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-   -   What about this amp design ? (http://www.diyaudio.com/forums/solid-state/13517-what-about-amp-design.html)

Ford_V6 8th April 2003 04:20 PM

What about this amp design ?
 
2 Attachment(s)
What about this one ?
Did someone built this ?
Some impresions about it ?

Freddie 8th April 2003 05:18 PM

HPPA
 
I've built this amplifier about 4 years ago. A friend of mine still uses this amp. It's sounds pretty good, but I haven't compared it to my new amps.

The amplifier is called HPPA (High Performance Power Amplifier) and it's designed by Bert Molenkamp in the Netherlands.

One thing I do remember about this amp was that it was pretty hard to get the bias stable. You MUST use a 5mm or thicker U- profile to mount the six output transistors and use a large heatsink. A temperature controlled fan is also recommended.

Bert also recommended the MJ3281A/MJ1302A instead of MJ1500x transistor. And MJH6284/6287 instead of the TIP142/147 darlingtons. But I used the transistors in specified in the schematic.

The BD791/792 might be hard to get, but you can use BD139/BD140 instead. Those four transistors must be placed on the same heatsink.

/Freddie

Ford_V6 8th April 2003 06:42 PM

Does anybody here have a working PCB for this baby ?

annex666 10th April 2003 09:29 PM

I noticed in the design the long-tailed pair uses an adjustable current mirror instead of a simple adjustable current source - what is the advantage in doing so??

Andypairo 12th April 2003 02:55 PM

Quote:

Originally posted by Ford_V6
Does anybody here have a working PCB for this baby ?

I made a couple of these amps some years ago and I must say they were quite good indeed.
I have a PCB layout in BMP format (200 dpi) only, components placement has to be "hand-made".
Driver transistors are mounted on the main heatsink as well as the BD139 which sets the bias current.

Cheers

Andrea

Andypairo 12th April 2003 02:56 PM

2 Attachment(s)
Damn attachment method.... here it is

Ford_V6 13th April 2003 07:12 AM

thanks great

Andypairo 24th April 2003 09:03 AM

Let me know how it works if you build it..

Cheers

Andrea

Ford_V6 24th April 2003 07:16 PM

If i decide to built'it i will post the results here !

cunningham 1st July 2004 11:48 PM

Re: What about this amp design ?
 
Quote:

Originally posted by Ford_V6
What about this one ?
Did someone built this ?
Some impresions about it ?


Question... why have 2 BD792? It seems the first one is to be saturated so why the other?

try using 2 rectifier diodes instead of the 39Ohm resistor. It would be safer.

:xeye:


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