George and Ralph, not really interesting in starting another discussion on the differences between Voltage Paradigm amps (generally solid state amps with very low output impedances -- high power SS amps can generate high current) and Power Paradigm amps (usually tube amps with higher output impedances).
Suffice to say that as Ralph and Al (Almarg) have said many times, if a speaker was designed and voiced to be driven by a Voltage Paradigm/SS amp, using a high output impedance Power Paradigm/tube amp will likely result in acoustic colorations. The reverse case also being true.
But hey, not all acoustic colorations necessarily sound bad. ;-) |
Play yes Atmasphere, but really you and I both know they were not able to give a flat 20hz to 20000hz into those hard loads.
They acted more like they had tone controls in them and made the FR look like a dogs hind leg.
I have a old friend that has two pairs of Stax F81's and not even his mighty Rogue Magnum 150 monoblocks drives them as well and with flat FR with a vice like grip as a good stable BJT amp can, like the big Krells and such.
Cheers George |
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Bombaywalla, yes, Roger sets the impedance of his ESLs quite low, to make them more compatible with solid state. ...the Moscode 600 is a hybrid employing Mosfet output stage, even though it has a lot of watts!!, mosfets don't do current like a BJT (bipolar)output can
This is why it wouldn't drive the ESL's, as with ESL's the impedance curve can dive to below 1ohms at places and very capacitive as well, and for this a solid state amp should have a BJT (bipolar) output stage that is high current and be very stable into capacitive loads. Georgelofi, I'm pretty sure that is not the right explanation. Keep in mind that a much smaller amp with tubes, the Dynaco ST-70, was able to play the Stax, with only 35 watts. Those older Moscodes had problems (IMO) unrelated to the fact that they used MOSFETs (IMO the topology itself was an issue). We had customers play the Stax with our original MA-1s (which back in those days made about 100 watts) and they seemed to play well together. The old MA-1 was an OTL with no feedback and a fairly high output impedance, yet sounded find with the Stax. So 'current' is not the answer. Stable into capacitive loads- that makes more sense as that is something true of both the ST-70 and the MA-1. |
Frogman hi, the Moscode 600 you mentioned not being able to drive the ESL's very well.
I believe that the Moscode 600 is a hybrid employing Mosfet output stage, even though it has a lot of watts!!, mosfets don't do current like a BJT (bipolar)output can
This is why it wouldn't drive the ESL's, as with ESL's the impedance curve can dive to below 1ohms at places and very capacitive as well, and for this a solid state amp should have a BJT (bipolar) output stage that is high current and be very stable into capacitive loads.
Cheers George |
Hi Atmasphere,
nice to have met you in person at RMAF2013. I always enjoyed listening to the Classic Audio Hartsfield & T1.4 & they were sounding very good with your amps.....
I believe that Roger Sanders has also done a great job with his s.s. amps - ESL Mk2 & Magtech - to drive electrostatic speakers. I listened to his speakers in the Sanders Sound Labs room & I really liked the sonics there as well. So, the s.s. world is not totally shut....
thanks. |
I will let the more technologically astute (Atmasphere) explain the reasons why, but one of the most eye-opening and educational experiences for me happened about twenty years ago. I bought my first pair of Stax F-81 electrostatics (known to be a highly inefficient and brutal load) after hearing them sound glorious in a friend's system. My amp at the time was a NYAL Moscode 600 capable of 300w at 8ohms and 500w at 4 ohms; it is a hybrid design with ss output stage. I thought, surely the Moscode can drive the Stax with no problems. Wrong! The Moscode sounded thin, flat, and DEAD DEAD DEAD, with no dynamic verve. I tried various cables; no better. Then, for the hell of it, I tried a rusty old Dynaco ST70 (35w) that I had bought at a local TV repair shop for $50 and was my first pure tube amp. I figured, what the hell? Result: MUSIC!! The Stax's suddenly sounded the way I remembered them; sweet, refined, detailed, dimensional, and within an admittedly limited dynamic range, very ALIVE and dynamic. I drive my current Stax's with Manley tube mono's with great results. |
Sure(the 303 being the first)- But not until 11 years after Walker demonstrated his first truly full-range electrostatic speaker(in 1956). Around the same time that everyone else(McIntosh, ARC, et al) was bowing to SS and the output power demon. |
Rodman9999, Quad also made ss amps. |
Here are just two speakers that are not a good match with tube amps the Infinity Kappa 9 and an Acoustat not shown is the phase angles which can make them even worse as seen by the amp.
http://www.rageaudio.com.au/index.php?p=1_12
Note the low impedance dips (left scale) at 2ohms and down to .5ohm and at what frequency (across the bottom), this is where tube amps will have trouble. (right scale is the phase in degrees not plotted) when this goes into the minus figure with low impedance together then it can become an amp killer at that frequency.
Like this graph of the the Genesis 5.2
http://www.stereophile.com/content/genesis-advanced-technologies-52-loudspeaker-measurements
And this one of the magico Q5
http://www.stereophile.com/content/magico-q5-loudspeaker-measurements
This one of the Sonus Faber
http://www.stereophile.com/content/sonus-faber-cremona-elipsa-loudspeaker-measurements
Cheers George |
I am presently running audiovalve challenger 180 monoblocks driving soundlab M2's with excellent results.I am able to roll el34,6550 and kt88's with these amps and the results are stellar. |
MartinLogan CLX speakers work very well with small tube amps and 50W is more than enough, according to Hi-Fi World. The reviewers were adamant about it in their CLX review. |
Probably why Quad, aka- Peter J. Walker(RIP) & 'The Acoustical Manufacturing Company', has been building a line of tube amps, for so many decades. |
Something like 80% of our MA-2 amplifier production has been for Sound Lab owners.
The Quad ESl 63 as been a good match for our M-60 and MA-1 amplifiers. Martin-Logans (which have a lower impedance) usually require a set of ZEROs (http://www.zeroimpedance.com) to work with many tube amps. The CLS-1 is an exception- its impedance was set higher and so is easier for tubes (M-L really wants their stuff to work with transistors, so even though they sound better with tubes, their impedance is usually set lower so transistors will have an easier time with them).
Some of the old Accoustats were an easy load for tubes and some were not, as Accoustat was trying to crack the solid state market too. If one of the higher impedance Accoustats, IME 50-60 tube watts is plenty of power.
The fact of the matter though is that the nature of tubes where they do not always act like a voltage source (which is the ability to double power as impedance is cut in half) is an advantage when trying to drive the higher impedances that an ESL often has. Unlike a box speaker where the high impedance in the bass can be the result of a box resonance, the high impedance of an ESL has nothing to do with resonance and so they still need power to drive them even though the impedance is high. Tube amps do this better than transistors.
As an example, a 600-watt transistor amp can't make any more power into a set of Sound Labs than you might get from a 150 watt tube amp. Put another way, a lower powered tube amp can often make as much or more power than a more powerful transistor amp when driving ESLs.
In short, ESLs and tubes have been one of the better combinations in audio for the last 55 years. |
Yes yes yes tubes love stats ,,,, I have jolida mono blocks w/ my Martin Logan's clsiiz !,,, |
Sound lab speakers have chosen Wolcott amps to drive their speakers. these amps can handle the most difficult load |
ESL 63 and US monitors have an intentionally benign impedance curve that is nominally 8 ohms an is rather flat compared to other electrostats. The lower the output impedance of the amp, the better. |
I do not have experience with your amp, but I run my Martin-Logan Aerius i speakers with tubes by choice. I use 130W monoblocks and they made the Plinius SA250 (and several solid state others even more so) sound sick. A well constructed tube amp can sound much more lively than solid state amps provided you do not push them too hard. Friends with more experience of Martin-Logans believe tubes are preferable. If you are thinking of spending $2,500 on electrostatics then your musical tastes do probably not include playing drum and bass at 120dB, right? So what you lose by not using solid state will not be very important. If you are buying an electrostatic its probably because you want the transparency, purity, grainlessness, lack of cabinet resonance etc that the electrostatic can offer. Why spoil this with the electronic nature of solid state sound? You will probably just love the sound of your tubes when you hear them through some 'stats (preferably a hybrid for reasons stated in previous posts). The only problems you might encounter will occur because you want to play them louder than your amps can deliver. Try it. |
With stats you have to be careful because the impedence curve varies a lot. You may have some trouble in the bass since some tubes cannot drive very low impedences. If you do not want to change your amp, which by the way is a very good one, you should try the Maggie 1.6. These are different from stats since they have a very flat 4 ohm impedence. I have the Maggie 3.6R and am driving them with OTL tubes with great success. The web site is www.magnepan.com. |
Just checked with two experienced sources. Your amp will work fine with Original Quads - use the 4-ohm tap. |
Dabble, I believe your amplifier would work well with most hybrids, but not necessarily with full range electrostatics. The reason is that full range electrostatics usually have a very high impedance in the bass, often over 50 ohms, and your amp would not put out much power into this load and so would clip prematurely. Electrostatics typically have a very low impedance at high frequencies, but with the CJ this shouldn't cause a significant frequency response anomaly. And remember there is relatively little energy up around 20 kHz, so the amp is not likely to clip as a consequence. I sell Sound Lab electrostatics, and they have a couple of hybrids that would work with your amp. I think the Martin Logan and Inner Sound hybrids would work well also. Avoid used Acoustats or Martin CLS's as they will give your amps a severe pain in the output stage. Historically Connie J. EL-34 based amps work well with Quad 63's (& USA Monitors), which are full range electrostats. I have a few reservations about these Quads, however, and personally prefer the Originals. But, I have no experience driving the Originals with EL-34 based amps, so while I think it would work I don't really know. I'd like to ask some specific questions that might help me make a more educated recommendation. Don't worry, I'm not going to push my product at you. I am one of you, not one of them. Audiokinesis@home.com. |
I recently changed from a highly rated 400 wpc @ 4 ohms solid state beast to 100 wpc (triode mode) Cary SLAM-100 monoblocks driving Martin Logan SL-3 hybrid electrostats. The sound with tubes is far superior at low, normal & loud listening levels. At VERY loud levels the SS was better. Ultimate bass extention was better with SS, but this is offset by a more realistic bass tone with the Cary's, particularly on strings. Sound stage, presence, musical realism, emotional impact - all far better with the tubes. |
I've had great luck with Martin-Logan Aerius speakers mated to my Audio Research VT-60 (50 w/ch) |
You're better off not using electrostatics or ribbons with your amp. Besides wattage, this type of speaker needs an amp with high current delivery capabilities into difficult loads. You ought ot look elsewhere. Proac Studios is usually a good match for CJ electronics. But in my opinion your amp does not warrant a $2000+ speaker. You'll be better off with sub $1000 speakers, like Proac Tablettes, or Sound Dynamics 300i. rgds, david k. |
