Atma-Sphere amps with Eggleston Andra II's

I own a pair of Atma-Sphere MA2 Mk2.3 OTL monoblocks that are probably the one part of my system that will staying put for a long, long time. Currently, speakers are Dynaudio Confidence C2's. Preamp is an Atma-Sphere MP1 MkIII.

I'm looking to change/upgrade my speakers. As good as the C2's are, i.e., extremely coherent, very natural and detailed, nonfatiguing, they certainly don't have much "slam" factor. Now, I mostly listen to classical, jazz, and female vocals at moderate levels, but once in awhile still throw on some Cream, ZZ Top, Seger, ELP or whatever that demands some volume and presence in the low frequencies. I have been reading that the Andra II's can provide most, if not all, of the C2's traits but also add the missing lower octave and slam.

My question to Andra II owners is this: will 220 watts of OTL power drive the Andra II's properly? The MA2's can handle 4 ohm loads without difficulty as long as there are no crazy phase shifts. I am mainly concerned about running my amps dry.


Bill: Although the MA2 Mk2.3 has power, they are not ideal for your speakers. Your speakers are a nominal 6 ohm speaker but has some impedence drops that are not ideal for OTL's. I would either get other amps or look at other speakers.
Hi Bill,

You might consider e-mailing Ralph Karsten with your question and include a link to John Atkinson's measurement page from the 2002 Stereophile review of the Andra II. Ralph's a very straight shooter. Here's the link showing Atkinson's impedance measurements:

The Andra II's impedance dips to 3 ohms at 60 Hz. At high volume levels (probably around 108-110 dB peak at 1 meter) that would likely be where your amps would run out of steam first. But run it by Ralph to see what the man says.

Not that it's any of my buisness, but if you have MA-2's and are looking for world-class dynamics you might consider the 16-ohm Classic Audio Reproductions T-5. The combination would be capable of clean peaks over 120 dB, with virtually no thermal compression below 115 dB. I don't sell Classic Audio Reproductions speakers but do think highly of them. I do peddle Atma-Sphere, just so you know.

Best of luck to you,

i have andra-2's and m.levinson 33h amps which is a great match. plus i've upgraded my wires to transparent ref-mm. after recently hearing halcro-driven wilson alexandrias i STILL couldn't be happier with my system. the andras only need 100W, and your amps have twice that. plus the andra-2 is easier to drive than the andra-1's. i am going to upgrade my speakers soon due to my cavernous room, so if you're interested let me know.

I would have to agree with Jtinn on this issue. The AS amps are great, but Dynaudio drivers tend to like Solid State amps that are High Current.
I own a pair of Andra 2's. I agree with Jtinn. The speakers need some power. French fries's Levinson 33h must have alot of current. I think the 33h are 150 watt @ 8 ohm. I've talked with Egglestonworks several times about amps and preamps. They recommend a good solid state amp in the 500 watt range. At CES, they were using the Pass Labs 600.5 mono blocks and they were very happy with the 600.5's. I'm using a 300 watt Jeff Rowland 302 amp and feel that I run out of power on occasion. I've had the Andra's up to a 97 db peak on my Radio Shack db meter. Normally, I run my amp between 85 and 92 db. You have to slightly push the amp, (or is it the speakers), to get a well balanced live sound. They are awesome speakers. The Andra's have excellent dynamics. I listen to alot of Pink Floyd, Cream, and Hendrix lately. Guitar especially sounds just like the real thing. Bass and synthesizer are excellent as well. The speakers are capable of room-(my room 14'w x 28'l)- shaking bass response. Great speakers, but probably not a good match with your current amps though. Good luck. Stan
I've only heard the Eggleston Andra IIs with the big MAC 1200 wpc monoblocks. As you can guess they rocked pretty darn hard. From listening, the speakers do like a lot of power.
I totally agree that the Andras like a lot of power.

However, I'd have to question the need for 500w or more. I'm sure it depends on the amp, but I'm happily running my Andra IIs off of a BAT VK-500 amp w/ the BAT-PAK (250wpc into 8 ohms) and I have never felt that I need more power. They are firing into a decent sized room (25' x 20'). I occasionally listen at levels that average 95db, and on transient peaks, I notice no compression or clipping with this amp.

Perhaps a lot has to do with the amount of energy that the amp is able to store in its caps. The BAT with BAT-PAK stores a staggering 1100 joules vs. 350 joules with no BAT-PAK.

The speakers really do come alive above 85db, guitar and piano are simply stunning, and lifelike vocals to boot.
1markr, I agree about the Bat having alot of reserve power. I used to have a Bat vk5i preamp that I was using in my current system and it had an unreal amount of reserve power for a pre. I also agree that the speakers come alive above about 85 db. The 500 watts is what Egglestonworks has said several times in conversation. Your mileage may vary. Stan
i don't know enough about atma-sphere amps or otl tube gear,
but all speakers have impedence dips, some go to 2 ohms for sure. but an amp with 220W should be able to comfortably drive
a wide range of speakers. i've used rowland m-12's (200W), a krell fpb-300, and a levinson 23.5 (200W) as well as the 33H
on the andras- even when they were series-I's- and NEVER was worried about having enough power.
French Fries,

The Atma-Spheres and other output transformerless tube amps roughly approximate a "current source", unlike most amplifiers which approximate a "voltage source". In English, that means the Atma-Sphere amps deliver less than their rated power into a low impedance load, and more than their rated power into a high impedance load. This is just the opposite of the way most amplifiers (especially beefy solid state amps) behave. In addition, OTL amps typically have a high output impedance (low damping factor) which further makes a low impedance speaker less likely to be a good pairing.

As Duke notes (twice) and others have confirmed, you will not get superlative results using yr AS with the Andra. I.e., you'll get good sound -- but NOT what you bought the equipment for.
The music will be refined and s/what lacking in ultimate energy (upper -> mid bass will be too "polite").
With yr amps I would strongly recommend high sensitivity hi impedance spkrs wearing powerful drive units (wide-range). Audiokinesis gives a good recommendation above. Tannoy (prestige series), rethm, horn-loaded models etc would be fine.
The sound you'll get will be outstanding
The OTL's, as correctly stated, are intended to use with high impedance, especially electrostatics (like Soundlab), speakers. The Dynaudio drivers need current and amps with a good damping factor in order to get the best results. Actually it is strange that your match with the C2's is still good...
Anyway, if you want to keep the AS, why not bringing your amps to the nearest Eggleston dealer and listen for yourself ?
Just a thought by an Eggleston lover.
Don't sell your amps - they are far too good! Think of other speakers - Kharma 3.2 come to mind - that's what I use with AS 2.2s and the sound is remarkable
As an MA-2 owner, I've been quietly reading this thread because I've never heard the MA-2s with the Andra IIs and they may well not be a good match with this particular speaker. However, unlike typical OTL amps, the MA-2s are designed with a low impedance output and are incredibly versatile in the speakers loads they will drive exceptionally well, and with tremendous bass authority.

For example, they have proven to be a great match with Avalon Eidolons (4 ohm nominal load, 3.6 ohm minimum) and with the Magnegpan 3.6 (which will challenge many amps).

I'm not trying to suggest they would be a good match to the Andras, but some very broad statements have been made here that might lead some to think that the Atma-Sphere MA-2s would not be a good match with lower impedance speakers across the board, and this is demonstrably not the case.
I'm of two minds on this discussion. On the one hand, I had Andras which have been converted to Andra II's, and there is no question that the original Andras couldn't be driven by less than 300-350 watts per side. When I spoke to Eggleston, they reminded me that the A IIs were rated at 200 watts MAXIMUM, and told me any good 100 watt solid state amp would probably be fine although they could handle much more, and specifically recommended McIntosh amps as a great match. By the time the A II's came back from the factory, I had a demo pair of Mac 501s waiting, and the combination has been extraordinary, especially when I added a pair of Purist Dominus speaker cables. Having said that, and having 500 watts available per channel, the fact is the Macs have meters, those meters reflect that the amps never put out more than 125-150 watts on the loudest passages of the largest classical synphonies, and that in my 23 x 13.5 x 9 living room, it would be unbearably loud to open the system up further--and I regularly listen from the eighth row of Carnegie Hall, so I know what an orchestra sounds like going full out. Without getting into the need for reserve output capacity on an amp, I don't believe the Macs have ever put out 200 watts with the AIIs, and I wouldn't rule out your present amps just because they are rated at that level. As to your particular amps, I don't know them well enough. I'd certainly listen before ruling them, or the A IIs, out.
Lot of responses but... hey Bill ! Are you still here ? What did you decide to do ? Let us know, I believe we are all curious...