My first SOZ project

[Mallard]

Hi together,

because of the possibility to get a lot and good information and
help for my Son of Zen project I just want to explain what I ment
to do. I plan to build 2 mono amps with 10 or 15 Watts output
each. At the moment I try to collect all the components I need for
that project. I want to use the IRPF240 transistor and Caddock resistors, these are good alternatives to the quite expensive
Vishays. I think 100Watts per resistor is a good choice for that
output voltage. Does anyone know these resistors from Caddock?
At the moment I'm looking for a good source of rectifier diodes,
has anyone a hint? Furthermore I'm looking after 2 power transformers with about 600Watts with 2x30V output each. Any
advise what a good choice can be for that?

I have a further question regarding the power supply. I want to
create quite a big chain of electrolyt capacitors, on the proposed
schematic of the SOZ power supply there is a coil between the
capacitors. Do I need to place such a coil between each capacitors
if I have more than 4, lets say 10 capacitors? Or what is the reason for that coil, this question may sounds quite stupid for some of you but this my first DIY amp I'm bulding. So please
excuse my question I pledge improvement of the quality of my
questions!

I would be thankful if someone shares his/her knowledge about
his/her SoZ project!

Thanks in advance and Regards,

Mallard

[moe29]

check out the thread i posted just a couple of days a go...
it's still on the front page of the Forum

SOZ unbalanced input wiring question

Be prepared for a MASSIVE amp if you want 15 watts out of this
circuit. Double that if you're going to build monos.

if you want that much power why not build a Zen V4? Even more
so if you have unbalanced sources...

(i'm asking myself this same question, so i thought it was only
fair to ask you too!)

moe29

[Mad_K]

-Which Caddock resistors are you talking about? If it's the MP9100, they are not suited because they have only 2000 hours load life. I recommend the aluminium housed resistors from Arcol (HS/NHS series)

-Rectifier; get a decent 50A 400V standard rectifier.

-Transformer; To hit your target 10-15W, I would suggest two 750VA with 2*24VAC.


-You don't need the coil per see, but if you're going to use very sensitive spreakers (you should), then it can be beneficial. The purpose of the coil is to create a pi-filter, which dramatically reduces the ripple from the PSU. You only need 1 coil per rail; place it in the middle of you cap array C-C-C-C-L-C-C-C-C.
Another way to go is to make the PSU regulated as descibed in the Zen V.4 article, as the coils can be expensive/difficult to get.

Good luck!

[Mallard]

Originally posted by moe29
[B
if you want that much power why not build a Zen V4? Even more
so if you have unbalanced sources...
moe29 [/B]

moe29,

I think the SoZ is, especially for beginners, much easier to build as the Zen V4.
The fact that I don't need any pcb for the SoZ is an importand factor for me.

Mallard

[Mallard]

Originally posted by Mad_K
Which Caddock resistors are you talking about? If it's the MP9100, they are not suited because they have only 2000 hours load life. I recommend the aluminium housed resistors from Arcol (HS/NHS series)

-Rectifier; get a decent 50A 400V standard rectifier.

-Transformer; To hit your target 10-15W, I would suggest two 750VA with 2*24VAC.

Yes, I'm talking about the MP9100. Do you them a bit better?
Thanks for you hint, I'll check the pricing

Mallard

[moe29]

Hi Mallard!
I didn't mean to talk you out of building what you want to, but you can purchase professional quality PCB's and a matched
set of Q's from Pass DIY - they will ship international. For a
beginner that's a huge advantage! You're left to your own to
match Q's for the SOZ. Plus the Zen V4 won't require quite the
extensive heat sinking that the SOZ will, exspecially at 15 watts.
750 VA Transformers are big and expensive. 100 watt power
resistors can be hard to find and strat to get more expensive...

Just some food for thought. I'm no audio guru by any means, but
i think you shouldn't write off a Zen V4 so quickly. And when
Mr. Pass comares it's sound quality with the Aleph 3...
That's pretty sweet!

Good luck on whatever you choose!
(there's a mini-A lurking around on this forum too...)

moe29

[Mad_K]

-With the right speaker, a SOZ can outperform A3 and ZV4.

SOZ=An extreme amp! (I used to have one).

However, I changed to an A30, because I built new speakers in the 87dB/m range..

[Mallard]

Originally posted by Mad_K
-With the right speaker, a SOZ can outperform A3 and ZV4.

SOZ=An extreme amp! (I used to have one).

However, I changed to an A30, because I built new speakers in the 87dB/m range..

Mad_K,

I've constructed a pair expo horn speakers in the past. They are in the 90 dB/m range.
Why do you think it's so important what kind of speakers I'm using together with SoZ?
I've heard that a horn speaker would be the best for the SoZ, isn't it?

You mention SOZ=extreme amp, why? Only because of the heatsinking? Or does it sound extreme good


Mallard

[Mad_K]

The SOZ is an extreme amp any way you look at it... It requires massive heatsinks, massive PSU, consumes power like a , produces a lot of heat, requires a lot of space, are expensive etc..

The SOZ are picky with speakers, because it uses (passive)constant current sources/has a low DF/low power. Therefore it cannot compensate for dips and rises in the speakers impendance. The outputpower does not rise with lower impendace loads, it falls. Because of the low DF, it requires a speaker that don't mind about this. Etc..

A High-Efficiency (95db+) speaker with a relatively flat impendance is best for SOZ.
But this is a function of your musical taste, listening room, listening habits (volume) and speaker dB/amp Wattage.

It can sound extremely good though!!! Very direct, clear, fresh and true to the source.
My 8W SOZ played really good with my ME2 speakers as long as I used the impendance correction filter (This makes the ME2 a flat 4 ohm load at 92dB/m). And played music that was nice Jazz, simple acoustic recordings. With more complex material at higher volumes, it started to sound more harsh and compressed (showing off those big nasty teeth )

Another thing: As the SOZ has very little sonic signatur on its own, it very much adapts itself to what's infront of it. My experience is that it doesn't really show it's full potential until you hook it up with a BOSOZ driven from a balanced source.

That said, I think it is an amazing amp, and you should build it and experience all of this for your self. You'll learn a lot, have lots of fun, and have a jolly good time!

I must admit I sometimes dream of having two 30W SOZ monoblocks on the floor driving a big pair of high-sensitivity speakers...