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Tube Amp for Martin Logan Speakers

Hi, I love tube sound through my Martin Logan Aerius-i fronts and Cinema-i center. I currently have a Butler 5150 which is a hybrid, but it busted on me and would cost $700 to fix. I've had china stereo tube amps that were pretty good and gave true tube sound, but not enough drive for higher volumes. I live in condo, so not like I can blast music anyways but still. I got the Butler because I wanted 5 channel tube sound for home theatre (The piercing sound from my Denon 3801 receiver was not pleasant to my ears). It appears there are only three multi-channel tube amps around, from Mcintosh, Butler 5150, and Dared DV-6C. The latter two are hybrids, and the last one was one of the worst tube amps i've ever heard. I have no clue why 6Moons gave the Dared a 2010 award, but maybe it's because it produces only 65W.

So since multichannel tube amps are hard to come by, and they tend to be hybrid, I was thinking maybe it would be best to get three true tube monoblocks to power my fronts. Thing is I wonder if they will be underpowered for my speakers, and not sure which ones are decent for the price. Maybe China made ones would suffice, and they still go for pretty expensive price. I'm wondering if anybody knows of a decent powerful tube monoblock that is affordable, because I can't pay $3000 per block. or maybe best to just repair my Butler. Thing is, I'm not confident that it is reliable. The tubes are soldered in which is weird, and i've taken it to a couple repair guys who both said that the design is not good, because it's very tight inside and more susceptible to being fried from DC voltage areas. it's too sensitive.

Any suggestions for tube monoblocks, even if china made ones? the holy grail for me would be Mcintosh tube amp, but they are hard to come by. Thanks.

smurfmand70
georgehifi's avatar
georgehifi
4,966 posts
 
03-17-14: Unsound: Once again I disagree with Atmasphere's oft-repeated assertion

Agreed, I have yet to listen to a Zero Autoformer that has worked without causing other problems.

A simple way to hear what they do wrong, is to put one between an amp that has no problem driving the speakers/load with out it.
Then you will hear what they do wrong with it in.

In my view they are a bandaid fix to allow an amp that has no chance of driving the speaker by it's self, to make it usable with that speaker. And I use the word usable lightly.
Far better off getting the right amp for the said speaker to start with.

Cheers George
j_stereo
119 posts
 
I ran Martin Logan Aerius-i with an Audio Research VT60 on the 4 Ohm taps and it sounded great (wish I would have never sold that amp) and I listen fairly loud. At the time I also had a Bryston 3B and believe it or not, the ARC gave the percerption of similar power (same sound level at the same Pre-Amp volume position) and the ARC was smoother with a larger sound stage. Of course it got hot (especially the output transformers) but it never bothered it.
atmasphere's avatar
atmasphere
7,068 posts
 
I take it Unsound, that you are an advocate of increasing distortion :) Because by disagreeing with me, that is exactly what you are doing.

Let's try that on for just a moment. Usually in high end audio we are interested in getting rid of colorations and just having a neutral presentation; the fact that equipment does have colorations sparks a lot of conversation as we both know. We also know that the ear translates distortion into tonality- for example the 2nd order harmonics make tubes amps sound more lush.

So what you seem to advocate is to use a lower impedance loudspeaker, as the amplifier will certainly be more distorted. Because that *is* what happens. You can see it in the specs of all amplifiers in existence. None have decreased distortion with decreased impedance. So the only conclusion available to me is that you seem to want the amp to sound more distorted. If you are all like 'no, that's not me, why are you putting words in my mouth?' then you and I are on the same page, which means that you do indeed want to get the impedance higher as that will reduce the distortion coming from the amplifier.

George, take a take a look at the links on this page:

http://www.zeroimpedance.com/zeroimpedance_002.htm

Paul Speltz has a letter from Steve McCormick, stating that his amps (which can drive 4 ohms effortlessly) sound better driving 4 ohm speakers through the ZEROs. The reason is simple: distortion is lower. That translates to 'smoother, more detailed' as far as the ear is concerned.

Bruce, what will happen in the scenario you describe is that the amplifier probably will have a problem on the higher impedances. Voltage Paradigm amplifiers often do. However, if that amplifier happens to also use tubes, it will do better into the higher impedances than a transistor amp will.
unsound
6,115 posts
 
^A lower impedance can help; extend frequency response, improve the linearity of frequency response, and as you've already noted can increase dynamic range.
If autoformers were such a panacea, why don't more (any?) speaker manufacturers include them in their products? If not speaker manufacturers, why don't more (any?) cable manufacturers, especially those that like to add such boxes to their products, terminate their offerings with them? I wonder what % of people that have audio gear incorporate autoformers in there systems? I'd hazard a guess that it's quite low.
One letter from one amp manufacturer (even one I respect) that might suggest that his products sound better into higher impedances, does not convince me that pros of higher impedances don't outweigh the cons. IME, I seem to prefer systems with speakers that have lower impedances over those with higher impedances. Now I don't go looking for these things, but a pattern has emerged. With this I can only come to a hypothesis that the distortions you make mention of; are less significant than the other considerations that come into play towards all that makes listening enjoyable.
georgehifi's avatar
georgehifi
4,966 posts
 
Atmasphere: George, take a take a look at the links on this page:

I have Ralph, and I stand by what I said, I have even put them on my system which definitely doesn't need them, and the sound took a big step backward.

They are sometimes a "recommendation" for OTL's as they allow them to drive speaker that would not otherwise be a good match for. Best off changing the amps or the speakers.

""They are a bandaid fix to allow an amp that has no chance of driving the speaker by it's self, to make it usable with that speaker."

Cheers George
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