[Mossback]

 

  The 717 is definitely the right amp to get in the door with the O2. The KGSS is a better amp than the 717, but that's about to be replaced by the much better HV, which should be a big improvement and will likely be the pinnacle of SS amplification available for electrostatic phones for some time. Currently it's DIY only, but supposedly a commercial version may be available at some point in the future. The BHSE or WES would be better still, but if you want to push the O2 to the max, you need the DIY T2.

 
what's a T2? i've learned many of the acronynms but not quite all of them.
 

   717 + O2 is indeed an awesome combination. I have not felt the urge to upgrade or change anything ever since.

 

 

   O2/717 combo is great

 
when i got home last night i watched the Auburn-Oregon game, at half-time i went and plugged in the Stax combo and let it play. after the game i started to listen. it was a bit thin sounding but seemed to get better by the minute. initially i used a long XLR cable directly into my digital player (which is not a balanced design). later i moved it and plugged it into the 'record out' on my darTZeel preamp (which is a single ended circuit design). this was better. by this time it had been playing for maybe 4 hours and it was sound sweet and natural. nice bass, little grain, very refined. i let it continue to play all night and this morning it was still a bit better.
 
i enjoyed it and look forward to spending more time with it.
 
mostly i listened to hirez digital (176/24 and 192/24) thru the server. i've not yet tried any of my tt's or RTR decks.
 

   I did not care for the O2/717. Sounded dry, and a bit dark and lacked in hall ambiance. Bass can sometimes be a bit overwhelming too.

 
this is all about one's reference. i'll withhold any sort of comment on whether i think it is dry or dark until i spend more time.  
 
 

  While I clearly prefer my WES over the 717 with the O2, I think the 717 is a good choice for O2 and you might consider keeping what you have and quitting head-fi before your upgraditis eats your wallet.

 
great advice. unfortunately it's a bit late for me on that issue.

 

[DaveBSC]

Quote:

 

  The 717 is definitely the right amp to get in the door with the O2. The KGSS is a better amp than the 717, but that's about to be replaced by the much better HV, which should be a big improvement and will likely be the pinnacle of SS amplification available for electrostatic phones for some time. Currently it's DIY only, but supposedly a commercial version may be available at some point in the future. The BHSE or WES would be better still, but if you want to push the O2 to the max, you need the DIY T2.

 
what's a T2? i've learned many of the acronynms but not quite all of them.

 
The T2 was the legendary flagship tube amplifier that Stax created for the original SR-Omega about 15 years ago. The Omega 2 demands voltage swing to really get moving and perform at its best. The SRM-007tA / SRM-007tII have 340V, while the SRM-717 and SRM-727 have 450V. The SRM-T2 had 630V. Unfortunately they are extremely rare and expensive, and from what I understand ran hot enough to cook your breakfast on, so I don't think reliability is so hot. The Gilmore DIY version fixes those usability problems.
 

 

 

[Amarphael]

I've opened the bottom and traced it to a resitor called R57 that's a part of a row right next to the "STAX" imprint, It measures at 4.8MOhms and 120VDC~, I measured the one after called R56 and gives 280VDC~ and less than 1Mohms. the one after is again 120VDC and somthing... What else?

 
Quote:

Try to open the bottom of the case and see if you can see the trace from there or
look for a resistor that has a value in MOhms (it will be quite laborious to find it but i assume that it's the only one with a high value like that on the board and will be placed on the main board not the little ones). 

 

[Mossback]

Quote:

Quote:

 

  The 717 is definitely the right amp to get in the door with the O2. The KGSS is a better amp than the 717, but that's about to be replaced by the much better HV, which should be a big improvement and will likely be the pinnacle of SS amplification available for electrostatic phones for some time. Currently it's DIY only, but supposedly a commercial version may be available at some point in the future. The BHSE or WES would be better still, but if you want to push the O2 to the max, you need the DIY T2.

 
what's a T2? i've learned many of the acronynms but not quite all of them.

 
The T2 was the legendary flagship tube amplifier that Stax created for the original SR-Omega about 15 years ago. The Omega 2 demands voltage swing to really get moving and perform at its best. The SRM-007tA / SRM-007tII have 340V, while the SRM-717 and SRM-727 have 450V. The SRM-T2 had 630V. Unfortunately they are extremely rare and expensive, and from what I understand ran hot enough to cook your breakfast on, so I don't think reliability is so hot. The Gilmore DIY version fixes those usability problems.
 

 

thank you for the answer to my question. that one looks interesting. i'll add it to my (growing) list of headphone toys i might pursue.

 

[DaveBSC]

Quote:

thank you for the answer to my question. that one looks interesting. i'll add it to my (growing) list of headphone toys i might pursue.

 
Sure. Here's a picture of Kevin's version. Not nearly as pretty as the Stax original of course, but it also shouldn't melt itself

 

 

[Mossback]

Quote:

Quote:

thank you for the answer to my question. that one looks interesting. i'll add it to my (growing) list of headphone toys i might pursue.

 
Sure. Here's a picture of Kevin's version. Not nearly as pretty as the Stax original of course, but it also shouldn't melt itself

 

does Kevin sell ones like that? i have custom output electronics for my Studer A-820 which look like that.....so the 'audio-jewelry' aspect is not hugely signifiicant to me.

 

[n3rdling]

No

 

[DaveBSC]

Quote:

does Kevin sell ones like that? i have custom output electronics for my Studer A-820 which look like that.....so the 'audio-jewelry' aspect is not hugely signifiicant to me.

I don't think KG or Spritzer offer any amps for regular sale. If you wanted a DIY T2, you would probably need to find a builder.

 

[dw1narso]

@padam and svyr: thanks for your replies..., so basically price does not lie...

 

[svyr]

I've opened the bottom and traced it to a resitor called R57 that's a part of a row right next to the "STAX" imprint, It measures at 4.8MOhms

that one looks similar to what went from the bias wire to the bias section in srm-1. measure BEFORE it. (alternatively if there's a resistor connected in series to it, then before that one. You may also want to take a non-blurry picture of the board where you measure...and possibly at the back, so people know where the traces are going)

For bias, when I was measuring the SRM-1 pro bias part, before the 2x 2.2M resistors - the meter (nice fluke one) momentarily showed 580, then droped to 420 (c302 dc to grnd). So 460 sounds reasonable.



Out of interest, why are out trying to measure it anyway? Does it sound bad or is broken or something?

 

[green0153]

Quote:

Quote:

I've opened the bottom and traced it to a resitor called R57 that's a part of a row right next to the "STAX" imprint, It measures at 4.8MOhms

that one looks similar to what went from the bias wire to the bias section in srm-1. measure BEFORE it. (alternatively if there's a resistor connected in series to it, then before that one. You may also want to take a non-blurry picture of the board where you measure...and possibly at the back, so people know where the traces are going)

For bias, when I was measuring the SRM-1 pro bias part, before the 2x 2.2M resistors - the meter (nice fluke one) momentarily showed 580, then droped to 420 (c302 dc to grnd). So 460 sounds reasonable.



Out of interest, why are out trying to measure it anyway? Does it sound bad or is broken or something?
 

svyr is right...
 
Maybe it's easier with a picture.
 
http://gilmore2.chem.northwestern.edu/images5/gilmore4_2.png
 
in this picture you will see a 4.7MOhm resistor near the BIAS output.The point to measure i right after that resistor.
You have to follow that logic on your amp and find the end of the series of resistors.

 

[crumpler]

Just auditioned an SR-007 Mk2 today for about 45mins in a local STAX headphone shop, probably the only one around here in Singapore. It was driven out from the SRM-007tII and it sure is sweet sounding.
 
Stax is really opening a whole new world of headphones to me. I just picked up one of the Spritzer amps he had on sale just a while ago and am really looking forward to experimenting with Stax. I'll probably put an inventory freeze on all headphone purchases till the launch of the C32 before deciding if it is indeed worthwhile to jump aboard the stax flagship. Else, i think an SR-507 or O2 would also do very nicely.

 

[Gradofan2]

Me too...
 
Enjoying my 507's and SRM-007tII also... and the combo is great!  Great resolution, clarity and detail and a very balanced sound, no frequency is overemphasized / underemphasized... and... a nice soundstage, also.  While I like my dynamic phones with my WA6SEm... I really like the refined sound of the Stax setup.  And... the bass of the 507's is great... good impact and very dynamic... while the mids are warm and rich... and the highs are extended and clear, without any etch, or stridency. 
 
Everyone should try these at least once.
 
Quote:

Just auditioned an SR-007 Mk2 today for about 45mins in a local STAX headphone shop, probably the only one around here in Singapore. It was driven out from the SRM-007tII and it sure is sweet sounding.
 

 

[Michgelsen]

As far as I know, you can't get PCBs either, because only a limited number were made, for a few DIYT2s.
 
Quote:

Quote:

does Kevin sell ones like that? i have custom output electronics for my Studer A-820 which look like that.....so the 'audio-jewelry' aspect is not hugely signifiicant to me.

I don't think KG or Spritzer offer any amps for regular sale. If you wanted a DIY T2, you would probably need to find a builder.

 

[Gradofan2]

Can anyone tell me how much of an improvement the WA GES makes over the 007tII (or point me to a discussion of the GES vs the 007tII), if any???
 
While I think the 007tII is great... just wondered if there are any significant improvements in sound quality - though, I'm not sure how much better it can get.
 
Update:  I did find this one...
 
http://www.head-fi.org/forum/thread/311269/impressions-woo-audio-ges-upgraded-stax