Ultimate sounded ZEN (Var I) vs good sounded used Aleph 5

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A customer of me had buy used Aleph 5 for 1500 euros and compare it to a diy ZEN from an other guy - a diy project, supervised by me 10 years ago - go to
http://www.diyaudio.com/forums/pass...itional-op-amp-ultimate-sounding-phl1230.html

For the aim of compare by the Aleph 5 user the integrated MFB high pass unit of ZEN was removed
(see schematic).
The loudspeaker of the user with Aleph 5 are fullrange versions (FOSTEX "FE 103E" inside in diy vented box from the old French magazine 'l Audiophile)

Compare to high end AB amps like Accuphase the Aleph 5 sounds clearly better at low and mid level. But the ZEN again provides a spectacular increase of sonic quality in all respects compare to the Aleph 5 (see attachement of schematic and photos of this ZEN amp - unfortunately without pics of power supply - only similar transformers)

What could be the reason?

I guess, the reason could be the internal power supply and transformer by Aleph 5 and the not exist large bypass polyprophylene caps of 200 uF from Arcotronics in parallel to the present smoothing capacitors. Additional the enhanced filter characteristics through the highly oversized halogen transformers.

If my estimate right, I am planning an outdoor power supply for the Aleph 5 in the same quality than that one of the ZEN with very large halogen transformers (redesign for lower voltage isn't a problem for me).

Is my estimate wrong, the user must perform the same diy project of ZEN (much more expensive than external power supply for Aleph 5).

What are your suggestions, what I should do ? The clone of the exist ZEN or an outdoor unit (power supply) for Aleph 5?
 

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With full-range, I would think the zen is better suited. My many zen projects included one that was biased @ 4 amps/ch, powered by 1500VA 45V trafo with 350,000uF capacitance, it completely blew my diy Aleph 5 away with similar power supply, on my speakers anyway. 8m PS cabling sounds a bit like a hassle, if not detrimental. Over-build the PS on the zen, increase voltage and bias, done and done!!

-john
 
Interesting. Thank you for your advices. From which brand are your 1500 VA transformer and the 350.000 uF caps?

8m PS cabling sounds a bit like a hassle, if not detrimental. -john

This was done causes certainly space conditions. The suited power supply of the mentioned ZEN are behind the bookcase cabinet on the opposite wall (far away from the audio components).
 
trans is Plitron, caps are a mixture of Sprague and Mallory...not really important IMHO.
The quality of the caps is important; if you use such with scew terminal, Sprague and Mallory are a good choice. Not so important is the capacity value itself (in opposite to the values for ESR).
By a newer ZEN project I use 4 pieces 47000uF/63V (3pc for power supply and 1 pc couple capacitor between amp + speakers) from this series:
http://www.ftcap.de/downloads/elektrolyt/datenblaetter_2009/GW2009.PDF
one of the best exist caps for such projects
I recommend still the 63V versions, even if only max 27V is present.
 
The quality of the caps is important; if you use such with scew terminal, Sprague and Mallory are a good choice. Not so important is the capacity value itself (in opposite to the values for ESR).
By a newer ZEN project I use 4 pieces 47000uF/63V (3pc for power supply and 1 pc couple capacitor between amp + speakers) from this series:
http://www.ftcap.de/downloads/elektrolyt/datenblaetter_2009/GW2009.PDF
one of the best exist caps for such projects
I recommend still the 63V versions, even if only max 27V is present.

You really gotta get a grip.

The Aleph has no place with a single high eff. FR driver. On the contrary, the old Zen sure has, for obvious reasons.

Sure it's easier to keep talking nonsense, than actually dealing with the facts.

Magura :)
 
I don't understand this:
The Aleph has no place with a single high eff. FR driver. On the contrary, the old Zen sure has, for obvious reasons.
Why has Aleph no place at full range drivers?
And what means "obvious reasons" in your mind?

by the way - you will note by study of the data sheet, that the FE103E driver isn't a high efficiency version.
 
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The re-read John's explanation, and the articles regarding the topic, published by Nelson Pass.

Trouble is that you tend to insist looking for reason in religion.
You're not going to find it there.
No amount of fancy caps, resistors, or power switches, is going to change the topology signaure. Magura :)

Most amp developers claim also, that a well-designed circuit topology no need excessive demands on the quality of components like caps, transformers and other stuff (I suppose, you also think so).

But my (and some other) practical experiences contradict mostly these statements clearly. This means for me at the same time, that only ultimate quality by certainly devices (and necessary also perfect wiring management) may sound differences audible expose between different circuit topologies.
If someone broke this rule (unfortunately, most often the case), nobody can say about sonic advantages and disadvantages by different circuit topologies.

I don't looking for reason in religion. Only clear facts count for me.

By the way - you recommend papers without precise references.
Nelson Pass have a lot articles there
http://www.passdiy.com/articles.htm
Pass Labs: Articles
And who is John? John Curl or John Linsley Hood ? and which paper?
 
The Zen has an output resistance of about one ohm for a damping factor of about eight. With the bass challenged FE103, this would warm things up a bit and possibly make the speaker sound better. Try a one ohm resistor between the Aleph and the speaker. Sometimes speakers are designed to suit amplifiers with highish output resistance. They would sound thin, perhaps harsh, on an amplifier with a low output resistance/high damping factor. The speaker may work better with an amp with highish output resistance.

Jim
 
You really gotta get a grip.
The Aleph has no place with a single high eff. FR driver. On the contrary, the old Zen sure has, for obvious reasons.
Sure it's easier to keep talking nonsense, than actually dealing with the facts.
Magura :)

Completly nonsense. I have now check the Aleph 5 with the power supply from the ZEN. Therefore I must disconnect the power line to the "ZEN" circuit and redesign the Aleph-5 for the lower voltage. Additional I must create a virtual GND and I have enhance the idle current to the same value than the ZEN.
The sonic results now much more closer to the ZEN circuit than before. Residual differences are negligible. This means, that I recommend a right designed outdoor power supply for the Aleph 5. The differences between the 1 ohms resistor in series to the loudspeaker deliver also completly other sound. But the kind of difference are not comparable to that between the orig. Aleph 5 and ZEN.

"Trouble is that you tend to insist looking for reason in religion" - claims Magura at post #8 .
True for some guys, but not for me.
 
With full-range, I would think the zen is better suited. My many zen projects included one that was biased @ 4 amps/ch, powered by 1500VA 45V trafo with 350,000uF capacitance, it completely blew my diy Aleph 5 away with similar power supply, on my speakers anyway. 8m PS cabling sounds a bit like a hassle, if not detrimental. Over-build the PS on the zen, increase voltage and bias, done and done!!
-john

It agrees with my guess, that big advantage of simple Zen scematics is in the simple current source load for the gain transistor. This precludes influence of the PS electrolytics. Almost 99,99% of amps makes PS electrolytics involved in output signal path, and these caps usually are not demanded to be audiophile grade. Therefore many people say that all amps sound similar. In Zen schematics electrolytics are also present at the output, but people cares a lot about its quality. I guess the enclosed schematics implements in many aspects your approach to Zen upgrade.
 

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It agrees with my guess, that big advantage of simple Zen scematics is in the simple current source load for the gain transistor. This precludes influence of the PS electrolytics. Almost 99,99% of amps makes PS electrolytics involved in output signal path, and these caps usually are not demanded to be audiophile grade. Therefore many people say that all amps sound similar.
I agree. This is so by the most amplifiers so (I have explain more in detail by an other thread here by diyaudio). Because the drawing technique by schematic creating however arises the impression, that the capacitors of the power supply does not lie in the signal pad (and most developers fall out in this impression).

What about sonic differences between this Mitsubishi MOSFET
http://www.rfparts.com/pdf_docs/RD/rd100hhf1.pdf
and that one normally used in the power stage - have you compare both?
 
I agree. This is so by the most amplifiers so (I have explain more in detail by an other thread here by diyaudio). Because the drawing technique by schematic creating however arises the impression, that the capacitors of the power supply does not lie in the signal pad (and most developers fall out in this impression).

What about sonic differences between this Mitsubishi MOSFET
http://www.rfparts.com/pdf_docs/RD/rd100hhf1.pdf
and that one normally used in the power stage - have you compare both?

I have ordered RD100HHF1 and plan to make a try. My previous experience with the radio transistors CP650 (or russian KP903) in buffer preamp was very very positive. I guess the RD100HHF1 must be phenomenal for audio, look at their Ciss, it is almost flat and only 260pF. It seems that just small and flat Ciss makes a transistor close to a tube. I think the Return of Zen schematics is a correct basis for such a trial.
 
It agrees with my guess, that big advantage of simple Zen scematics is in the simple current source load for the gain transistor. This precludes influence of the PS electrolytics.

Just to confirm my understanding: It's only true to say that the PSU capacitors are outside the signal path for the earliest Zen designs where the current source was actually constant. The later designs used a modulated current source (aka Aleph) and in these designs the PSU capacitors are in the signal path as they would be for any PP amplifier.
 
Just to confirm my understanding: It's only true to say that the PSU capacitors are outside the signal path for the earliest Zen designs where the current source was actually constant. The later designs used a modulated current source (aka Aleph) and in these designs the PSU capacitors are in the signal path as they would be for any PP amplifier.

You are partially wright, all designs with the modulated current source, they are a 50-50% compromise between the Zen1 and PP designs. So, they are less dependent on PS electrolytics than PP, but more than Zen1. This 50-50% situation allows diminish strongly the PS effects by big enough polypropylene shunt capacitors.
 
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