x soz

[jh6you]

2) the reason is, that if you slowly turn the knob, You want one volume level to go direct into the next, and not first into level zero and then the next. I should sound like a continuous shift from one level to another without any interruption.

Thanks for your comment.

With my old but new speakers (8-ohm, 97dB, see the photo), usually I play moderate sound, by turning the volume up and down within 3-4 steps. Merely once in a while, I make loud sound.
My idea with Switch A/B attenuator is, eg, that for normal listening, I select 4.7k of Switch A and play the sound up and down within Switch B. Occasionally, however, I might select 1k of Switch A and play a bit louder sound up and down within Switch B.
Easy getting of 2x6 rotary switches at low cost is the first background, of course.

I hope the switch A/B attenuator, even if not the best, will be feasible without technical problem. I will be happy with any further advice as this is only a plan yet.

Thanks again.

JH

[ralf]

Originally posted by Henrik
Ralf
My XSOZ powersupply is somewhat different than what is normal for the SOZ.
I run it at a single rail supply, regulated with a kind of capacitance multiplyer. After the supply, I divides the rail with some resistors and couples them to an IC (Shame on me!!!) voltage follover and then some 220uF Blackgates, all this forms a virtual ground. This supply is silent, You cant hear any hum, shshsh or what ever, no nothing.
Any way, I will reconsider this solution once more.

When I turn on my XBSOZ I can only hear a little noise in the Dynaudio D28 tweeters, but only at a distance from 5-15 cm.

Henrik,

got any schematics of PSU and capacity multiplyer?

what will the voltag be, you drive your XSoz, mine is +-35V Dc in moment, but i use big heatsinks, and i think i kan go easy to -+45V.


Ralf

[Henrik]

I can post it in the evening, within 12 hours.

[Henrik]

Ralf

I have attached the scematic of my setup for the SOZ, I have just changed the values and added new parts for the X-feedback.

The original reason for this kind of supply was, that I had two 2X33V 500VA torodial transformers, and I did my first testamp with them, and then they have bin there since.
I got the idear from www.lcaudio.dk in Denmark, they call this for "No noise ground" an they are still using this virtual ground in their preamps.

As I wrote before, I will consider this psu once more, but I am quite happy with it for now.

[Henrik]

By the way, the regulation is from Andrea Ciuffoli´s Class A Power Follower on http://www.audiodesignguide.com/my/index.html

[ralf]

Can onyone explain me the difference to this virtual battery psu?
How should it be dimensioned to work proper with SOZ?

http://sound.westhost.com/project15.htm

Regards,

Ralf

[AMPMAN]

Henrik, I thought that the point of andres supply was to eliminate large caps? also I do not see x in your diagram.

[Henrik]

Ampman

You are right about Andreas consept, and at the moment the cap after the regulation is only 220uF BlackGate, wich makes a good job. But I have tried some Blackgate 4700uF 50 volt, and that makes some big difference, so I will use these when I rebuild my XSOZ. But before regulation You need more capacitance than Andrea uses in his setup, otherwis the deep bas will suffer, at least thats my expierience.
The reason why You dont se the X is because this is an old diagram of my former SOZ wich I have modified to an X, I only posted this diagram for the powersupply. You can find my XSOZ at this page x soz

[ralf]

How much do you pay for the Audionote 1W Tanalresistors an where do you buy them?

Ralf

[Henrik]

Ralf

As I se the "virtual battery" it is just a very effective ripple filter, nothing more.
I think Andrea Ciuffoli´s is better than the one from ESP, both regarding ripple rejection and load current max. because of the mosfet used. You gets a slow turn on because the 220uF cap has to charge through a 100K Ohm resistor, about 5-10 miniutes, also they forms a very low and effective lowpass filter that feeds the gate of the mosfet wich controels the voltage of the mosfetsource.

I bought the tantalumresistors from the Audio Note dealer in Copenhagen, and they cost about 7,50 Euro each.
You can find a dealer on Audio Notes homepage: http://www.audionote.co.uk