Greetings from South Africa

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Hi!

I have been lurking on this forum for quite some time now, but feel the time has come to finally break cover!

I am an industrial engineer, who pays the bills by working for a major bank here in Johannesburg. DIY audio has been one of my hobbies for a very long time, and I can attest to never having had any other amplifier or speakers than those I built myself!

At present I am working on a fairly big 4-channel power amp, with matching speakers. I opted to go all out, so am doing everything, from making the pc boards, through to machining the enclosures myself.

I hope this forum will not only provide me with the opportunity to exchange lots of knowledge, but also keep me all fired up!

Regards,

Willem Fick
 
4 Channel and 8 Channel Amps

Hi,

If you like hybrid amps and parallel drivers, come to the LM4702

driver on the search engine.

There is a need for designers of output stages for the 100-300

watt LM 4702 driver.

You said 4 channel amps.

Why not 4 LM4702 drivers for 8 channel amps or N channel amps,

with simultaneous tube and semicoductor drivers for mixing.

Mark

P.S. You can guess that I am not a 1 "best" output stage type.
 
Introductions

Hi Willem

Welcome to diyaudio! I' writing from Cape Town, still the sleeping city but with a promise of warmer weather here for the weekend.

I am a record collector, have a fascination with Garrard 301/401 turntables and build moving coil phono cartridges for fun! My amps are vintage Leaks, some Quads and modern stuff like Arcam. One day, I will build a tube amp...

bulgin
 
Hi folks!

Sorry for the delayed response, but my life is rather hectic at times...

Thanks for all the warm words of welcome, as well as for your invites to join in on some of the threads!

Mark, I did the search as you suggested, and found the topic very interesting. I do however already have a design, originally done around the K135/J50, but now being modified for newer K1058/J162 (I'll still need lots of help on this!). The enclosure is all but complete, including having machined the heatsinks to the requirement of these modules, so no swerving off track for me I'm afraid.

Kanwar, I spent quite a bit of time looking at your designs and discussions, and as a long standing admirer of all things switched am really impressed. Unfortunately I am not nearly as competent a designer as yourself, or most others on this board, but I hope to learn from the best!

Bulgin, I have VERY current hungry speakers, so am afraid valves won't do! I do however appreciate them form an aesthetic perspective though, and love the idea of an amp "lighting up" with music! ;)

Shaun, as soon as I can dream up an alias (give me two minutes!), I'll be joining up at avforums! I have been out of the DIY circuit for a long while, but may well have a bit to add!

Regards!

Willem
 
Hi Willem, I built am amp about 12 years ago from a PCB print In a magazine I forget which one, it was used on stage for about a month and then stored until I wanted to use it about two weeks ago, plugged it in and it blew fuses. It has two K135 and two J50 T03 cased transistors in it, all I do is follow the schematic when I build anything my theory know how extends to ohms law and that’s about it, but I muddle through and I am very careful. I would like to use the transistors on another PCB, have you got a circuit yet? If could you point me to a schematic or better still a PCB layout you would make me a very happy bunny, I have got some 2SK1058s and some 2SJ162s and I believe they are the same, so the circuit would do for both. ? I don’t see why I couldn’t make an extra PCB as a bribe. Cheers.

arrsix:clown:
 
arrsix,

The design I have is probably still older than yours, and also originally came with K135/J50 pairs. It isn't exactly an amp that'll set the world ablaze, as it has two stages only, but it's easy to build, cheap, and sounds just fine to me! I made a couple of clones of it over the years, but due to financial limitations (I was a poor student), never got 'round to doing a proper CAD layout. I would imagine that it is possible to simply substitute the 135/50 pair with 1058/162, though I guess some modification might be required, other than purely layout. I will take the time to do a layout and schematic on Eagle soon (as well as my first thread on this forum!), and promise to let you have a copy.

Warm regards!

Willem Fick
 
As far as heatsinks are concerned, I consider myself very lucky! I came across a company here in SA that sells heatsinks cut and machined to size. The leftover bits they however sell as scrap for very little money indeed! the last time I paid them a visit I bought 30-odd sections of 100x200 mm heatsink sections for the equivalent of around US$0.50 a kilo!
 
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