Dreadhead

Yup I guess so I find at least with Justin he doesn't tune anything, the amp is the input plus gain and current delivery and that's it. If I want to color the sound I can do so with my DEQ2496 and I have extremely fine control though I generally do not move anything from measured dead flat + 5 to 7 dB roll off for proximity effects due to the fact that mastering studios have roll off at the speakers. I'll be the first to admit that I'm strange though. Though I don't know anyone who's normal .

Hello everyone, I'm thinking about buying an electrostatic amp and I'm leaning towards the KGSS because of my general dislike of tubes and the fact that when you change the tubes you can change the sound etc. I prefer to have such things under control (barring damage, SS is the same now as it is in a year). That said if the BHSE is only uses the tubes for the high voltage swing capabilities and is entirely transparent then maybe that's a better bet. On paper it has a lot more voltage swing etc. At least initially I will be using the Koss ESP950s but I figure I'll end up with O2s as well. They'll all have to go though my correction process and then I'll see if electrostatic is worth it to me. If not I'll stick to dynamics and sell off the electrostatic. I'll be honest and say I don't expect the electrostatics to improve much on the corrected dynamics or even on the ER-4s/AE-2 combo that I listen to as my portable. The latter probably the most accurate and transparent combo with no correction that I have heard, though even Ety states that Electrostatic is supposed to be even more accurate. I heard the KGSS powering 02s and I'll be honest and say I preferred it to an ES-1 and HE90s (but then the owner switched the tubes sense and that combo improved). What says the peanut gallery? I'm buying this as a "I'm done" amp so I'm not so concerned about the price difference.

Well the time I tried them they were with an S frame at maximum which apparently overlaps fairly closely with a M frame at minimum. The secret as best I can tell with them is that they seal with your head. Otherwise If you pull them slightly out of position I can totally understand what people say about the "seashell" effect.

d_rayman, I don't own qualias but I've done some very detailed listening on a pair that fit great. With perfect fit they are very transparent headphones and have a great soundstage. They are very flat and detailed so on a lot of recordings the bass will be less than you expect and the highs will be harsher than people are used to (especially if you listen to HD650s). The most similar headphone that I've heard out of the box is the ER-4S. Good luck with your expensive experiment Congrats.

Thanks for the insight on the DAC issue. The problem is that if you have a nonlinear system (which it shouldn't be but is) and put in multiple frequencies then you end up with first the nonlinear responses to the frequencies themselves (harmonic distortion), and difference frequencies (aharmonics). Nonlinearity is a PITA as the saying goes. I wonder if you're phasing all the signals relative to each other and causing actual distortion due to the beat pattern that actually comes out the other end clips digitally. Unless you introduce random phasing to your audio signals that's almost certainly going to cause serious issues that would appear to be other things. I'm not entirely sure what you mean by DIM. Intermodulation? Thanks for the advice.

nice

USG (and the other person that asked before), I honestly thought I did. I was fairly gutted with these findings. Through this process I've discovered that my DAC3 makes it very easy to do A/B on the signal because all you have to do is increase the digital volume control 6db when you go balanced to SE or -6db when you go the other way. I have confirmed that this is exactly what happens too by measuring the actual headphone output with my measurement mic setup. I'm spending some time with the HD650s doing this A/B between the two doing the process described above and I have become fairly convinced I don't hear anything but I'd say that I haven't reached a full conclusion yet. I certainly would be stunned to but I really want hear a difference. If I do manage to find one then I'll have to devise a test to find that effect before I'll buy it the other way. So for now I sit pretty much in limbo with a fairly strong leaning towards no effect (with HD650s too). For example yesterday I was 30 minutes into a session and was convinced I'd found something and that I was listening to SE and then I looked down to discover I was in balanced. The problem is that unless you do a very careful volume match with and SPL meter and without moving the headphones doing an A/B is close to impossible and balanced is naturally 6dB louder than SE and louder nearly always wins in audio stuff (all else being equal). That said I'm not selling my GS-X so don't PM me I have no plans to do A/B on GS-X vs AE-2 but as the measurements show I don't think they'd be conclusive either, in the end they are both amazing amps. I am consistently amazed by the AE-2 and I am convinced it is better than the Total Bithead I had before (and will again once it returns from repair).

Dusty, I did volume match the two signals (physically) but to get the full scale maximum to be 0db (1.0000) then you need to divide the signal by the maximum amplitude observed to make sure that the signal varies between -1 and 1 so that's what I mean. Sorry if you know this but I figured I'd be detailed so that other could understand too. I'm not entirely sure what they do in digital compression but I would think it would be similar but for a different purpose.

And the original balanced signal (just to show it's fairly complex):

Here is a longer 10 second sample and a comparsion of the difference between the signals: Blue: dBFS difference between SE and balanced Green: dBFS difference between balanced and balanced As I said not much difference.

Ok well I did a quick and dirty version of the recorded music: Radiohead, In Rainbows, 15 Step (about the first 45 sec) I took two recordings of the song using the balanced signal so that I could compare two recordings that are "identical" to the error of sampling frequency (44.1 kHz) and then I did a SE recording of approximately the same time. I then loaded the two balanced files matched the start time using a search algorithm to find the first peak over a certain amplitude and assumed they matched (fairly inaccurate but I did not want to interpolate). I then normalized the next two seconds of audio and calculated the decibel difference between the two: -45 dB (not bad considering the "dirtiness" of my method) I then compared one of the balanced recordings to the SE recording using the same exact method and guess what -43dB. That means that the two recordings have almost identical behavior. 2dB difference between SE and Balanced is VERY low on the noise floor. I think even more proof that balanced doesn't seem to make any real difference once you volume match.

Sorry if I came of combative I'm a bit of an arguer . I just was surprised at you saying THD was unimportant (which I think I misunderstood). I actually have first hand experience as part of this measurement binge where the THD was actually the killer for the use of a particular pair of headphones (The SA5000s had to be retired). It pretty much made them un-listenable when I corrected the dips in response at some frequencies. The D5000s and HD650s don't have the same issue though. All I'm planning on doing is looking at the DB difference between the two signals vs time. I'm not a big "psycho" anything kind of person You may find my other thread about turning one headphone into another (which I also have working).

In other news I just realised why the noise floor was higher on the balanced setups. It is because to volume match the signal both amps have to be working at 6db lower gain which of course raises the noise floor by the same 6dB that I just realised is the difference I saw. So at least that makes sense.

First off the THD numbers I'm pulling are from an FFT based approach as you can see in the plots that I put earlier in the thread. Also far as I'm concerned it shows a lot and others appear to agree since it's a pretty standard test. I think I have the option for a couple other signals with the signal generator and I will see if there are any others of interest. Actually I was thinking about it this morning and what I will do is find a piece of music (rock? classical?) and and do a volume match recording using the SE and balanced and compare the recording through time after doing some time matching and normalizing the signal. With the software I have this should be pretty easy to do. I'll give it a swing this afternoon and we'll see what happens but I'm pretty sure the signal will come back through the mic identical to a very high degree.

pfair use even....

I had not seen them in their amplifier reviews. The do talk about the output impedance of the amp though. I'm not talking about the headphones here I'm talking about the amp.

Oh well at least I figured out why my THD readings were so different than luvdunhill's and that's because as with any good nonlinear effect the THD varies a lot with the amplitude of the forcing. If I decrease my amplitude at 1kHz until the signal has an amplitude of 75db then the THD drops to .05% (-66db) which is much more on the order of what he was reporting. When I volume match at the two though I still don't get much variation between SE and balanced.

I'm not arguing it's interesting I'm saying I don't see the point in an amp to amp comparison. It appears that it's not but I can't see how different amps are going to change the physical properties you're trying to see. I'm not looking to put Headroom out of the headphone testing business anyway.

Yeah that's my finding too. The software I'm using is Room EQ Wizard (freeware) and it does everything using a sweep and impulse. Using 4 sweeps and impulses etc it takes over a minute to generate one curve. The THD calculation is done separately but within the same software. I'm using a Edirol FA-66 and a Behringer ECM8000 measurement mic with and have the calibration curve for the mic as done by a lab and posted on the REQ website. Are you sure you didn't move your headphones at all in the balanced/unbalanced comparison, I thought I saw those curves before and that you had switched cables at the headphone. I used an adapter specifically so that I could avoid touching the headphones at all, because my experience is that if I move the headphones a little bit it makes a sometimes order 1dB changes to the response I measure out the other end.

An IRF is not a test with tones it's a impulse (which is very wide banded in frequency space) and tests the speakers (or rooms or panels or ships) response over a range of frequencies at the same time and the transition between these frequencies. The only thing the IRF doesn't really capture is the THD because that's a nonlinear effect in general.

Torpedo, Thanks for the measurements. I'll have to look around more. The software I have computes the the harmonic distortions as well but I didn't want to type all of them in. I only checked at the 500 Hz that Stereophile usually uses and at 1000 but I can do it at any frequency. It's just not as organized as your friends and I can't get much above around 11-12kHz because the harmonics are above my allowed maximum of 24kHz (the software only supports 48kHz sampling). If lower THD is what you get that sounds good to me I'll take a look tonight.

Grawk, Actually I plotted the IRF which is both frequency and phase response and that's all sound is. They are identical. From my understanding control is the ability to deal with the resonances of the phones and that appears to be the same or they would show up in the frequency respons. The IRF is not a static graph by any stretch of the imagination. I'll be honest and say I was very very suprised by these results and I'm trying to figure out another test but I can't see one right now.

Yeah I know that. It's not the point though since I can't see how it being a head would make any difference to the comparison. The curves would be different but they would still lie on top of each other unless you think the head has an effect on the driver. I'm not making binaural recordings I'm using it to calibrate to flat at the entrance of the ear not to the ear drum. It's essentially like a coupler that a lot of people use for the same purpose.

To be honest you're missing the point. I am not showing the results for the headphone I'm showing that the headphones produce the same sound out the other end with all these different combinations of amps. I will look into the speaker workshop but to be honest I don't see how the various amps would be seeing a different impedance if the response was the same.