Beelzebub: 25 Watt for 8 Ohms

[hbtaudio]

Real 25 pushpull class A watts into 8 ohms with impressive sound potential - here's a really quick thought, what do we all think?

Quick to set up and completely uncomplicated - it's supposed to be the Beelzebub.

 

[hbtaudio]

Perhaps one more note:
like any true class A representative, the electrical losses are enormous. Each MOS-FET must easily be able to dissipate 31W in heat, i.e. more than 60W in total.

 

[lineup]

Interesting.
What MOSFETs?

 

[hbtaudio]

Interesting.
What MOSFETs?

I (in fact) simulated with IRFP250 and IRFP9240.

maybe EXICONs
are fine (?)

 

[stv]

Very diabolic name!

 

[BSST]

Interesting.

You might tie the 220uF to ground rather than B+ to avoid supply noise/distortion.

 

[lineup]

IRF540/9540 if you want TO-220 package

 

[mr_zener]

Interesting. Double boot-strap, I'd suspect this would work quite well, is this in simulator stage?

 

[Drbulj]

Love the name, and hell hot simple design!

 

[lineup]

The Class A push-pull seems to work.
My SPICE gives the THD is 0.002%
See image.

There are several issues I'd like to improve.
For example the input which has very bad PSRR.

 

[6A3sUMMER]

Simulations of a MOSFET amplifiers is a good thing.
Keeping an actual MOSFET amplifier from becoming a Power Oscillator instead of a Power Amplifier, sometimes is a different thing.

Let us know when you get it working.
Thanks!

 

[hbtaudio]

There are several issues I'd like to improve.

The basic motto is "hifi creative":
I am happy if you improve the "Beelzebub" design or simply change it according to your ideas.

However, the project should retain the name and live up to it.


greetings,
HBt.

 

[hbtaudio]

Let us know when you get it working.

Do you mean the day when Beelzebub reached nirvana in the alpha state?

Basically, the project, or rather my quick thought, is completely open, open to every self-builder and self-thinker - ultimately it is a suggestion.
However,
I would be very happy if the name is retained and thus represents a kind of reference.


HBt.

 

[lohk]

Something different! Please keep the concept - and the very cool name.
Another amplifier to make and try, such a long list! But I like the approach, which seems quite fresh to me.

 

[hbtaudio]

The circuit is based on a fairly old idea and a tip I got from an old master at the beginning of the millennium. I put it into practice as an experiment at the beginning of 2005.

 

[adason]

So you built it in 2005 then?

 

[lineup]

The basic motto is "hifi creative":
I am happy if you improve the "Beelzebub" design or simply change it according to your ideas.

I have changed a bit.
1. Increase the gain. Now is x16.
2. Using darlington VAS. With 2 transistors that is.
3. Decoupling the input. With one capacitor.

THD is now 0.0008%
Thanks to the darlington VAS, which improves distortion with 12 dB.

 

[hbtaudio]

Considerations for the practical implementation of the project:

• Switch-on delay, DC protection, output relay
• Soft start of the power supply unit
• Parallel connection of two MOS-FETs each' with Rsource=1Ohm (MOX 2W) || 1Ohm (MOX 2W)
• Two separate, effective heat sinks for N & P - MOS
• Protective resistor, up to 470Ohm Rbase of U3
• min100VA toroidal transformer (or better), 2 * 18Vac
• freewheeling diodes on the outputside
• protection for V_GS with Z-diodes

 

[hbtaudio]

Keeping an actual MOSFET amplifier from becoming a Power Oscillator instead of a Power Amplifier, sometimes is a different thing.

Absolutely right, but I'm not afraid of that in the case of Beelzebub - you only know after the first test setup (and then, if the worst comes to the worst, you have to take remedial action). This is a risk that every self-builder simply has to take.

 

[stv]

I'm not afraid of that in the case of Beelzebub

don't fear the devil!