[eric65]

Arnaud,
 
If the transformer (1:50 of the Wee box) is indeed seriously rolling off the mid highs with the RKV-II amp and SR-009 headphones, how we explain that we obtain the same results of measurement (at the microphone), under the same conditions, with the amplifiers for electrostatic headphones Stax : SRM-007t 2 and SRM-727 (a priori devoid of transformers)?
 
 
B: comparison of  009 headphones with amps RKV-WEE / SRM 727 / SRM 007t2 (NB: level benchmark standard for amplifiers: 73 dBA SPL at 1 kHz with the 009)
free-field measurements :
 
500 Hz : 73,2 dBA / 73,0 dBA / 73,3 dBA
1 KHz : 73,0 dBA / 73,0 dBA / 73,0 dBA
2 KHz : 75,0 dBA / 75,0 dBA / 75,5 dBA
5 KHz : 71,5 dBA / 67,7 dBA / 68,2 dBA
10 KHz : 76,5 dBA / 69,9 dBA / 71,0 dBA
12.5 KHz : 62,0 dBA / 56,0 dBA / 61,0 dBA
 
Conclusion : significant roll-of at 12.5 KHz (relative to the frequency control 1 KHz) with the three amplifiers RKV-WEE / SRM 727 / SRM 007t2 + Stax 009.
 
http://www.head-fi.org/t/677809/the-stax-thread-iii/2820#post_10759879
 
 
My results are as follows: for 6 distinct frequencies (250 Hz 500 Hz 1 KHz; 2 KHz; 5 KHz; 10 KHz)
Voltage measured, depending on the frequency, in input of the Wee (and therefore in output of the RKV) with the transformers 1:50 of the Wee, and with for load an electrostatic headphones Stax SR-009 145000 Ohm of impedance.
 
Signal sinus 250 Hz : 0.205 V (relative gain : 0 dB)
Signal sinus 500 Hz : 0.203 V (relative gain : 0 dB)
Signal sinus 1 KHz :  0.201 V (relative gain : 0 dB)
Signal sinus 2 KHz :  0.193 V (relative gain : - 0.3 dB) (to compare to the +2 dB of your graph, but with best ratio transformers for you : 1:6 vs 1:50)
Signal sinus 5 KHz :  0.160 V (relative gain : - 1.9 dB) (to compare to the -4 dB of your graph, but with best ratio transformers for you : 1:6 vs 1:50)
Signal sinus 10 KHz : 0.115 V (relative gain : - 4.8 dB) (to compare to the -17 dB of your graph, but with best ratio transformers for you : 1:6 vs 1:50)
 
http://www.head-fi.org/t/677809/the-stax-thread-iii/2820#post_10760957
 
Eric

 

[AngryAudiophile]

In terms of technical and raw data, the 009 is better than the 007s.  However, I still enjoy the 007s more when it boils down to musicality and pure enjoyment.  I found the 009 to be too harsh and too boring with tone.  I've now owned all the 007 revisions and the 009s and decided to keep the 007 MK 2.5.  Found it to be the most enjoyable out of the entire bunch.

 

[kevin gilmore]

guess I will just have to build one to verify that my synthesis is correct.
 
http://gilmore.chem.northwestern.edu/rkvboard.jpg

 

[eric65]

  guess I will just have to build one to verify that my synthesis is correct.
 
http://gilmore.chem.northwestern.edu/rkvboard.jpg

 
Information relayed on HCFR
http://www.homecinema-fr.com/forum/post178202430.html#p178202430

 

[rgs9200m]

I think it's more appropriate to compare something like the Hifiman 560 to a Stax, rather than the Senn 800 which still is well within the dynamic camp to my ears. 
Stax and Hifiman emphasize texture and speed and intimacy and closeness and microscopic insight, while the 800 is more about continuousness, flow, and the wide open spaces.
And the HD800 is a bit, sort of, uh, jazzy.
(In my stable: HD800, HE560, SR009.)

 

[complin]

So have HiFiMan fixed the fatal flaws with the 560 as it was withdrawn for a while?
 
Quote:

  I think it's more appropriate to compare something like the Hifiman 560 to a Stax, rather than the Senn 800 which still is well within the dynamic camp to my ears. 
Stax and Hifiman emphasize texture and speed and intimacy and closeness and microscopic insight, while the 800 is more about continuousness, flow, and the wide open spaces.
And the HD800 is a bit, sort of, uh, jazzy.
(In my stable: HD800, HE560, SR009.)

 

[davidsh]

Yes, they have fixed the flaws. Now there's just the usual QC issues.
Microscopic insight and HE-560 doesn't sit too well with me by the way.

 

[mechgamer123]

Anyone here have any idea how much a pair of original SR-Lambdas in mediocre condition (pads need to be changed, headband is falling apart, foam is deteriorating, the cable has had some repairs done on it and still cuts out sometimes in the left driver) is worth with a SRD-7 SB amplifier? I'm looking to buy one but honestly I have no idea how much it's worth and neither does the seller. The 6 pin standard bias plug looks to be fine, contrary to what I originally feared, that I would have to buy a new SB connector. It seems I need to pull apart the driver enclosure and resolder the cable, if that's even feasible that is...

 

[davidsh]

I'd pay tops 150$ considering condition. Probably worth more, I'd say 200$

 

[Keithpgdrb]

In that condition, I'd also say about $150. Should be less, but they are going for higher prices now.

 

[Audio Jester]

Has anyone had to pay for a repair to 009's due to channel imbalance? I am after a guide on cost. Thanks.

 

[davidsh]

Has anyone done testing wrt excursion, frequency response and distortion with varying volume? After all the low maximum excursion of 'stats is an issue wrt producing low bass, and it must be harder for the dirver at higher volumes.

 

[n3rdling]

Tyll et al have tested them at 90 and 100 dB...no major signs of spiked distortion.  If the drivers and amp/bias are all functioning properly distortion should never really be a problem, even at low frequencies.  In fact, they generally kill dynamic drivers in terms of bass and sub bass distortion, and the advantage becomes even greater at increased volume.  The FR also doesn't seem to change much...you will probably hear a difference naturally though due to Fletcher-Munson/loudness curves. 

 

[davidsh]

I just wanted to know what planars have over stats in the bass, and thought to myself it might have to do with high tension and low excursion of the stat diaphragm.

 

[kothganesh]

Just go the 009s and going non-stop with the KGGShv. Now the light dawns about why things said about it are said indeed ! Time to shut up and go back to the music.