Electrostatic Headphone Measurements

[TMoney]

Gu Sensei's post of measurements of the SR-009s from a Japanese Stax thread raised some interesting discussion. While the measurements he posted are interesting as a conversation piece, there are questions about the quality of the data and methodology of the testing. The measurements are not nearly as useful as the type of through headphone measurements that our very own Tyll Hertsens has been making and posing over on the Inner Fidelity site.

In the want for more objective data on stats, Tyll has graciously agreed to measure electrostats if we can send them out to him in Montana.

The plan will be to coordinate people sending in their gear so that Tyll can measure the electrostatic lineup we are able to get to him off of a single electrostatic amplifier. As Tyll does not presently have an electrostat amp, we are going to have to send one. Voltron has volunteered his 007t, but if anyone has a higher end amp they'd like to send we can use that instead.

I'll be sending along my 009s as well as helping coordinate the effort. As Tyll is only able to measure a few headphones at a time, we will be assigning shipping dates via PM and the spreadsheet..

If this sounds like a good idea, and if you are willing to send in some electrostat gear to Tyll for measurement, please leave your information in the spreadsheet here. It will be great to have some quality measurements for the Stax range.

Edited August 23, 2011 by TMoney

[Tyll Hertsens]

Hope this is okay with everyone. Just make sure your gear is in needed in the spreadsheet, and then PM me and we'll coordinate the gear movement.

Al, I am interested in the loan of an amp for a few months to get some cans measured. I have no idea if yours is a good one to use, or if I should be using another amp. I'd be happy to hear suggestions from others. I reckon I should use something as ballsy and neutral as I can so that the measurements reflect the headphones most accurately. So, suggestions welcome.

Um ... once an amp is covered, I can measure one to three headphones a week, roughly. Headphones would be here one to two weeks. I try to move the DIY cans quickly, but have only been moderately successful. Anyway, I'll try to get them back quickly.

Looking forward to measuring some stats!

Edited August 23, 2011 by Tyll Hertsens

[screaming oranges]

I got something you can borrow for a month or two, Tyll.

My life's been so hectic I haven't been enjoying much of my gear lately (not to mention working 7:30am to 8:30pm sometimes).

I just need some rest from, well, everything,

I have two other amps to keep me company while you do your thing.

[TMoney]

Thanks again for doing this, Tyll.

Once we get you an amp we can start assigning specific dates for people to send their gear on the spreadsheet so you don't end up with a glut of gear sitting around idle.

[deepak]

I got something you can borrow for a month or two, Tyll.

My life's been so hectic I haven't been enjoying much of my gear lately (not to mention working 7:30am to 8:30pm sometimes).

I just need some rest from, well, everything,

I have two other amps to keep me company while you do your thing.

Very nice offer SO and TMoney.

[Tyll Hertsens]

I got something you can borrow for a month or two, Tyll.

Wow! That's very cool man, thanks. But the question is: should I be using a tube amp to do measurements? Would there be too much characteristic (second order for example) distortion on a tube amp to ferrit out a clean view of the headphone? Would I be better off with a dryer, but more technically accurate solid state amp so as to see the characteristics of the headphones more clearly?

You'll have to pardon my ignorance guys, just have done many measurements of estats. The ones I have done were really weird though, so I'd love to know I'm off to a sure start. Don't want to have to do this stuff twice.

What does the Stax mafia think?

[screaming oranges]

I'll let everyone chime in on what they think, but my offer stands regardless.

[Tyll Hertsens]

I'll let everyone chime in on what they think, but my offer stands regardless.

Thanks, man, I really do appreciate it. Great to know there's a way forward, just looking for the most productive way.

[Horio]

If I ever get the things back from Yama's, I've got a pair of SR-007 Mk2's you can measure.

[n3rdling]

Only recommendation I can think of is to try to make sure the earpads fully seal, otherwise you'll get some bass roll off. Thanks for doing this, very cool!

[spritzer]

Nothing wrong with using that particular tube amp (BHSE) since it is mostly SS and the tube output stage doesn't behave like a "normal" tube amp. It's also about as good as it gets.

[TMoney]

SO and Tyll, once you guys are ready to send and receive the amp, I'll go ahead and send along the 009s to get the ball rolling on this project. Might as well get it kicked off with a bang.

Short of having a DIY T-2 to measure, the 009-BHSE combo ought to produce results that rival or surpass anything Tyll's measured so far. It'll be especially interesting to put the "009s are bright" claim to the test. I don't really hear it myself, but the measurements should give us a definitive answer. At this point only time will tell.

N3rdling... thanks for the advice on the ear pads. I hope once the project gets underway you might consider volunteering a few highlights from your collection if you are feeling up to it.

[Hopstretch]

Nothing wrong with using that particular tube amp (BHSE) since it is mostly SS and the tube output stage doesn't behave like a "normal" tube amp. It's also about as good as it gets.

Yay. If there was a Stax Mafia, which there isn't, such a group would clearly have an interest in ensuring their "thing" be evaluated under the best possible conditions. Also, it would obviously be extremely unfortunate for all of headphonedom if Tyll's measurement suite totally accidentally blew up, burned down and sank into the swamp.

[Tyll Hertsens]

Nothing wrong with using that particular tube amp (BHSE) since it is mostly SS and the tube output stage doesn't behave like a "normal" tube amp. It's also about as good as it gets.

That's what I was waiting to hear. Estat measurements coming up. PM on the way SO!

Wait ... what's this about a swamp?

[spritzer]

We should have some KGSSHV's up and running in a few months (I'm going to build a few) so a TOTL SS amp would be available for testing then. Still the KGSSHV is more of an effort to approach the Blue Hawaii in performance but not having tubes to worry about (and people debating different ones) does have its advantages.

I'm going to send you something to test Tyll but it will have to wait until I first receive and have time to completely refurb then. First off would be my utterly mint and SR-1 set (circa 1962-4) to show just how good first generation Stax was. I also have a SR-X Mk1 incoming which was the first set Stax made for the Pro market. One of only two Stax sets I've never tried (the other being the impossible to find SR-2) so I'm really looking forward to testing it out. Now with these vintage sets you need a normal bias amp with not too much output voltage as they will arc violently when fed too much juice (ditto for the HE90) so I have a 1969 SRA-3S preamp incoming which is perfect for this. One of the best amps Stax ever made (just ask Kevin, he had one back in the day) which I'll completely rebuild to not fall into the same trap as Hi-Fi News when testing vintage gear.

Yay. If there was a Stax Mafia, which there isn't, such a group would clearly have an interest in ensuring their "thing" be evaluated under the best possible conditions. Also, it would obviously be extremely unfortunate for all of headphonedom if Tyll's measurement suite totally accidentally blew up, burned down and sank into the swamp.

It would certainly be a shame is something like that were to occur...

[screaming oranges]

If you want the details about my particular build for documentation purposes, Justin would be the man to ask. Mine is #17, if I'm not mistaken. I'll try my best to get it out by Saturday... along with MK I (I think it's MK I?) in a separate box. I won't be able to use the cans without the amp anyway, so....

[TMoney]

Cool. If the BHSE ships on Saturday then I'll plan on shipping out my 009s on Monday.

[ujamerstand]

Tyll, I'd be interested to see if differences between amps can be measured with your setup. If you need a KGSSHV I can definitely send one your way along with my sr-507 in a few months. spritzer and I could probably coordinate who sends which version of the KGSSHV.

[n3rdling]

Glad to see the mafia's elaborate plan to turn Tyll into a Stax fanatic is working accordingly...

[Tyll Hertsens]

I'm a pushover.

[arnaud]

Hi Tyll,

I sent you an email at inner fidelity adress in regards to waterfall plots, any plan to include that in the standard tests? Purrin posted some example in the sr009 thread and it's quite useful at revealing resonances. In case you don't have the tools to post-process it, I wouldn't mind generating the graphs for you from the impulse response data...

Otherwise, I could mail you my 009 but I am a bit concerned with damage during transport, esp. since we never got confirmation that the troubles with previous batch were not related to transport...

[Horio]

I think TMoney already volunteered his 009's for measurement, so you'll be able to see how they measure and not worry about your phones being damaged during shipping.

[purrin]

No! no! arnaud is supposed to mail his SR009s to me!

Actually that's OK, the ED order is supposed to come in any day now. Maybe.

[John Buchanan]

......so I have a 1969 SRA-3S preamp incoming which is perfect for this. One of the best amps Stax ever made (just ask Kevin, he had one back in the day) which I'll completely rebuild to not fall into the same trap as Hi-Fi News when testing vintage gear.

The one I heard in Melbourne was far better than the SRA12s that I had at the time. Terrific amp, IMHO.

[Tyll Hertsens]

I've put my address info on the spread sheet. Gear on the list so far can be sent at y'alls convenience.