All ESL panels I know of follow this descending impedance curve, which is a problem for a lot of amplifiers since most amplifier’s have rising impedance at the upper end of the frequency spectrum, resulting in an overall significant net loss of output.
This is in addition to current limiting, which thanks to music being bass heavy, is less of a concern.
Tube amplifiers rarely have the low output impedance (anywhere) that solid state amps do so they start at a disadvantage.
However this is all basic electrical / and voltage dividing theorems. The final choices about matching any given amp to any given speaker has to include the speaker’s acoustic output and room.
Given the impedance curves of the amps and speakers you can predict reliably that amp X’s electrical output will drop 6 dB at 20 kHz with a given speaker, but I can’t tell you if you’ll like it. :)
"
They need about 15 Watts of the best amplification you can get your hands on."
"
The Quads will play up to about 100 dB, which is much louder than I play music even when playing loudly.
"
"
The second downside is that they are a difficult load for the amplifier
to drive. They are highly reactive loads (primarily capacitive). Their
impedance drops as the frequency increases. This makes the Quad ESL a
bad choice for single ended tube (SET) amplifiers.
"
I think I can figure out why this guy isn't an authority, desperate or not.
"The second downside is that they are a difficult load for the amplifier to drive. They are highly reactive loads (primarily capacitive). Their impedance drops as the frequency increases. This makes the Quad ESL a bad choice for single ended tube (SET) amplifiers."
IMO it is a somewhat misleading oversimplification to categorize the ESL57 as being either an easy load or a difficult load.
It is a difficult load in the sense that its impedance descends to low values in the upper treble region, due to the capacitive nature of the impedance. Although even in that region its impedance is not nearly as low as the sub-1 ohm impedances of some other electrostatics, such as many of the Martin-Logan designs.
However, that difficulty is of course mitigated by the fact that most music contains relatively little energy in the top octave, where the impedance is particularly low.
It is an easy load in the sense that damping factor is a non-issue **with respect to bass control,** as Atmasphere indicated, because of its high impedance in the lower parts of the spectrum.
However, it will be a load that is **revealing** of amplifier differences, not only because of its transparency and musical resolution, but because differences in damping factor among different tube amps, and also between tube amps and solid state amps, will have tonal consequences.
Damping factor is inversely proportional to an amplifier's effective output impedance. (I add the word "effective" to indicate that I am referring to output impedance taking into account the effects of whatever feedback may be present). The interaction of the amp's effective output impedance and the speaker's wide variations of impedance over the frequency range will certainly have tonal consequences, especially among different tube amps, and between tube amps and solid state amps. Less so among different solid state amps, since their effective output impedance is near zero in most cases.
In any event, the bottom line with respect to the tube-friendliness or lack thereof of the ESL57 is perhaps indicated by the fact that it was designed before solid state amps existed.
Wrote this false and misleading statement (<----- a paraphrase of how atma has posted):
The ’original Quad’ (as bdp24 put it) is an easy load to drive. Differences in damping between amps is one of the few things that **isn’t** audible on the speaker, owing to the fact that in the bass range the impedance is rather high. This reduces the difference heard between an amp with say 10:1 damping factor as opposed to one with 100:1.
Rather than argue with someone desperate to be an authority, I submit this link:
To actual musicians, the "feel" of the instrument is what counts, and Strads (not all of course) seem to have a feel and tone that people who play them really like, thus they might play better using them. Nobody disputes that fact really, and since there are a limited amount of zillion dollar Old Master built instruments out there, most good musicians can’t get near one…so, of course, they use other things and sound fine. Note that among Strads and other old and great violins the utility is often tweaked (i.e. repairs are made) that would be blasphemy among "vintage" guitar players (something I actually know something about as I am personally vintage). I saw a 50s Stratocaster advertised at Mandolin Brothers that didn’t actually work because to make it work you’d have to replace an original part (an original tone or volume pot or something), and that would make it less valuable!…love that…also, since Brazillian rosewood isn’t legal now (new stuff anyway), Martin Guitars is taking guitars from the 60s and 70s (a less than "special" era) apart for their rosewood, and making new and expensive high end guitars out of the backs and sides…clever bastards. The good news is there are thousands of great instrument makers doing fabulous work these days, so great instruments are available.
This is a reason why I strive to make my speakers easy to drive. Easy to
drive means they will sound great across a variety of amplifiers and
electronics.
+1
Not surprised by your finding as Quad ESL can be an extremely tough
load. Differences in amplifier damping (output impedance) would be quite
audible. This only proves one of the major design issues with Quad.
This passage is false.
The 'original Quad' (as bdp24 put it) is an easy load to drive. Differences in damping between amps is one of the few things that **isn't** audible on the speaker, owing to the fact that in the bass range the impedance is rather high. This reduces the difference heard between an amp with say 10:1 damping factor as opposed to one with 100:1.
OTLs are traditionally thought to not be able to drive 'tough loads' but OTLs can drive the Quads with ease. The real issue here is that the Quad is pretty transparent and does not need a lot of power, so its that 'first watt' that becomes so vitally important. Many traditional solid state designs are not so good at that first watt. Put one on a 'scope sometime and look at how they behave. Usually they have much higher distortion in the first watt than they do at higher powers until they approach clipping.
Not surprised by your finding as Quad ESL can be an extremely tough load. Differences in amplifier damping (output impedance) would be quite audible. This only proves one of the major design issues with Quad.
Also want to say, we are lucky to be alive right now. There are some wonderful Women and Men making violins, violas and cello’s these days for relatively paltry sums compared to buying a Strad.
Anyone who gets a chance to listen to an accomplished violinist should also be grateful for a chance to hear such remarkable craftsmanship.
So my previous remark was about violins. Any half hispanic, half asian lady, mostly single, concert violinist between 35 and 45 years old who would like to come to my home and prove I can’t tell the difference in which violin she’s playing, please let me know so I can arrange a time.
Now, about amps.
I can make speakers more "discerning" of amplifiers than others. I learned this trick from a famous speaker maker’s crossover. Lower the impedance and make it particularly reactive in the mid bass and voila, now you can tell the difference between several amplifiers which in a "Lesser" speaker you could not.
This is a reason why I strive to make my speakers easy to drive. Easy to drive means they will sound great across a variety of amplifiers and electronics. I think this is part of what is going on. There are a lot of good modern amps which sound really similar. We live at a time when many amps sound free of glare and harshness or grain, smooth, extended and potent with easy to drive speakers, but not all speakers are easy to drive. :)
For those who wish to be dominated by their speakers however, I can point you at some famous brands. :)
The idea that you can’t tell the difference between a violin or viola you know very well and others is nonsense.
Not only do they have a specific character, over time the fibers and resins break down depending on how they are played, which musician’s can tell, while listening or especially while playing. The elasticity of the entire piece changes over time. Ask any violin maker.
Now, can I hear a recording and say "Aha, an early Stradivarious!" NO, i really can’t, but I am sure i could become accustomed to a particular instrument and hear it vs. others.
Because all properly designed and built amplifiers not in clipping sound exactly the same, of course ;-). But seriously, shadorne's assertation that "well built amplifiers....." can be proven to be untrue by hooking up a low-powered class-A amplifier (a Pass Labs or First Watt would be nice) to, for instance, the original QUAD ESL, a very transparent loudspeaker. My Bedini 25/25 driving my QUADs sounds dissimilar from my two high-powered class-A/B amps doing the same. As Nelson Pass suggests, it is an amp's first couple of watts that matter the most!
Why couldn’t they pass the test? The same reason why a panel of experts cannot tell the difference between a Stradavarius and any other well made reasonably good sounding violin. Did anyone ever pass one of The Amazing Randi's $1 Million challenges? I don't think so.
Everyone knows that well built solid state amplifiers designed to stringent specifications and tolerances are going to sound very much alike at low volumes.
It would be a huge surprise if that weren’t true - it would mean that all those measurements and engineering principles and the consistent improvement in amplifier performance are completely wacky and wrong.
It is when you stress a SS amplifier that differences may be audible - at higher SPL and with challenging loads or with dirty power or when driven close to clipping and where distortion rises rapidly.
That said, there will be very small differences even at low volumes but these will extremely difficult to discern reliably with most music sources unless using very specific test signals.
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