Finally building my BOSOZ

[raincheck]

Hi,
You people are awesome, please help me decide a few things before I start soldering! Im building the Bosoz, I previously built the BOZ which i used tkd pots, infinicaps, and a few tweaks here n there...its stuffed into a crown IC150 preamp chassis. It is awesome!!!
I now want to build the BOSOZ and have gathered most parts. I'm doing a two chassis setup(separate power supply). I have a couple of Sonic Frontiers chassis...SFL-1 and another that will be the power supply.

Ive read threads about using a 3 amp transfomer ....Is this really such a sonic improvement?

I was thinking of replacing each 1000 uF cap with 2200uF caps. Is this a good idea?

Would IR soft recovery diodes ok or a benefit to use? From reading Nelsons article he does not seem to be a fan.

Where can I get 5? pin XLR's or decent DINs for the umbilical cord between chassis. Any suggestions would be greatly appreciated!!!
Thanks!!

and THANKYOU Nelson Pass!!!!!!!!

 

[paulb]

Some people have commented on an improvement by using a massively overrated transformer. I have trouble understanding why. On the other hand, if you think it will, it probably will.
On the other hand, more C will probably make a difference. Maybe consider a regulator or Cap multiplier circuit.

 

[timo]

You can get Neutirk and Switchcraft XLR's very resonably priced from Markertek.com.

Why do you think you need 5 pins for the umbilical though?
I use a 4 pin neutrik xlr on my separte PS for my BOSOZ.

 

[oliverniekamp]

I have substituted my 120VA with a 360VA transformer for my Aleph L and it improved the sound, it gets more open, but i think you can get bigger improvements for less money.

 

[SteveG]

Maybe the people with the bigger transformers are putting more current through the differential pair (with current sources, or lower resistor values). This would make an improvement to the sound.
Steve

 

[Apogee]

Reading this thread brought back to mind an article that I'd read a few years ago... I had to search to find it...

If you think back on the old PS Audio equipment, they were experimenting with large power supply transformers very early...

They were actually marketing products with the large transformers because they sounded better even though at the time they weren't sure why...

It's a combination of lower impedance and higher inductance of the bigger transformers that makes the difference...

http://www.stereophile.com/showarchives.cgi?222

Just for fun...

http://www.psaudio.com/articles/scrapbook.asp

For what it's worth...

Steve

 

[oliverniekamp]

Naim takes 560VA for there preams, they started this overkill in the 70th or early 80th.
Not to say their so called highcaps are so good, but they use big transformers and large capacitors. But only one stage for filtering...

 

[Peter Daniel]

If better power cord makes the difference, why wouldn't a bigger transformer? As to diodes I'm curious myself. The best way to check the difference is to try both types in the circuit and compare.

 

[raincheck]

Thanks!!
I was going to run a ground on the 5th pin of the umbilical cord, with a larger wire also between chassis. Whats the best way of doing this?

 

[timo]

Raincheck.

If you look at the pcb layout in the article you'll see that the power gets split at the signal board not on the power supply board. I'm using a 4 pin/4 conductor umbilical from my separate ps chassis to the signal chassis as follows:

DC+
DC-
Earth(chassis) ground-going to the ground pin of the power cord
Circuit gound-taken after the thermistor

Hence-4 pins/ 4 conductors.

I'm no expert but I don't think the signal board cares if you run 4 DC conductors to it or just jumper each + &- at the signal board itself. Thats what I did and it runs fine on the bench. I would be far more concerned about maintaining chassis ground between the two separate chassis and providing the signal circuit with the proper post-thermistor ground.

Again, I'm no expert so anyone with more experience please chime in if I'm wrong or right about this.

 

[raincheck]

Thanks for the reply...Im going overboard on this preamp, I've got a BOZ that amazes me so If I'm going to upgrade...I was going to feed power dual mono to two stereo preamp boards that each only have one channel used. Im doing this because it make my life easier when mounting in its chassis. What a decent guage/wire to do this with?

Rave On