrader200]

The power losses to run 50w class A while being capable of 300W will heat the room.

 

[jxdking]

Class G?

 

[stocktrader200]

Could work but adds another transformer and extra complexity.

 

[Andersonix]

Baby steps: If you rub one of Nelson's Adcom 5400 amps the right way, you're halfway there...

Thread 'PS hack for Adcom GFA-5400'

2020-10-17 1:40 am

This ingenious hack squeezes in a CLC for the front end PS, while also tripling the PS capacitance of the output stage. PS ripple is so low on the front end that my Fluke meter can't read it, and PS ripple on the output stage is cut to one-third.
I put taller feet to help cooling and dialled the bias up to almost 4W in class A, where it idles on the warmer side.
Also I put in multi-turn pots for easy bias and DC offset adjustments, <1% matched source resistors, Kerafol pads, and new electrolytics all around. Used my nibbler to cut a nice rectangular hole for the power entry. Very pleased!

• Andersonix
• Replies: 4
• Forum: Pass Labs

 

[meanman1964]

Could this amp be something for you.
Thel Audio Accusound 100 .
Switchable between Class A and Class AB .
DC protection onboard , voltage rail from 20 Vdc and 95Vdc and 1 Ohm stable .
More info trough email .

 

[Gill.T]

@meanman1964 , that looks interesting, Would you share some more information about it?

 

[meanman1964]

It's mine and maybe for sale .
It's a design from a German diy audio brand Thel Audio . Uses IRF240/9240
Pic of the inside of one mono block .

 

[meanman1964]

Output power specs