Amplifier motherboard

[wahab]

The IRFP360 is not fundamentally different from IRF240 or 250 ,
only the Gm change a little....

 

[apexaudio]

The RC circuit which is in paralel with one side of the current mirror
should be suppressed.
Although the amp become instable without it, it is the source
of a hard rail sticking in the negative going of the signal when
clipping occur...

Anyway, i wont go further in simulations, as it s time consuming,
and the design need a complete rework, sorry for apex...

Thank for your time Wahab, there is no point to use this topology for quasy complementary Nfet output stage.

 

[wahab]

Well, i think that this RC circuit with the current mirror is not
good even with a darlington output stage as it will also produce
a rail sticking when the amp is overloaded, so it would be better
to find another mean to make the amp stable, whatever the output
stage..

 

[apexaudio]

150w 4r

MOSFET Amplifier with IRFP250. BD139 on heatsink with IRFP250 for termal stability.

 

[apexaudio]

This circuit sound with accent on high frequency not used since 1995.

 

[apexaudio]

Arcam Alpha 10 output stage use IRFP360 in quasy complementary configuration, did you have schematics?

Here is schematics: Auto BIAS and DC Servo

 

[apexaudio]

Here is schematics: Auto BIAS and DC Servo

Did anyone try to implement this auto bias circuit?
Regards

 

[engel dela pena]

apex,
mirror image of this please,
bottom side pcb
regards

 

[apexaudio]

apex,
mirror image of this please,
bottom side pcb
regards

In thread
http://www.diyaudio.com/forums/solid-state/163159-150w-mosfet-amplifier-irfp250x2-4.html
post #34,
Regards

 

[AndrewT]

post4.
Is C6, R2 & R8 a bit of +ve feedback to increase the input impedance (bootstrap) or something else?

 

[apexaudio]

post4.
Is C6, R2 & R8 a bit of +ve feedback to increase the input impedance (bootstrap) or something else?

That feedback have small influence on input impedance.

 

[zeraphine]

Hello apex, is it possible for you to post the PCB layout and Schematic for your AMP motherboard, it can be extremely useful for many amp projects I guess, thanks a lot, keep up the awesome work 🙂

 

[apexaudio]

Hello apex, is it possible for you to post the PCB layout and Schematic for your AMP motherboard, it can be extremely useful for many amp projects I guess, thanks a lot, keep up the awesome work 🙂

I must redesign this project, and separate drivers boards, like PC motherboard. Then you can use some old PC case for amplifier,
Regards

 

[irvynejay]

My new project. On motherboard PCB are PSU 0,+/-100V and 0,+/-15V; Soft-Start for X-former; DC and Anticlick speaker protect; Balanced/Bridge circuit and two Amplifier driver who can run all kind output stage Bipolar, Darlington, Mosfet with Complementary or Quasycomplementary circuit.

Can you pls share pcb on this circuit mile?

 

[apexaudio]

Can you pls share pcb on this circuit mile?

I will share pcb, but I must finish output stage first.
Regards

 

[QQ12e5k1]

waiting for the PCB design.....🙂

 

[apexaudio]

waiting for the PCB design.....🙂

Output stage for 'Amplifier Motherboard' work in class E with tracking dawn converter for rail voltages. Rail voltages for outputs is +/-6V DC, and converter increase rail voltage with input signal up to +/-120V DC, and thats mean over 90% efficiency like in class D, but with class AB sound quality.
Power will be 1800W with only 4 pairs of outputs + mosfets for converter.
I will share schematic soon.
Regards

 

[apexaudio]

Exsample for amp with tracking dawn converter: Sunfire 2700W/3,3R by Bob Carver

 

[QQ12e5k1]

will you share the pcb design??

regards

 

[apexaudio]

will you share the pcb design??

regards

I will, but I must test amp with converter first (in my free time🙂),
Regards