which tube mono blocks?

I run electrostatics that are 4Ohm @ 86dB. I currently use 200w Class A SS mono's. Which tube amps should I get to try?
Atma-Sphere Music Amplifier MA-2 Mk. III
VTL of similar wattage
The Vac PHI 300 could be run as monoblocks, if you choose to buy two of them. (However, it is also set up to be run as a stereo amp. As a stereo amp it runs at 150 wpc, and as monoblocks, they run at 300 wpc.) The cost of two of these amps is rather pricey though @ $15K each, (so $30K a pair). (Although I believe that a used one is for sale for $8K here on Audiogon, (and if you need another one to use as monoblocks, I can give you a lead, as I believe I know someone who will be selling one soon.) I will also state that I have only heard it run as a stereo amp though. (And, it very well might work just fine as a stereo amp for you, as my friend has speakers with very similar spec's to yours, although his speakers are probably slightly easier to run as the sensitivity is about 89 db. His speakers do have 12" woofers though, which do suck up the power!)

I will state that this amp was among the finest high powered amps I have ever heard. (The three best I have heard are the hybrid Lamm M2.2 monoblocks (220 wpc - $22K), the solid state DarTZeel NHB-108 (100 wpc - $16K), and now the tube VAC PHI 300).

My friend directly compared this amp to his Lamm M2.2s, and while it will not replace his Lamms, it was very impressive nonetheless. The Lamms have a somewhat deeper and quicker bass response, and they seem to have slightly better quickness, especially when it comes to that initial attack that percusive instruments have, (such as the piano). So, if you demand the very best in bass response, and relish that initial attack of percusive instruments, the Lamms will come out ahead. (At least they did in our auditioning, which admittedly was with only one VAC, rather than with two of them run as monoblocks. Running two of them together as monoblocks might boast the power enough to raise the bass response up to equal, or possibly exceed, the Lamms. But then again, maybe not, and maybe it might detract from the wonderful mid-range and treble response - see below.)

And, it was in the mid-range that the VAC is really something special. If female vocals are your passion, I recommend that you not hesiate to audtion the VAC, it is that good. (And yes, even slightly better than the Lamms! Maybe not quite as neutral, but this amp sounded incredibly sweet.) In addition, the treble response of the VAC is ever so slightly better than the Lamms. (They have an added sparkle to the sound that cymbals have, that makes for a truly amazing treble response.)

I will also point out that this amp run hot. (Hotter it seemed than both of the Lamms together, and the Lamms will warm up a room a few degrees.) I recommend that if you run two of them, that you have A/C, which my friend does not have. In addition, the cost to retube this amp would be somewhere between $500-2,000, (per amp), depending on the tubes you choose to use. (i.e. stock or NOS), so it will ultimately be more expensive to run than the Lamms.

Or, if you don't have to have true tubes amps, you can "settle" for the hybrid Lamm M2.2s, which only have one tube in each amp! (At 2/3's the cost!) And IMHO, are sonically the VAC's equal, as they each have their own strengths and weaknesses.

My two cents worth anyway.
hmm. what can I try so I don't have to spend $12k or more though. anything lower priced that's worth trying to see if I like what I hear (i.e. VTL MB125)?
Well, you could try out the VTL MB 450s. They are very good, and very powerful. Used they run around $4,500. (I doubt the MB-125's (100 wpc) would work very well, as they are not powerful enough, IMHO.)

(You are on the right track though, as you will need very powerful amps with those speakers. You might want to stick with solid state amps, as tube amps this powerful tend to be somewhat expensive, and generate a fair amount of heat. And, can cost a bundle to retube!)
11-19-08: Detlof
Atma-Sphere Music Amplifier MA-2 Mk. III
Hasn't Ralph "Atmasphere" Karsten posted around here that all OTL amps prefer to work into higher impedance loads? The higher, the better, due to distortion issues.(did I get this right?)

I'm pretty sure he has recommended using Speltz Zero's impedance-matching external transformers to raise speakers below 4 ohms up to a more workable range.

Anyway, back to the original question. Jtwrace's Final 1000i's are actually rated in the 3 ohm range according to the website:
The simplicity of the new Inverter Technology™ design insures speaker impedance will remain well above 4 ohms across the entire frequency spectrum for the smaller speakers and above 3 Ohm for the larger models.
The 1000i are the largest panels they make and Dick Olsher's 2007 review states that they actually dip into the 2 ohm range.
Ronald Buining, one of Final's designers and engineers, explained that since the treble is emitted by a narrow strip, the speaker's capacitive loading is reduced. And it is primarily the reduced capacitance that is responsible for the impedance magnitude remaining at about 2 Ohm around 20kHz for the 1000i.

If that low of impedance and high power are a must, then think about Wolcott amplifiers. They are famous for driving the largest Soundlab A-1 panels without breaking a sweat.

Otherwise, get some Zero's and use the 3x or 4x multiplier taps, your tube amp choices will open exponentially.
I have a pair of Acoustat Spectra 33's and when in use they are powered by VTL 300 Deluxe Mono Blocks. Plenty of power with lots of finesse.
I suspect none of you who have responded so far have heard the Coincident 211 Dragon monoamps - 80w/channel . They are superb and are a must audition .
While I am partial to NAT Audio since my firm also imports the line, I would like to suggest doing some research on this incredible line and more specifically on the model called "Generators" that can run any loudspeaker from 2ohm up to 16ohm and is 180wpc into 8ohm and 240wpc into 4ohm. They are within the price range of what you're looking to spend.
www.nataudio.com and www.musicalsounds.us

Good luck

If I'mn not mistaken, Wolcott ads say they are designed to be run with demanding loads, in particular flat speakers. they should fall into your budget as a stereo amp. Monos might not though.

check 'em out, they're very well regarded and a long standing company. Whenever I see them posted here they sure don't stick around long.
Darkmoebius, just for the record, I stated that about **all** amplifiers, tube *or* transistor!

To restate: If your goal is sound quality, your investment in your amplifier will be best served by a higher impedance speaker (8 or preferably 16 ohm), all other things being equal. If your goal is sound pressure and you have a transistor amplifier, that goal will be better served by a lower impedance speaker such as 4 ohms.

All tube amplifiers are challenged by 4 ohm loads regardless of the technology of the tube amplifier. In the case of a transformer coupled amplifier, you often loose an octave of low frequency bandwidth going to the four ohm tap, and distortion increases, usually along with a slight loss in power.

People often talk about the ability of a transistor amplifier to double power, but if you already have found tubes to be preferable, then you also know that that ability has nothing to do with good sound, so long as you choose the right speaker. There really are two paradigms that tubes and transistors loosely fall into, and if you mix equipment from the different camps, you will get poor performance. See


for more information.
Post removed 
get rid of the speakers....
>>11-20-08: Missioncoonery
get rid of the speakers....<<

Here's a real audio genius.
11-20-08: Audiofeil
Here's a real audio genius.

another tool
Hey Missioncoonery,

The original post did not ask for anything other than recommendations for tube amps to try. I assume because he just wants to try tube amps after having had solid state amps, (which most of us have also thought about at some point).

He definitely did not ask for comments regarding his speakers, and whether he should keep them or not.

It is pretty apparent that you and Bill (Audiofeil) are about to start a flame war, and from my neutral corner, your original post started this. (Although, in your defense, I can see that Bill came on a bit too strong with his critique of your post!) I would advise you to tone it down a little, before the Audiogon board gets involved, and starts handing out punishments.

My two cents worth anyway.
Audio Valve challenger monos class A, xlr rca,easy auto bias can run kt88, el34, 6550, shows if tubes need replacing, stable into low ohms, great for stats.
.Kurt_tank .Yes, you correct..Audiofeil/Bill seems to have issues with several users on this site from what I have read.Point taken,My comment was simply this..The original poster was asking about what tube amps to try with a very difficult speaker.The best solution IMO if he wants to get into tube amps is to replace the speakers with an easier load.
How about the Rogue Zeus monoblocks @ 225 watts and reasonably priced used - at least compared to some of the other options referenced.
thanks for all the posts and keep them coming. I will be keeping the speakers so that's no an option.


FWIW, my opinion is that seeking a tube amp to drive your low sensitivity, low
impedance speakers will be frustrating and ultimately unsatisfactory.

Stay with Class A solid state, or perhaps one of the new digital amp products,
i.e. Spectron, Jeff Rowland or H20. Frankly with your history as a Clayton
Audio dealer, and considering the stellar reviews of Clayton amps, I find it
intriguing that you are not satisfied with Clayton amps on your speakers.

Otherwise, I agree with the suggestion of changing your speakers to a tube
friendly design if you desire tube amplification.

It's the old "square peg/round hole" paradigm.
11-20-08: Atmasphere
Darkmoebius, just for the record, I stated that about **all** amplifiers, tube *or* transistor!
Thanks for setting the record straight, I had a feeling I was getting something wrong.

just want to try something different. VERY happy with the Clayton's.
The best options have been mentioned Atma-Sphere MA2, Wolcotts, big VTLs; all will be costly...Cheers,

Canary Audio CA-160 monoblocks. I am using these to power Piegas, which is no small feat. These are powerful EL34 based amps that should do what you need.

What do you guys think of the Van Alstine Ultra 550? Can it compete with any of the above mentioned products?
11-23-08: Jtwrace
What do you guys think of the Van Alstine Ultra 550? Can it compete with any of the above mentioned products?
Not exactly an apples-to-apples comparison what with the VA Ultra 550's output being power MOSFETs instead of tubes.
These: (http://www.audiogon.com/cgi-bin/cls.pl?ampstube&1232672742&/Antique-Sound-Lab-hurricane-mo) Some info: (http://www.vacuumtube.com/antiquesoundlabs.htm) BTW: The amps listed are not mine.
Oh well, its easy - look at one of Joule-Electra OTL monoblock (or AthmaSphere) you can afford and the end of it. If you never matched OTL with electrastatics then you never been in heaven!

Good Luck!
I would like to add another recommendation for Wolcott monoblocks...if I had to describe them in one word it would be "effortless".
I agree but had trouble with their reliability when I owned them. One of the Monos was faulty right out of the box.
my Atmas together with my Sound Labs are indeed a match made in heaven- as long as you are reasonable with your SPLs. If not, Siegfrieds are the way to go. A tad better bass control, but though not bad there either, not quite the delicacy or the uncanny closeness to a live event of the Atmas in softer passages.
I have sailed a long journey of amps, which sometimes makes me wonder if I should write a book on this topic:)

But the summary of the book would end up with summary of my amps (here I mention tubed or hybrid amps only even though I have had several solid state amps as well).

I have owned Conrad Johnsons, Audio Valve Challenger, Jadis JA-500, Lamm M2.1, Llano, and have also tried out a few other tubed amps for short while. My speakers have included Avalon Ascent, McIntosh, Legacy Focus, and various Apogees (Fullrange, Diva, Scintilla, Duetta, Stage).

My current Speaker is a modified Apogee Fullrange.

Out of all the amps I have owned or listened, nothing compares to Tube Research Labs GT-400 or GT-800. These
amps stand head and shoulder above anything else in terms of transparency, details, delicacy, balance, control, power, liquidity, or any other performance measure.

The next best amp was the Jadis JA-500 even though the Audio Valve was good too.

My current TRL GT-800 (weighing over 1000 lbs) is easily the final frontier in amps for me.
11-25-08: Gallant_diva
Out of all the amps I have owned or listened, nothing compares to Tube Research Labs GT-400 or GT-800. These amps stand head and shoulder above anything else in terms of transparency, details, delicacy, balance, control, power, liquidity, or any other performance measure.
I wouldn't doubt that, but for $10,000 speakers, it seems a bit unrealistic to go with $140,000 amps even if it might be (remotely)possible to find them for $70k used.
Rodman9...- The Hurricanes surely pack a punch and a sweet one at that. They are a dream match for my Alon's which like a bit of power to shine. Someday I will take the plunge
Gallant diva, hm interesting: I've owned the JA-500, actually preferred the JA 200 for delicacy, used them both with stators, but they do not, for my ears at least, even come close to the performance of the OTLs I own. Just goes to show how tastes are different!
A 1000 pound amp?

I'd have loved to seen the look on the truck drivers face when they told him to drop that one off this morning.

... but at $140K it must come with a motor driven chassis so you can drive it home.

... but at $140K it must come with a motor driven chassis so you can drive it home.

Blindjim and Jtwrace: $140,000 is an insance price for an amp. I can get you the amp at $139,000. Hey, in this tough economy time, every dollar counts.
Try the Thor Audio 60 watt tubed monoblocks. I've seen them for sale for about $5000.00 a pair. They sound great.
I'd see if those Coincident Dragons would work with those speakers and put the rest towards a Porches 911!I'd still walk away with a chunk a change
i just acquired a pair of quad 57. i am looking for a tube amp. although i am considering a dyna stereo 70, i just missed the opportunity to purchase a cj mv 125, which is my first choice.

yesterday i heard an accuphase 50 watt amp, from the late 80's. i would love to audition that amp on my quads.
FWIW: While researching tube amps also research tube types. My VTL's can take 6550's and KT-88. I like having that option. Search the forums there are many that go into great detail about how a particular type/brand sounds.
I've got a Dynaco St70 running my Quads. I've had the amp wired in triode put gold plated rca's and had 5 way binding posts added. It also has a tube preheater installed. I run the amp with a Dynaco pas 3. I have a Krell,Classe,Avi monblocks, and Opera Consonance M8oo monoblocks. The Dynaco is still my favourite. It puts out about 12 watts a channel. By the way i've never ran anything but tubes on the Quads. After 50 years they still have the best midrange of any speaker made. One last comment. The m800 i also run them in triode at 35 watts per channel and they sound sublime.
I know these are priced out f your target price area, however, I just wanted to let you know that these mono amps are capable of driving load impedances and are rated to drive as low as 1.5 ohms with 340 watts available, the modified for 2009 models have two extremely large transformers and 8 6550 tubes per mono block. These are my dream tube mono amps. These amps were specifically developed for low impedance speakers and will drive just about anything on the market today.


I heard these driving a set of B&W Nautilus 800's and they exhibited so much control over the bass and speaker that you would have thought a pair of subs were being used and that the wattage may have been way higher then advertised. I was just posting this as there are tube amps capable of driving very low impedance loads.