How should I build the Son Of Zen. Hardwired or using PCBs?

[Erik Johansson]

Originally posted by swede
I'm currently building an Aleph30, which will do good for me. I also buy my stuff mainly in Gothenburg.

I usually buy my stuff at Tema Elektronik, but they are closed for the next couple of weeks (the guy owning the store is on vacation). He has reasonable prices for most of the stuff you need; transformers, caps and rectifiers. Usually he has all transistors as well.

Where in Gothenburg do you usually buy your stuff? Elfa (=expensive but good)?

Best regards,
//magnus

I buy most of my stuff from Tema Elektronik too! He doesn´t have matched transistor pairs does he?

/Erik

[promitheus]

I would do this hard wired or with a small pcb on every mosfet for connections.
There aren´t so many parts to connect anyway.

[Erik Johansson]

Originally posted by promitheus
I would do this hard wired or with a small pcb on every mosfet for connections.
There aren´t so many parts to connect anyway.

My thoughts exactly...

If I can just find some matched FETs around here I´ll be set.

/Erik

[swede]

I don't think he sell matched transistors, but from a lot of 30 you will "easily" find 6 sets of 3 matched transistors (I believe) if you get it from the same production batch run.

I wonder how many people from Gothenburg there are on this forum. This calls for a meeting!

Best regards,
//magnus

[PedroPO]

Check this site:

http://www.passdiy.com/gallery/soz-p8.htm
I've build that soz.

It has no reason for pcb because there are only 10 components per channel and all of them require heatsink (including rectifier bridge).

this amp has only +-5W and needs 10kg of aluminium to work at 50ºC.

I plan to build another soz with 15 W and the heatsinks I got weight 25kg!!!

Be very carefull in the choice of heatsink!!!!

If you need drawings (dwg) for the case and components layout just ask.

( in this version I used a small pcb to hold the supply caps, but on the next one I will use 4 cans with 150000uF each, so goodbye pcb, it's all hardwire!

Pedro Oliveira

[PedroPO]

about the transformers:

Check page 3, fig 4 of the pdf about SOZ in www.passdiy.com

There you can calculate an aproximate value for the transformer.

In My 5watt version I bougth a 250VA 12+12 transformer because I tested earlier with a 600VA 25+25 with a lamp dropping the voltage do 12+12 and measured the current and it was 0.7A @ 220V (both channels) , so its ok and works fine.

For the 15 Watter I asked Nelson Pass and he thougth that it was ok (2x600VA 25+25) so i guess that is REALLY ok ( you should thrust god and don't ask).

I've personally tested it and the current draw is about 1.2A @220V per channel.

I bought my toroids at www.farnell.com. they are great and ship in the next day via UPS!!!

In regard of mosfet matching, I bought a dozen of them in a plastic ruller and they were all from the same series. nevertheless AFTER I build the amp I measured the DC offset to make sure and all was ok. For the 15W version you should take more caution about the DC offset.

Hope I've helped

Pedro Oliveira

pedropo@netcabo.pt