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Amplifiers shootout for Stax 009 (Eddie Current Electra, AudioValve RKV + WooAudio Wee, Stax... - Page 3

post #31 of 71

Hello.

 

Icenine2 rightly ask at the Cavalli Liquid Lightning thread :  what is the subjective influence of the visual aspect of the amplifier on the objective results that can be achieved with a blind test freeing the visual aspect of the amplifier ?

 

Quote:

Quote:
Originally Posted by h.rav View Post
 

Maybe it's just me but I don't get if anything is cleared. An amp that expensive should at least be built with the best build quality, design and parts. Look at how BHSE is made. That is the benchmark.

 

 

Originally Posted by Icenine2 View Post
 

 

Yes.  How it "looks" is the benchmark.  I would love if one of the headphone gatherings had a blind test between different amps of every ilk.  Its not like speaker rigs.  All you'd have to do is have the phone cable switched to different amps behind a blind.

 

http://www.head-fi.org/t/584238/review-cavalli-liquid-lightning/300#post_9853119

 

 

We have carried out such a single-blind test on 8 September 2013 with four amplifier with headphones Stax SR 009 (see link):http://www.head-fi.org/t/681814/amplifiers-shootout-for-stax-009-eddie-current-electra-audiovalve-rkv-wooaudio-wee-stax-srm727-srm007t2

 

The most expensive amplifier and the best (and the most  beautiful) on the paper of the lot (Eddie current Electra) was indistinguishable from two of the other three amplifiers (less expensive and less rewarding aesthetically) : The Stax SRM 727 and the combo RKV + Energizer Wee.

 

The right question was to know what would have been the classification of beautiful amp (BHSE) or less beautiful amp like LL in such a blind test, in comparison to these other amps?

 

We will probably never know the answer, but my intuition tells me that we would have probably had some surprises, such as those obtained with our blind test of our 4 amps of 8 September  (for the record, the results of our blind test of 8 September did not show significant differences between the Electra, the combo RKV-Wee and SRM 727, unlike the SRM 007t2 who got a very bad score (significant difference)

 

Eric

post #32 of 71

 

Hello everyone,

 

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 the headphone 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 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 !

 

See link on the French forum HCFR: : http://www.homecinema-fr.com/forum/post177801131.html#p177801131

 

Eric

 

 

post #33 of 71

Otherwise, 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)

 

 

Potentiometer RKV 15 h (mean level "medium to high" loudly enough for me): 7.42 Volts (77.5 dB SPL)

 

 

 

 

Potentiometer RKV to 17 h (max) (mean level "strong" too hard for me): 12.72 Volts (83 dB SPL)

 

 

Potentiometer fully RKV (17 h) and with the Wee transformers bypassed, I just registered to a peak voltmeter level of at least 56 volts on a percussion (large drum) in a jazz recording of Henry Texier "Mad Nomads" that corresponds to a peak noise level of at least 96 dB SPL !

 

Otherwise, I always confirms the high degree of transparency and clarity of sound, and the realism and the strong presence of the vote.

Always zero audible distortion or noise (breath).

 

Be careful : to operate the combo RKV-Wee with enough gain (the transformators Wee shunted), it is imperative that the source (dac) has an output with an enough high level ; if it is not the case, the amplification gain of the RKV will be too weak to reach an average level expected of listening of 80 to 84 dB SPL (enough to use) and  a maximal (peak) modulation of 96 to 100 dB SPL.

 

Eric

post #34 of 71

The challenge !

 

I challenge any amplifier for electrostatic headphones , including the legendary T2 (if there really is one that still works without hum ) to do better than my combo RKV -Wee + 009 (transformers of Wee shunted) on my source ( Audiomat Maestro Ref D1 + Drive) for listening on headphones Stax SR -009 with EQ levels amps to get an average level, the output voltage of the amplifier , not exceeding 10-15 Volts RMS (ie means listening sound level of 80 to 84 dB SPL) and peak level of not more than from 50 to 80 volts RMS (or spikes modulation level not exceeding tuned from 95 to 99 dB SPL) .

Above these levels in amplifier output voltage , all other amplifiers, including the small SRM 252, make a louder sound , probably too hard for most of us , but certainly not better .

 

I am extremely confident in this challenge !

 

If I lose, the winner will receive a bottle of Sauternes Bastor Lamontagne (Bordeaux) over 20 years of age.

 

Eric

post #35 of 71

Is The determining criteria your ears or the the person's who is replicating your system?

post #36 of 71

So now you are trusting your subjective belief that the bypassed transformer setup is better - or are you going to do this blind?

 

Also, do you really listen at 80 plus db all the time?

 

And it should be a minimum a mag of '90 d'Yquem for the trouble.

post #37 of 71
Quote:
Originally Posted by eric65 View Post
 

If I lose, the winner will receive a bottle of Sauternes Bastor Lamontagne (Bordeaux) over 20 years of age.

 

Eric


Can you just send me the Bordeaux? 

post #38 of 71
Quote:
Originally Posted by DefQon View Post
 


Can you just send me the Bordeaux? 

 

Only if you merit !   :)

 

post #39 of 71
Quote:
Originally Posted by georgep View Post
 

So now you are trusting your subjective belief that the bypassed transformer setup is better - or are you going to do this blind?

 

Also, do you really listen at 80 plus db all the time?

 

And it should be a minimum a mag of '90 d'Yquem for the trouble.

 

Yes, I'll keep my combo RKV-Wee with 009 + Wee transformers shunted due to the very net increase in transparency, micro-information and presence (after wee transformation) ; micro details, micro-contraste and the duration of reverberations (really extended) are much better, as well.

 

The maximum noise level <100 dB SPL does not bother me ; I keep a dynamic> 55 dB SPL on some CDs in a quiet environment (noise at home < 40 dB SPL), which enough for me. Otherwise, no risk of going deaf too.

 

For more information and understanding you can also read these links (in French) (use google translator if necessary)

 

 

http://www.homecinema-fr.com/forum/post177805582.html#p177805582

 

http://www.homecinema-fr.com/forum/post177804569.html#p177804569


Edited by eric65 - 10/13/13 at 1:57am
post #40 of 71

Here's a thought that I share with you : why RKV -WEE (transformers WEE shunted) seems so good at listening to the electrostatic headphones Stax SR -009 ? (for listening limited to 100 dB SPL , but with a dynamic about 70 dB in a quiet environment, exceeding the dynamic of the best LP limited to 55-60 dB).

 

Well, just imagine the following construction :


Imagine what can give excellent electrodynamics Sennheiser HD-800 headphones (300 ohm impedanc ) with OTL tube amplifier Audiovalve RKV Mark II for electrodynamic headphone ( 2 x 3 Watts Class A , 60W consumption ; more 80 Volts RMS output ) ; well, the result is not bad, and also for the resulting synergy : amplifier / headphones.

 

Now imagine the same OTL amplifier for headphones electrodynamic , but this time in tune with electrostatic headphones class of Stax SR -009 (directly coupled) , with no interposed between him and transformers headphones to curb ( transformers of WEE bridged ) ; the sound is fully liberate : now compare the inertia of the mobile equipment ( membrane + coil ) electrodynamic headphone HD -800 with fine electrostatic membrane electrostatic headphones SR 009 , there is no picture and you then easy to understand how easily and quickly the slightest sound detail will be reproduced by the couple RKV/009 ( for torque RKV/HD-800 ) , it is a question of moving mass .

 

Finally, imagine the electrical work required by RKV to operate the HD- 800, the load for the amplifier ( impedance ) between 300 and 600 Ohms , and although the 009 electrostatic headphones directly connected to RKV , charge the headset to the amp is then almost zero ( insignificant ) ( the helmet is " not seen" by the amp ) ( Stax headphones 009 have145 000 Ohms impedance ) and the RKV works empty,  almost in tension (where he excels the most) with a maximum output voltage indirectly measured at 85 Volts RMS ( giving a peak sound level measured at 99.6 dB at 50 Hz, a percussion one of my CD without audible distortion , if not my ears that do not appreciate that very moderately as SPL , especially if extended ) .

 

In short, by the addition of all these data : direct coupling of electrostatic headphones ( 009 ) on a tube amp OTL for electrodynamic headphones working here with an insignificant load (almost empty) with a headset whose inertia membranes is extremely low compared to that of a (very good) electrodynamic headphones, so we understand perfectly why the results in listening can be as good and exciting (for noise < 100 dB SPL) , especially if synergy of operation between the headphones and the amp is good, that is to say that the sound signature of the amp and headphones marry well.

 

Eric

 

http://www.homecinema-fr.com/forum/post177812481.html#p177812481


Edited by eric65 - 10/17/13 at 7:25am
post #41 of 71

Eh, whaat......

Contrary to popular belief, electrostatic headphones do put a load on an amplifier.

 

Think of a capacitor charging and discharging.  That requires current flow, and hence, a load.

post #42 of 71

New : RKV mark 3.

 

Suggestions made to rkvfather to upgrade its amplifier for use with Stax headphones such as the SR-009

 

http://www.head-fi.org/t/4619/audiovalve-rkv-mk-iii/15#post_9953382

post #43 of 71
Quote:
Originally Posted by wink View Post
 

Eh, whaat......

Contrary to popular belief, electrostatic headphones do put a load on an amplifier.

 

Think of a capacitor charging and discharging.  That requires current flow, and hence, a load.

 

About AudioValve RKV mark2 (2300 Euros TTC), what I can say is that it is a great amplifier that works very well with a very good synergy with electrodynamics Sennheiser HD-600 and HD-800.

It can also be used with Stax headphone (SR- 009) through a Wee box (WooAudio Wee energizer) and Jack Adapter --> Input the Wee HP with using multipliers transformers tension Wee (Ratio: 1:50): very good results, at least as good, see better (in a blind test) compared to the amplifier Stax SRM 727 (best amp Stax currently producing approximately 3 K Euros) and even that amplifier Eddie Current Electra (one 4K dollars amplifier).

 You can get an even better sound by shunting the Wee transformers (which retained only for use for the bias voltage generator 580 Volt) for the fifth pin Stax headphone: advantage: its the best ever sound obtained with a Stax SR-009 (best that with the SRM 727 and Electra amp) (sound more transparent, natural and more presence); disadvantage: limited level of between 70 to100 dB (SPL) with listening with headphones Stax SR -009 with sensitivity at 101 dB / 100 Volts RMS, knowing that the mk2 RKV can get 80 volts RMS for an input of 2.8 volts RMS signal with a very high impedance headphones (145,000 Ohms for the Stax SR- 009).The amplifier will work mainly in voltage, where he excels.

 

Eric

post #44 of 71
Quote:
Originally Posted by rgs9200m View Post
 

Just  a suggestion here since I see you used a PS Audio Power Plant (a regenerator)... 

Quite a few years back I tried a PS Audio Power Plant (the 3-something model, PS300 I think) on my Stax SR007 (mark 1) phone / 007t amp system,

and it completely ruined the sound (I described this sometime back here in the forums somewhere).

 

The amp started running very hot, the tubes lit up brighter than before, and the sound turned bright, aggressive, with thumping bass, and it was unlistenable.

This was completely opposite to the mellow sound I heard without the power plant.

I later used a Shunyata Hydra with this system with no  problems, just some subtle improvement in the highs.

 

I actually called PS Audio to ask if this was normal and they said it does happen with some tube amps, and in fact this was a common complaint.

They took the amp back and refunded my money.

 

So I think the Power Plant may have wrecked the Stax amp sound.

(And God knows what it did to the other amps.)

 

interesting..............i'm have a ps300 and will have to go downstairs and see if my BHSE is plugged into it or not..........in any case, a comparison is in order!

post #45 of 71
Quote:
Originally Posted by cat6man View Post
 

 

interesting..............i'm have a ps300 and will have to go downstairs and see if my BHSE is plugged into it or not..........in any case, a comparison is in order!

Thanks. Nice system you have there sir.

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