Last Saturday three Salt Lake City Pass fans gathered at my home to listen to and compare four Pass amps. The amps listened to were the Mini Aleph, the Aleph 3, and a pair of Aleph 2's. We also listened to one channel of a Zen ver. 3.0. All amps got at least an hour warm up before any listening was done. First at bat was the pair of 2's which are biased at higher than normal level. The typically neutral sounding 2's lived up to their name and were detailed and had good sound staging and resolution and really excellent dynamics.. However when the Mini Aleph was hooked in it sounded considerably better with increased resolution and sound staging over the 2's. The Mini also had an apparent slightly brighter top end and was able to drive the Dynaudios to decent levels. Next up was the Aleph 3 which was another major step up in improvement in just about all aspects. While its top end was similar to the Mini its soundstaging and resolution has to be heard to be appreciated!! The one working channel of the Zen was next hooked up and initial thoughts were that it had a very tube like sound but Zen again very different from a tube amp. It didn't seem to have the resolution that the Aleph 3 or the Mini posseses but a single channel comparison was not totally meaningful at least to me. The owner of the Zen has promised to repair it and return for further comparisons. But for now the Aleph 3 was the clear winner (pun intended!).
The system consisted of Dynaudio Audience 9 speakers, Rosenblits Grounded Grid line stage, a Pioneer DV-45A multi format CD player, Gotham Audio Star Quad amp interconnects, and Kimber 4TC speaker cabling.
It was alot of fun and showed how good DIY stuff is. Hopefully the Zen owner will return in the next month sometime with his Zen fully working for further comparisons. If any other Salt Lake City Pass fans, Krell fans, or any other Audioaholics are interested in gathering in the near future please contact me. Nelson is of course invited to attend anytime
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The photo shows the amps.....Left to right Zen Ver 3.0, Aleph 3 nesting on top of of one of the Aleph 2's, and the Mini on the right.
Mark
The system consisted of Dynaudio Audience 9 speakers, Rosenblits Grounded Grid line stage, a Pioneer DV-45A multi format CD player, Gotham Audio Star Quad amp interconnects, and Kimber 4TC speaker cabling.
It was alot of fun and showed how good DIY stuff is. Hopefully the Zen owner will return in the next month sometime with his Zen fully working for further comparisons. If any other Salt Lake City Pass fans, Krell fans, or any other Audioaholics are interested in gathering in the near future please contact me. Nelson is of course invited to attend anytime
.The photo shows the amps.....Left to right Zen Ver 3.0, Aleph 3 nesting on top of of one of the Aleph 2's, and the Mini on the right.
Mark
Attachments
The 2's have a standard supply with 120,000 per rail, 760 va toroid.
The Mini has a 320 va standard supply with a single 120,000 Panasonic cap per rail.
By standard I mean there is no CLC or CRC type filtering going on in the supply, just a bridge feeding a capacitor bank.
The 3 has a 500VA toroid with a CLC type supply. A single bridge feeds 54,ooo mfd, then a 2mh toroid choke followed by another 27,000 mfd. All three Alephs used IRFP240 devices, the Zen has IRFP044. I also won't attribute all of the 3's sucess to the CLC supply. This is a design that Nelson hit the nail on the head with. It sure upheld its classic status by quite a margin!!
Mark
The Mini has a 320 va standard supply with a single 120,000 Panasonic cap per rail.
By standard I mean there is no CLC or CRC type filtering going on in the supply, just a bridge feeding a capacitor bank.
The 3 has a 500VA toroid with a CLC type supply. A single bridge feeds 54,ooo mfd, then a 2mh toroid choke followed by another 27,000 mfd. All three Alephs used IRFP240 devices, the Zen has IRFP044. I also won't attribute all of the 3's sucess to the CLC supply. This is a design that Nelson hit the nail on the head with. It sure upheld its classic status by quite a margin!!
Mark
I built a pair of the 60 watt X's and was not impressed and sold the boards to another person on these threads. When I ahve more time to spend on them I will make another attempt as I have alot of boards left. Right now the KSA-50 clone is my latest project(Don't anyone tell Nelson!). The X will come about again after that is finished. As for line stages.... its pretty hard to beat the Grounded Grid.
Mark
Mark
The Aleph 3 has a couple of things going for it. One is that the stock version has the highest proportionate bias of any of the Alephs. Another is that, of the stock Alephs, it has the least number of output devices for the front end to push. I'm not saying that you can't push the other Alephs a little further here and there, but don't count the little feller out just because it's the baby of the family.
The Mini-A isn't a "real" Aleph, of course, nor even a Nelson Pass design, per se. I make no claims for it other than it's a simple project for those who are curious about the Aleph topology. I would certainly urge people to build a genuine Aleph as soon as finances, etc. allow, and not depend on my toy version.
Grey
The Mini-A isn't a "real" Aleph, of course, nor even a Nelson Pass design, per se. I make no claims for it other than it's a simple project for those who are curious about the Aleph topology. I would certainly urge people to build a genuine Aleph as soon as finances, etc. allow, and not depend on my toy version.
Grey
Beautiful amps all, Mark.
I think the preferences between the amps have more to
do with taste and associated equipment than actual
superiority of one versus another.
Of the Alephs, they are all of course, 2nd harmonic in their
characteristic.
And then the X types come in with a balanced SE stage and
hand you a 3rd harmonic, and you really notice the distinct
difference.
After a long time with simple 2nd vs 3rd harmonic character,
I've come to appreciate the differences, similar in the manner
we think about red vs white wine. The First Watt amps are
a fine example, with the F1 being a 3rd harmonic and the F2
being a 2nd.
The 2nds are typically richer and have more bloom, while the 3rds
are more dynamic and usually seem to offer more clarity.
Everybody seems to think they like 2nd harmonic best, but
historically, I have surmised that about half the population
likes 2nd and half likes 3rd at any given time, and among
those are a lot who can switch back and forth with a smile.
I think the preferences between the amps have more to
do with taste and associated equipment than actual
superiority of one versus another.
Of the Alephs, they are all of course, 2nd harmonic in their
characteristic.
And then the X types come in with a balanced SE stage and
hand you a 3rd harmonic, and you really notice the distinct
difference.
After a long time with simple 2nd vs 3rd harmonic character,
I've come to appreciate the differences, similar in the manner
we think about red vs white wine. The First Watt amps are
a fine example, with the F1 being a 3rd harmonic and the F2
being a 2nd.
The 2nds are typically richer and have more bloom, while the 3rds
are more dynamic and usually seem to offer more clarity.
Everybody seems to think they like 2nd harmonic best, but
historically, I have surmised that about half the population
likes 2nd and half likes 3rd at any given time, and among
those are a lot who can switch back and forth with a smile.
The Mini-A isn't a "real" Aleph, of course, nor even a Nelson Pass design, per se.
If I am not mistaken these are built with the same circuit as the "real" Aleph with some improvements from the (how to improve an Aleph thread).
Did you build the Mini-a boards?
Take apart that POS A3 in the bent housing and replace it with a mini.
If I am not mistaken these are built with the same circuit as the "real" Aleph with some improvements from the (how to improve an Aleph thread).
Did you build the Mini-a boards?
Take apart that POS A3 in the bent housing and replace it with a mini.
Mike,
I've got one Mini-A (built on your boards) running in the living room with an old Dyna PAS-3 preamp. I was listening to Miles Davis on it not long ago. I've begun pulling parts to build a second one; there's a small pile of stuff not far from my work bench.
The A3 you sent does not qualify in my book as a POS in any way. It is slowly being modified. I have begun with the power supply. The transformer remains. I etched a PC board for the caps. I've gone CRC with the second leg being some of those big caps from ApexJr. I have other things in mind, including the possibility of Evil Experiments.
Yes, the chassis is filling up pretty rapidly.
When I say that the Mini-A isn't a real Aleph, I'm trying to distinguish it from the commercial Alephs or the Zen project version on www.passdiy.com. Obviously, it is an Aleph in the sense that it's a cut-down Aleph 3, but I'd rather that people didn't blame Nelson for my fiddlings. It wasn't his fault--it's just something I threw together for fun and as a stepping stone to the Aleph-X. I'm pleased that it seemed to hold its own in the shoot-out, but we need to apportion blame and credit properly. Nelson created the Aleph circuit, so he gets the credit. I came along and took it upon myself to make a little one. If it sounds good, great. But make sure that the back-slapping goes to Nelson, not me. I was just playing around.
Grey
I've got one Mini-A (built on your boards) running in the living room with an old Dyna PAS-3 preamp. I was listening to Miles Davis on it not long ago. I've begun pulling parts to build a second one; there's a small pile of stuff not far from my work bench.
The A3 you sent does not qualify in my book as a POS in any way. It is slowly being modified. I have begun with the power supply. The transformer remains. I etched a PC board for the caps. I've gone CRC with the second leg being some of those big caps from ApexJr. I have other things in mind, including the possibility of Evil Experiments.
Yes, the chassis is filling up pretty rapidly.
When I say that the Mini-A isn't a real Aleph, I'm trying to distinguish it from the commercial Alephs or the Zen project version on www.passdiy.com. Obviously, it is an Aleph in the sense that it's a cut-down Aleph 3, but I'd rather that people didn't blame Nelson for my fiddlings. It wasn't his fault--it's just something I threw together for fun and as a stepping stone to the Aleph-X. I'm pleased that it seemed to hold its own in the shoot-out, but we need to apportion blame and credit properly. Nelson created the Aleph circuit, so he gets the credit. I came along and took it upon myself to make a little one. If it sounds good, great. But make sure that the back-slapping goes to Nelson, not me. I was just playing around.
Grey
Nelson,
Thanks for the kind comments!! Its been alot of fun over the last few years building these. Its thanks to you that are we able to persue great hobbies like this. I agree that differnet amps are like differnet wine and cheese and should you show up in SLC some day we'll be sure to have some good stuff around for you!
When I was working on the Aleph 3 that I built for Lyndon he had mistakenly put in a 100 ohm resistor for the 1K in the feedback loop, this problem was the subject of another thread here about three weeks ago. The resultant output clipped at about 12 watts and the distortion was around 4%. The funny thing is that this amp actually sounded pretty darn good this way....... the reason was that it was all even harmonic distortion content and our ears don't seem to mind this too much.
The top trace in the attached photo shows a 10 watt 10 khz output into a resistive 8 ohm load. The bottom trace shows the resultant distortion content at the output of the distortion analyzer(Sound Technology 1701A). This distortion content looks pretty awful..... and it is! After replacing the 100 ohm resistors with the correct 1K value it clipped at about 27 watts into 8 ohms and had less than .25% distortion content, still all even order. Unfortunately my digital camera was left at wotk that evening so I can't show you that resltant distortion content after the resistir change but what was there was but a fraction of what was on this photo and very different looking.
If I have time tommrrow night I will hook up my Mini-A and do the same thing and take photos. Instead of just sending it to the scope, I will run the resultant distortion into my HP-3580 Spectrum analyzer and take a shot of that and post it. What you will see is that Alephs tend to only exhibit even harmonic distortion residuals. This is seen on the spectrum analyzer as a pip at double, four times, and so on of the original frequency. As the frequency goes up the residuals go way down to below the diaplay level of the analyzer in quite a big hurry.
Other amps that exhibit odd order will show pips at odd multiples of the original frequency. An old solid state amp like a Phase LInear will show residual harmonics at both even and odd frequencies!! Thats one reason they sound lke YUCK!
Mark
Thanks for the kind comments!! Its been alot of fun over the last few years building these. Its thanks to you that are we able to persue great hobbies like this. I agree that differnet amps are like differnet wine and cheese and should you show up in SLC some day we'll be sure to have some good stuff around for you!
When I was working on the Aleph 3 that I built for Lyndon he had mistakenly put in a 100 ohm resistor for the 1K in the feedback loop, this problem was the subject of another thread here about three weeks ago. The resultant output clipped at about 12 watts and the distortion was around 4%. The funny thing is that this amp actually sounded pretty darn good this way....... the reason was that it was all even harmonic distortion content and our ears don't seem to mind this too much.
The top trace in the attached photo shows a 10 watt 10 khz output into a resistive 8 ohm load. The bottom trace shows the resultant distortion content at the output of the distortion analyzer(Sound Technology 1701A). This distortion content looks pretty awful..... and it is! After replacing the 100 ohm resistors with the correct 1K value it clipped at about 27 watts into 8 ohms and had less than .25% distortion content, still all even order. Unfortunately my digital camera was left at wotk that evening so I can't show you that resltant distortion content after the resistir change but what was there was but a fraction of what was on this photo and very different looking.
If I have time tommrrow night I will hook up my Mini-A and do the same thing and take photos. Instead of just sending it to the scope, I will run the resultant distortion into my HP-3580 Spectrum analyzer and take a shot of that and post it. What you will see is that Alephs tend to only exhibit even harmonic distortion residuals. This is seen on the spectrum analyzer as a pip at double, four times, and so on of the original frequency. As the frequency goes up the residuals go way down to below the diaplay level of the analyzer in quite a big hurry.
Other amps that exhibit odd order will show pips at odd multiples of the original frequency. An old solid state amp like a Phase LInear will show residual harmonics at both even and odd frequencies!! Thats one reason they sound lke YUCK!
Mark
Attachments
I'll be bringing my Aleph 30 to the upcoming DIY AZ event in Tucson if anyone with a different Aleph in the area wishes to replicate this experiment.
http://www.madisound.com/cgi-bin/discuss.cgi?read=332418
Rob
http://www.madisound.com/cgi-bin/discuss.cgi?read=332418
Rob
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