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Topic: Re: Cool running AB amplifier.. with good sound.

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Posted by Romy the Cat on 07-25-2006

Since the summer is here and since may playback generates more heat then Pittsburgh Steel plants, and sine my Monitor project end up more or less successful I would like to find a very cool running class AB, SS amplifier with which I would driver my “monitors+”

I was truing to drive the SL600+ with other amps beside the Lamm M1.1 and was not able to get any good results. It is not that Lamm was better but other amps, for whatever reasons, did not deliver any more or less acceptable sound at all. Defiantly, going for a cool running AB little amps I would accept some worsening of sound but still I would like do not go too far into weaker sound.

So, I think about a stereo amp, relatively small and cool running, not expensive (a few hundreds bucks max), that would be able to do 100W-150W. Regarding the price, I might go for more expensive cool-running amp but in that case it should deliver a superior performance, or at least to be equal to what. Lamm M1.1 goes. I doubt that I will find such amps and such reasons.

Anyhow, if you have anything in your mind then let me know…
The caT


Posted by Wojtek on 07-30-2006
There is a lot of noise around "NUFORCE" class D amps on the net. Their 100W integrated should be only 1K$ over your budget;0) I didn't have much luck with tripath based amps ,but this one is designed by some missile black science guru so maybe it is worth something. And also your favorite bathroom magazine "The obsolete sound" awarded this product. With your connections it should be easy to get one for audition.
RGRDS. W

Posted by guy sergeant on 08-03-2006
Hi Romy,

I listened to the bigger brothers of this last weekend. The first smps amps I have heard that I didn't need to turn off straight away. Certainly cool running with plenty of power. It wouldn't replace your valve amps but might be entertaining with the SL600's

http://www.belcantodesign.com/prod_eOneS300i.html


rgs

Guy

Posted by Gregm on 08-03-2006
This would involve some researching... thus introduing (possibly unecessary) complexity: look for a Sony or Yamaha or Sansui "power j-fet" amp. These were produced s/where in the mid '70s and should be very cheap now. I have listened to a Yamaha (called "B2"I think) that was surprisingly good -- either that or I was expecting horrible results and was pleasantly surprised... here's a link I found that catalogues these products: http://conlui.hp.infoseek.co.jp/theory/htm/e/hp018e.htm

Or, just go buy a powerful 2-channel pro amp from a large manufacturer like Crown (shudder); at least the asking price will be moderate compared to "hi-fi esoterica" and the device rugged... even a well maintained Quad 405 (?) they used to play their 63 spkrs years ago.

Anyway, the problem is we all offer ideas -- but no-one has come up with a tested proposal, myself included Smile
Cheers

Posted by Romy the Cat on 08-03-2006

 Gregm wrote:
This would involve some researching... thus introduing (possibly unecessary) complexity: look for a Sony or Yamaha or Sansui "power j-fet" amp. These were produced s/where in the mid '70s and should be very cheap now. I have listened to a Yamaha (called "B2"I think) that was surprisingly good -- either that or I was expecting horrible results and was pleasantly surprised... here's a link I found that catalogues these products: http://conlui.hp.infoseek.co.jp/theory/htm/e/hp018e.htm

Or, just go buy a powerful 2-channel pro amp from a large manufacturer like Crown (shudder); at least the asking price will be moderate compared to "hi-fi esoterica" and the device rugged... even a well maintained Quad 405 (?) they used to play their 63 spkrs years ago.

Anyway, the problem is we all offer ideas -- but no-one has come up with a tested proposal, myself included
Gregm,

Frankly it was the direction where I was looking with optimism. I know that in '70s and 80s some consumer companies did “better” SS amps then what they usually produce. I know Sansui had their AU-X1 amp that was reportedly in the matching class with their Sansui TU-X1 tuner (to which I have a tremendous respect). I personally do not anticipate that their amps would perform as good as their TU-X1 perform among tuners but I would defiantly like to hear it. The problem is that it is very large, very-very large. I know that Yamaha and Denon produce some very interesting amps at the same time, including relatively expansive monoblocks. They nave r made available on west but when I dealt with Japanese folks then the amp they were available. Thos amps reportedly sound better then the regular crap that they made but I do not know if their “better” is still would be at near-acceptable level. I have some people I know promising to me the wonderful sonic quality from
Nakamichi PA-7 amplifier. The PA-7 was quite popular, very available on West and it was their top of the line amp. I had this amp and it was absolute unusable sonically. So, being me, I would prefer to try some consumer amps probably if no one audio-freak pass any positive comments about it… :-)

Yes, they are some options but as you pointed well, no one, insulting myself, come up with a tested proposal. So far I specialize on complaining regarding the poor quality of advised amplifiers…  :-)

Rgs,
The caT


Posted by Antonio J. on 08-03-2006
I owned a Luxman LV-117 which I found pretty "right" musically driving some 93dB/w/m JBL's I had eons ago. In its time, there was a LV-103 which was also well regarded, but that I never listened to, so I cannot talk about it. They can be found from time to time at Ebay for very sensible prices.
I remember the LV-117 as a way more musically interesting integrated than the Krell I had later (but I was quite ignorant by that time and I traded it), and that any other NAD, Rotel, Onkyo, Denon, Marantz or Sony at the time I bought mine (late 80's), pretty powerful driving more difficult speakers than the JBL's, and run quite cold. It kept me very happy for 15 years. I don't know how it would compare to any Sansui.

Posted by Wojtek on 08-03-2006
Hey, but what about all those Brit amps from 80' s- 90's ? I had an "Exposure XXV" 60W integrated .Very modest looking amp without tons of circuitry like those Japanesse behemots. I was into <resolution > and detail at that time so I sold it, but I think I would apreciate it more now. Also Bedini 100/100 -big smooth sound should be perfect for casual back ground listenning (it is a stereo power amp though)
RGRDS, W

Posted by cv on 08-04-2006
R,
Please excuse me if this is straying from the subject... feel free to move.

Anyway, I was in NYC until Wednesday evening, and I assume I know what is motivating you to abandon Macondo/Melquiades in the hot summer months... what I don't understand is this:

You have a system which is, lower midrange and up, something like 109 db/W efficient, and very splendid with it (as is the bass, which, optimally,  requires Super M).

Why not build some low power solid state amps?

I would be very, very tempted to take 1 or 2 12V batteries, and use them to power some MOSFET followers, single ended class A.

For the source load, I would have some 1:1 bifilar transformers wound on nickel or amorphous cores, 2 such amps per stereo channel, one coupled to the Fane, one to the S2/T350. Effciency would approach 50%, you would only need to dissipate a few watts per channel and your 7 ohm Placette output could drive them with ease.

Ok, 3 per channel, an extra one for the fundamentals horn...

You wouldn't get the unique "reality-reconstruction" effect of the 6E5p, but it should be super transparent and would free you from the ravages of daytime electricity.

Ie each amp circuit consists of a mosfet, transformer and cap couple biasing circuitry (depending on DCR of transformer). Shared lead-acid psu. Not much at all.

For the bass - well, I think you may have to bite the bullet and find a non-insulting, more conventional solid state amp. If the Zarathustra is truly 150W in class A, I shudder to think how much power it is blasting into the room (ie not via the speakers).

I have no experience of the proposed scheme, but am very close to trying, given the 110 degree weather...

cheers
cv

Posted by Wojtek on 08-04-2006
Roman wants to "test" other amps on the monitors .It is quite impossible on tri-amped Macondo-maybe he will become a rewiever -heheheh. I can assume that Macondo is so absorbing that it is impossible to just play a background music or work and not to be distracted -right??? Anyway, everybody is buying Celestion 600 SLi and waiting untill Roman will find the right amp for it. Seems like he is having fun, thats all about in this hobby. He is trying to rationalize it with the heat problem but we all know that he can afford AC in his house blah, blah He just needs some new toys to play and doesn't want to look like casual moron :0). RGRDS. W

Posted by Romy the Cat on 08-04-2006

Chris, I have no experience with good sounding SS amplifier that might drive high sensitive horns. I also have no expertise to build such an amp. From what I trued before I have learned that in order to sound more or less acceptable the SS should run a pure class A. Well, a few watts class AA SS should not be a big deal to make, well theoretically….  An idea of heaving a SS single ended amp for 10W is not bad idea as well, but who build them and who can assess how thy sound while they build them?  To deal with the Pass’ “First Watt”- level people and to be satisfied with the amplifiers that make the single driver speakers to sound like “live music”. Thank you, I have heard a lot of Pass amps and a lot of Lowther speakers….

I kind of keep thinking about it for a whale and my first step into the direction that you propose will be the new version of Zarathustra.  Dima has been running the out stage and it currently despites 300W deep into class A; he also claims that is proprietary bias (working name is Newton bias, it is no joke, there is a reasons for this name) allows him to get exactly 50% efficiency… The amps is PP but it sounds very different then SS that I heard, at least the AB version was and I did not hear the Zarathustra Class A version yet.  Now is the interesting part. There is a lot of very kinky solutions in the new Zarathustra and one of them is an ability to run this amp as 150W and … as I would say 10W in class A, presumably with no compromise to sound (wish us good luck). I do not mean that the amp will be switching into class B after 10W but it will all together dissipate juts 20W by it’s output stage and never will find itself switching into class B. (we drop both current and voltage). So, when I get Zarathustra I will try to run it in 20W mode for instance and to see if it able to do anything worthy with horns…

The idea to have a separate low power SS and biamp it with a powerfully SS for bass is wonderful but I would like if I wish to flip a switch and to turn the “big” system on, driving the Macondo with what it should be driven with. If I have a small parallel system (SS+ SL600 and sub for instance) then it is easy to do. I defiantly DO NOT want to disconnect 4(5) cables form Macondo and connect them to something else. Not to mention that the Dominus cables do not sound good for a few days after they were disturbed…

Still your idea give some food for thoughts….

Rgs,
Romy the caT


Posted by horny on 02-05-2009
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worth trying, if you can assemble them:

http://www.aksaonline.com/

http://www.aksaonline.com/products/products.html

AKSA forum

rgds

horny

Posted by zanon on 11-16-2009
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How about more current integrateds with old-school designs.

Harmon Kardon 3490 is a SS integrated stereo amp. I'm guessing it's class AB, but it does not say. Yamaha has one that is similar.

Onkyo 5AVL is 40W class D integrated.

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