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Anyone with direct experience with Angstrom Research from Italy?

160.62.7.250
Posted on April 16, 2015 at 03:54:56
morricab
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 They have some of the most complex looking power supply designs i have ever seen for an amplifier. Their design concept seems right in nearly everyway (except perhaps being push/pull), with an ultra stable incredibly regulated power supply and no feedback.

Looks like potentially reference level gear but I have learned to never judge these things based on the looks or even the coolness of the design.

 

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No but did you see these images? , posted on April 16, 2015 at 05:49:24
Awe-d-o-file
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Interesting PS. These images were from an eBay ad.

E
T




ET

"If at first you don't succeed, keep on sucking till you do suck seed" - Curly Howard 1936

 

RE: No but did you see these images? , posted on April 16, 2015 at 09:02:32
morricab
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 yes, the stuff is amazingly well made and uses tons of tubes...particularly for the power supply. Wild indeed...

 

RE: No but did you see these images? , posted on April 16, 2015 at 09:08:14
A.Wayne
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 Interesting design, Tubes in the wrong section thou ... :)

 

RE: No but did you see these images? , posted on April 16, 2015 at 09:30:29
Caucasian Blackplate
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 Wow, I've never seen protoboard in a finished high end product!

 

RE: No but did you see these images? , posted on April 16, 2015 at 10:00:50
A.Wayne
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 Point to point wiring , whats wrong .......? I'm more concerned about the tubes lying sideways...

Regards..

 

RE: No but did you see these images? , posted on April 16, 2015 at 13:47:35
morricab
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 Why? Nothing wrong with that...military style :)

 

RE: No but did you see these images? , posted on April 16, 2015 at 13:57:49
Caucasian Blackplate
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 That's not point-to-point wiring at all. That's protoboard. Protoboard is for prototyping, proof of concepts, etc.

 

RE: No but did you see these images? , posted on April 16, 2015 at 15:09:53
Caucasian Blackplate
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 Sideways tubes are a big concern with some directly heated tubes, as the filaments can sag and hit the grid.

Often times the datasheet will specify how the tube is to be oriented if operated horizontally. The KT-88 sheet says pins 4 and 8 must be in the vertical plane.

 

RE: Anyone with direct experience with Angstrom Research from Italy?, posted on April 16, 2015 at 18:37:40
hahax@verizon.net
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 A friend has owned several that he got while traveling to his home in Italy. I've seen and heard the latest integrated. They're beautifully made with superb power supplies from what I saw. I heard his amp but with speakers I was unfamiliar with but it seemed to do quite well with no obvious problems. Sorry I can't be more informative than that.

I do know it's a small operation but it has been around for quite a while, not a new boy on the block by many years. The one review from France I saw was very complimentary. The article describes the sound as between McIntosh mellow and Audio Research austere if that helps with good bass control.

The amp uses no overall feedback and is different in being a bridged amp, two amps per side hooked together.

 

RE:what's wrong with push/pull design? [n.t.a.], posted on April 17, 2015 at 03:36:05
wangmr
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 .

 

RE:what's wrong with push/pull design? [n.t.a.], posted on April 17, 2015 at 06:38:31
beppe61
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 Hi taken from the article by Mr. Pass in the link

" ... The push-pull symmetry topology has no particular basis in nature. Is it valid to use air's characteristic as a model for designing an amplifier?
If you accept that all processing leaves its signature on the music, the answer is yes. One of the most interesting characteristics of air is its single-ended nature... "

it makes sense i think.
The pull-phase is a negative pression (depression) that never happens in reality. When an object makes a sound the sound level is always from O up, never negative. Silence is 0dB.
In the single ended amps there is only push without pull ?
Kind regards,
bg

 

Sideways 6SN7's ok? Valvet Soulshine8 comes to mind., posted on April 17, 2015 at 09:45:30
Rick W
 Wondered if it stressed pins. Pic linked.

 

RE: Sideways 6SN7's ok? Valvet Soulshine8 comes to mind., posted on April 17, 2015 at 10:35:18
Caucasian Blackplate
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 You'll have to see what the datasheets say.

 

RE: No but did you see these images? , posted on April 17, 2015 at 11:16:39
Palustris
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 "That's not point-to-point wiring at all. That's protoboard. Protoboard is for prototyping, proof of concepts, etc."

Exactly! That unit is a prototype. How many fully engineered products have a piece of electrical tape preventing capacitors from shorting to another component? The construction techniques may look like a piece of consumer gear to those who have never been in electronic manufacturing, but to the DIY builder this looks very familiar.

 

RE: No but did you see these images? , posted on April 17, 2015 at 11:42:56
Caucasian Blackplate
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Looking at other gear from them, protoboard seems to be pretty common. I would be very nervous having octal sockets soldered to protoboard, as there isn't a lot of meat to solder to, and pulling a tube out of one of those sockets may rip the socket right off the board.

 

RE: No but did you see these images? , posted on April 17, 2015 at 12:28:21
Palustris
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 At least there is no electical tape covering the caps. I would be willing to accept that these are hand made units built in very limited quantities that preclude the use of PC boards. They still look like prototypes though; just like something engineering would hand off to manufacturing.

 

RE: No but did you see these images? , posted on April 17, 2015 at 14:29:33
A.Wayne
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 Prototype with full silk screen , i doubt it ,

 

RE:what's wrong with push/pull design? [n.t.a.], posted on April 17, 2015 at 15:57:20
pictureguy
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 Your model falls down when you consider that ZERO PSIG is 14.7 PSIA.
So, sound may not be able to get 'less loud' than zero db,
you DO have COMPRESSIONS above atmospheric pressure and RAREFACTIONS which are below.
In that sense, push-pull DOES exist.
Too much is never enough

 

RE: No but did you see these images? , posted on April 17, 2015 at 18:00:25
Palustris
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 "Prototype with full silk screen , i doubt it , "

Well, your skepticism is well founded if this is a small outfit e.g., a few guys in a garage. But if this is a real company engineering, marketing and manufacturing all have to sign off on the front panel, so it needs to be established early on in the design process. Engineering will design the functionality, marketing will ensure it complies with the company aesthetic, and manufacturing will find a supplier and get engineering samples. The prototype will be built to look like a finished product as far as possible so that marketing can produce the promotional materials and it can be shown to the sales guys who talk it up with the distributors. That's how a real company operates. Again, if this is two guys in a garage, that may not be the case.

 

" RAREFACTIONS ", posted on April 18, 2015 at 02:02:55
beppe61
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Hi do you mean that musical instruments can cause RAREFACTIONS ?
maybe singers yes ... when they suck air in to sing.
What i meant is that complete silence is the reference level.
You cannot go lower than that level.
Maybe i have not completely understood the explanation of Mr. Pass.

Kind regards,
bg

 

RE: No but did you see these images? , posted on April 18, 2015 at 07:56:00
Wojciech
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 Proto board or not it's a Point to Point technique , no? It's actually way more time consuming than regular PtP and looks "cleaner" I would prefer the tube sockets to be attached with screw/nut to the board but I don't think it's a big concern. Looking at the PSU not many DIY guys build that way and non of the manufacturers I'm familiar with. I wouldn't mind buying that amp.

 

RE: " RAREFACTIONS ", posted on April 18, 2015 at 09:14:51
pictureguy
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 Yes, complete silence is a reference level. Just try to ACHIEVE that in practice, however.
It takes special rooms and design to get the SPL down to such levels. ZERO SPL would be roughly the same as absolute Zero. You know it's 'there' but can you get to it?

ALL sound is composed of pressure / rarefaction. If you want just pressure, go under water a few feet. LESS pressure? Go UP in a plane with the door open. Or up a tall montain. The guys that climb the tallest peaks bring OXYGEN cylinders.

I just wonder about how MUCH the difference is in the micro-pressure DURING a sound wave?
Too much is never enough

 

RE: " RAREFACTIONS ", posted on April 18, 2015 at 09:44:49
beppe61
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Hi so you mean that Mr. Pass is wrong in his statement ?
Excuse me but i am really trying to understand here if what he is saying is right or wrong.
The poster was asking what could be wrong in push-pull amps i search and found the Mr. Pass argument in favor of single-ended amps and against push-pull.
Thanks.
Kind regards,
bg

 

RE: " RAREFACTIONS ", posted on April 18, 2015 at 10:14:47
pictureguy
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 I tend to disagree with Pass. Air is NOT just pressure, but when a sound producing element moves it produces pressure on one side and a rarefaction on the OTHER. 'The wave' of sound.

Do I MISunderstand Pass? Maybe. Where is the rest of the article?
Too much is never enough

 

RE: " RAREFACTIONS ", posted on April 18, 2015 at 10:25:21
beppe61
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 Hi and thanks for the explanation
Link to the article attached

One thing is sure ... he is very convinced on his position.
At the end he states ... " Regardless of the type of gain device, in systems where the utmost in natural reproduction is the goal, simple single-ended Class A circuits are the topologies of choice " ... stilling all doubts about his thinking.

Kind regards,
bg

 

RE: " RAREFACTIONS ", posted on April 18, 2015 at 11:22:03
pictureguy
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 I believe it is possible to agree with Pass on his ELECTRICAL stuff without necessarily buying into his model of sound in air. It is clear that sound reaching your ear is composed of BOTH pressure higher AND lower than 'still air'. Whatever that happens to be on any particular day or time. Sound is NOT like wind blowing where you can measure a static positive pressure.


Too much is never enough

 

RE: No but did you see these images? , posted on April 18, 2015 at 20:19:24
Caucasian Blackplate
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 Full silk screen isn't necessary, but if you want to put tube sockets on a PC board, you'll want through plated holes.

 

RE: " RAREFACTIONS ", posted on April 18, 2015 at 23:49:06
beppe61
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Hi and yes i think so me too.
And honestly i am a little out of my reach here. I am not a scientist.
I mentioned that article because is the only one that i have found about the push-pull vs. single-end approach.
However it is a very interesting topic. Many audiophiles like the single-ended approach especially with tubes.
Thanks again.
Kind regards,
bg

 

misunderstandings, posted on April 20, 2015 at 08:55:41
morricab
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 Think about a drum head. It vibrates in both the forward and backwards directions when the membrane moves forward it compresses air and when it moves backwards into the drum body it will pull some air (as the membrane displaces air will move to fill the vacuum). However, it is a single membrane creating the distinct sound and not two separate membrance pieces moving in opposite directions.

A single ended amplifier will amplify both the positive and negative aspects of the waveform without a handoff that invariably creates crossover distortion unless the push/pull amplifier is biased in Class A. Another sideeffect of push/pull is the cancellation of even order harmonics. This is not an effect seen in nature. Natural instruments and sound sources usually have monotonic harmonic structure (2nd, 3rd, 4th harmonic etc. in an exponential decay). A well designed SET amp will have the same monotonic distortion pattern as seen in nature.

A perfect push/pull amp will have NO even order harmonics. In practice though, they will have a 2nd order about the same size as the 3rd harmonic but then the evens will drop off quickly after that.

In nature pretty much everything is single ended push/pull is a purely human conception of how to make an amp more efficient but not really more correct.

That being said, I have heard some extremely good sounding push/pull amps but they lack the coherence of a really great SET, IMO.

 

RE: misunderstandings, posted on April 20, 2015 at 10:46:44
beppe61
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Hi and very interesting indeed and thanks a lot again for the very valuable explanation.
Therefore single ended designs have indeed some very strong points.
Maybe a good compromised would be to keep single ended operations at least to a certain power level and use a push-pull booster for the higher powers.
Like single-ended up to 10W and the last stage push-pull, of course when higher powers are required.
Thanks again.

Kind regards,
bg

 

RE: misunderstandings, posted on April 21, 2015 at 05:21:00
hahax@verizon.net
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 However an SET amp can not amplify even a simple sine wave correctly. It compresses the negative side of the wave compared to the positive side. So the amp is inherently non symmetrical and therefore non-linear. And this problem is caused by the topology of single ended and therefore not correctable. Fortunately this distortion sounds good to many.

 

RE: misunderstandings / thanks for your explanation [n.t.a.], posted on April 21, 2015 at 05:38:19
wangmr
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 .

 

RE: misunderstandings, posted on April 21, 2015 at 07:34:52
A.Wayne
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 Yes, many if not all love distortion, clipping is most favored ... :) BTW, the New Pass Amplifiers are considered to sound like an SET with PP power and drive...


Regards..

 

RE: misunderstandings, posted on April 21, 2015 at 08:14:32
morricab
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 Under clipping conditions you would be likely correct but well below that I think they are symmetrical enough not to cause too high distortion (my JJ amp is about .1% at 1 watt). If it was as bad as you say then it would be several % at all power levels.

 

Very Italian, posted on April 21, 2015 at 10:47:20
jedrider
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 If it doesn't look good, what's the point??

 

RE: misunderstandings, posted on April 21, 2015 at 20:55:41
hahax@verizon.net
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 That's where the high SET 2nd harmonic distortion comes from.

 

RE: Very Italian, posted on April 21, 2015 at 21:10:57
Wojciech
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 The point is , it probably sounds better than any currently manufactured American tube amplifier....

 

RE: Very Italian, posted on April 24, 2015 at 07:03:37
morricab
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 Exactly what I was thinking. To be honest I haven't had an American made amp in while. There are of course some very good ones, but I don't recall ever seeing such an extreme design before as the Angstrom amp...if only they would do a SET...

 

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