A Shockingly Straightforward Query

Good morning to the Community!  I am in the market for new amplifiers and have it narrowed down to the Bob Carver 350s or the Theta Prometheus.  The selected amps will be driving a pair of Martin Logan 11A speakers.   I have heard that the Carver monoblocks are a good fit for my speakers but am still impressed with the Prometheus. 

I am intentionally excluding the rest of my gear as I simply don’t want to make this question more complex than it already is.  In addition, the option to audition these amps is not feasible.   

PLEASE – no haters or flamers!

So, Carver or Theta?  Thanks and a great weekend to all!!

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I heard the Carver 350 amps at the 2017 RMAF and they sounded wonderful and very engaging.  The power was effortless. I think the Theta is a digital amp.  If I am right, the Carver 350 would definitely be the better sounding amp. 
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I have personally owned a few Carver amplifiers but not his latest tube efforts.  I am also a current Martin Logan (Montis, which was replaced in the line up by your 11As, so very similar) owner.  I think you need to be very careful pairing a tube amplifier with ESL panels.  The impedance mismatch is known to roll off the high end.  When I first got my MLs, I was using Wyred4sound amplification.  I did not particularly care for class D with them.  Just my $.02, but I would be inclined to look elsewhere, especially if you do not have the opportunity to try them first.  The Martin Logans are possibly a little more picky about amplification than other speakers.
Carver warrants tubes for 5 years and stats like the voltage of tube amps, Carver monos is my vote.
I have the Carver Crismon 350 monoblocks.
mac 2600 tube pre with SF Olympica 3s.
Carvers are wonderful. Clear, smooth and detailed. 
I sold my solid state 300x2 two days after getting them. 

Since you can't audition either one then the choice is simple: buy the one you can return no questions asked.

If neither one can be returned then the choice is even easier: keep looking.
  Bob Carver 350s or the Theta Prometheus. The selected amps will be driving a pair of Martin Logan 11A speakers.

"MartinLogan doesn’t publish impedance, phase-angle or frequency response curves for this speaker. However, they do state that their impedance dips significantly at higher frequencies. This low impedance, (0.6 ohms at 20KHz) with a corresponding increase in phase-angle suggests that amplifiers that aren’t stable into low impedances shouldn’t be used.
MartinLogan’s online FAQs recommend an amplifiers that doubles in wattage between eight and four ohms and again increases its wattage at two ohms. This would seem to eliminate most amplifiers from consideration."

 This tells you what sort of amp to look for, and it's not tubes, if you want to extract the very best out of these speakers.
But if your happy with "a bit of a compromise" the the Carver tubes will be fine.

Cheers George  

Thanks to all!

George - I'm not happy with "a bit of compromise" at all.  Are you thinking something along the lines of Pass Labs monoblocks? 

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an10490413, for what its worth, I use Pass Labs amplification with my Montis (INT-150).  I'm sure many others will work as well.
an10490413 OP18 posts03-05-2019 7:09am

Thanks to all!

George - I’m not happy with "a bit of compromise" at all. Are you thinking something along the lines of Pass Labs monoblocks?

Yes they need amps that are stable, but that can also supply current, so look for amps that can "almost" double (or considerably increase) their wattage from 8ohm to 4ohm and again from 4ohm to 2ohm.

Cheers George
I find it difficult to respond as I'm simply too shocked by the straightforwardness of this query.

You might also want to go to the Martin Logan Owner's website and inquire there.

My choice would be the Carver amps.  I'm sure the Theta would work great, but I'm not quite sold on digital amps.

I've heard the Carver's and they are nice. 

I have owned Martin Logan speakers and currently own a pair of Monolith IIIs with Krell KBX crossover and Pearless woofers.  My Audio Research REF 250 amps work and sound just fine thank you.  With my Mark Levinson 23.5 or Modifiied Bedini 250/250 mk II on the woofers, I'm doing just fine.

If you can demo the Carvers in your home  with your system and the same with the Theta, that would be the way to go.

If not, find some dealers that sell the amps with those speakers and go listen.  If that isn't possible, then go listen with similar setup.


The Carvers are the way to go. They will drive any electrostat. They will drive Apogee Scintillas that can dip to 0.75 ohms. You will not regret ever purchasing these amps. Go to bobcarvercorp.com and read all about these amps.
+1 tdybare1
I wouldn't hesitate at all with the Carvers for your MLs

My 100W x 2 Rogue does a beautiful job at driving my little Maggie 1.7s, at any volume I care to listen. Am considering the Carvers myself if/when moving up to a Sound Lab or larger Maggi.........Jim