Which is Better?

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Cephas

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Joined 2002
#1
Hello everbody.
I am a new member, and a begainner for DIY Audio

I want to bulid my Pass amp , and hard to Choose
which is better .. Zen ? SOZ? Aleph?

I want to bulid Zen before. But hard to to match speaker..

Is Aleph 1.2? more hard to bulid then Aleph4?

How many Mosfet can find 1 pair almost?
I heard that 10 mosfet can get 3 Pairs.

I can't find IRF244 can it bypass it with IRFP244? IRFP240? IRFPXXX...etc? need change resistors? re-Biasing?

the new Penultimate Zen is 35W Output??

Can I buy R-core Transformer on internet?

🙂 Sorry many many question...
thanks for all
 
#2
> I want to bulid my Pass amp , and hard to Choose
> which is better .. Zen ? SOZ? Aleph?

I think that the Aleph is the best design and not that hard to make. I am currently working on the Aleph 2, as are several others on this forum.

> Is Aleph 1.2? more hard to bulid then Aleph4?

An Aleph 2 should be fine. It uses 12 output devices (irfp240) per channel, and the 1.2 uses 24. In terms of 100W vs 200W, 100W is more then enough to suit my needs, unless you have highly inefficient speakers.

> How many Mosfet can find 1 pair almost?
> I heard that 10 mosfet can get 3 Pairs.

I bought 125 IRFP240, and am matching them next week. I will post my results. I matched 8 IRFP044 and got 4 pairs.

> I can't find IRF244 can it bypass it with IRFP244? IRFP240?
> IRFPXXX...etc? need change resistors? re-Biasing?

use the IRFP240.

> r core

Just use toroid tranformers. That is the going standard for audio amplifiers. Good ones are available from Plitron

I get mine locally from: Victoria Magnetics

--
Brian
gte619j@prism.gatech.edu
 
#4
Cephas said:
i want to direct input CD Signle to the Aleph ( no pre amp)
i need to change something?
Click to expand...

You will need some sort of volume control for this, rather then adding a potentiometer to your inputs of your Aleph, I would build a simple passive crossover, as mentioned here:

Passive Pre-amp post

One more thing, when I build my Leach Amp, I just added potentiometers to the inputs and it works fine with just the input of the cd player going into it. I like the way it sounds using my pre-amp better.

--
Brian
gte619j@prism.gatech.edu
 
#6
Cephas said:
Thank Brian,

The power consumption of Aleph 2 is 500W/ch
so I need 2 1000W Transfromer for stereo?

48v X 0.707 (RMS) output Volt?

is it right ??

thx.
Click to expand...

Yes 2 x 1000VA transformers would be good.

Aleph 2 has +/- 45 Volts DC rails so the transformers should have secondaries of about between 33Volts AC and 35Volts AC. In practice, the theoretical values dont account for power supply resistance, non-infinite capacitance, non-perfect capacitance, diode drops, mains voltage sag, etc. so we generally divide the required DC voltage by between 1.2 and 1.4 to determine the required AC voltage for the transformer secondaries. The exact figure depends on how over-rated the transformers are and how much capacitance we are using along with local power conditions etc.
 
#8
Compare if Aleph 4 is 48VDC (Aleph 2 is 45VDC)
they same are 100W o/p
the Circuit is similer.
some R and Cap is diff.
and one use MPSA18 other use ZTX450

which Circuit is better?

can i use the Aleph 2 Circuit to make a Stereo?
or Aleph 4 Circuit to make Mono?

Thanks.
 
#9
Cephas said:
Compare if Aleph 4 is 48VDC (Aleph 2 is 45VDC)
they same are 100W o/p
the Circuit is similer.
some R and Cap is diff.
and one use MPSA18 other use ZTX450

which Circuit is better?

can i use the Aleph 2 Circuit to make a Stereo?
or Aleph 4 Circuit to make Mono?

Thanks.
Click to expand...

Both circuits are very similar .... i believe the Aleph 2 may have a slightly higher bias than the Aleph 4 and therefore it should be sonicly superior at least marginally so.

Yes you can make a mono or stereo version of either schematic.

The slightly higher rail voltage of the Aleph 4 is primarily to account for the greater load placed on the power supply and hence greater voltage droop.
 
#11
Yep, the Aleph 2 has a somewhat higher bias than the 4. On average, higher bias is a good thing. The circuits have enough 'give' in them that you can run the rail voltage up or down a bit without discombobulating things. Get your rail going, then set your bias as high as you think you can get away with. Watch the heat dissipation. Those who are brave (foolish?) enough to run a water-cooled heat sink system can drop a lot of heat...

Grey
 
#12
Actually, the Aleph2 Service manual states 300W draw per amp. This is consistent with slightly lower rail and slightly higher bias cf the A4.

So 1000VA is actually overkill. 650VA will be OK and 800VA very comfortable indeed.

We keep going over this, am I missing something or is my brain fading again ?

cheers, mark

PS: "Of all the things I've lost ..... I miss my mind the most" 😕
 
#13
Power factor of the linear bridge / caps power supply is one reason for substantially over rating the transformers .... there are many other reasons .... given that the Aleph 2 only draws 300W per channel and not the 500W per channel cephas stated earlier in this thread (yeah i was too lazy too look it up the 1st time 😀) 600W would be the absolute minimum i would use.... 1kVa would be being rather generous indeed.....
 
#17
Hi all,

What a great forum this is... Where people know what they are talking about 🙂

I have just decided that I will build myself an Aleph amp soon too... But I've more or less run into a kind of luxury problem: Which Aleph will I build? The best of course... But they all look so mucht the same.. Only the Aleph 0 and 0s have different topology, and the rest seem only to differ in Power consumption and -delivery.

When finished, My Aleph(s) will have to drive my Piega P5LTD, which are 4 ohms nominal, and dip at just under 3 ohms. I find it crucial that the amp will remain stable under all circomstances driving that load. Also, I would like to have my amp deliver enough power to "Open up the volume" once in a while, but I don't want it to draw 500W/ch contiuously like the ALeph 1.2. I think that would be a bit overkill....

I can't decide just reading the specs and the schematics in the service manuals, so can you guys give me some tips?

Thanx,
Bakmeel
 
#19
It sounds to me like 100W into 8 ohms would be enough for you, which is what the Aleph 2 and 4 provide. The differences between the two is that the Aleph 2 was designed as a pair of monoblocks, dissipating 300W per channel. They are biased higher then the Aleph 4, which was designed as a stereo amplifier dissipating 500W for stereo.

I also asked Nelson Pass, and he felt that the Aleph 2 sounded better due to the slightly higher biasing.

I feel that the Aleph 1.2 is definately overkill for most situations.

--
Brian
gte619j@prism.gatech.edu
 
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