SET amplifier (for AvantGarde Duo's-original) recommendations

I have AG Trios and have demoed many amplifiers on these high efficiency speakers.  The good news is you do not have to spend a lot of money on amplification to get really excellent sound.

I have two integrated amplifiers that I alternate with as they have rather different sonic attributes. My favorite is the Elekit  TU-8600 with the Lundahl transformers.  Herb Reichert has reviewed these and are in his reference system.  They sell for around $2200. My second amplifier is a Sophia MC-300 A which has a more full sound and bigger image. This amplifier is a little more expensive at $4000.

On the downside, the efficiency of these speakers makes mitigating hum a top priority so be sure to demo before you buy.

Once you become accustomed to the dynamics, both micro and macro, of high efficiency horns you will find it hard to go back to conventional drivers.

I have been running Duo’s since 2006 with Atma-Sphere S30 Mk3 OTL stereo amp. The amp is dead quiet and produces a wonderful sound. At ear-splitting levels it wasn’t even showing 1W on the meter.

I’ve recently changed to AGD Audions and these are also a terrific match with the Avantgardes. You could also have a look at Atma-Sphere Class D monoblocks which are getting great feedback.

I agree with @lubachi that you don’t necessarily need to spend a lot on an amp for these speakers as they are so easy to drive with their high impedance/efficiency.

Oh boy! there is a wealth of information here- I cant thank you enough for all the suggestions.  There's a lot to ponder.  One thing that surprised me is that in some cases we are talking about very low wattage amps and I was always a little concerned that while the speakers are very sensitive as some 100db, the nominal 8Ohms impedance, albeit good, would require a little more power  (that said, the Mastersound Compact 845 is overkill in the other direction).  It sounds like I should reconsider my assumption.

@rocketiii
I have been intrigued by Atma's- at the risk forcing you into worn out cliche's how does the sound these compare to a SET or Audion's.  Good to know they are quiet which brings me to

@lubachi
Hum is one indeed one of my biggest concerns.  The problem is that auditioning is not always easy.  Someone had indeed suggested Sophia electric to me (the 300b mono's) and it sounds like noise is unlikely to be an issue assuming these are as quiet as the MC300 you mention.  I'll look into the Elekit as well- it is interesting you prefer this to the Sophia.
As for the addictive nature of the immediacy of horns it is indeed very hard to go back (though I am still very impressed by the Thiels when I get a chance to hook them up).

@blisshifi
I have heard about Oliver Sayes and seen some of his amps pop up for sale.  And since I live in Westchester and work in NYC this sound very intriguing. How does one get in touch with him?

@jaybarnett 
I had not heard of these.  I'll take a look

@dishawasha 
I have looked at these, but as I mentioned above I simply thought that the DUO's needed a few more watts,  I have to say the Triode Labs look ver impressive in terms of fit and finish.

@antigrunge2  and @acresverde 

Yes, Atma sphere keeps coming up- and I have never tried OTL so I would love to audition (and it would like not to have to deal with 75lbs beast- thus the acceidnt with the Mastersound).

@carlsbad 
Those Decware amps look amazing- not familiar with them and it sounds like I should be.  So really?  I can get away with 2 watts?
Just by everything that has been written so far seems like I was dead wrong about the required wattage- if this is indeed the case this opens a whole new other world of possibilities.

@brandonw 
I would indeed be interested. Please tell me more- email is pgastone@
aol.com.

@corelli 
Another one I was not aware of!  And I thought I was generally well versed in the possible alternatives.

@needfreestuff 
A lot of good press for the LM's- my only concern is that a couple of times I have heard they aren't always super quiet.

@vinylvalet 
Yes, I saw that Audion- thanks for the heads-up.  My budget is $5k but I wouldn't mind going a tad lower if possible.  YTha said, the unit in question has a great reputation- a similar version is listed on the Music Room website.

@dekay 
Wavelength make great products but they are  out of my price range.

So it sounds like
a. I should castt a wider net to include lower powered SETs
b. 300b might not necessarily be the only choice.

There is a seller that has a Mastersound 300b for a little over $4k but then of course there is the shipping and a tube upgrade (they are all stock- they are ok but there is scope to upgrade).  And with everything I have read here I am staring to lean towards exploring some of these great suggestions.

I owned & very much enjoyed first the Uno's purchased in about 2001 & then upgraded to the Duo's in 2003 which I kept for about another 6 years until I decided to try a pretty high end surround sound system based on Dynaudio Contour line of speakers.  I was watching a lot of movies at that time as well as listening to music & only had room for one system.  I know the Avant Gardes pretty well & they are very special & great in many ways. 

I used an Art Audio PX25 SET power amp & an Aesthetix Calypso preamp w/ excellent results w/ a very good Basis table/ arm & a nice Naim CD player. The amp is 5 watts per side & more than enough power to drive the Duo's to loud volumes in a big room & sound great!  It uses a special tube that not many have heard of (the PX25) which has a beautiful midrange & high end & w/ the powered subs of the Duo's, I don't really know about the bass. I think they are now very expensive ($17K) but might be in your price range for a used one? I would suggest that whatever amp you get, try to find one that is fully point to point wired so it can repaired by any good tech w/ a schematic years from now if needed. 

Here's a few thoughts on the Duo's that might help regardless of what amp you wind up with:

1 - They are not easy to set up & get dialed in & expect this to take a while. Distances form boundaries, from each other, from you, toe in angle etc. all can have enormous effects on the sound!

2 - Getting the subs dialed in also takes patience w/ both volume & frequency selections. I sub's amps are very susceptible to hum & ground loops as I don't think the power supplies in them were that great. The original versions of these speakers had different subs which got improved after a few years, not sure which you have & I don't recall what the different sub models were called. I didn't have a power conditioner back then but one might help if this is an issue. 

3 - The stock jumper speaker wires that go to the different drivers aren't great that came w/ the speakers & I had some custom ones made by a wire maker friend of mine that greatly improved the overall sound. I think even a decent wire from Audioquest would help out a lot.

BTW, I have since realizedI can't live w/o horn loaded speakers if I really want to enjoy music that sounds close to live as opposed to good "hifi" sound so I sold my surround sound system & got back into horns & tubes w/ Volti Audio Rivals & a Rogers High Fidelity integrated amp. Both are really good! Still have my Basis turntable set up (new cartridge) & now stream w/ an Innuos Zenith. Music is fun again!!

@pgastone Your locale feels really familiar. I used to live in Valhalla and commute into midtown daily until I moved into NYC for 12 years, though I’ve now been in Minnesota for about 5 years. 

I’ll PM you directly on Oliver’s amp as well as more details on mine.