Aleph mini or 3 with my heatsinks?

[sqlkev]

Hello,
I've been wanting to venture into the Pass realm , and the generosity of a forum member made that came true. He offered to give me 2 pairs of heatsinks and 2 pairs of BrianGT Aleph pcbs (link here for specs and pictures For sale: Heat sinks)

Looking at the size of the heatsink, I think they're rather large and can probably used for the aleph 3. What do you think?

I also got 4 smps from Shinobiwan. Each can supply 12vdc, I can surely use each running mono to an Aleph mini, I figure I can parrallel them to meet the requirement of the Aleph 3.

This is my very first project, I don't expect it to be perfect and will ask lots of questions.
What do you suggest so far?

TIA,
Kev

[Dennis Hui]

Hi Kev,

Those are nice heatsinks, but I think they still might be a
bit small for an Alpeh 3, if used without force cooling.

http://www.aavidthermalloy.com/cgi-b...=Change+Length

At about 100W dissipation (Aleph3/30), the temperature rise
will be close to 50C.

I think you can build a very nice mini-A with those heatsinks.
What impendance are your speakers? You can adjust the
voltage/bias of the Aleph to match.

Cheers,
Dennis

[sqlkev]

Dennis,
Thanks for the reply. I have a few more questions.

-What would be the "safe" threshold temperature for any class a amp?
If I don't plan to play the amps in long sessions (2-3hours max), is the heat at 50c dangerous to the amp?

-Regarding to power supply, a pair of these (http://myweb.tiscali.co.uk/nuukspot/...clonesmps.html ) be able to power an aleph stereo amp? should I use a pair of the smps to drive only 1 channel?

-Also on power supply, do I need the power supply pcb from briangt?


I'm running all sorts of speakers at home. (who on here isnt? )
Most are 8ohm, but some are 4ohm.

Sorry for all the questions, I've tried to search on the subject of building the mini aleph and came across lots of good technical info. Not much on the simplier stuffs for a new guy like me though. Maybe I ought to search some more.

Cheers,
Kev

[herm]

I'll handle the temperature question:

It's fairly well accepted around here to run aleph clones at a
30c rise. I have read of a few people who run at close to
50, but I know of at least one who had trouble.

Hey Kev, have you read the Zen series? There is a lot of info
to be found in the manuals. Look here:

Pass DIY

herm

[sqlkev]

I guess I'll stick with the mini alephs Eric

Excuse my ignorance, are these zen variations similar to the alephs?
or are they all different animals?

I so want to order up some parts, but I think I need to read up much much more.

[trango]

Regarding to power supply, a pair of these (http://myweb.tiscali.co.uk/nuukspot...nclonesmps.html ) be able to power an aleph stereo amp? should I use a pair of the smps to drive only 1 channel?

This is an interesting idea! Please let us know if/how it works

[herm]

The Zen amps are meant as learning experiments. Most of the
operational concepts of the aleph will be covered by one zen version
or another.

Nelson put lot of time and effort into the documentation
just so people like us can get a grip on the basics.

He spells out things like heat dissipation, idle current, and
a dozen other basic topics that you should get familiar with.

You can't do it over night! Just keep reading, and keep
posting questions like you have been.

herm

[Dennis Hui]

Originally posted by sqlkev


-Regarding to power supply, a pair of these (http://myweb.tiscali.co.uk/nuukspot/...clonesmps.html ) be able to power an aleph stereo amp? should I use a pair of the smps to drive only 1 channel?

Cheers,
Kev

Hi Kev,

With a pair, you can get a +/-12VDC supply @ 6amps.
The current capability should be enough to power a
pair of mini-A's. The voltage, however, is a bit low.
At that voltage, you are probably looking at 5 or 6 watts
into 8 ohms. You can easily increase the bias to
about 2 amps per channel for about 10W into 4 ohms.

If you use the SMPSs, you will not need to use a power
supply board like Brian's. You may, however, still want
to add a bit of capacitance at the +/-12 V outputs.

Actually, I wonder if it's possible to wire up four SMPSs
to get a +/-17VDC supply. That would be a good
voltage for this application. Or perhaps you can
look around local surplus shops for a nice 15-0-15
transformer in the 200+ VA range for building a
'regular' power supply.

Cheers,
Dennis


P.S. Don't order parts yet!

[jleaman]

Originally posted by Dennis Hui
Hi Kev,

Those are nice heatsinks, but I think they still might be a
bit small for an Alpeh 3, if used without force cooling.

http://www.aavidthermalloy.com/cgi-b...=Change+Length

At about 100W dissipation (Aleph3/30), the temperature rise
will be close to 50C.

I think you can build a very nice mini-A with those heatsinks.
What impendance are your speakers? You can adjust the
voltage/bias of the Aleph to match.

Cheers,
Dennis

Those heat sinks would be good for a set of stereo aleph mini a's.. They are pretty small for a aleph 30. Most class a designs want lots of heat sink. The mini a's im running x 4 are using per channel a heat sinks 12" x 5.5" x 1/5" ( fin's )

They get pretty warm. I think i have my bias at 1amp might be more on the smd version.

[sqlkev]

Thank you for the info guys!

Dennis,
I've already bought the smps power supplies, total of 4. I'm fine with just 10watts/channel. Although, if needed, I can use the smps for other projects and buy more power supplies.

It's kinda hard to mess up and learn when I don't have the parts yet.

Does it make sense to add fans to these amps?