[eric65]

Hello, for information, here are several photographs transmitted by my Moscow friend Alex for the last production of Dmitri Gubchenko (father of the Demograf)
 
New electrostatic amp by Dmitry Gubchenko with very powerful tantalum tubes
 

 

 

 

 
New electrostatic amp by Dmitry Gubchenko with very powerful tantalum tubes
 
Link :
 
https://translate.google.ru/translate?sl=ru&tl=en&js=y&prev=_t&hl=ru&ie=UTF-8&u=http%3A%2F%2Fforum.doctorhead.ru%2Findex.php%3Fshowtopic%3D27179%26st%3D75&edit-text=
 
and 
 
http://www.homecinema-fr.com/forum/post178217448.html#p178217448

 

[Demograf]

Greetings to all the forum members of head-fi . I now have very little time, but a little later 
I can provide information about unique projects.

 

[Farkhat]

  Greetings to all the forum members of head-fi . I now have very little time, but a little later 
I can provide information about unique projects.

 
Hello, Friends! Hello, Dmitry!
 
Let me introduce my friend - Dmitry Gubchenko aka Demograf from Moscow (Balashikha city). He is the author of amplifiers for electrostatic headphones, and many other high-end components. Last successful project Dmitry, he was working on a half-year - is built on the power of tantalum tubes.

 

[JayM481]

Lots of back reading here. My eyeballs are already both in one socket after a few dozen pages, let alone the many hundreds (thousands?) in the various Stax threads. 
 
Anyway, after a lot of reading, I still have questions. They'd probably be answered with some patience and determination, but I have only so many years of life left 

 
I'm basically a speaker guy, and 'till now only use headphones rarely, and only started recently. As an electrostat speaker owner I gravitated to Stax, and managed to pick up a Lambda Pro/SRM-1/Mk2 set a while ago. A very different experience from speakers, but beguiling in it's own way. 
 
From what I've read so far, it seems the consensus (or at least the majority view), is that amps make a significant difference with headphones, or at least that's the case with Stax earspeakers. Given that, and the combo I currently have, what would be a reasonable upgrade of the amp? I'm a bit of a valve/tube guy, though I'm not particular about it - my current preamp is valved, but my speaker amp is SS. I could see one of the Stax valve hybrids as having an advantage if driven directly from a digital source, but using my preamp? Note that I have a number of sources, so the preamp isn't negotiable.
 
What about the earspeakers themselves? How do the Lambda Pros stand up to other Lambda variants, including the modern versions? If I'm looking to upgrade is there something to aspire to, or should I look at the new Omegas (007s, I can never justify 009s to myself or my wife)?
 
Final question, I'm considering a second hi-fi setup for my "office" (inverted commas because it's more a closet). It's a small space, and I was originally thinking of a small pair of speakers configured nearfield, but after experiencing the above combo I think the Stax will be my choice. However, I'm limiting the budget a lot for this, as I have most of the necessary kit already. The most economical solution appears to be an energizer, rather than a full amp, as I have a couple of amp options (a 40W valve integrated, and a pair of Leak TL12+ valve monos are two options). New choices for energizers seem to be the Woo WEE (probably pushing the budget a lot for UK sourcing), with other options being vintage Stax energizers with pro bias. Are there any issues with these and valve amps? It may seem a silly question, but when it comes to hard-to-find or unobtanium output transformers this is a "better ask than try" situation.
 
I'll undoubtedly have many more questions, and maybe some observations, as time goes by. 

 

[gepardcv]

What about the earspeakers themselves? How do the Lambda Pros stand up to other Lambda variants, including the modern versions? If I'm looking to upgrade is there something to aspire to, or should I look at the new Omegas (007s, I can never justify 009s to myself or my wife)?

I don't have answers to most of your questions, but I will say this: there's a *huge* difference in the sound signature of the 007s compared to the 009s and the (current) Lambdas. It isn't some slight, subtle, barely audible thing: the 007 is way darker than any other Stax I heard (307, 009, original SR-Omega). I compared 007s and 009s side-by-side from a BHSE and from a LL2T prototype, and found it startling. There's far more difference between the 007 and the 009 than there is between the 007Mk1 and 007Mk2, or the 009 from a BHSE and the 009 from a KGSSHV. Honestly, I thought the 307 sounds more like the 009 than the 007.

 

[davidsh]

How do you like the 307 in general?

 

[gepardcv]

I've been thinking about the sound signature of the SR-007, and how well it would interact with older recordings. I generally prefer the brighter sound of the SR-009 and the Lambda series, but that really just extends to relatively recent, well-recorded music.
 
When it comes to older stuff, especially pre-stereo, I find that high-end gear makes it sound even worse and more harsh than cheap speakers or earbuds. I'm thinking Yehudi Menuhin records from the 1950s, the original Rachmaninov playing Rachmaninov from the 1920s, and even older stereo recordings from the 1960s and 1970s. Perhaps a dark, non-super-revealing headphone like the SR-007 could sweeten the sound? (I don't have access to one to compare.) Does anyone here who listens to older "classical" recordings have experience on making them sound less fatiguing and more, well, "hi-fi"?

 

[gepardcv]

  How do you like the 307 in general?

It's excellent. It's a Stax, and we're on the Stax thread, so I'm obviously a fan.
 
I never compared it to the 407 or 507, but I can tell you that the 307 sounds great. Not out-of-this-world-spectacular like the 009, but the 307 is rich, detailed, and very pleasant to listen to. It's fairly comfortable, once you figure out how to adjust it to your head (the rectangular cups can be weird, depending on your skull's shape).

 

[JayM481]

  I've been thinking about the sound signature of the SR-007, and how well it would interact with older recordings. I generally prefer the brighter sound of the SR-009 and the Lambda series, but that really just extends to relatively recent, well-recorded music.
 
When it comes to older stuff, especially pre-stereo, I find that high-end gear makes it sound even worse and more harsh than cheap speakers or earbuds. I'm thinking Yehudi Menuhin records from the 1950s, the original Rachmaninov playing Rachmaninov from the 1920s, and even older stereo recordings from the 1960s and 1970s. Perhaps a dark, non-super-revealing headphone like the SR-007 could sweeten the sound? (I don't have access to one to compare.) Does anyone here who listens to older "classical" recordings have experience on making them sound less fatiguing and more, well, "hi-fi"?

Here I can contribute, I think. The issue with older recordings is that the "master" (be it tape, shellac master disc or other master) rarely will have any musical info above 15kHz, and often nothing higher than 7kHz for the really old stuff, other than noise. In this case I think the source would be the culprit, as most modern sources, even modern LPs, will have capabilities far above that in the HF. The Stax will only reproduce what they're fed, so the "harsh" is captured in the recording. 
 
The way I make older recordings sound less fatiguing is to use suitable playback kit - in my case it's usually a record player with a suitable cartridge/stylus/phono preamp combo playing the original big black disc. CD/digital transcriptions of the older stuff rely on the quality of the transcription, and though there are many dedicated engineers out there who do that, there are many who aren't as dedicated, and even the dedicated ones may transcribe some noise because the loss of musical content may be greater than the benefit of noise reduction. Many a wonderful recording in 78 sounds flat and lifeless when transcribed if the engineer is too heavy-handed with the de-click and other noise reduction.

 

[FrankCooter]

Greetings to all the forum members of head-fi . I now have very little time, but a little later 

I can provide information about unique projects.

 


Welcome to Head-Fi !

I'm curious about your amp. I've played around with DHT's in electrostatic amps myself.

Perhaps it's just a translation issue, but the 3C24 is not a power tube as Eric implies. It's more like a directly-heated 6SN7.

 

[n3rdling]

  Lots of back reading here. My eyeballs are already both in one socket after a few dozen pages, let alone the many hundreds (thousands?) in the various Stax threads. 
 
Anyway, after a lot of reading, I still have questions. They'd probably be answered with some patience and determination, but I have only so many years of life left 

 
I'm basically a speaker guy, and 'till now only use headphones rarely, and only started recently. As an electrostat speaker owner I gravitated to Stax, and managed to pick up a Lambda Pro/SRM-1/Mk2 set a while ago. A very different experience from speakers, but beguiling in it's own way. 
 
From what I've read so far, it seems the consensus (or at least the majority view), is that amps make a significant difference with headphones, or at least that's the case with Stax earspeakers. Given that, and the combo I currently have, what would be a reasonable upgrade of the amp? I'm a bit of a valve/tube guy, though I'm not particular about it - my current preamp is valved, but my speaker amp is SS. I could see one of the Stax valve hybrids as having an advantage if driven directly from a digital source, but using my preamp? Note that I have a number of sources, so the preamp isn't negotiable.
 
What about the earspeakers themselves? How do the Lambda Pros stand up to other Lambda variants, including the modern versions? If I'm looking to upgrade is there something to aspire to, or should I look at the new Omegas (007s, I can never justify 009s to myself or my wife)?
 
Final question, I'm considering a second hi-fi setup for my "office" (inverted commas because it's more a closet). It's a small space, and I was originally thinking of a small pair of speakers configured nearfield, but after experiencing the above combo I think the Stax will be my choice. However, I'm limiting the budget a lot for this, as I have most of the necessary kit already. The most economical solution appears to be an energizer, rather than a full amp, as I have a couple of amp options (a 40W valve integrated, and a pair of Leak TL12+ valve monos are two options). New choices for energizers seem to be the Woo WEE (probably pushing the budget a lot for UK sourcing), with other options being vintage Stax energizers with pro bias. Are there any issues with these and valve amps? It may seem a silly question, but when it comes to hard-to-find or unobtanium output transformers this is a "better ask than try" situation.
 
I'll undoubtedly have many more questions, and maybe some observations, as time goes by. 

 
I would probably try to upgrade to the SR-007 if looking for a major upgrade.  The Lambda Pros are excellent, but they really don't sound that much different on various amps IMO.  If you find the top end a bit harsh, you can change your amp to a SRM-T1 and that could help things a little.  You'd notice a pretty drastic difference going to the SR-007 though, and the SRM-1 should be fine driving it.  If you find yourself really loving the SR-007's sound you can always upgrade your amp later, as those headphones like as much power as you can throw at them.  Try to demo a pair of 007's if you can.
 
Quick rundown of differences:
Lambda Pro: A little bright, medium sized soundstage with large vertical images, nice mid bass kick with sub bass roll off, slightly scooped mids
SR-007: A little dark (especially on less powerful amps), soundstage size varies a bit with recording but for the most part it's a little smaller than the L-Pros, imaging possibly the best of any headphone, sub bass goes deep with very little roll off, mids are more forward, upper mids/lower treble has a dip that makes even poor recordings sound good but can make certain instruments sound off at certain notes (trumpet doesn't have much bite), treble is pristine.
 

  I've been thinking about the sound signature of the SR-007, and how well it would interact with older recordings. I generally prefer the brighter sound of the SR-009 and the Lambda series, but that really just extends to relatively recent, well-recorded music.
 
When it comes to older stuff, especially pre-stereo, I find that high-end gear makes it sound even worse and more harsh than cheap speakers or earbuds. I'm thinking Yehudi Menuhin records from the 1950s, the original Rachmaninov playing Rachmaninov from the 1920s, and even older stereo recordings from the 1960s and 1970s. Perhaps a dark, non-super-revealing headphone like the SR-007 could sweeten the sound? (I don't have access to one to compare.) Does anyone here who listens to older "classical" recordings have experience on making them sound less fatiguing and more, well, "hi-fi"?

 
It's one of my favorite headphones for this exact reason.  I can listen to music on youtube all day with it and a lot of the nasties will stay in the background.  It's a pretty unique headphone in this regard...usually headphones that do this are pretty crappy, but the 007 manages to make almost anything sound pretty damn good.

 

[zolkis]

I should note that though the 007 mk1 sounds indeed darker than the Lambdas, they are more 'shouty' and I prefer the 007. The 009 is more open without being shouty. That said, with the modded pads my 007 sounds more open than my TH900, with better treble, too, with slightly less, but bigger feeling bass. To me it just sounds wonderful, with no trace of treble haze or shininess, super revealing and musical.

The current form of the mod is replacing the lower hard foam part of the original pad insert with 100% wool felt ring of same thickness, getting rid of the spring, eventually trimming very slightly the upper part in the front side for even more open sound, and in my case mod the leather part to allow for a slightly bigger opening. Plus, adjusting the arc correctly, starting with a shape like the arc of the 009.

I also have a hunch that the openness of the 009 is partly due to its shallower pads with bigger opening. I am waiting for a 009 replacement pad to test this hypothesis with the 007.

Of course in stock form the 009 blows others out of the water. I can only imagine what a modded 009 could do... Judged by the direction pads seem to change sound, they could sound even better with slightly deeper pads.

 

[Demograf]

actually these lamps 3C24 1960 volts full amplitude in the se scheme and 3900 volts in push-pull scheme . I think that it is enough for good control of any electrostatic . when the anode voltage is applied 1380 volts .

 

[milosz]

 
I am always surprised that in a headphone forum people think cross-feed between speakers is a good feature.  Crossfeed is simply an artifact which  messes up the stereo cues present in the signal, which in commercial material are primarily interaural amplitude differences, i.e. loudness differences between the two signals. Speaker crossfeed creates 2 extra channels, sometimes called phantom channels in which say, the left speaker sends its signal to the left ear and then to  the right ear with a delay for the additional time to get across the head  (and vice versa for the right speaker).  Periodically someone comes up with a set-up to cancel the crossfeed /phantom channels.  Carver had an electronic system, and Polk built a series of speakers in which each box essentially has 2 speakers, one for the correct signal and the other for a cancellation signal for the opposite channel.  I have had the Polk SDA1 for years and it is quite effective over a fairly narrow listening location.  What does  it sound like?  Like headphones but in real space such that you almost think you can touch the performers.    Polk made these for about a decade and finally dropped the line in part because of resistance from audio dealers who didn't like having to handle fairly expensive speakers which made conventional speakers appear obsolete.
 
 
For anyone interested here is a starting point http://www.polksda.com/

Look into  http://www.princeton.edu/3D3A/PureStereo/Pure_Stereose4.html   http://masisaudio.com/bacch/thesolutions/bacchsp/   etc

 

[zolkis]

  Look into  http://www.princeton.edu/3D3A/PureStereo/Pure_Stereose4.html   http://masisaudio.com/bacch/thesolutions/bacchsp/   etc

 
Did you mean http://www.princeton.edu/3D3A/Publications/Pure_Stereo.pdf
This is impressive. Especially #20.