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Question about amps for the Stax SR-009 - Page 45

post #661 of 722
Since getting over the cold I had, I've tried the PH's with and without the dampers I have, and to my hearing I can't hear any difference.
However, with what I'm now hearing, I'm not sure if the SQ can get any better.
Golfnutz said using the PH's is like an upgrade to the source, and although before using the PH's I was very happy with how my source sounded, since using the PH's my source ( to my hearing ) sounds even better.
post #662 of 722
I'm sure I read a post Golfnutz wrote saying the 009's had greater soundstage using the PH's with the BHSE, and I've also found that, IMO not to the same level as the HD-800's, but it's still easily noticeably.
post #663 of 722

 

Audiovalve RKV mk2 - OTL tube headphone amplifier 

+ Siemens PCL 805 tubes http://www.audiovalve.de/rkv/audiovalve%20rkv%20mark2.html

 

 

 

WooAudio Wee (Voltage transformers (1:50) bypassed) ; SR-009 Headphone in direct on OTL RKV amp.

(NB : the transformer of the Bias voltage 580 V DC of the Wee box is preserved; It remains connected on the fifth slot Stax female connector from the Wee)​

 

 

" In conclusion: listening headphones Stax 009 with the RKV amp (in live)  without use the voltage transformers (1:50) of Wee, is much better than if  we connected the transformers.

The resulting gain with the RKV with voltage transformers shunted is obvious and this amplifier should be now considered one of the best amplifiers to be associated with the 009 (for a listening level not exceeding 100 dB, which in practice is more than enough) in any case much better than with the SRM 007t2 amp (even with the Wee transformers plugged), better than the SRM 727 amp (without the wee transformers) and probably also better than the Electra amp, if we considered the gain of the Electra on the RKV (with the Wee transformers connected) as enough moderate (see non-significant in blind listening), while the gain of the RKV (without the Wee transformers) seems to me (yesterday evening) really so obvious compared to the RKV amp with the voltage transformers of Wee connected." 

 

Link for more info : http://www.head-fi.org/t/504489/woo-audio-electrostatic-energizer-new-product-from-woo-audio/75#post_10299803

.


Edited by eric65 - 2/24/14 at 9:52am
post #664 of 722

Hello Eric65

 

how did you disconnect the transformer from the WEE ?

post #665 of 722
Quote:
Originally Posted by Hun7er View Post
 

Hello Eric65

 

how did you disconnect the transformer from the WEE ?

 

Hello Hun7er

 

Cut the wires blue and Red output of two voltage transformers (1:50) Right and Left of the Wee (the two right transformers on the photo above). 
Directly connect the 4-wire (R +, R -, L +, L-) output of the RKV on the 4 slots (R +, R -, L +, L-) to the Stax female connector from the Wee.
(NB: the L - and R - wires are welded on the same headphone jack, side RKV jack. The RKV amp  is a headphone amplifier with unbalanced jack output)
For tool: a pair of scissors, a voltmeter to test the wires connector, and a roll of tape. that's it! :) 


Edited by eric65 - 2/24/14 at 10:41am
post #666 of 722

Eric65 thank you. if I understand these transformers provide more power ? But If I have a powerful amp it doesn't matter.

post #667 of 722
Quote:
Originally Posted by Hun7er View Post
 

Eric65 thank you. if I understand these transformers provide more power ? But If I have a powerful amp it doesn't matter.

 

This is not as simple as that, to directly use a Hi-Fi amplifier with the Stax headphones SR-009, without using the voltage transformers 1:50 from the Wee.
In most cases, the amplifier does not come out enough volts to operate correctly, with sufficient sound level, the Stax electrostatic headphones (without using the voltage transformers 1:50 from the Wee).


This is not so much the power of the amplifier (into 8 Ohms) which is necessary, but a strong capacity of voltage output (> 100 Volts RMS) of the amplifier with a high impedance Headphone (> 1000 Ohms) (that correspond to a very low load for the amplifier who works mainly in voltage).


The PCL 805 of the RKV amp (OTL amp) tubes are capable of out more than 100 Volts RMS with a 2.8-Volt input signal, which corresponds to a sound level >100 dB SPL with an headphones Stax Sr-009 of sensitivity 101 dB / 100 Volts RMS (I measured it).

 

Very few Hi-Fi amplifiers are capable of out 100 volts RMS.

 

The atypical (and endearing) OTL RKV mk2 headphone amplifier is able to do; for this, it is quite exceptional (such as sound), especially that it excels at working with high impedance headphones, see very very high impedance (as the 145.000 Ohms Impedance Stax Headphone), that is to say, mainly in voltage, where the PCL 805 tubes excels.  


For low headphone impedances (< 100 Ohms), it is less good and begins to color the sound and lose in dynamics and precision (you must then use it with the impedancer, but which also reduces the sound quality by "eating" information).

 

Eric

 

PS : To know the output voltage of a power amp P (Watts) on R (Ohms): 

V (Volts) = sqr (P * R)

For example, if P = 100 Watts and R = 8 Ohms then V = sqr (100 * 8) = 28 Volts RMS


Edited by eric65 - 2/24/14 at 10:26am
post #668 of 722

Eric your figures don't seem to tie in with AudioValve's specification?

 

tech. describtion:

  • OTL - transformer outless tube amplifier
  • double mono construction
  • Alps volume control
  • 1 pair 6,3 mm stereo jacket for headphones
  • tubes: 4 * PCL 805 (PCL 85 or 18 GV 8 - german old TV "vertikal" ampl. tube )
  • power output: each channel 3 watt SINUS,  ( between 100 to 400 ohm loads )  
  • bandwide: 15 - 100 000 hz
  • damping 3600 !
  • distortion 0,002 % at 1 Watt-200 Ohm load
  • max. output voltage 80V
  • sens. 0dBm
  • IC - full autom. - controlled bias
  • class - a
  • power consumption min. 60 watt
  • size 360*200*120 mm (d.w.h.)
  • weight 6kg
  • patent full automatic servo tube biasing
post #669 of 722

Hello, complin

 

Explanation :

 

Output 80 Volts RMS (and more) for the RKV mk2 is only for a load > à 2000 Ohms, not for a load of 100-400 Ohms.
I have realy mesured a 102 dB SPL level sound with my microphone with the Stax SR-009 directly plugged on the RKV amp, that correspond at an output voltage of the RKV amp > 100 Volts RMS (for an headphone stax (009) of sensitivity : 101 dB SPL / 100 Volts RMS).

 

Link to measures : http://www.head-fi.org/t/681814/amplifiers-shootout-for-stax-009-eddie-current-electra-audiovalve-rkv-wooaudio-wee-stax-srm727-srm007t2/45#post_10001640

 

(NB: for 102.4 dB SPL with a nominal sensitivity of Stax headphones (SR-009) : 101 dB / 100 Volts RMS, requires that the RKV so a little more than 100 volts RMS output, but here on a load very weak (with very high 145000 Ohms impedance) (NB: PCL805 tubes RKV are given out for 80 volts on a load Ohms 2000, the nominal impedance for the use of these first 805 PCL tubes, originally used on CRT televisions, is between 4000 and 16000 ohms , these tubes may run up to 170 volts and 0.20 A in output pentode in mode)

 

 

Eric


Edited by eric65 - 2/25/14 at 3:04pm
post #670 of 722

Audiovalve RKV OTL tube headphone amplifier is an very great amplifier : the RKV mk2 amp directly coupled on the Stax SR-009 (in mode pure OTL, without impedancer and without voltage transformers (1:50) from the Wee connected), is for me, the best association with this estat headphone, and, it seem too, the RKV mK3 amp (symetric amp) but without OTL mode,  with the JPS Abyss headphone, which the association seems quite happy (here, necessarily, with the use of the integrated impedancer because this orthodynamic headphone has a low impedance of 46 Ohms, in addition to low sensitivity). 


Edited by eric65 - 2/25/14 at 3:02pm
post #671 of 722
Quote:
Originally Posted by TheAttorney View Post

All 8 of my PH's rattle a lot when tapped. Even when not tapped, but just left on and fully warmed up with no music playing, one or two of the first set would occasionally rattle in a minor way, more like a faint whine. My second set whine all the time! I can hear it up to about 3 feet away in a quiet room.

None of this seems to affect the SQ through the phones, which is still glorious in the BHSE. However, in a few days I will receive my Herbie Halo tube dampers and I'm curious to see if they can improve the SQ further. I know that Dave didn't notice any difference on his JJ's, but I'm trying for myself with a different kind of damper. Simply touching the tube with fingers (when cold obviously) greatly reduces the rattle when tapped, so there is some chance that a damper may make a difference.

Only to confirm the EL34PH that was rattling is now perfectly fine and quiet. I've also tried the tube dampers, first on the power tube and then only on the preamp tubes: on the EL34 they don't seem to make any difference (and honestly they are quite ugly LOL) but they work on the 6SL7s, not a night and day difference but better focus. Will try without to confirm if I'm imagining differences :-)
post #672 of 722
Quote:
Originally Posted by realmassy View Post


Only to confirm the EL34PH that was rattling is now perfectly fine and quiet. I've also tried the tube dampers, first on the power tube and then only on the preamp tubes: on the EL34 they don't seem to make any difference (and honestly they are quite ugly LOL) but they work on the 6SL7s, not a night and day difference but better focus. Will try without to confirm if I'm imagining differences :-)


So Massy, how are the PH's sounding now? Some of your earlier comments didn't seem overly positive, just wondering if they've changed to becoming more of what maybe you expected.

post #673 of 722
I'm happy about them Golfnutz. They are good, but probably in my amplifier the difference between different power tubes is not great, while the preamp tubes have more influence. Having said that i've stopped looking for a different quad of EL34 as I can't really notice any weakness
post #674 of 722
Before I bought the Esoteric K-01, I auditioned it at the place I got it from, however I only got to hear it via a speaker set up.
The speakers were Tannoy Westminster Royal se and the amp used along with the K-01 was the Esoteric A100.
I only listened to one CD which was Jean Michel Jarre's " Oxygene ".
The reason I'm mentioning this is because the music was so life like, if someone had said Jean was in the room playing, I'd have believed them.
IMO, a headphone system will never come close to a life like sound that a good speaker system can get close to, but since using the PH's with my BHSE, my 009's have given me the closest to life like sound I've heard from a headphone system.
Before getting the PH tubes, and listening to headphones and speakers, it wasn't often I got over excited with what I was hearing, but since listening to my 009 / BHSE / K-01 using the PH 's, there's been times when I've felt shivers going up my spine.
We all have our favourite headphone combo's, but IMO anyone that's serious about headphone listening, need to at least have a listen to the 009 / BHSE while using the PH tubes.

P.S. I guess a good source might also help with the SQ.
post #675 of 722

A good recording of music with if possible a good source (top dac type MSB, Esoteric, dCs, Total-Dac, Audiomat, etc), a good amplifier (one of those mentioned above) and the 009 Stax Headphone, of course :), and we can have shivers going up spine or the chair of chicken, or the tear in the eyes. It's the magic Stax !

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