Amplifier circuit from Elektor

[pepbox]

Hello to you all, does anyone know where I can get a copy of the following article in Elektor, "High-Power AF amplifier" it used Hitachi MosFets and was in a 1986 edition, any help would be most appreciated. Pepe

 

[nigelwright7557]

Here is a Hitachi lateral mosfet amplifier circuit.
I took this and added numerous improvements for myself.
I added decoupling of front end from output stage.
I changed front end transistors to mpsa42/92.

If you cant find mosfets for it I used ALF16N16W and ALF16P16W lateral mosfets.

An externally hosted image should be here but it was not working when we last tested it.

 

[pepbox]

Hello Nigel, thank you for the information, unfortunately this is not the article I was looking for the one I wanted either used 8 Toshiba Mosfets and the other one used Siemins BUZ musfets, but I will try this one anyway, thanks once again Pepe

 

[mabery]

Hello Nigel, thank you for the information, unfortunately this is not the article I was looking for the one I wanted either used 8 Toshiba Mosfets and the other one used Siemins BUZ musfets, but I will try this one anyway, thanks once again Pepe

I recall the Crescendo and Mini Crescendo amplifiers using 2SK135/2SJ50 pairs
I have build the Mini version and etched my own pcb during those years for my guitar combo amp. Worked very well...

I still have the PCB and the ILP HY-83 preamp module. the amp cab was destroyed

 

[mjf]

......yes,the crescendo has four hitachi fet per channel.......

in the elektor "audio-schaltungsbuch" there is an amp called "gigant" with 8 hitachi fet per ch......

and a "buzamp" with 4 buz23 per ch.

 

[el156]

Here is the BUZ23 amplifier...i made one years ago,very good amp, then sold it and the owner is still very pleased with it.

 

[jlithen]

I just bought a buzamp from Germany.
It looks like **** inside, even if parts are of good quality. Someone really likes paint 🙂

I fixed some bad contacts and would like to adjust BIAS, trimmers were firmly glued and difficult to replace, but my questios is, what is proper BIAS?
One channel was about 80mA and the other about 8mA
I would have thought 100-200mA is good?

Supply is 2x55VDC and there is a big enough heat sink.

 

[tvi]

http://www.designfactory.co.za/audio/Elektor1986.pdf third entry from gooogle search

 

[jlithen]

Still wondering what the BIAS is meant to be, but I got quite far by measuring and tuning 🙂

Anyway power fets were far from matched, but I adjusted so that lowest voltage over 1/4ohm resistor bunch was 14mV = 56mA
I guess the highest was up to about 200mA then.

Results are pretty impressive for such a garage build. 1W 1kHz 7ohm

Must say I am also impressed by the simplicity of the signal route.
Maybe this is a good design after all!

 

[poynton]

Try this :.....


Ray's Audio Page

Down the page is the Crescendo

Andy

 

[jlithen]

el156 can you please share the text from your book.
The photos you attached are of the article about the amp I have and I think this is also the other amp pepbox is interested in.

 

[jlithen]

Oh it was in Portuguese. Well if you find the BIAS value please tell me. And also how to adjust the temp protection. I guess I could figure out this much myself too from the text if I had it.
On some forum I found some text in German, but it had to be missing something, as I did not find any mA values.

Sorry if I was unclear in the beginning. My buzamp is the one with two BUZ23 FETs in parallell as in el156s photos 🙂

 

[Juergen Knoop]

Sorry if I was unclear in the beginning. My buzamp is the one with two BUZ23 FETs in parallell as in el156s photos 🙂

that one was meant to have 100mA per FET; resulting in 200mA per channel.

 

[Juergen Knoop]

maybe this helps

 

[jlithen]

Wunderbar. Vielen Dank!

 

[Juergen Knoop]

found something today:
Projekte

 

[jlithen]

Anybody want my Buzamp boards?
I got tired of the painted and messy mechanical design of this amp.
Would take hours to make it tidy and noisefree 🙁