Having owned every kind of magnetic - Maggie type, ribbon ,ML, and
Sound labs. The size also of the panel has a lot to do with demands.
by far these panels are far better controlled with the High Current of a Solid State
Amplifier, where Vacuum tubes are Voltage driven .Current is what you need
to get ultimate control ,with a Vacuum tube preamp you can still have the sonic signature you want. I have used 100wpc tube smps with them but dynamics suffer say compared to a Pass labs 350 power amp. |
Ralph, It's amazing how you keep such a cool head and give such great responses. How many thousands of times have you done this?
I hereby nominate you to the Audiogon Pantheon/Hall of Fame.
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Bag, The ORIGINAL ML CLS was a match made in heaven for a tube amplifier; it was a nominal 16-ohm load. After I auditioned a pair in a store, I bought them immediately and loved them in my home system, although they were a bit bass shy. I related this same story somewhere else earlier in this thread. Very shortly after the CLS debut, ML could not leave well enough alone; they rapidly replaced the original with the "CLS II". This is the speaker to which you refer when you speak of difficult to drive. Foolishly, I replaced my CLSs with CLS IIs without knowing much about the difference between them. Turns out, the II had a hellacious impedance dip at mid-frequencies, as you say, I think down to 2 ohms at something like 1-2 kHz. This was bad for any amplifier, and it sounded awful with my then Futterman OTL tube amplifiers. ML got the message very quickly and replaced the II with the IIz, which was merely a bandaid on the problem they introduced when they went from the original CLS to the CLS II. To my ears, the IIz bore no comparison to the original CLS in greatness. At that point in time (when the II was replaced by the IIz), I called the factory and asked them what was up. They told me quite frankly that they did not care much that I could not drive the CLS II or even the IIz with my OTL tube amp; they were playing to the SS amplifier owners. If you like the IIz with a tube amp, look around for a pair of original CLSs; they are Quad 57-like in their midrange transparency, only with more oomph. Way better than any version of the CLS that came after them.
All flat-panel ESLs (and magneplanars too) will have issues with beaming, increasingly at treble frequencies. I am not sure that the ML curve or the SL pseudo curve completely cures this problem. If you love ESLs, you live with it. I also don't think that the curvilinear design of the ML speakers is a "real" issue in causing audible distortion. It's a theoretically real issue that a competing manufacturer, like Sanders, can use in advertising. The original CLS was one of the lowest distortion speakers I have ever heard in my life.
I heard the Sanders amplifier (not his speakers) extensively driving my friend's large Acoustat speakers. He and I were very underwhelmed, despite all the bloviating about voltage. He sold the amplifier within a few months and replaced it with a Berning ZH270, a pair of them, in fact.
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So bagwell, are you saying you haven't found a tube amp that works for you with full range electrostats or with any electrostats (including hybrids)? |
Very few amps can drive the CLS (esp. of that time), which is why they -IIz came out pretty quickly. ML's with dynamic bass are not that difficult to drive with some tube or hybrid amps - which is the topic.
Off topic - I've never heard any tube amp that could drive some tough full range panels such as Scintilla's, or the CLS. The CLS IIz can be driven, but not by any reasonable priced tube, and I've never heard a tube amp that doesn't make drums sound like a rotten tomatos getting hit with a mallet when trying. I owned mine for 15 years, and with 3 dealer/friends vying for my business I heard just about all of them.
No matter what amps I try, I always end with back with my Nelson Pass products - which besides the Aleph Series can drive any panel or hybrid and avoid the SS hardness tube heads so dislike.
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Being a long-time Quad ESL (original 57's) owner, a small sweet spot is old news to me! |
@bdp24 From my conversations with Roger, it’s based on frequency response. Most curvilinears at the time were not very flat without significant EQ.
Roger's stuff is flatter, with much better dynamic range. Earlier stuff did not have very well matched woofers though, that's improved.
Now if some one could convince him to make a 2 part ESL panel for better horizontal dispersion he might own the speaker world. :)
Best,
Erik
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Sanders have some of the smoothest frequency response and best imaging in the lot. HOWEVER, the sweet spot is 1mm wide. You'll love it, but as soon as you move around it's merely a good speaker. In the sweet spot it's spectacular.
I have no experience with McIntosh at all I'm afraid. :)
Best,
Erik
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Thanks for the advice Stewart, I got your point about the Sanders ESLs. As I said, I haven't heard them, but on principle I don't think I'd be interested in a speaker that was that directional. |
Sound Labs are the only electrostatics I have never heard.....
The Sanders are not a set of tradeoffs, they are in my mind unlistenable
because of how you must be positioned in the room........
I think the MC275 would be a great amp for stats in a reasonably sized room. I would however, go substantial solid state with a great tube preamp and use Magnepan 3.7s which I think are more musical than ML (although I’ve only had experience with a couple of models)
I’ve seen lightly used pairs of 3.7s for 3K which is quite unbelievable actually........ |
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Thanks Erik, Do you have any experience with the MC275? Do you think that in mono parallel configuration it would be a good match for Martin Logans? I haven't heard the Sound Labs or Sanders ESLs, but I'm sure they are both fine speakers with their own set of trade offs. |
Sanders does indeed disavow curvilinear.....his goal is to remove the room and it's issues as much as possible.....
In theory it makes sense, and if you listen to Sanders at a show, you will leave the room impressed.......but listening to a pair in someone's living room, they are the most aggravating loudspeaker I have ever experienced by a wide margin.....you hear all about "sweet spots".....in the case of the Sanders, you will have a close relationship w/ the sweet spot because you'll need to be square in it to hear anything remotely musical at all......It's not head in a vice, it's head in a tightened vice......
the Acoustats, ML's and Magnepan's I've experienced did not suffer from this at all..... |
I believe Roger Sanders was involved in the design of the original Martin-Logan model(s), but now disavows the curvilinear principle and design, not using it in his own ESL. |
@tomcy6 An "autoformer" describes the construction of the output transformer, while "output transformer" describes it's function. In this case they describe the same part of the amplifier.
In an autoformer there is no secondary winding, and therefore, no galvanic isolation compared to a dual coil transformer.
Best,
Erik
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That's a well known question for Martin-Logan's design. Most ESLs are not curvi-linear, however. Most are truly planar. The Sound Labs may appear to be curvilinear, but the apparent curve is composed of an array of planar facets, created by stretching the mylar over a frame. Apart from the SLs, almost every other ESL is flat in fact and in outward appearance. None of this pertains to the ease or lack thereof of driving ESLs with this or that amplifier.
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tomcy6: Here is Dick Olsher on "Curvilinear" diaphragms from Sterophile: "A truly curved diaphragm (à la MartinLogan) can have wide horizontal sound dispersion, but the problem is its limited linearity at low frequencies, where large excursions are required. When the diaphragm is pulled forward, it is stretched, increasing tension. When pulled back, its arc of curvature decreases, which causes it to lose tension. This difference in tension in the two halves of a push-pull cycle severely limits the linear excursion range where distortion will be low. What's a poor designer to do?" Read more at http://www.stereophile.com/content/sound-lab-1-electrostatic-loudspeaker#KSGYY7hMRcYqtpsY.99 |
Audioman, ESLs (like Sound Labs) are not "controlled" by a high power amplifier in the same way that the misinformed might say that an electromagnetic speaker (like a Magneplanar) is controlled by high power. Electromagnetic speakers, woofers in particular, generate a back EMF by virtue of the fact that there is spurious motion of the undamped diaphragm, to which a coil is attached, in the field of the stationary magnet structure. A high power SS amplifier can ameliorate the problem, which manifests itself as a loss of bass definition, by virtue of its low output impedance. Norman Crowhurst showed decades ago, however, that the output impedance of the amplifier does not need to be so infinitesimal as it often is for modern SS amplifiers, in order to achieve this goal.
The reason some might like to use a high power SS (or tube) amplifier on a Sound Lab is because the crossover network wastes amplifier power at midrange frequencies. However, like Ralph said, a good 60W to 100W tube amplifier is to my mind optimal. Sound Lab recently cured some of this problem by modifying the crossover. ESLs, except at very high frequencies well above the range of hearing of most audiophiles, are NOT inherently current-loving speakers at all. In fact, the impedance is inherently quite high across the midrange and the speaker could be said to need a voltage amplifier. I am glad of this, because the amplifiers you named are wretched, with the possible exception of the Pass Labs. Furthermore, the "big Krells" were notorious for upchucking when coupled to ESLs, because they were unstable into a capacitative load.
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Electrostatics love current .much more then Voltage as with a Tube amp.
put a Pass Labs 250.5 , Big Krell, or Coda amplifier and you will get tighter bass ,better dynamics and control
as well as speed. Even Maggie love power,Soundlabs for sure. |
Stewart, I apologize for the tone of my remarks; I was feeling playful, and perhaps that came across as hostility, which was not my intent. It seems impossible to get my point across to the assemblage, which is simply to re-state that one should make one's own decision on amplifier power and type based on the electrical characteristics of the speaker. Period. There is no one correct answer that fits all situations. Of course, this goes for any type of speaker. Sadly, most modern day ESLs are difficult loads for tube amplifiers, not because of the operating principle of an ESL per se but because of crossover design. Martin-Logan is chief among the guilty. But they really don't care; they assume you will buy the latest solid state behemoth to drive their speakers. Try a Quad 57 or a KLH 9 sometime (both nominal 16-ohm loads), and you will know what I'm talking about.
And, since you brought up magnetic/planar speakers, others are now starting to discuss them as if there is any parallel with ESLs. Apart from size and shape, there is not. To run a magnepan with a tube amplifier, one should consider using the Zero autoformers. I used to use Zeros with my Sound Labs, until I got some advice on how to "fix" their fundamental impedance characteristic.
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Damn oregonpapa, that is a BIG room! In the 80's I heard the Acoustat 1+1, 2+2, Three, and Four driven by ARC (D-75 and D-150), but they can use all the power they can get. Same with Maggies, of course. I'll be setting up a pair of Tympani T-IV's soon, and have an only 200w/ch amp for them, a PS Audio. There are guys throwing 2000 watts into them! But the room is pretty small, so hopefully 200 will be enough for the bass panels. They will be bi-amped, with either a tube or SS 100 watter on top. |
bdp24 ...
In an earlier post, I mentioned that I used a pair of "loaner" Atmosphere 60 watt mono amps for a couple of years to drive the Acoustat Four's I used to own. Then I switched to an ARC Classic 60. The ARC produced better base, the Atmosphere took the honors in the mid-range. Both amps were under powered for the Acoustats.
On night a friend brought over two of Frank Van Alstine's 250 watt solid state amps with one of Van Alstine's bridging devises. We used high quality IC's to hook everything up.
We sat in total amazement when those hundreds of watts started driving those huge electrostatic panels. At the time, the room size was about 25 x 40 ... and the room was totally filled with non-distorted sound. No matter how high I cranked the volume control, the speakers and amps went right along with the program. Haven't heard anything like it ever since. I have to admit, I sometimes pine for that system. |
If one can bi-amp Maggies (or any other magnetic-planar speaker), solid state on bottom and tubes on top is a killer combo. It's the bass drivers that suck up all the current. |
LewM,
What part of "I know they're different" did you not catch? At least you didn't write that I'm full of Baloney again.......Having said that, your explanation of the differences (the differences I acknowledged).....are spot on.
You and others seem to have taken my opinion and tweaked it to say that I say a SS amp is best with Electrostatic, or Magnetic planar for that matter.....It's not really SS versus Tube it's current... Would a world class 150W tube amplifier sound better than it's identical but smaller stablemate say at 50W.......I guess some would say YES.....I say in most cases, the 150W would sound better.......When you get beyond that....solid state of course becomes prevalent.....I love tubes on electrostatics, and most of the electrostatics I've had, save for the Martin Logans were driven by tubes....but I never had the headroom or effortlessness I reference here.......In the case of the Magnepans I have now.......it's quite different......they simply WILL NOT SING without a couple of hundred watts......they'll make music, but they won't sing....
but when I feed them nearly 2KW into 4OHMS like I have on tap with the Brystons.....everything takes on an effortlessness that's hard to describe......
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Dear Stewart, You wrote, "There's no analogizing......and I know they're different (that's why they're not both called electrostatic)" Wrong! Your magneplanars and even ribbon tweeters are electromagnetic, not electrostatic. In your speakers, the diaphragm is "wired"; the signal is conducted through wires glued to the diaphragm, which causes it to move back and forth in a magnetic field, much like any other traditional type dynamic speaker. In an ESL, a the diaphragm carries a very high voltage on its surface, and the signal is applied to the stators, stationary wires front and rear of the diaphragm, causing the diaphragm to move due to electrostatic forces. Therein lies the way in which ESLs are totally different. Furthermore, ESLs, being electrostatic, do not produce a back EMF, as do electromagnetic speakers, so the whole idea of "damping factor", the reason some say that only SS amplifiers can provide "clean" ("tight") bass, goes out the window.
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We are devolving into semantics.
The alternative to "tight" in my mind is "flabby" or "boomy" which is what usually happens when your speakers go low enough in frequency to exacerbate room modes. +-20 dB peaks and valleys are quite real and detrimental to musical enjoyment.
However, a system that lacks those peaks and valleys, and is flat to 16Hz in the room is a marvelous thing indeed. :)
Best,
Erik
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Atmaphere wrote
"Some people like it, but in the real world there is no such thing as ’tight’ (thump but no body) bass. That’s an audiophile thing; but if you listen to real, live music you won’t be hearing ’tight’ bass."
+1 Tight bass sounds unnatural to my ears . Drum , bass guitar ... ect . I have never thought while listening to these instruments "man that is tight" complete opposite actually . "man that bass lingers" is what i hear .
Tight bass can be found with electronic music . And can be judged when listening to it . |
But in my experience, a good dose of juice gives electrostatic
loudspeakers (to stay on topic) a more effortless quality better kick in
the lower registers.... I've yet to hear a solid state amp play bass properly on an ESL, in particular Sound Labs and Quads. On transistors can make thump but have no definition (output impedance is too low). If you don't understand that last statement then you probably listen to a transistor amp. Transistors fail to make bass power on many ESLs (the ML and Sanders being exceptions as their overall impedance is set really low) simply because of the 10:1 impedance curve. Its simple physics- on many ESLs they simply run out of voltage (which is why the bass power is limited). At the same time the speaker is overdamped in the bass so the combination is weak bass without definition. Some people like it, but in the real world there is no such thing as 'tight' (thump but no body) bass. That's an audiophile thing; but if you listen to real, live music you won't be hearing 'tight' bass. |
LewM
There's no analogizing......and I know they're different (that's why they're not both called electrostatic)
I have owned LOTS of electrostatic loudspeakers over the years and I have owned Magnetic Planar speakers over the years, and yes.....it is my opinion that both benefit from a lot of juice.......if that makes me full of baloney, then so be it.....does it mean that folks can't get a good sound at reasonable levels with a 60 watt Atmasphere tube amp? no! But in my experience, a good dose of juice gives electrostatic loudspeakers (to stay on topic) a more effortless quality better kick in the lower registers....
As to Sanders using 900w amps, his speakers are afterall hybrids, with very prodigious bass at the shows and he will place anyone who comes to his room perfectly on axis in 3 chairs placed along the center line......Once those people buy a pair and get them home, they find out that they again must place their chair along that center line......if they move their head 4 millimeters to the left or right, the soundstage will collapse as will all the detail......I had a friend buy a pair used, drove 400 miles to pick them up , along with the Magtech amp.....got them home, played them for exactly 5 minutes, then put them on Gon.....
I have owned Quad ESL63s, I have owned Acoustat 2+2's with heavily modified Servo amps from their original model X, I have owned Martin Logans. I now own Magnepan 3.7s The Magnepan 3.7s absolutely obliterate any electrostatic loudspeaker I have ever owned or heard....they are anything but cold and they capture the natural decay of musical instruments better than any speaker I've heard.....and like you, "That is only my opinion"
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Dear Tim (Pryso), Let me help you with that. Stewart is full of baloney if he insists on analogizing a magneplanar type speaker with an ESL. They may both be "flat", but that's about where the similarity ends. The principles of their operation are completely different. Thus also their typical impedance characteristics and inherent efficiencies, respectively, are very different. ESLs that need lots of solid state power are ESLs that were designed with SS amplification in mind and which typically contain crossover networks that grossly waste amplifier power and in the process also create nasty impedance dips at or near midrange and bass frequencies. If he prefers SS amplifiers to tube amplifiers, that is another matter, and there he is entitled to his opinion.
Frankly, magnepans leave me totally cold. They are dead sounding; they fail to capture the natural decay of musical instruments. Only the later iterations that incorporate a ribbon tweeter are at all listenable, to me. And that is only my opinion, of course. The thread is about ESLs, however. |
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stewart, "Planars whether it be magnetic or electrostatic sound their best when fed prodigious solid state juice....."
Some years ago I heard a Magnepan demo at the CES where they were driving MG 3.6s bi-amped with Bryston amps (no recollection of which models). I can't say their sound was pleasing or even interesting.
However I've also heard MG 3.6s driven by a 100 watt ARC tube amp which sounded musical and highly enjoyable.
Does this mean I'm right and you're wrong? Or you're right and I'm wrong? I'll say neither one. Only that different folks have different preferences and there are no absolutes.
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Those effects will become increasingly pronounced as speaker impedance
in that octave decreases relative to amplifier output impedance,
everything else being equal. Al, as I mentioned earlier, the impedance curve of any ESL is not a graph of its efficiency (unlike a typical box speaker; this is due to the fact that the impedance curve is based on a capacitor). The fact of the matter is the efficiency curve looks a bit different and often ignores the impedance curve. This is why an amplifier that acts as a voltage source will tend to sound bright on an ESL and might not make so much bass. none of it negates the fact that ESLs and Magnetics
require a lot of wattage to really sing.... This statement is really questionable. If it were completely true a 15-watt amp would not do so well on Quad ESL57s (but they do- Quad used to make a 15-watt tube amp that was made for the ESL-57). Or a 60-watt amp on Quad ESL63s and Accoustats (we've sold lots of our M-60s to such owners). I've seen 70-watt amps play Sound Labs quite nicely. We sell a good number of our MA-1s (140 watts) to Sound Lab owners. We also have a number of customers running M-60s on Magnaplanars (although they use a set of ZEROs to allow the M-60 to deal with the impedance). The reason the Sanders needs such a powerful amp is that the speaker is inefficient. This is a conundrum with ESL designers- how to place the diaphragm... closely spaced so its easier to drive (might not handle excursion well)? Widely spaced to handle excursion (will be really inefficient)? A speaker that **requires** a 900 watt amp to drive it is next door to criminal (and FWIW the Sanders does not seem to need that sort of power). The last thing you want to do with **any** amplifier is make it work hard (such increases audible distortions that make the presentation harsher and less detailed; exactly the opposite of what you want on an ESL). If you've set up your system properly, your amps won't be working hard most of the time. |
stewart0722Planars whether it be magnetic or electrostatic sound their best when fed prodigious solid state juice..... That really depends on the specific speakers. You're certainly mistaken if we're talking about Infinity Betas, for example. |
Everything you say bdp is absolutely correct.......
but none of it negates the fact that ESLs and Magnetics
require a lot of wattage to really sing....
That's why Sanders amps are typically 900w into 4 ohms
Can't get there with tubes, at least not w/ reasonable size/cost
restraints......although I've heard musical results with stats
and tubes, they just haven't had much authority at reasonable
to higher spls |
Good info Lew. Yup, 14k is inaudible to me too now, thanks to over fifty years of performing and attending live shows, some with excruciatingly loud SPL. I had molded ear plugs made when I was in my 30’s, but the damage had been done. Youngins’, don’t put it off, use protection! Stewart, ESL's and Magnetic-Planar loudspeakers present quite different loads to an amp, ESL's a very reactive one, M-P's a resistive. In addition, ESL's benefit from a voltage source type amp, M-P's a current source design. That's why Roger Sanders makes an amp for each type loudspeaker. Right Lew? |
Planars whether it be magnetic or electrostatic sound their best when fed prodigious solid state juice.....
I have Magnepan 3.7s and I use Bryston 28BSST2's
I do couple it with a full tube pre (Convergent SL1 Renaissance)
I don't think I give anything up to a full tube rig in terms of overall
musicality, but I gain a lot in terms of headroom..... |
I think Al and I did allude to such issues. It is not the high frequency information per se, unless you are talking about RF, which is never good for any system, but how the load (the speaker) reacts to those frequencies in a way that then feeds back on the amplifier. Traditional SS amplifiers that use a lot of Negative FeedBack (NFB) tend to be driven into oscillation by the capacitative nature of an ESL as load. Any modern design worth its salt should be Ok in this regard, probably including those made by FVA and RM, two of the oldest old timers in the business. (No disrespect intended; I suddenly find that I am an old-timer too.)
By the way, for most adult males beyond the age of 35 or so (which is almost certainly all of us here), even 14kHz is well beyond audible. Yet, I perceive that wide bandwidth is a "good thing" in electronics.
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From my reading, I am aware of another consideration in these matters. The way an amplifier circuit reacts to very high frequencies presented to it, frequencies too high to be heard on their own, can affect the behavior and sound of the amp. A barely-stable circuit can be driven into oscillation by those frequencies, creating ringing and different forms of distortion. Frank Van Alstine and Roger Modjeski have discussed this area of amplifier design in their writings, and it is an important consideration with ESL loudspeakers. They benefit greatly from an "unconditionally" stable amplifier. Both Frank and Roger make such amplifiers, though they are not alone in doing so. |
Great post, Lew. Thanks! The only thing I would add is in connection with this statement near the end:
... it is my opinion that so long as the impedance remains reasonable at
least up to 10kHz, the low Z above that frequency is nothing to worry
about; there is very little energy demand on the amplifier for
frequencies above 10kHz...
The low energy demands in the top octave will of course work to the amp's advantage, as you indicated. I would add, though, that there can still be effects in that region on tonal balance and in how accurately high speed transients are reproduced that will vary as a function of the relation between amplifier output impedance and the speaker's impedance characteristics in that octave. Those effects will become increasingly pronounced as speaker impedance in that octave decreases relative to amplifier output impedance, everything else being equal. Although as you indicated the specific relation between those characteristics that will be sonically optimal very much depends on the particular speaker and the particular amplifier. Best regards, -- Al |
I would only add one point to this discussion. It is folly to talk about "tube amplifiers" and "ESL"s in general terms, because each and every tube amplifier and each and every ESL in the marketplace has its own idiosyncrasies of design that strongly influence the interaction between the two. In my opinion, tubes and ESLs ought to be an audio match made in heaven. (I have owned nothing but tube/ESL systems since the early 1970s.) However, in the era of solid state hegemony, many ESL companies have designed and marketed products that are tailored to work well with SS amplifiers, which usually has a corresponding negative effect on the capacity of the speaker to be driven by a tube amplifier, and/or there are designs with complex crossovers that impose impedance curves unfriendly to tube amplifiers. Martin Logan seems to have adopted a pro-SS amplifier philosophy many decades ago. Their original ESL, the CLS, had a nominal 16-ohm impedance and was a beautiful match with the Futterman amplifiers that I owned at that time. They followed that up with the "CLS II", which I bought before auditioning them, just because I loved the original CLS so much. The CLS II was a gross mismatch for an OTL tube amplifier like the Futterman, because it introduced circuitry that created an impedance as low as 2 ohms at critical midrange or upper midrange frequencies. Zero autoformers did not exist at that time, and the mating of the CLS II with my Futtermans was a disastrous non-starter. The moral of this story is that it behooves any buyer to educate himself as regards the technical aspects of the components he wishes to match together in one system. There are no rules one way or the other.
I am now using Atma-sphere amplifiers to drive Sound Labs 845PX speakers. Frankly, this was not a perfect situation until I made some rather drastic modifications to the Sound Lab input circuit such that the speaker now presents an impedance that is 20 ohms or higher across the audio band up to about 5kHz, where it falls to about ~8 ohms and ends up at ~2 ohms at 20kHz. (I know this, because I made the measurements myself.) As someone else pointed out, an ESL is in effect a giant capacitor, and there is no avoiding a drop in impedance at very high frequencies. However, it is my opinion that so long as the impedance remains reasonable at least up to 10kHz, the low Z above that frequency is nothing to worry about; there is very little energy demand on the amplifier for frequencies above 10kHz, and the capacitative nature of the load should not bother a good tube design, whereas it can play havoc with SS amplifiers. I might add that, thus modified, my 845PXs can be driven by much less than 50W of good tube power. The ~100W Atma-sphere amplifiers are loafing even during loud passages.
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What a wonderful thread, I enjoy an education on audio any time, to all the contributors, thankyou, as much experience I have with audio, it is delightful to learn, cheers gentleman. |
The Music Reference RM-200 Mk.2 does itself have a 2 ohm tap. Great amp. |
If they have a 2 ohm tap I would expect them to work fine.
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McIntosh has autoformers in their solid state amps and specifies that the rated power of the amp remains the same into 8, 4 or 2 ohms. In the MC275 tube amp they call the output transformer an output transformer but in the specs they list it under Autoformer. In stereo mode they say it outputs 75 watts into 4, 8 or 16 ohms, and in mono parallel mode, 150 watts into 2, 4 or 8 ohms. |
Ralph, I’d still like to get your opinion on McIntosh amps with
autoformers. Just in general, do you think they are a good sounding amp
compared with other amps in their price ranges? Do they implement their
autoformers well? Would they be a good choice for driving speakers with
difficult impedance loads? Theoretically, of course. We all know that
good sound depends on many factors in a given system. I was not aware that Mac was still making those; in the old days their autoformers worked quite well. But with those older amps I would not be asking them to drive anything much below 4 ohms. The only thing difficult about the MLs is usually their impedance. Beyond that its my opinion that its a Bad Idea to make any amplifier work hard by making it drive a 'difficult load'. What happens is you get more distortion, usually of the type that make the resulting sound harsher and less detailed. This is why I've recommended the ZERO so often in the past, as it allows the amplifier to drive an easier load. I don't think the Macs have impedance taps below 4 ohms but usually they do employ a fair amount of negative feedback so they should work alright on ML loudspeakers if not pushed too hard. |
ivanj, I asked about McIntosh because I have read many threads where Ralph recommends Zero autoformers for hard to drive speakers and even for not hard to drive speakers. Since McIntosh makes amps with autoformers designed specifically for a particular amp, I thought they might be a good solution for speakers with very low impedances and wanted Ralph’s or anyone else’s opinion on that match. Is it a good one or are Macs just not a good match in spite of his recommendation of autoformers? I know some people just don’t like the sound of Mac amps and point to the autoformers as the reason. Why do you say that the curvilinear design is fundamentally flawed? |
McIntosh equipment and ML’s are both sold by the same retailers, is that the reason for the question? My friend was a huge, enthusiastic McIntosh dealer until they went with Magnolia/Best Buy. Due to his kindness I have tried various McIntosh amps on various electrostatics. I know that the McIntosh amps are not a good match for (full-range) electrostatics beginning with QUADs. The OP should find out if they offer another solid state amp with lots of current to drive the electrostatics. You might stay away from Levinson amps too.
Yes, the Classe’ 45 watt VHC amp should drive electrostatics well. Bravo with sticking with a great amp! Reich is a brilliant designer.
Unfortunately the Martin Logan’s "curvilinear" membrane is a fundamentally flawed design. That, among other reasons, is why they have to offer a 5 year warranty.
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Long time ML user since 1979. I've owned SL3's, Aries i's, ReQuests, CLS, Monolith III's, and now Theos.
I've been on Audiogon since 1997. There's always been a myth that ML's are "harder to drive." I drove SL3's with a lowly 35 watt Prima Luna. I drove CLS to satisfying levels with an 8 watt SET amp! Currently I'm using a Dennis Had Inspire firebottle KT88 SET to power Theos.
Each individual has different audio needs. We each listen differently. I listen to jazz, in a smaller room now. But even when I had a larger room I drove ML's to very satisfying levels with Manley 450 mono's. In fact, I've never had a more satisfying audio experience than pushing a pair of CLS' with those Manley's.
I'm big on tube amps for ML's....and I sewed my audio teeth on Pass, Threshold, Plinius, and too many other amps to mention.
It's not a one size fits all audio world. What works for me won't necessarily work for you. And that's as it should be.
If I had a friend with a pair of SL3's I'd be wondering more about how much longer are those panels going to last, as that speaker went out of service in 2002? |
When I read all of the responses saying that tube amps will have problems driving Martin Logan speakers, I just had to make my first post on Audiogon.
I have 2 Audio Research VT100 Mk IIs bi-amping a pair of Martin Logan SL3s. These speakers have never sounded better. The sound is organic and natural sounding. If the recording has a lot of spacial information and depth, it is revealed in the presentation. If the recording is flat, that too is revealed. Cymbals sound the way they should. Vocals, including female, just sound right.
Before bi-amping the SL3s, I had one VT100 amp. The sound was similar but there was less depth and the stage wasn’t as wide. Also, large orchestral works just didn’t have the presence that they should have. This was the reason for a second amp. NOTE: I do not listen at high volume levels. The stereo is in a loft so the left and right speaker are not presented with the same wall configuration which just messes up the stage width and depth at high volumes. Plus, I want to be able to listen to my stereo for many years. ;)
BTW, my pre-amp is also tube based.
Recently, I wanted to get away from two amps and tubes. I read a lot about Pass Labs amps and purchased an X350.5. I liked some of what it did but ultimately the sound was just unnatural with overblown bass, etched highs and an odd midrange. Every time, I switch back to my VT100s, I found that I enjoyed the music more. I returned the Pass Labs amp.
I am now looking for a more powerful tube based amp so I can go to a single amp.
My experience for what it's worth.
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One data point.
I use Martin Logan CLS (original) in one system and although I have auditioned tube amps with them, I have found that solid state amps with good power supplies work by far the best. Mine are run with a stereo Classe DR3 VHC (a whopping 45 watts).
Not saying that the magic tube amp isn't out there, just that I haven't found it. |
