Ultra series preamps and FET-Valve power amps

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modular747

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Ultra series preamps and FET-Valve power amps
« on: 11 Nov 2005, 04:48 pm »
I've read, on this site, mention about new "Ultra" series preamps and power amps and got the impression they were in production.  I couldn't find anything about them on the AVA website.  Is there any detailed information about them available?

Thanks

avahifi

Ultra series preamps and FET-Valve power amps
« Reply #1 on: 11 Nov 2005, 05:57 pm »
Because I was put out of commission for a while recently for health reasons (see Mr. VanAlstine is recovering thread), there are some things that have just not gotten done around there.  Among these are an updated web site with all new product descriptions and photos and a new paper catalog.

I am recovering well, but my first priorities are existing orders, making sure the new circuits and hardware are working properly (they are) and dealing with the huge pile of paperwork backlog from day to day operations.

The Ultra SL and EC preamps (and the Transcendence Eight tube preamp) are finished, perfected, and in production with the new black/gold faceplates and functions, and with their new mother boards.  These units all feature much improved layouts and very significant power supply upgrades (eleven separate regulated power supplies for each unit - all built into the new mother board).

The Ultra DAC is in the final stage of testing with no problems and we are about 30 days from having this unit also moved to the new chassis (see the thread showing our faceplates).

The Ultra 350 and 550 amps are also finished and new sheet metal for them is about 2-3 weeks out.

Each new unit represents a major upgrade in layout and power supply and grounding and in musicality too.

I will post photos as soon as we have time to get them done.

Frank Van Alstine

modular747

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Ultra series preamps and FET-Valve power amps
« Reply #2 on: 12 Nov 2005, 01:06 am »
Quote from: avahifi
Because I was put out of commission for a while recently for health reasons (see Mr. VanAlstine is recovering thread), there are some things that have just not gotten done around there.  Among these are an updated web site with all new product descriptions and photos and a new paper catalog.

I am recovering well, but my first priorities are existing orders, making sure the new circuits and hardware are working properly (they are) and dealing with the huge pile of paperwork backlog from day to day operati ...


Thanks for your prompt reply.  I'm sorry you were ill and had such an ordeal (I read your report on it), and I'm glad to hear you're recovering well now.  Looking forward to your new Ultra series.

M. Halperin

guest1632

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Ultra series preamps and FET-Valve power amps
« Reply #3 on: 13 Nov 2005, 12:31 pm »
Quote from: avahifi
Because I was put out of commission for a while recently for health reasons (see Mr. VanAlstine is recovering thread), there are some things that have just not gotten done around there.  Among these are an updated web site with all new product descriptions and photos and a new paper catalog.

I am recovering well, but my first priorities are existing orders, making sure the new circuits and hardware are working properly (they are) and dealing with the huge pile of paperwork backlog from day to day operati ...


Hi Frank,

Well, Could you then please post new prices here for the new/current stuff? So you have done some upgrades to the solid state gear too. hmmm, So what would you say is the major differences between the FetValve stuff versus the SS gear? Is it a night and day difference? Say, if I were to walk in to a room, would the difference be obvious, or is it subtle at best?

Ray

avahifi

I will try to answer some of your questions
« Reply #4 on: 13 Nov 2005, 05:14 pm »
First of all OmegaStar solid state equipment as compared to Ultra hybrids.

We feel the OmegaStar equipment is about as musical as you are going to get with all solid state technoligy.  The equipment is open, big soundstage, glare and grain free, wide range, dynamic, and quiet, and of course much less expensive than the hybrid and tube units.  It is lacking (as are all solid state audio components I have ever heard) an intangable ability to reach way into the emotions of the musician.  That may or may not be important to you depending upon your expectations and the quality of your associated equipment.  I can tell you that the market has changed significantly in recent years.  Most clients now go for the hybird and tube equipment.  I think those with more significant budget constraints are off doing multi-channel home theater stuff and have never reached the point of hearing or understanding what they are missing.

Those that have got the message about the beauty of real music reproduced correctly are going for the very best they can afford, and that is our hybrid and tube equipment.

Will a casual "walk in the room" listener hear the difference and find it obvious?  It depends upon the listener.  Some will, some will not.  It depends upon past experiences and expectations.  Its kind of like a cruise ship experience.  If you have never been on a cruise, then a Princess or Carnival cruise will likely seem really wonderful.  If, however, you have been a Crystal or Raddison client, then "stepping down" to a Princess cruise will seem pretty "ho hum" and mass produced.

Anyway, there have been no recent changes to the OmegaStar product line and no pricing changes either.  The web site and catalog are current regarding these products.

To be continued.

Frank Van Alstine

guest1632

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Re: I will try to answer some of your questions
« Reply #5 on: 13 Nov 2005, 09:52 pm »
Quote from: avahifi
First of all OmegaStar solid state equipment as compared to Ultra hybrids.

We feel the OmegaStar equipment is about as musical as you are going to get with all solid state technoligy.  The equipment is open, big soundstage, glare and grain free, wide range, dynamic, and quiet, and of course much less expensive than the hybrid and tube units.  It is lacking (as are all solid state audio components I have ever heard) an intangable ability to reach way into the emotions of the musician.  
Quote

Hi Frank,

Well, let me rephrase my question. I've been around this hobby for at least 30 years now, so I would be aware of the subtle stuff if presented with it. So assuming for this discussion, a person has some knowledge how to listen to audio, and they walk in to a room. You present them with two different listning situations, one with just the SS stuff and the other with the FETValve stuff. Is the FetValve an obvious difference, like night and day, or is it like a cloudy day to a nice sunny one. Or is it at dusk to dark? How's that for analogies?

Ray

skrivis

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Re: I will try to answer some of your questions
« Reply #6 on: 14 Nov 2005, 03:40 pm »
Quote from: avahifi
First of all OmegaStar solid state equipment as compared to Ultra hybrids.

We feel the OmegaStar equipment is about as musical as you are going to get with all solid state technoligy.  The equipment is open, big soundstage, glare and grain free, wide range, dynamic, and quiet, and of course much less expensive than the hybrid and tube units.  It is lacking (as are all solid state audio components I have ever heard) an intangable ability to reach way into the emotions of the musician.  That may or may not ...


What are the differences from a more objective viewpoint? As an engineer, what do you see as the difference between the OS and Ultra equipment?

Why is SS lacking as compared to tubes?

Is the Ultra gear actually more correct, or are its flaws simply more pleasurable?

I'd also like to point out that the OS gear lets plenty of the "emotions" through. :) I'm pretty picky and I'm very happy with it. It lets the music through(TM). hehe

WEEZ

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Ultra series preamps and FET-Valve power amps
« Reply #7 on: 14 Nov 2005, 06:34 pm »
skrivis,

A long time ago, someone said that one of the reasons that tubes sound different from transistors is that tubes are a valve and transistors are a switch.   :o

A mosfet acts more like a tube (that same someone said...). Can't remember who, though.

WEEZ

skrivis

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Ultra series preamps and FET-Valve power amps
« Reply #8 on: 14 Nov 2005, 08:06 pm »
Quote from: WEEZ
skrivis,

A long time ago, someone said that one of the reasons that tubes sound different from transistors is that tubes are a valve and transistors are a switch.   :o

A mosfet acts more like a tube (that same someone said...). Can't remember who, though.

WEEZ


That's not what I was really looking for, but thanks. :)

WEEZ

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Ultra series preamps and FET-Valve power amps
« Reply #9 on: 14 Nov 2005, 11:30 pm »
:lol:

I know, but hey- I've always remembered that analogy. And at my age, I don't remember much, so there you have it  :)

WEEZ

guest1632

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Re: I will try to answer some of your questions
« Reply #10 on: 15 Nov 2005, 01:51 am »
Quote from: skrivis
What are the differences from a more objective viewpoint? As an engineer, what do you see as the difference between the OS and Ultra equipment?

Why is SS lacking as compared to tubes?

Is the Ultra gear actually more correct, or are its flaws simply more pleasurable?

I'd also like to point out that the OS gear lets plenty of the "emotions" through. :) I'm pretty picky and I'm very happy with it. It lets the music through(TM). hehe

]
FETs and tubes have some similar characteristics. As a general statement, transistors dieal with a lot of odd order harmonics. Tubes on the other hand let 2nd order even harmonics through, which is more pleasurable to listen to. As a General STATEMENT, I don't want people to get bent out of shape here, but the "tube" sound traditionally, or has had the reputation of being  in times past, fat or bloated bass very rich in forward sound in the mids, and a laid back highend. That's how tube stuff at least  it used to sound. Now for SS gear, it can be fast, tight in the bass, not much happening in the mids, and a rather harsh topend.  Now these are big generalities. As a kind of rule of thumb, a very very very well designed piece of tube gear versus a very very very well designed piece of solid state gear will be in a lot of respects pretty close to each other in sound. Design of tube equipment has come a long way, as well as transistor stuff. They both have their strengths and weaknesses. What Frank has done is to take the good characteristics of the tube and add it to the FET stage, so you have the best of both worlds, both SS and tubes sound.  I'll let Frank go more in to the tech stuff. Now, that probably did not answer your question huh?

Ray

WEEZ

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Ultra series preamps and FET-Valve power amps
« Reply #11 on: 15 Nov 2005, 02:41 am »
Ray, you are correct- good designs or either genre will sound great.

Tubed amplification will usually allow for greater ambiance and 'air'; as well as a more 3D soundstage, therefore more 'realism'. To some, this could be heard as 'subtle'. To others, it is night and day.

WEEZ

guest1632

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Ultra series preamps and FET-Valve power amps
« Reply #12 on: 15 Nov 2005, 02:54 am »
Quote from: WEEZ
Ray, you are correct- good designs or either genre will sound great.

Tubed amplification will usually allow for greater ambiance and 'air'; as well as a more 3D soundstage, therefore more 'realism'. To some, this could be heard as 'subtle'. To others, it is night and day.

WEEZ


Well Weez, I think that the transistor designed stuff that the vendors here on the circle sell will do the same stuff as some of the tube gear. Now, to be fair, I haven't heard any of the equipment except for the Purist, and any of the tube stuff, but I'll almost wager that the SS stuff will produce a good 3D sound stage, and have a lot of air too.. I'm not partial to either format.

Ray

skrivis

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Ultra series preamps and FET-Valve power amps
« Reply #13 on: 15 Nov 2005, 02:18 pm »
Quote from: WEEZ
Ray, you are correct- good designs or either genre will sound great.

Tubed amplification will usually allow for greater ambiance and 'air'; as well as a more 3D soundstage, therefore more 'realism'. To some, this could be heard as 'subtle'. To others, it is night and day.

WEEZ


I might suggest that these are all due to distortion. :)

avahifi

Ultra series preamps and FET-Valve power amps
« Reply #14 on: 15 Nov 2005, 02:49 pm »
Our take on it is that vacuum tubes have a significantly higher overload immunity in summing the input with the feedback (maybe 200V or so) while a solid state design might have half a volt or so at best.  Thus feedback related transient corrections can be handled way better with vacuum tubes.  However, tubes have high output impedance and low drive current and cannot drive loads downstream very well and their linearity suffers.

We would suggest that solid state harshness is essentially feedback related overload, and vacuum tube "mush" is essentially high distortion caused by the tube trying to drive a load it cannot.

The object of the Fet Valve transimpedence amplifier circuit is to make a "super tube" with high input impedence, low output impedence, extreme immunity from feedback related overload, high output drive current, and very wide bandwidth.  And thus eliminate both of the problems described above.

As we learn more and more about the way the transimpedence amplifier is working, we have improved its operation significantly over the years and now with the new Ultra mother board we are really happy with the overall musicality we are able to get.

Frank Van Alstine

skrivis

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Re: I will try to answer some of your questions
« Reply #15 on: 15 Nov 2005, 03:11 pm »
Quote from: Ray Bronk
]
FETs and tubes have some similar characteristics. As a general statement, transistors dieal with a lot of odd order harmonics. Tubes on the other hand let 2nd order even harmonics through, which is more pleasurable to listen to. As a General STATEMENT, I don't want people to get bent out of shape here, but the "tube" sound traditionally, or has had the reputation of being  in times past, fat or bloated bass very rich in forward sound in the mids, and a laid back highend. That's how tube stuff at least  i ...


Well, this also wasn't really what I was looking for. This type of thing dates back to a paper that compared tube versus SS circuits for use in mixing boards in the studio. The statements about odd order vs. even order can really only be made in the context in which they were in that original paper - at full clipping. They were talking, IIRC, about THD levels in the range of 5% and up.

They were also talking about the raw input from the mics or electronic instruments. The problems that a mic amp or line amp in a mixing console see are not the same as what a stereo preamp will see.

I would agree that an overdriven tube circuit is likely to sound better than an overdriven SS one. I'm just not sure how relevant these behaviors are during normal operation of a stereo system.

Furthermore, the article dealt with circuits that were really badly behaved when they clip. Frank claims (and I believe him) that AVA equipment doesn't get into trouble nearly as much as the limits are reached.

So, now we have to figure out how much normal program content will actually push the limits of the circuitry. To me, it doesn't sound like AVA equipment runs that close to the ragged edge. You have to be abusing the gear before that happens. (Frank?)

I suppose I've just been conditioned over the years into feeling that better sounding circuits will be provably better behaved cicruits. I'm not quite hearing that concept in the info AVA is giving on the latest gear. There's more of a "we don't know exactly why" and "it just sounds better" kind of thing going on to explain why the tube gear is superior. It may very well be true, but it's not the approach I'm used to. :)

It's not really meaningful anyway. I trusted Frank when he said a given circuit was better and talked about engineering reasons why it was better. I trust him now when he says the tube gear is better than SS; I just miss the more engineering-based explanations. :)

guest1632

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Re: I will try to answer some of your questions
« Reply #16 on: 16 Nov 2005, 01:19 pm »
Quote from: skrivis
Well, this also wasn't really what I was looking for. This type of thing dates back to a paper that compared tube versus SS circuits for use in mixing boards in the studio. The statements about odd order vs. even order can really only be made in the context in which they were in that original paper - at full clipping. They were talking, IIRC, about THD levels in the range of 5% and up.

They were also talking about the raw input from the mics or electronic instruments. The problems that a mic amp or line  ...


Hi Skrivis,

Well, first of all, I was pointing out extremes. Both the odd order of SS and even orer of tubes are still present today. the obvious choice is a balanced aproach so that both sets of harmonics are removed or attenuated so they both do not play a significant role here in audiophile stuff. In the earlier days of transistors, you had the crossover junction which produced major harshness. Transistors have come a long way in that regard. The FET if my understanding is correct doesn't suffer from that design flaw, and its inherit behavior is more like tubes. Now, the best gear theoretically is gear that has no sound character of its own at all. Like I said, if a properly designed tube and SS say a preamp is designed correctly, both pieces whether they use tubes or SS, will sound pretty close to each other.
 
"Our take on it is that vacuum tubes have a significantly higher overload immunity in summing the input with the feedback (maybe 200V or so) while a solid state design might have half a volt or so at best. Thus feedback related transient corrections can be handled way better with vacuum tubes. However, tubes have high output impedance and low drive current and cannot drive loads downstream very well and their linearity suffers.

We would suggest that solid state harshness is essentially feedback related overload, and vacuum tube "mush" is essentially high distortion caused by the tube trying to drive a load it cannot."

The above 2 paragraphs don't necessarily say that tubes are better than SS gear at all. Frank is just pointing out the advantages of both sides, tubes and transistors. That 2nd order harmonic thing that tube do so well is still inherit in any tube designed equipment, and is the the nature of the beast. We can debate the merits of both formats all day long. Like I said in earlier posts, Frank has come along and correctly combined the best in SS and the best in tubes gear to make a product that might be hard to beat anywhere. Why don't I own it? ... Well, it's a matter of ... like a lot of us, money

Ray

skrivis

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Ultra series preamps and FET-Valve power amps
« Reply #17 on: 17 Nov 2005, 03:33 pm »
Quote from: avahifi
Our take on it is that vacuum tubes have a significantly higher overload immunity in summing the input with the feedback (maybe 200V or so) while a solid state design might have half a volt or so at best.  Thus feedback related transient corrections can be handled way better with vacuum tubes.  However, tubes have high output impedance and low drive current and cannot drive loads downstream very well and their linearity suffers.

We would suggest that solid state harshness is essentially feedback related  ...


Ok, that makes sense. Thank you for the info.

skrivis

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Re: I will try to answer some of your questions
« Reply #18 on: 17 Nov 2005, 03:40 pm »
Quote from: Ray Bronk
Hi Skrivis,

Well, first of all, I was pointing out extremes. Both the odd order of SS and even orer of tubes are still present today. the obvious choice is a balanced aproach so that both sets of harmonics are removed or attenuated so they both do not play a significant role here in audiophile stuff. In the earlier days of transistors, you had the crossover junction which produced major harshness. Transistors have come a long way in that regard. The FET if my understanding is correct doesn't suffer from  ...


I hadn't yet seen Frank's latest post when I wrote mine. (Perhaps we were writing at the same time.)

My whole point is that a lot of companies and people (not AVA) espouse the whole odd vs. even order distortion harmonics as the reason for the "superiority" of tubes, and that it all seems to go back to a paper written 40 years ago that doesn't really even apply to home audio.

Frank's explanation about handling of feedback is exactly what I was looking for. :)