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

till said:
I´m not very experienced and i built ZEN variation 2 and bride of ZEN handwired.

build SOZ handwired! you won´t need much more that the Mosfets , some wire, and a very very big heatsink to mount everything on it.

Yes there are very few components. Also, I just found a guy selling 10000uF/63V Rifa PEH169 caps cheap, these should work well in the SOZ psu right?

Also, how powerful must the transformer be for 2x10W or 2x15W output and what voltage should it be for those outputs?

/Erik
 
AudioFreak said:


Minimum Safe Ratings are as follows
Assuming standard transformer --> bridge --> caps bank type power supply.

2x10W = 900VA @ 2 x 22V
2x15W = 1.3kVa @ 2 x 27V

900VA for 10W? Oh I said 2x10W... does that mean you meant a single transformer for both channels? Or is it THAT power hungry? I think I saw someone in the gallery having built a 2x5W SOZ using a single 250VA 2x12V transformer and he was planning on building a 2x15W version using dual 600VA 2x25V transformers.

What kind of power can I get using a 600VA transformer? That´s the largest ones I can source locally and they come in 2x12V, 2x18V and 2x24V versions.

/Erik
 
Erik Johansson said:


900VA for 10W? Oh I said 2x10W... does that mean you meant a single transformer for both channels? Or is it THAT power hungry? I think I saw someone in the gallery having built a 2x5W SOZ using a single 250VA 2x12V transformer and he was planning on building a 2x15W version using dual 600VA 2x25V transformers.

What kind of power can I get using a 600VA transformer? That´s the largest ones I can source locally and they come in 2x12V, 2x18V and 2x24V versions.

/Erik

I quoted total for stereo so if you are building mono blocks 1/2 the VA rating for each channel

for 600VA you can get about 13.5W mono using 2 x 24V.
 
AudioFreak said:
To calculate the transformer rating, look at the total power draw of the circuit then divide by 0.62 to get minimum total VA rating. Those caps should be fine I think but you'll need more than 10 of them for a stereo pair.

Reading the papers I just printed from www.passdiy.com about the Zen and SOZ I just can decide which of the two to build. The SOZ is soooo simple and I love it for it, but the Zen is designed for unbalanced use (I don´t run balanced) and doesn´t seem to need as big transformers, although it is more complicated to build.

What I really like about the SOZ is the simplicity and that everyone seem to love it.

/Erik
 
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
 
swede said:
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
 
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
 
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

[email protected]