what would you do?

[PixelPlay]

Hi
First off apologies for something that has been discussed to death, however due to being limited to a apple mac my problem hopefully will become clear. I am building a pair aleph 4 mono's.
Due to not being able to run Duncan amps PSU designer on the mac platform I am unable at this time to simulate any configuration in order to decide what would be best with the torroids and caps that I have on hand. I have read over many many posts and have been swayed from one direction to another without being able to decide.
I have the following power supply components per mono:

2kva 35-0-35, 240v 50hz x1
33000uf 63v caps x6
27A 600V IXYS FRED Bridge Rectifier x2
enough heatsinking for the standard or higher bias if needed, limited only to rail voltage.

If this was your build and with cost not necessarily a limiting factor (within reason, I have come this far and would hate to have to limit the possibilities)

I would like to order the rest of the PSU components and would like your help.

Thank you for your time

Apple macs do have their limitations!

 

[Nelson Pass]

Sounds fine. The Aleph 4 was more or less a stereo version of
the Aleph 2, so you're pretty much building Aleph 2's with a
beefed up supply.

It looks like you can make use of a CRC or CLC configuration in
the power supply, which will reduce your noise.

 

[PixelPlay]

Hi Nelson,
Thank you for you prompt reply. From reading the many PSU posts it would seem that the CLC configuration would have the lowest noise floor. Being unable to simulate the PSU and from some of your previous posts would I be in the ballpark with 2.2mh iron cores? Would this have a significant effect on reducing the rail voltage? I would like to get the most out of the supply.

Thank you again

regards,

Greg

 

[GRollins]

There are advantages and disadvantages to iron core inductors. The good is that the inductor is physically smaller. The bad is that it can saturate, meaning that the iron core soaks up all the magnetic flux that it can, then it kinda quits doing its part. This happens at high current, which is pretty much what you're going to be dealing with if you're building a class A amplifier like the Alephs.
So what to do?
See if you can locate air core inductors. Air doesn't care about magnetic fields and doesn't saturate. The 2.2mH figure will do just fine. Speaker inductors will do just fine, so if you get stuck look at the inductors available for speaker crossovers.
The rail voltage is more a function of the DC resistance of the copper windings. The larger the gauge of the wire, the lower the resistance. The lower the resistance, the less voltage you lose...so big is good.
If you're sufficiently motivated, you can wind your own inductors. After all, it's nothing more than a coil of wire. If you want the lazy man's way out, buy a kilogram spool of heavy wire and hook up both ends (one end is usually available down in the center of the spool). It's not that elegant, but it will get the job done.

Grey

 

[PixelPlay]

Thanks Grey
That sounds like the way to go. I have been following the post on making your own inductors. I suppose that some large foil types would also do the job.
Correct me if I am wrong then the set-up would be CLCC?
I will source some heavy gauge inductors or try to build my own.

Thank you for your help

Regards
Greg

 

[Nelson Pass]

Perhaps a CLCLC, or a CRCRC. Don't underestimate the
effectiveness of CRC type filters.

 

[PixelPlay]

Hi Nelson,
What values would you suggest for the R in the CRCRC configuration?

On another note do you like any of the Australian vintages?

Regards
Greg

 

[Nelson Pass]

I use 4 parallel .47 ohm devices in FW stuff. Generally whatever
won't burn up and gives me .1 to .5 ohms depending on the
application.

Yes, a well tempered Shiraz.

 

[GRollins]

Yes, a well tempered Shiraz.

And here I was thinking that it was a well tempered clavier...shows what I know.
Actually, some of the Australian GSMs are pretty good, too.

Grey

 

[spzzzzkt]

Stopped off at Chateau Tahblik on the way back from a nature recording trip this afternoon. They do some particularly nice reds - Shiraz and Cab Sav - that are worth trying if you can get hold of them in the US. If you don't mind white their Marsanne is nice, and even better with 10 years of bottle age.

Using a Mac is no limitation - I'm running Duncan's PSUD on a G4 laptop with VirtualPC 6 and Win2k Pro... VirtualPC was rapidly wrecked after MicroS**t bought it to gain access to the virtualization technology - 6 is still almost usable - but there are other viable options.

http://www.macwindows.com/emulator.html

 

[PixelPlay]

hi
I have VirtualPC but what a nightmare, I uninstalled years ago and swore that I would not use it again. I have the new mac pro on order however they are delayed due to nvidia and the 8800 GT. Fingers crossed it will arrive sometime soon.

Now on to things that matter: Have you tried Kaesler Old bastard shiraz?

Cheers
Greg

 

[spzzzzkt]

VPC is the path of last resort to be honest... Only used for running e-tax and a handful of quirky utils. Early versions weren't too bad and VPC5 could even be used to run linux and unix operating systems.

I can't recall having tried the Kaesler shiraz - I'll keep an eye out.