Are there real differences between electrostatic amps?

[krmathis]

Quote:

Originally Posted by Oedipus Rex /img/forum/go_quote.gif Well, there are huge differences between designs and power resources in normal solid amplifiers as well.

Correct!
And most of us claim there are a difference between amplifiers for dynamic headphones as well, just like there are for amplifiers for electrostatic headphones.

The power supply probably make the most difference.

 

[Bullseye]

Impressive thread!

He asks for the "skeptics" take on this and he gets response from some big believers in everything...

Well, for what I know and because I have also been interested in this question that the OP has written, I -still- haven't found any RMAA or measurements when using an electrostatic amplifier. I have not found how electrostatic amplifiers perform in the FR curve w/o any load and w/ load, so so far we have speculation.

What we want to achieve with an electrostatic amplifier is pretty much what we look for when using a non-electrostatic headphone amplifier. To maintain the FR curve flat without adding any substantial (audible) distortion and with the lowest noise floor possible.

I tried to find an answer to that, getting inside the wolf's mouth. You might want to read this to know what was it all about, and I will try to explain here as well: http://www.head-fi.org/forums/f5/sta...estion-440481/

I wanted to try some STAX headphones. Due to my take on any non electrostatic amplifier, I wanted to find out the same question you asked. The difference between all the STAX amplifiers seemed to rely on the maximum output voltage, that varied between the basic amplifier and the most expensive one. The other differences didn't have anything to do with SQ, just aesthetics and functionality.

As I relied on subjective opinions, I wanted to know if driving the most expensive headphone by STAX (Omega II) with the most basic -and cheap- amplifier could be enough not to get any distortion when using it on moderate levels. Well, more that one people said that you could. Others said that it was a no-no, others said you wouldn't get all the potential, etc...

I got various answers, and got a clear answer (not final) to what I was trying to find out. All of them didn't think the same, for some it was good enough, for other it was plain crap. I prefer to believe that the most basic unit will give you enough voltage to drive your headphones without taking them into distortion and getting a nice SQ out of them without needing to sky rocket the prices.

Sorry for my diffuse writing. I am listening to music at the moment and get lost with it.
And my conclusion could be wrong as well, but if I were to be wrong, you would be spending $300 (price of basic unit on audiocubes2) instead of wasting >$1000 on other "better amps".

Hope this helps you.

 

[JaZZ]

Quote:

Originally Posted by Oedipus Rex /img/forum/go_quote.gif um ok, let me rephrase the question, and this is a question for the SCEPTIC side of the fence, I don't want to get into arguments. So, what I want to know is, are there more difference between the electrostatic amps than there are between normal solid state amps? Is it possible that the HEV70 is really underpowered and subclass, or are the improvements of the "subjective nature"?

A friend of mine has a HE 60 with the HEV 70. He wasn't satisfied with the sound, so he upgraded to a Stax SRM-717. According to him this combo sounds much better.

As far as solid-state amps go, I have experience with SRM-1, SRM-Xh, SRM-313 and SRM-727II. The latter, the Stax top model, sounds clearly best to me: finest resolution, highest detail, strongest bass. I also liked the SRM-313, which was leaner, but sounded refreshing and clear. The SRM-Xh sounds rather lean, also slightly dull and somewhat breathy. I liked it nonetheless, although it sacrifices quite a bit of the electrostatic resolution. The SRM-1 was my first electrostatic amp. The then setup was so different from my current setup that it's impossible to compare. However, from memory I would characterize it as slightly sterile and scratchy.

Obviously I can't take position on the skeptic side, since there's no reason anymore for me to be skeptic in terms of amplifiers sounding different. Electrostatic amplifiers are just amplifiers with uptransformed signal and additional bias voltage, so fundamentally the same as dynamic amps when it comes to sonic differences.
.

 

[Nerull]

I can understand the skepticism, especially considering that the amp is likely (if you are to get a "step-up") going to be expensive. It may be worth your time to actually find someone to borrow an amp from (a KGSS, for example). If you aren't skeptical about dropping that much dough for something (especially in audio!) you'd have to be nuts or rich.

More to the point, there is a significant difference in driving an electrostatic headphone vs a dynamic one. This stems from the fact that not only does the electrostatic headphone require a high voltage, it is also a primarily capacitive load, which presents some interesting challenges. Just sticking an audio transformer on the end doesn't cut it, in other words. Methods by Chu Moy are found here:

HeadWize - Project: Notes on DIY Electrostatic Headphones by Chu Moy

Designing an adequate power supply is also a sort of challenge. Most importantly, though, is the headphones interaction with the amplifier. It wouldn't surprise me at all if they didn't sound the same, as the load is very different than a primarily resistive one (especially for transformer coupling).

~Thomas

 

[kh6idf]

I just got the SRS-2050II combo, the SR-202 phones with the SRM-252II amp. Even this basic set sounds amazingly good to me, exceeding my expectations. At least with these phones the 252II amp is very nice sounding. I have the volume set to about half of the maximum for a comfortable listening level, so it appears to have plenty of power for the 202s.

 

[Oedipus Rex]

Thanks for all the responses!

Quote:

I just got the SRS-2050II combo, the SR-202 phones with the SRM-252II amp. Even this basic set sounds amazingly good to me, exceeding my expectations. At least with these phones the 252II amp is very nice sounding. I have the volume set to about half of the maximum for a comfortable listening level, so it appears to have plenty of power for the 202s.

That was my first electrostatic setup and it is fine

The difference between any dynamic headphone I have heard and the basic stax set is bigger than the difference I have heard between different electrostats, though I haven't tried the omega or big orpheus yet.

Quote:

Designing an adequate power supply is also a sort of challenge. Most importantly, though, is the headphones interaction with the amplifier. It wouldn't surprise me at all if they didn't sound the same, as the load is very different than a primarily resistive one (especially for transformer coupling).

Ok, good to know. I'm seriously considering a better amp, as I'm going to be listening to electrostats for long time (the baby orpheus is the third electrostat set I have owned, and I doubt I stop before I have either the Omega or the Orpheus..) What strikes me bit suspicious with the DIY stuff like KGSS is that how could somebody come out of the blue and design better amp than company like Stax that has spent decades of R&D in developing their amps. So, if I do decide to upgrade, I'm pretty sure I get a stax amp, unless somebody is selling their blue hawaii for peanut money.

Btw, I noticed on local hifi bulleting board, that somebody is selling the Stax SRM-T1s for 500 euros and Stax SRM-006t II for 800 euros.. Is SRM-006t much worse than the new SRM-007 version? And what about SRM-T1s? Which one of those is the better deal?

thanks again everybody

 

[grawk]

DIY amps have a higher parts cost than commercial amps. And well, the Blue Hawaii was a scaled back SRM-T2.

 

[Uncle Erik]

Don't underestimate DIY amps. They're often superior to commercial amps, built to far higher standards and are picked over by serious geeks.

If there's a problem with a DIY amp, it usually gets spotted by someone and ironed out. Not so with commercial designs. Those often are designed to meet a certain price point, with corners cut and cheaper parts substituted.

Those of us who do build often hunt down the very best components and take a lot of care in the construction and casework. I'm working on a Gilmore electrostatic amp (the AC coupled all triode) and spend Sarurday at Apex picking out some very nice components. I'll build it point-to-point with ceramic tie points that just aren't available anywhere. I was lucky to find enough of them in a dusty old box. I couldn't even commission an amp with these parts.

Also, consider that a lot of DIY amps are adapted into commercial offerings. The ones that do are another thread entirely, but many of them out there are very, very similar to what the community has developed.

 

[SmellyGas]

0 Quote:

Originally Posted by Oedipus Rex /img/forum/go_quote.gif In response to my simple question not only did you decide to resort to an adhominem argument, but you used that argument against somebody who hasn't even taken part in the discussion.

Unfortunately, a lot of the responses you received to your original question are protoypical. The overwhelming majority of contributors on head-fi are under the impression that amplifiers can substantially alter sound quality. Most can relay stories of how they listened to amplifier A and later upgraded to amplifier B, and noticed XYZ changes...or they've heard amplifier C and it didn't sound good compared to amplifier A. When pressed, none of them will report that their comparisons were blinded, or even level-matched, and sometimes, the amps aren't even compared in the same sitting. Anybody familiar with experimental design would place very little weight on their observations, because we know that the dramatic amplifier differences reported can EASILY be also explained by placebo effect, differences in level, and/or nonperfect audio memory. What complicates matters more is there is a "shared delusion" that propagates here. Almost everyone on head-fi believes that amplifiers have large audible differences. When they go to meets, they all listen and everyone around them claims to hear differences, and they discuss their findings. And they also share their listening reports here. There is social pressure to believe that amplifiers make a difference. If you can't hear differences between amps, then you really don't belong in the elitist club of hi-fi. Someone even suggested that I leave because I reported that I could not hear differences between headphone amplifiers. Imagine that.

I've read the article you referenced. I've read several others. My profession requires me to interpret and make decisions based on published evidence, and out of consistency, I also evaluate the evidence available on amplifiers. As far as I can tell, there is a preponderance of evidence that LOUDSPEAKER amplifiers do not make the dramatic differences in sound reproduction. Even with different amplifier topologies, circuit design, IC chips, components, etc. - no substantial differences, as long as there is flat freq response, the amp is not drive into distortion, there is low output impedance, etc.

Are there any blinded listening tests for headphone amps??? Not that I am aware of. But we can try to extrapolate - are the loads any different from loudspeakers? Yes. Are they different enough to invalidate the loudspeaker amp evidence? I don't know. So maybe. I have tested 4 different dynamic amplifiers and I couldn't hear big differences among them at all. So I don't honestly don't think that they make a huge difference.

Then we come to electrostatic amps. Very few people have them here, compared to dynamic amplifiers. The amplifier circuit is so different from loudspeaker amplifiers, that I am convinced that the data is not generalizable at all. This means that the ONLY data you will have as to whether stat amps influence stat headphone sound comes from... asking people here who have experience with 2 or more amps with the same stat headphone to offer their opinion. That's it. And I would say ~100% of the people here who own 2 or more electrostatic amps belong to the belief system that amplifiers make dramatic differences in sound quality. They get very offended when you suggest otherwise. They get very offended when you even REMOTELY suggest otherwise. But are they correct? I don't know. There's no way to obtain convincing evidence, unless they do a blinded, controlled comparison. I sincerely doubt that will happen.

So, I had the same question as you (and Bullseye). Are there real differences between electrostatic amps? I tried asking if people could hear differences. 100% of the time, people responded yes they could. This is a given. Then I asked if people could provide an electronic or engineer's explanation as to how electrostatic amps differences could cause differences in sound quality. I got a lot of generic answers - answers that obviously satisfy a lot of the people here, but are too simplistic to survive basic scrutiny. Many people talked about "insufficient power" with the lesser amps. When it was pointed out that the stat headphones are capacitative loads and that very little current (and hence power) would actually be drawn, people got irritated. After all, everybody here knows that more expensive Stax amps are more powerful - therefore it must be stupid to point out that this particular explanation doesn't make sense for the aforementioned reason. So I gave up. Nobody could provide an electronic reason as to how electrostat amps could significantly influence electrostat headphone sound quality.

So in the absence of controlled listening tests, and in the absence of an electronic/engineer's explanation as to how the amp can possibly affect the sound reproduction, you are only let with anecdotal, uncontrolled, reports from people here, along with opinions that may be part of a shared delusion.

The short answer: There is insufficient evidence to suggest the presence or absence of differences between electrostatic amps.

 

[Uncle Erik]

SmellyGas, what's your take on measured differences made with standard electronic test equipment? Amplifiers inarguably measure differently. Measurements have been made many times and show consistent results no matter the test equipment or tester. Between actual measurements and what I hear, there is sufficient evidence for an actual difference.

I don't "believe" in cables and other tweaks where no measureable differences can be found.

 

[SmellyGas]

Quote:

Originally Posted by Uncle Erik /img/forum/go_quote.gif SmellyGas, what's your take on measured differences made with standard electronic test equipment? Amplifiers inarguably measure differently. Measurements have been made many times and show consistent results no matter the test equipment or tester. Between actual measurements and what I hear, there is sufficient evidence for an actual difference. I don't "believe" in cables and other tweaks where no measureable differences can be found.

I'm not sure what you mean. "Measured differences between amplifiers? Are you referring to frequency response nonlinearity, distortion, dynamic range, stereo separation, etc? Are there differences between loudspeaker amplifiers? Absolutely. Are LARGE differences in these measurements audible? YES. If two amplifiers have large differences, then I would expect them to sound different. Examples: amplifier driven to distortion with 20% THD, amplifier with strange -6db rolloff between 10-20khz.

However, the real question is, do commonly sold loudspeaker amplifiers truly have differences in these measurements that are large enough to be audible? USUALLY NOT. We're talking flat frequency response from 20-20k with perhaps 0.2 or 0.5 difference in linearity, typically at the extremes of the audio spectrum. We're talking THD < 0.08%, dynamic range 90dB+, etc. You can flip through your favorite loudspeaker amp reviews, and look at the independent measurements. I have yet to see an amplifier that had measured problems that I thought woudl be audible. Maybe there are some. Perhaps in tube amps.

So here's my take on it:
- differences in loudspeaker amp measurements are not typically audible
- blind listening tests done on large samples with lots of different amps have failed to demonstrate significant differences in loudspeaker amplifiers
- I personally have not convincingly heard major changes when I upgraded my power amps, whereas upgrading speakers made huge differences
- if you read The Audio Critic, the review amps all the time. They comment on the circuitry/topology far more than the fluffy audio magazines, and they are basically the best of both worlds - knowledgable like the audio electrical engineer and also audiophiles. They have reviewed more power amps than most people have heard in a lifetime, and they maintain that amps do not sound different, as long as they are not driven to distortion, they have low output impedance, and have a reasonably flat frequency response.
- in fact, the only "evidence" that supports the notion that amplifiers make a difference are: product literature, unblinded listener reports, audio equipment retailers, and magazines driven by advertisement and what people want to hear

So people can believe whatever they want. My particular belief is based on my experience, objective and published data, and the expert opinion of people who are knowledgable about both engineering and audio.

 

[jcx]

there are some differences in Voltage and Current output that appear to correlate with some of the subjective opinion here

more V and I, up to BHSE seem to give better reputation here - the exception is the Koss E90 amp which claims +/-600V but gets panned for cheap construction, Class AB operation, internal cap coupling to Hi V drivers and using op amps (the horror)

for some reason I haven't seen reports on using the Koss Amp with Stax or the Orpheus

but there is the usual uncontrolled subjective opinon going the other way:
http://www.head-fi.org/forums/f5/kos...5/#post3237463

 

[seacard]

Quote:

Originally Posted by Uncle Erik /img/forum/go_quote.gif SmellyGas, what's your take on measured differences made with standard electronic test equipment? Amplifiers inarguably measure differently. Measurements have been made many times and show consistent results no matter the test equipment or tester. Between actual measurements and what I hear, there is sufficient evidence for an actual difference. I don't "believe" in cables and other tweaks where no measureable differences can be found.

Erik,

Can you elaborate on this a bit? I'm really curious about this point. Are you saying that two well-designed amplifiers measure differently? If you can provide an example of what measurements you mean and what are the two amplifiers?

(It goes without saying that we should only be comparing two amplifiers that have no audible distortion, flat freq. response, low output impedance, high input impedance, etc.)

 

[grawk]

Quote:

Originally Posted by seacard /img/forum/go_quote.gif (It goes without saying that we should only be comparing two amplifiers that have no audible distortion, flat freq. response, low output impedance, high input impedance, etc.)

It may go without saying that we should, but that's the trick, isn't it? Instead, it should go without saying that we should be comparing real world amplifiers.

 

[Uncle Erik]

SmellyGas, the measurements you mention are usually taken with a dummy load that doesn' change value. Speakers and headphones have impedance curves, as does an amplifier. The power an amp delivers varies as the load changes. I think this is especially noticeable when listening to something as sensitive as headphones. Headphone impedance also varies greatly by brand and model, so it is difficult for one amp to cover, equally, everything that's out there. I'd think you'd find significan variation by ploting the impedance curve of the headphones against the output impedance curve of an amp. Even if two amps had identical distortion, power output, etc., they can still deliver that power very differently based on their output impedance.

No, I don't have charts or stats to back that up. However, I do think that's where the difference in amplifier sound mostly comes from. Also, many tubes aren't perfectly linear, so I think that can be an audible difference, too. I've seen sveral listening tests that didn't find an audible difference between solid state amps, but those tests have always excluded tubes.