The Stax Thread III
Oct 9, 2013 at 7:21 PM Post #526 of 25,666
For information.
 
You can listen directly, to the Stax SR-009 headphones, plugged directly into the amplifier Audiovalve RKV mk2, by bypassing the transformator amplifier input Wee (1:50 ratio) but keeping the bias voltage of 580 Volts of the Wee on housing on the 5th pin of theheadphone output jack Wee.
Advantage: undeniable increased transparency and presence.
Inconveniant: the listening level is limited below 100 dB SPL (for a maximum output level of the RKV amplifier limited to 80 volts on OTL mode).
 
The final level of quality for headphones on the 009 with the RKV no output transformers (no impedancer) or input (bypassing the transformer amplification of Wee) may exceed that of the Electra !
 
http://www.head-fi.org/t/681814/amplifiers-shootout-for-stax-009-eddie-current-electra-audiovalve-rkv-wooaudio-wee-stax-srm727-srm007t2/30#post_9874692
 
Oct 10, 2013 at 12:19 AM Post #528 of 25,666
 
   
They can't keep up with 009 sales and given the 1+ year wait for a BHSE, if they can do the amp for $5k and keep it in stock then they have a market. They also have distributors and retailers, which none of the other 'stat amp makers do. 

 
I've underlined and bolded the important part. If they are able to source the correct and appropriate parts capable of HV in the circuitry without the final amplifier costing beyond $5k than they may be able to pull off another T2 moniker high-end status amp. That's if they can. But I don't know about you but I think a T2 alike amp would be produced in much more limited numbers than the 009 earspeakers themselves. Given that they will have to source electronic parts from other manufacturers and such as almost none of the circuit parts will be produced in house unlike the earspeakers.

It would be no different to how the amps are produced now, nor the earspeakers, most parts of which are made by external companies. Agreed about the "if" though. 
 
Oct 10, 2013 at 4:48 AM Post #529 of 25,666
  For information.
 
You can listen directly, to the Stax SR-009 headphones, plugged directly into the amplifier Audiovalve RKV mk2, by bypassing the transformator amplifier input Wee (1:50 ratio) but keeping the bias voltage of 580 Volts of the Wee on housing on the 5th pin of theheadphone output jack Wee.
Advantage: undeniable increased transparency and presence.
Inconveniant: the listening level is limited below 100 dB SPL (for a maximum output level of the RKV amplifier limited to 80 volts on OTL mode).
 
The final level of quality for headphones on the 009 with the RKV no output transformers (no impedancer) or input (bypassing the transformer amplification of Wee) may exceed that of the Electra !
 
http://www.head-fi.org/t/681814/amplifiers-shootout-for-stax-009-eddie-current-electra-audiovalve-rkv-wooaudio-wee-stax-srm727-srm007t2/30#post_9874692


I guess the audiovalve wouldn't be happy to push such high voltages, wouldn't distortion be an issue? It's not much headroom after all.
 
Oct 10, 2013 at 5:58 AM Post #530 of 25,666
 
I guess the audiovalve wouldn't be happy to push such high voltages, wouldn't distortion be an issue? It's not much headroom after all.

 
With 6-10 volts average output voltage at the output of RKV (on a maximum 80 volts) for listening to an average level of 74-80 dB, and a load> 2 KOhms, there is no audible distortion. The degree of transparency and presence of sound is exceptional with 009 Stax headphones (without the 1:50 Wee transformers (bypassed)).
 
Otherwise, the RKV amplifier is used directly (without Wee transformator) to gain a high voltage (6-12 volts average ; maxi 80 Volts RMS), but with a very low power: maybe 40 mWatts to maximum output voltage of 80 volts RMS for a Stax 009 with an 145 KOhms impedance. (NB: the RKV can produce 3 Watts with a load of 200 Ohms)
 
Oct 10, 2013 at 6:05 AM Post #531 of 25,666
It is surprising the amplifier can handle a completely different load (I mean a mostly capactive load vs. the typical resistive / inductive load of dynamic or orthodynamic phone) than it was intended to drive.

You're a brave soldier Eric, I hope your gear survives the ordeal :)
 
Oct 10, 2013 at 6:33 AM Post #532 of 25,666
any balanced solid state amplifier can do this.
krell fpb 600 can do 400vppss. I tried it. Sounds very nice
but still a bit low on volume.
 
krell master reference amps can do at least 600vppss.
 
none of these amplifiers will even see the headphones
as a load, just run as open impedance.
 
Oct 10, 2013 at 10:54 AM Post #535 of 25,666
In the same vein there is a design pretty much ready for a proper push-pull electrostatic amp that can run at even higher voltages than the KGSSHV.  Almost all of the 'stat amps have single ended output stages but this one is fully complimentary... 
redface.gif
  Makes the T2 look simple though...
 
Oct 10, 2013 at 1:39 PM Post #536 of 25,666
Its called the TOGTE and it uses +/-750 volt power supplies.
 
which does seem to scare some people.
 
works with currently available parts. one of these days I will
finish the board.
 
Oct 10, 2013 at 2:29 PM Post #537 of 25,666
Decided to power up my lambda sigs after several weeks of collecting dust. They have worked for 2.5 hour straigth, no channel imbalance, but suddenly this screechy/squealing sound manifests...
 
Oct 10, 2013 at 5:05 PM Post #539 of 25,666
I must say that dust is pretty noisy, lol. I have had similar issues before, also with channel imbalance. Only reason why I post again (besides that it upsets me) is that I just can't seem to understand how dust can cause such weird things. Ohh well.
 

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