[tonyptony]

I tossed in a vote for an AVA amp in a thread on Audioasylum, and a fellow named Abe had a rather interesting comment as a follow up to mine. Here's the whole thread

http://www.audioasylum.com/cgi/t.mpl?f=amp&m=118992

Wonder what Frank would say.

[tonyptony]

I agree. I tried to be non-confrontational in my response, as things seem to very easily get out of hand on AA. I thought about saying that Frank has been basing his work on solid engineering principles for going on 30 years at this point, and that he's probably the last guy in the world in high end to use "smoke and mirrors", but I figured that would just start a flame war. I'm hoping my point about actaully owning a speaker that presents a difficult load would expose the truth.

[martyo]

I guess since it weighs close to 3 times the 550 the $6000 price makes sense. 
Seriously, I've heard and read very positive comments on the sonic attributes of Pass amps, I'll never know first hand, WAY out of my price range. They seem to be the antithesis of K.I.S.S. I think the Pass 350 has 48 output devices.
My brother told me of a review of the 550 where they compared it's sonic qualities to the Pass 350.

Thanks again Frank for your approach to all this. 

[BradJudy]

The largest stock audio transformer sold at Toroid Corp is a 1000VA unit that weighs 13lbs and is ~6"x3":

http://toroid.com/standard_transformers/rectifier_transformers/DataSheets/798.552.pdf

Given the dimensions of the case and the image on the website, I'd guess the 550 transformer is approximately the same physical size. 

I'm sure there are many amp makers putting larger transformers in their equipment, the only question is whether the AVA transformer meets the max output needs of the amp.

[tonyptony]

The largest stock audio transformer sold at Toroid Corp is a 1000VA unit that weighs 13lbs and is ~6"x3":

http://toroid.com/standard_transformers/rectifier_transformers/DataSheets/798.552.pdf

Given the dimensions of the case and the image on the website, I'd guess the 550 transformer is approximately the same physical size. 

I'm sure there are many amp makers putting larger transformers in their equipment, the only question is whether the AVA transformer meets the max output needs of the amp.

My bet, given Frank's untarnished reputation as a real engineer, is that it does.

I have nothing against Pass amps, mind you. I've heard them and they sound pretty darn good, but they're also pretty darn expensive. I suspect the engineering in those is pretty good, too. Nelson Pass has been around like Frank and has a good reputation. I can attest that my Pass X1 is a pretty good preamp. As owners of AVA equipment, I think we also can all attest to the quality of Frank's own designs. I have no doubt that my Ultra 550 can step up to any challenge presented to it.

[martyo]

As owners of AVA equipment, I think we also can all attest to the quality of Frank's own designs. I have no doubt that my Ultra 550 can step up to any challenge presented to it.

 

[Toka]

Hmmm...for a long time you could tell how good an amp was based on how much it cost...now I have to weigh them to determine the quality of sonics? 

[tonyptony]

I guess we're supposed to buy them by the pound, now. 

[gjs_cds]

I think an important point to make is to delineate between a gear's build quality and over-built gear.

Over-building an amp (relative to size and weight) doesn't make it better--it just makes it over-built.  Money wasted on the sake of pride and vanity.  (Which isn't necessarily a bad thing, if that's what one values.  The older Sunfire 2-channel amps were absolutely gorgeous works of art, for example.)

Frank's gear has always had excellent build quality, but not over-built to worthless excess.  And I think that's a definite asset.  Superb quality (comparable to any within true hi-fi) at obtainable prices.  (I mean--seriously; I'm sick and tired of people trying to tell me that a $5k amp is "affordable" and "reasonably priced".  Anyone with a family has better uses for their discretionary capital.)

Those that appreciate the music and EE design will appreciate Frank's value and ethic.  Those that have lingering personal insecurities and engineering ignorance simply choose not to acknowledge the distinction between Over-Built and Build-Quality.

[GBB]

I guess we're supposed to buy them by the pound, now. 

It's actually an old idea.  Sam Tellig started throwing the metric of price/pound out in one of his columns as a means of judging the value of a component.  And some other manufacturers have picked up on that idea.  See this from another Audiocircle Manufacturer:

http://www.odysseyaudio.com/value.html

It's not saying that a 250W amplifier has to weigh a certain amount.  I think it's clear that amplifier efficiency has a big role in determining how much one needs to overspec things like transformers and heat sinks.  Pass amplifiers are famous for running with their output transistors biased at high currents leading to larger transformers, larger heat sinks, and thus higher weights.  All that extra material costs money and a calculation of dollars/pound is an interesting way of assessing how much things are marked up over material costs.

But the weight of an amplifier won't tell you much about how it sounds but it will tend to tell you a bit about the design philosophy.  The more interesting question is whether or not things sound better for being biased at the higher levels that Pass uses., which will tend to go hand in hand with the higher weight.  It's a personal call, which is why it really pays to listen to equipment before shelling out.

--Gary

[rustneversleeps]

I doubt that anyone of you will use 250W/ch at any extended period of time. Your speakers only draw more power during complex musical passage, and when more dynamic passage in the music. Most of you may only use about 10 to 15 watts most of the time.

If I had to draw 250W/ch from Frank's amp for 24 hours continually, I don't think it would last for very long.

[WEEZ]

Sam Tellig is an amusing and entertaining writer. But.....

I think most people would be surprised at how little power is used when listening to music. Rusty says 10-15 watts. I'll wager half that. (That is, if you value your long term hearing)

WEEZ

[crossroadazn]

10-15w ? not true if you playing with Maggies my MG10/QR takes about 150w average to moderate level 

[martyo]

About wattage, I've got 4 12"s and a 60" ribbon per side, and I've blown the 5 amp speaker fuses in the amp a few times. My speakers use 2 4 amp slow blow fuses per side and on occasion I've blown one them. I could be wrong  but I'm  pretty sure I'm using quite a bit of the 550.

                                       

And I probably don't value my hearing as much as I should.  

[rustneversleeps]

I exaggerated a bit when I said 10-15 watts thinking some of you are making more than I do and have a huge sound room. 3 to 6 watts are for listening under normal condition.

Audio amp is not a DC power supply to power up equipment, it is an amp to amplifier music, so it's nice to have the reserve power for difficult music passages, 250w/ch gives your more reserve power than, say, 150w/ch, that's all.

[WEEZ]

Marty, on an instantaneous basis, you well might.

WEEZ

[YoungDave]

Sam Tellig started throwing the metric of price/pound out in one of his columns as a means of judging the value of a component.

That's a pretty accurate measure for the cost of commercial and military aircraft.  Often used as a rule of thumb.  Probably pretty fair for other highly engineered products, too...

If I had to draw 250W/ch from Frank's amp for 24 hours continually, I don't think it would last for very long.

I'll bet it would last approximately forever - provided it has adequate heatsinkage.  Your speakers would fry in a couple milliseconds, of course.  I've run amplifiers at 300 watts into dummy loads on my test bench for 24 hours or longer.  Components don't seem to care if they are run at 20C or 70C.  I don't know from experience with AVA gear, but I rather think that Frank uses adequate heat sinkage.  Not all manufacturers do - in fact most do not.  Stereophile reviewed a Krell a year ago that would not run at 1/3 power for an hour, IIRC.

Rusty says 10-15 watts. I'll wager half that. (That is, if you value your long term hearing)

5-10 watts sounds about right to me.  10 watts in an 8-ohm speaker is 9 volts.  Try to run a 9 volt pink noise or sine wave into your speaker and you will find it very loud indeed - you'd probably be in a heck of a hurry to turn it off, thinking you'd damage your drivers and your hearing.  10 watts with a 90 dB/w @1 meter speaker would yield 100dB and that is loud!  Using the standard rule of 3 dB loss for doubling of distance, if your chair is 12 feet away from the speaker you would still have 94 dB, which is louder than a lawnmower.

I've blown the 5 amp speaker fuses in the amp a few times

You can blow a fuse with transitory peaks, depending on amplitude and duty cycle, and still be running at "moderate" power levels, say, 30 watts average.

Cheers,
Dave

[rustneversleeps]

for the folks who blow their speaker or amp fuses, you are not following the factory instruction for not to abuse your equipment. Fuses are for protection, not for measuring how much power your speakers will draw.

 I've never blown any fuse and my Maggie plays plenty loud even with my 40w/ch tube amp, but for cleaner sound and a bit louder volume, I need more power for the speaker to push more air faster.

[Bigfish]

Guys:

Currently, I do not own any of Frank's equipment but there are manufacturers on this Circle which command a loyal following and Frank is one of them.  Frank stands behind his equipment and people who own it claim it has a very high level of performance.  He must be away this weekend because it is my experience he will defend his designs.  In this case I am looking forward to reading his response.  I personally do not think weight of a piece of gear should be equated to performance.  There are too many guys on this circle that would bench test a unit to determine if it delivers the advertised performance.  

Ken

[martyo]

For what started out as a slow Sunday on the circle this thread has sure picked up the pace.



Back to the boys for me,      this would be one of the times I tend to blow a fuse.   

In the end it's all about the music.