[TheChairGuy]

Hey Frank.....I know you try to keep 'rational' prices as your guide while devloping new amp models over the years.....but, unless I'm not aware of a dual mono AVA amp over the years, I've noticed you've largely been unswayed to make one that is dual mono.

I suppose I've been selling long enough to be curious as to how folks market their wares...but given the theoretical advantages of dual mono designs, I was wondering why you hadn't, or don't currently, market a dual mono amp  

I'm not sure if there is various definitions of dual mono out there....but I am talking about two transformers and mirror imaged stages in one amp chassis (two power cords really is over-the-top, but I suppose that would then make it fully dual mono mirror imaged in the same casework).  The current chassis, at least for OmegaStar's  SS units, seems to have ample room to accomodate a second transformer.

I think after 40 years selling amps you probably have rationale for this...I realize monoblocks might necessitate buying new casework and complicating many things for Audio by van Alstine, but dual mono's would largely NOT be a big logistical hurdle for ya'.  So, I'm wondering....

[philipp]

ChairGuy,
Doesn't the Stereo Phase Inverter Bridge already make this a reality?

http://www.avahifi.com/root/equipment/bridge/bridge_wiring_dual_mono.htm

[TheChairGuy]

Outstanding Philipp.....that would seem to answer the vast majority of my questions. Thanks  

I see that it can also be used with a single amp to, in Frank's words get, 'more power, better separation and improved imaging'.

Frank, do you need two exact amps for bridging purpses.  In my case, I own the 240/3 ex, could a second amp be the 240ex...or any other AVA amp?

I might possibly do nothing, but I love the upgrade possibililty path here.

[skrivis]

Outstanding Philipp.....that would seem to answer the vast majority of my questions. Thanks  

I see that it can also be used with a single amp to, in Frank's words get, 'more power, better separation and improved imaging'.

I had an AVA preamp with an inverter in it and I used to do exactly this. Since bass signals are often centered or even simply mono, a normal stereo setup would have both channels sucking on the same rail of the power supply when there's a strong bass event. If you invert one channel at the input, then invert it again at the output (flip the speaker cable on that channel), the bass event will be normal on one channel and of opposite polarity on the other. So, if it hits the + rail on one channel, it will simultaneously hit the - rail on the other channel. You get more efficient use of your power supply this way, and less chance for sags and such.

[TheChairGuy]

Very cool SK, thanks for the simplification.

I like the fact that if you have pretty sufficient power on tap already (in a 12 x 15' room with small, 87db efficient speakers that I sit 7-8' from, I do at 125 watts) that one can get that little bit of extra power, better separation and improved imaging.  In short, take an inexpensive trip up in audible quality.

So Frank..what does one buy for $499.00 in the Stereo Phase Inverter Bridge?  No need to give away any trade secrets (the technical stuff would be lost on me to be sure, but possibly not on others tuning in)....but, is there an extra transformer in there, caps, what?

Can it be used with any (single) amp regardless of make...or only van Alstine OmegaStar amps?

[skrivis]

Very cool SK, thanks for the simplification.

I like the fact that if you have pretty sufficient power on tap already (in a 12 x 15' room with small, 87db efficient speakers that I sit 7-8' from, I do at 125 watts) that one can get that little bit of extra power, better separation and improved imaging.  In short, take an inexpensive trip up in audible quality.

So Frank..what does one buy for $499.00 in the Stereo Phase Inverter Bridge?  No need to give away any trade secrets (the technical stuff woul ...

I suspect it's very similar to a regular OmegaStar preamp without the volume and balance pots or the input switches. You're looking at a power supply and line-level circuit boards.

For use with a single amp, I'm not sure that I'd say that $399 or $499 for an inverter is cost-effective. However, it's probably worthwhile as a $100 option to be built into a preamp. (Although I don't see it listed on the price lists on the web site.) It becomes more worthwhile if you're going to bridge 2 amps.

I feel that purchasing an OmegaStar DAC, preamp, or amp is a no-brainer. It's better than far more expensive gear and presents a real improvement. Let's say that OmegaStar gets you to 99%.

The Ultra equipment is not quite as persuasive simply because it's more expensive and the OmegaStar gear is so good. The Ultra stuff could get you to 99.9% or something.

I think I'd buy equipment something like the following progression:

OS amp
OS DAC
OS preamp
Ultra amp
Ultra DAC
Ultra preamp


I would rather spend my money on upgrading further down the above progression than to buy an inverter for use with a single amp.

That's just my opinion though, so YMMV. To me, using an inverter with a single amp is likely to be pretty subtle and won't make as big a difference as upgrading other components.

HTH!

[TheChairGuy]

Ooops, I read this the other day, but forgot to thank you for your input, SK.

The pecking order of potenital upgrades is a big help for future choices  

[skrivis]

Ooops, I read this the other day, but forgot to thank you for your input, SK.

The pecking order of potenital upgrades is a big help for future choices  

That's just my take on it. You might want to check with Frank to see what he says too.



Also, as for monobloc amps or dual mono, they cost more because you double up on some or quite a few components.

If a regular stereo amp has a well-designed power supply, there probably isn't a lot to be gained by going to dual mono in one case or monoblocs. AVA does a good job with power supplies and I'd think you're fine with their stereo amps.

The other area where you might see benefits with monoblocs is in crosstalk between channels. I don't really see this as a major issue either, and it's an area where AVA can easily measure the results, so I'm sure they have a good handle on this too.

In short, dual mono or monoblocs are really a solution in search of a problem.

Maybe there are benefits with tube monoblocs because of better cooling, but it's probably slight for most amps. (I guess those huge monster triodes might be different...)

Now, if you're looking at an amp like Dan Banquer's R.E. Designs LNPA 150 amps, it's a different story - maybe.

Dan really overbuilt these. Like a brick sh*thouse. As part of that, he split them into monoblocs. It was close to cost-no-object. So doing them as monoblocs was part of the overdesign. I don't know if they're better because they're monoblocs or not, but it can't hurt (other than hurting the price tag).

I'm pretty sure that my AVA OmegaStar amp outperforms the LNPA 150s, but Dan's amps are somthing to be admired too, and I'd like to have a pair if I had the bucks to do so. (Class D amps are the opposite in my mind. They're what you get when you can't afford something better. hehe)

[TheChairGuy]

(Class D amps are the opposite in my mind. They're what you get when you can't afford something better. hehe)

I think the D's have merits (remarkably clarity, very transparent, speakers do indeed disappear with the better ones, and abundant control over bass tightness/damping), and will be further refined in the future into more formidable contenders...the most gaulling thing I find with the majority of them is cost.  If they are not demonstrably better, but simpler to construct, then they should be at least cheaper than Class AB offerings. Perhaps it's just a little economy of scale needed in the Class D sector that will raise the relative values in the future?  That is, competition is rarely a bad thing for consumers.  

I see the majority of D amps priced above $1000.00 (not all, of course) in the marketplace.  Then I hear this wonderful AVA 240ex to my right all day that costs $899.00 and I say, why bother trying D's again anytime soon at the current costing structure??  And, it's getting better each day I use it - I swear..... or I'm just discovering new things on discs and it seems that way.

Tho many do much right, they are currently a class of amplifier in search of a better value proposition.  But, I won't rule them out farther afield.

[skrivis]

I think the D's have merits (remarkably clarity, very transparent, speakers do indeed disappear with the better ones, and abundant control over bass tightness/damping), and will be further refined in the future into more formidable contenders...the most gaulling thing I find with the majority of them is cost.  If they are not demonstrably better, but simpler to construct, then they should be at least cheaper than Class AB offerings. Perhaps it's just a little economy of scale needed in the Class D se ...

It seems to me that the major (offshore) manufacturers have jumped on Class D because it's smaller, lighter, and less expensive - not because it sounds better.

A number of people have been talking about cheap Class D products and finding them to be decent, but then they usually mod them and they get more expensive quickly. There are some high-end Class D products, and they're expensive from the get-go.

So I look at Class D products and then I look at an OmegaStar amp. (You're obviously seeing the same thing.) The OS is excellent, has plenty of power, and likely costs less. It's also built for the long haul. (Ask Frank about his rate of field failure.)

I'll certainly keep my eye on Class D amps, but for right now I'll stick with a plain old linear amp.


I was also thinking some more about dual mono amps. There's only so much room in a manageable size case. You need to keep the power supply or supplies away from the audio circuits, so the supplies will likely be a bit crammed together. Put a couple of transformers together and they're going to interact to some extent. The rest of the power supplies may interact too. So I'm not sure what you'll gain over one good power supply.

I remember seeing a small Bryston amp with dual power supplies. There it made sense because it was a 1U rackmount amp. Height is obviously limited and they were able to use 2 smaller transformers that met the height requirements. The same goes for the filter caps in the power supplies. Multiple smaller caps fit the height requirement better.

Still, the bottom line for me is that dual mono or monoblocs don't seem to be cost-effective. Frank's stereo amps do the job just fine.

[avahifi]

First of all, our amplifiers are essentially dual mono after the power transformer.  Much of the power supply is built into the audio boards themselves, and all have regulated power supplies for the small signal circuits, separate regulated supplies for each channel, and in the case of the hybrid amps, even separate 12V DC heater supplies for each tube.

The transformer is a 60 cycle device and has plenty of current capacity for the separate supplies after it.  There is no good reason for doing two transformers, it would simply raise cost.

We could do separate mono amplifiers for the Fet Valve series and make further musical improvements by using half of the heat sink capability in the big chassis for a regulated power supply for the output mos-fets too, in addition to the small signal regulation.  This would require as much heat sink and regulator transistor capability as what the output circuits require, because all the energy used by the output circuit is first delivered by the power supply, and a regulated output power supply would need to be as big as the output circuits.  Hope you understand this.

However, it would essentially double the cost of a stereo setup (two amplifiers required).  How many of you would be willing to pay for this?

Frank Van Alstine

[skrivis]

We could do separate mono amplifiers for the Fet Valve series and make further musical improvements by using half of the heat sink capability in the big chassis for a regulated power supply for the output mos-fets too, in addition to the small signal regulation. This would require as much heat sink and regulator transistor capability as what the output circuits require, because all the energy used by the output circuit is first delivered by the power supply, and a regulated output power supply would need to be as big as the output circuits. Hope you understand this. icon_smile.gif

However, it would essentially double the cost of a stereo setup (two amplifiers required). How many of you would be willing to pay for this?

Perhaps a fully-regulated amp would be the "ne plus ultra."

[TheChairGuy]

However, it would essentially double the cost of a stereo setup (two amplifiers required). How many of you would be willing to pay for this?

Ah, indeed that's the rub - as it rack space.

But, I think you may be surprised as to how many audiophiles would buy such an animal.  It being the highest expression of Frank van Alstine's 40 years of designing amplifiers.

I think you mentioned a while back that although the OmegaStar's are the better sellers, the trend buying your (more expensive) Ultra Fet Valve hybrid series was observed.  As long as you believe, and can sleep at night knowing you are offering top-notch value and musicality even at a much higher cost than you typically charge for amplifiers, you may want to take a run at it. 'Living within my conscience' is something I, too, grapple with in making many business and personal decisions.

$4000 amps do surely exist (many, not even monoblocks) - ostensibly with less value and engineering prowess than what you have proposed.

As you build custom / per order (I suspect), your downside risk is minimized.....while you may be granting every audiophile's dream at a cost that still won't require re-mortgaging the house to attain it.

Of course, my thinking cap is that of a sales and marketing orientation - I don't know what time is involved in designing a mono-block and how it might impact your limited time to address other issues at AVA HiFi. Those may be far more important matters to consider  

[Charles Calkins]

Thechairguy:
  Wouldn't vertical biamping with two stereo amps kind of be like having mono amps.


                                                   Cheers
                                                  Charlie

[avahifi]

By the way, the double posting above is just my attempt at providing "dual mono" performance.

Actually it would not take all that much to do a mono Fet Valve amp with complete regulated power supplies, including regulated output devices. I already have a stereo version of this running.  For in house use I can get by with running the output regulators and heatsinks closer to there limits, and cram the additional circuits into one stereo chassis, but that would not be possible for production units.  If you stop by and visit us, you can hear it.

It will not stop production of the stereo versions and will cost at least twice as much.

Frank Van Alstine

[modular747]

By the way, the double posting above is just my attempt at providing "dual mono" performance.

Actually it would not take all that much to do a mono Fet Valve amp with complete regulated power supplies, including regulated output devices. I already have a stereo version of this running.  ..., but that would not be possible for production units.  If you ...

Is it possible to add heatsinks to the sides of your chassis?  Would that be less expensive than using 2 chassis for "dual mono"?  As far as price goes, I purchased a Transcendence 400 in 1989(?) for $2400 - equivalent to >$4000 2006 dollars....

BTW, what is the supposed difference between "mono" and "mono-block" power amps?  From what I can tell, "mono-block" is an architectural term that was "borrowed" for marketing purposes to create the impression of massiveness - but I could be wrong.

[konut]

By the way, the double posting above is just my attempt at providing "dual mono" performance.

 ...

You're absolutely right! I immediately noticed better 'space' and 'imaging'. Frank, you're a pistol!  

[TheChairGuy]

By the way, the double posting above is just my attempt at providing "dual mono" performance.

Actually it would not take all that much to do a mono Fet Valve amp with complete regulated power supplies, including regulated output devices. I already have a stereo version of this running.  For in house use I can get by with running the output regulators and heatsinks closer to there limits, and cram the additional circuits into one stereo chassis, but that would not be possible for production units.  If you stop by and visit us, you can hear it.

It will not stop production of the stereo versions and will cost at least twice as much.

Frank, I do plan on stopping by next time I'm in Minny for biz if I can find time...how far are you from center Minneapolis?  I have some friends there, also.

It's usually sometime in May - July timeframe that I normally visit the area.

[avahifi]

I am really enjoying the posts here.  Tom's long dissertation was essentially preaching to the choir for me, there is little he said that I disagree with.  However, I have been told that a set of VMPS speakers will be coming my way soon and I certainly will not write them off in advance.

Where are we?  Woodbury is a east suburb of St. Paul, in the rolling hills of Washington county kind of southeast of the intersection of I494 and I94.  Its a new fresh suburb with the best of coffee houses and expensive women's shops.  The only high end audio store is in the old part of south Minneapolis, many miles from me. I plan a visit there one of these days soon.

Frank Van Alstine

[skrivis]

Is it possible to add heatsinks to the sides of your chassis?  Would that be less expensive than using 2 chassis for "dual mono"?  As far as price goes, I purchased a Transcendence 400 in 1989(?) for $2400 - equivalent to >$4000 2006 dollars....

BTW, what is the supposed difference between "mono" and "mono-block" power amps?  From what I can tell, "mono-block" is an architectural term that was "borrowed" for marketing purposes to create the impression of massiveness - but I could be wrong.

The added heatsinks, 2 chassis, and dual mono are really separate issues. Added heatsinks are for when you fully regulate the amp. Dual mono is when you stick another power x-former in one chassis. 2 chassis are for when you do fully mono amps.

In order to add heatsinks to an existing chassis, you need to add a bunch of holes on the sides. You can do that by hand with a drill and sheet metal nibbler (and it will look less than professional) or you can have the sheet metal shop do a run of special chassis. Those special chassis are going to be more expensive because you won't be buying them in quantity, plus you have to have a place to put them.

Dual mono probably is not worth the added expense. (There have been previous comments on this.)

So we get to 2 chassis. 2 normal chassis allows you to have fully mono amps. Since you don't have 2 channels in each chassis, you can use the extra heatsink area for the output stage regulators and have a fully-regulated amp. You're also using regular chassis that have already been designed, that the sheet metal place is already making, and that AVA already stocks.

I'm sure there are other reasons, but this is my take on it.