[sphinxvc]

^  I seriously think you need to read/search more.  Head-fi sucks...sorry, I mean Head-fi's search sucks, so use Google to site specific search head-fi.  Here's how.  There's years worth of answers to "novice" questions just like the ones you've been posting.
 
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Good post, Spritzer. 

 

[milosz]

Yeah  I'm less than pleased with the Head-Fi search algorithm, too.
 

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As far as "what DAC to use with electrostatic 'phones" - well, I suggest using a GOOD one.  Many many GOOD DACs out there.  There are also some GREAT DACs  and with a good amp and Stax phones you might hear the subtle difference between GOOD and GREAT DACs.
 
Seems to me the biggest differences in DACs are between sigma-delta DACs (Wolfson WM8741, ESS 9018)  and R2R DACs that use PCM1704  and so on.
 
There are also various approaches to the circuitry that surrounds the DAC- the analog stages and the power supplies.  These can have an impact on sound too.  You see things like the Audio-Gd DACs  which tend to use a large number  of "Class A regulator" power supplies and all-discrete analog stages with selected / matched transistors.
 
Then there are DACs like the Lavry DA2002, which takes the trouble to tightly regulate even the temperature of the DAC components and has a method to self-calibrate the resistance magnitudes in it's R2R ladder.
 
Even though these "uber DACs" offer good engineering and fine sound, there are also a lot of modestly priced DACs out there that will sound better than the DAC inside your MP3 player / cell phone / PC.  A used Cambridge DAC MAGIC can be reasonably priced; a MK 1 Musical Fidelity VDAC can also be gotten for very reasonable money and is a fine DAC for those who like a bit of "lush" sonic character voiced into their DAC.  TONS of respectable DACs out there.

 

[spritzer]

Quote:

Can you elaborate in which aspects the 727II is better then the 007tII for the SR009?

 
The trouble with both tube amps are the tubes being used.  They are only rated at 330V but asked to work at almost 700V so when you turn up the volume everything becomes compressed.  The 727 is a flawed design but at least it doesn't run out of steam so quickly. 

 

[agentsim]

Quote:

Quote:

Can you elaborate in which aspects the 727II is better then the 007tII for the SR009?

 
The trouble with both tube amps are the tubes being used.  They are only rated at 330V but asked to work at almost 700V so when you turn up the volume everything becomes compressed.  The 727 is a flawed design but at least it doesn't run out of steam so quickly. 

 
Does that mean that some judicious tube rolling on the 007tII could make it a better choice than the 727?

 

[Hun7er]

I discovered that they exist the SR007Mk2.5, how it differs by others revisions in sound quality ?

 

[Currawong]

Hun7er: Type this into Google's search box: 
 
 

sr007 mk 2.5 "stax thread" site:head-fi.org

 

[milosz]

Quote:

 
Does that mean that some judicious tube rolling on the 007tII could make it a better choice than the 727?

No, according to Spritzer, the problem is Stax is putting 700 volts on a tube designed for 300 volt maximum on the  plate.  No matter what tube you roll in to those sockets in the Stax amp, NONE of them will be tubes designed to run at 700 volts. The Stax has nine-pin miniature sockets wired for 6CG7 tubes.  
 
See  http://www.radiomuseum.org/tubes/tube_6cg7.html
 
A 6FQ7 will work in that socket, but it's only rated a little higher than a 6CG7.  (6CG7 is rated 300 volts max on the plate, 6FQ7 rated at 330 volts  http://www.radiomuseum.org/tubes/tube_6fq7.html )
 
So, you see, just trying GE  vs  RCA, etc, 6CG7's isn't going to get you a tube that likes 700 volts.  Nor is finding a pin-compatible tube like a 6FQ7... and I don't know any other tubes you could just plug in to the amplifier.  You could install octal sockets so you could use full-size tubes like pairs of EL34's, which are rated up to 800 volts on the plate.  But of course this is a much different tube and you can't just substitute it in the circuit without making substantial changes to the circuit.  So you'd have to redesign the whole output stage.... and before long you'd have something like a Blue Hawaii or DIY T2....

 

[padam]

Quote:

I discovered that they exist the SR007Mk2.5, how it differs by others revisions in sound quality ?

It is an SR007 with a few strange things added to its sound.
I would love to hear a port + spring modified pair as stock it really does not sound too good in my opinon.

 

[Hun7er]

Are you kidding me 

 
It seems that it is brighter than others revisions.

 

[padam]

No I am not. Brightness is a relative term.
The SR507 is bright as well but it has less dips and peaks in its FR than the SR007Mk2.5

 

[Operakid]

I'm in love with my first headphones, the 407 with the SRM-006tS and am so curious about the 009. I don't listen real loud, 85db peaks. Will this amp drive the 009 well?
 
Thanks.

 

[agentsim]

Quote:

Quote:

 
Does that mean that some judicious tube rolling on the 007tII could make it a better choice than the 727?

No, according to Spritzer, the problem is Stax is putting 700 volts on a tube designed for 300 volt maximum on the  plate.  No matter what tube you roll in to those sockets in the Stax amp, NONE of them will be tubes designed to run at 700 volts. The Stax has nine-pin miniature sockets wired for 6CG7 tubes.  
 
See  http://www.radiomuseum.org/tubes/tube_6cg7.html
 
A 6FQ7 will work in that socket, but it's only rated a little higher than a 6CG7.  (6CG7 is rated 300 volts max on the plate, 6FQ7 rated at 330 volts  http://www.radiomuseum.org/tubes/tube_6fq7.html )
 
So, you see, just trying GE  vs  RCA, etc, 6CG7's isn't going to get you a tube that likes 700 volts.  Nor is finding a pin-compatible tube like a 6FQ7... and I don't know any other tubes you could just plug in to the amplifier.  You could install octal sockets so you could use full-size tubes like pairs of EL34's, which are rated up to 800 volts on the plate.  But of course this is a much different tube and you can't just substitute it in the circuit without making substantial changes to the circuit.  So you'd have to redesign the whole output stage.... and before long you'd have something like a Blue Hawaii or DIY T2....

 
Answers like this are why I love head-fi... thanks

 

[Lan647]

^^

 

[mungwi]

Hi, I'm relatively new around here.  I just recently acquired an ESP950 and have read the E90 energizer leaves some to be desired.  Can someone suggest a good place to look for used Stax amps?  Would 580v pro bias be a good match for the 600v esp950?

 

[livewire]

Good place?
 
Japan? Ebay? With a bit of patience, here at HF. 
 
Pro bias works fine with the Koss. 
 
The E90 is quite good for a cheap plastic box, no real need to upgrade.
 
Will say that the ESP-950 pairs well with the KGSSHV.