[astrostar59]

JB, I have the Gungnir as well. Looks like we have similar listening levels

I think 2v is standard at an output impedance of 500k. My DAC puts out 2v but output impedance is very low at 10 ohms as it has output transformers at the last stage.
 
Also if the user has got RCA or XLR (single ended or balanced). Standard balanced can be 6v at least.
 
I noticed the 009s are quite a bit more efficient (louder) than the 007 MK2s.
 
The other thing is the music genre and how it was recorded. If you open up an AIFF and check for highest level at 0 db, look at the lower levels. In some music the lower levels are really not low at all, around -4 db for example on Rammstein or Alex M.o.r.p.h. (for example) The modern trend to pump up the lower levels to close on the peak levels which makes the recording sound a LOT louder.
 
So, not a science IMO. Lots of variables going on. I have my KGSShv set to 11 o'clock.
 
BTW I hate digital volume. I hav tried Audirvana+ and Amarra volume and it is horrid, lots of SQ loss. It seems miles better to run them 100% volume out then use a really high quality pot on a pre-amp or passive IMO.

 

[HemiSam]

I received my new SR-007A's about a week ago.  Playing them via my KGST.  They were quite a bit warmer and with more low end than I expected.  Tons of detail.  I loved them right away and fell asleep listening to them on the recliner a few nights within a week.  Couldn't get enough of them.
 
Unfortunately, a channel imbalance manifested itself....crap.  Lost a good bit of the sound out of the right side.  What a dip, especially for what should be a high-end product.  Back they have to go...
 
HS

 

[Earspeakers]

  I received my new SR-007A's about a week ago.  Playing them via my KGST.  They were quite a bit warmer and with more low end than I expected.  Tons of detail.  I loved them right away and fell asleep listening to them on the recliner a few nights within a week.  Couldn't get enough of them.

 
Yes the 007's are quite warm - too warm for my taste, especially the mk1's, but many people like it. Falling asleep with them is common! I'm fine with it though. 
 
On your KGST, did you build or buy? How stable is your balance and bias? I'm not sure if I'm having issues with this or not. 
 

Unfortunately, a channel imbalance manifested itself....crap.  Lost a good bit of the sound out of the right side.  What a dip, especially for what should be a high-end product.  Back they have to go...

 
Unfortunate! I wonder what physically would cause such an imbalance. It's just a capacitor, perhaps the coating reacting to a new environment?

 

[HemiSam]

   
Yes the 007's are quite warm - too warm for my taste, especially the mk1's, but many people like it. Falling asleep with them is common! I'm fine with it though. 
 
On your KGST, did you build or buy? How stable is your balance and bias? I'm not sure if I'm having issues with this or not. 
 
 
Unfortunate! I wonder what physically would cause such an imbalance. It's just a capacitor, perhaps the coating reacting to a new environment?

 
I have been following your build on head case.  No issues such as you are having.  headinclouds built mine.  Exceptional amp...really.  The detail and power (it's a 400v unit) with control is pretty darn impressive.  I was listening with the Koss ESP's for a good while before the 007's arrived.
 
Have you tried a Japanese made SR-007A?  I thought they were great while they worked properly.  Then again, I am a big fan of the HD650's.  The 007A's were brand new...none of the Mk1 stuff as I didn't want any issues yet I managed to run into a problem despite buying new.  I posted it here in case anyone runs into similar channel imbalance issues with their newer 007's.  I had read that was an 009 issue, but it appears it may be a broader problem for Stax.  
 
I found the 007A's very engaging and will be missing them while I sort out getting a replacement pair.  Damn shame, really.  I don't do bright very well...more of an analog guy so didn't see much point in buying the 009's.  I can always try them later if I get bored, but I really didn't see that happening...was very happy with the purchase until they failed.  
 
HS

 

[Earspeakers]

   
I have been following your build on head case.  No issues such as you are having.  headinclouds built mine.  Exceptional amp...really.  The detail and power (it's a 400v unit) with control is pretty darn impressive.  I was listening with the Koss ESP's for a good while before the 007's arrived.

 
The first bug was easy, a mislabeled silk screen. I can't say as I'm having trouble with calibration now, but I can't say I'm not. 
 

 
 
Have you tried a Japanese made SR-007A?  I thought they were great while they worked properly.  Then again, I am a big fan of the HD650's.  The 007A's were brand new...none of the Mk1 stuff as I didn't want any issues yet I managed to run into a problem despite buying new.  I posted it here in case anyone runs into similar channel imbalance issues with their newer 007's.  I had read that was an 009 issue, but it appears it may be a broader problem for Stax.  
 
I found the 007A's very engaging and will be missing them while I sort out getting a replacement pair.  Damn shame, really.  I don't do bright very well...more of an analog guy so didn't see much point in buying the 009's.  I can always try them later if I get bored, but I really didn't see that happening...was very happy with the purchase until they failed.  

 
I've got a new Japanese pair (not that it makes any difference) of 007's coming in this or next week. 

 

[NoPants]

The board isn't mislabeled if you use a 400V supply, the original value used to design the amplifier

 

[Earspeakers]

  The board isn't mislabeled if you use a 400V supply, the original value used to design the amplifier

Ha! Got me on that one, I concede. 

 

[kugino]

got ine

The first bug was easy, a mislabeled silk screen. I can't say as I'm having trouble with calibration now, but I can't say I'm not. 


I've got a new Japanese pair (not that it makes any difference) of 007's coming in this or next week. 

got one last week as well...but waiting for my 717 to come in later this week before giving them a listen. will report if I find any imbalance.

 

[HemiSam]

Hopefully no one else suffers the joy of channel imbalance on a new 007.  The KGST is a rocking good amp, regardless.  I very much like what it does for the Koss and what it did for my short-lived stint with the 007A's.
 
HS

 

[troymadison]

I'm getting pissed that I like the SR-507 so much that I'm thinking about getting a KGSSHV

 

[wink]

Just do it..  

 

[Earspeakers]

  Just do it..  

My God man, what he says, just do it!!! I got a 307/323S as an experiment. Ended up selling an extensive photography hobby to fund an extensive Stax hobby. Honestly though I'd be very happy with just a 307 and a KGST. 
 
I was listening to some of my old dynamic cans the other day. I could only use them for about a half hour before I get tired and have to put away. Not Stax which I'll happily use all day. Oddly, there's really not that much difference between them in a way, but there's an enormous difference too. Stax just steps over the Uncanny Valley. 

 

[dripf]

 
My God man, what he says, just do it!!! I got a 307/323S as an experiment. Ended up selling an extensive photography hobby to fund an extensive Stax hobby. Honestly though I'd be very happy with just a 307 and a KGST. 
 
I was listening to some of my old dynamic cans the other day. I could only use them for about a half hour before I get tired and have to put away. Not Stax which I'll happily use all day. Oddly, there's really not that much difference between them in a way, but there's an enormous difference too. Stax just steps over the Uncanny Valley. 

 
I've gotta tell you, my thoughts match yours. I bought the 3170 because I was suffering less with EQed Samsung buds than my dynamic pair. I was going to feed the Stax a DF EQ and be happy with an accurate, channel matched system that was free of complaints.
 
It didn't turn out that way. The 307 was reproducing music with a phenomenal and novel level of quality. String instruments were inherently pleasurable. I stopped using EQ.
 
I'm not sure what is happening here. Is the electrostatic transducer genuinely leaving dynamic in the dust? Or is it all a matter of frequency response? Are Audio-Technica headphones just inferior, where some dynamics perform equal to Stax?

 

[Earspeakers]

 String instruments were inherently pleasurable. I stopped using EQ.  
I'm not sure what is happening here. Is the electrostatic transducer genuinely leaving dynamic in the dust? Or is it all a matter of frequency response? Are Audio-Technica headphones just inferior, where some dynamics perform equal to Stax?

 
Yes agree that strings most easily show the differences between 'stat and dynamics. Large ensemble also. 
 
I don't think it has anything to do with freq response but rather transient response. My take is that the transducer element (the diaphragm) is 'locked' to the electrical signal, unlike dynamics which are more loosely coupled through a magnetic field. The amount of engineering it takes is pretty amazing, two inversely driven plates with a very high voltage bias and AC amplified signal, combined with an extremely low mass vibrator, only a couple square inches and all within an inch or two of your ear. Basically they threw everything they could at it to have absolute control over that transducer. 
 
The only dynamic I've heard that comes close is horns, but those have other issues I personally didn't like. But at that, it would be interesting if somebody combined a electrostatic driver with horn loading to match the impedance of air. Might be simple, just take a Omega driver and put it at the throat of say an Oris horn (I'd try it if I still had them). That would have to be the absolute pinnacle of transient response transducers. 

 

[xantus]

bigger is better... the pure size of sound being emitted goes to the Stax driver.
planar magnetics are getting close... but even an EL-8 open into a chord Hugo .. while nice.. still wasn't quite there.