= Aleph ?

[bearbearloo]

Dear All,

Wanna to build an Aleph amp, after searching a huge documents here and I have a little bit confuse....

About PSU,
Some DIYer use 4x 22000uf capacitors to build or 8x 22000uf to build mono block.
Some DIYer or PASS's A30, XA1000 use 12x 10000uf at PSU....

The followings are what I got which purchased from several group buy plus my stock.

- 2pcs of 25v 225VA transformer
- 24pcs of 10000uf capactor
- 2 PSU PCB, 12pcs 10000uf caps at each PSU
- 12 pairs matached IRFP240 + PCB
- Some Panasonic 3W resistors

Questions:
If I do it as Dual Mono by using the above parts;
- How many output it can produce?
- "3W" resistors enough?
- It similar or equal to Aleph which model?

- If you were me, will you give up or upgrade some exisiting stock to build a better one?

Thousand thanks and looking forward to see your advise.

[peterpan188]

When you mention board for the IRFP240, which one?

Peter

[bearbearloo]

Dear peterpan188,

First of all, thanks for your reply.

PCB is bought from China group buy which they claim is Aleph X.

- Aleph X use 12pcs of IRFP240 per channel?
(Some WEB site claim it use 8pcs only...)

- AX should use 4pcs 22000uf or 12pcs 10000uf per channel?


Sorry for too many questions and I am green at DIY or PASS Lab stuffs.

Thanks in advance!

[carpenter]

I like to start small, learn the design and grow it into something wonderful.

You might want to consider your first Aleph X an experiment. If you haven't fabricated the simple Aleph X, then start there. You'll have a good time with it and won't have too much work/effort on your hands should things go wrong--and things do go wrong from time to time. Just read the many posts of frustrated builders. Their problems do get solved, but there's less hand-wringing with smaller amplifiers and fewer parts.

Get you hands on some 12 volt transformers that rectify up to 15 volts or so. Save the larger voltage Aleph X for a second attempt after you learn from the first project.

It's a neat project, have fun.

John

[RoboMan]

You did not mention if your transformers are 25VX2 or 25VCT.

If they are 25VX2, the voltage of the transformers are a bit too high for Aleph-X. That means you'll get high power output (196W per ch. at 8 ohm with 14A bias) and a very high power dissipation (about 900W per ch. which your transformer cannot handle). You'll also need very very big heat sinks to handle such heat.

These transformers are more suitable for making Aleph5 with 50W per channel, if that is what you are looking for. And Aleph5 is much simpler for a beginner.

If they are 25VCT (12.5VX2), the voltage is suitable for making Aleph-X with an output of about 50W per ch. 8 ohm, bias 5A, 50% of Aleph current.

wuffwaff (william) has posted two Excel spreadsheet for calculating power output, voltage and current requirement etc for Aleph and Aleph-X. Here are links:

http://www.diyaudio.com/forums/showt...824#post552824
for axe-1-2.zip (for Aleph-X)

http://www.diyaudio.com/forums/showt...873#post406873
for aleph-power.zip (for Aleph 1 -5)

[bearbearloo]

Carpenter, RoboMan.

After reading your post, now I get much idea and know how to start, will study more base on your direction. Thanks a lot!

One more question,
I should use 4pcs 22000uf or 12pcs 10000uf per channel as filting?

pros & cons?


Cheers

[RoboMan]

Originally posted by bearbearloo

I should use 4pcs 22000uf or 12pcs 10000uf per channel as filting?

It really doesn't matter. Use whatever you already have in hand. Usually smaller ones perform better, they may have lower internal resistance, lower inductance. But it all depends on the actual quality.

You may also parallel a high quality low value (0.1 uF to 1 uF) capacitor with the big ones to improve the high frequency performance. I think there were discussions on this forum.

[carpenter]

Originally posted by bearbearloo
Carpenter, RoboMan.

One more question,
I should use 4pcs 22000uf or 12pcs 10000uf per channel as filting?

pros & cons?


Cheers

There are several techniques for assembling power supplies. You will enjoy reading Zen revisted, and versions two, three, and four to learn about pi filters, zener voltage regulators, capacitance multipliers, etc.

I'm very fond of the LC filter. In my ZV7-T power supply, I use a 10amp, 10mH inductor followed by two parallel coupled 20,000 uF computer grade caps. This power supply is simple and effective.

Someday, I may try the capacitance multiplier.

Use as much capacitance as necessary to remove ripple--let your ears be the judge. Bypass the large caps with the smaller caps. Bypass those with even smaller caps closer to or on the pcb. I read this makes a good capacitor. Zen version 4 demonstrates how to filter your supply right before an input buffer.

Lots of neat stuff in those Zen articles!!!!! Even if you don't fabricate Zen amplifiers, you can learn loads from Nelson. In fact, read all of them.

John

[bearbearloo]

Carpenter, RoboMan.

Thanks again!

[bearbearloo]

Can this heatsink handle A5, A2 or AX

Dimension : 140¡Ñmm 32¡Ñmm x 380mm