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AudioValve LUMINARE & VERTO : for Stax headphones and for all dynamic headphones - Page 15  

post #211 of 348
Quote:
Originally Posted by cucera View Post


The luminare is allready sold via ebay germany and the seller is using your pocture Eric, but via photoshop enhanced to a T2 and bhse. And in a German forum a seller tried to persuade me the Luminare is better than my BHSE with technical nonsense. But he didn't expect me to be an engineer.

It is unbelievable how this Stuff is pushed and makes me resent the whole story even if it is good. Guerrilla Marketing of the annoying sort.


I actually sent an email to Mr. Becker about the false advertising / usage of image that does not belong to him (I am the one who made the mock up picture with T2 and BHSE).

 

Suffice to say I never received a reply.

 

So the intent is certainly to blur the lines between the reality and the world some are dreaming.

 

My post was to highlight how ridiculous the statement was. The designer's response was to use the image without explanation, in order further promote his product, whatever, it doesn't affect me.

 

In the end, I wish audio valve all the best with their endeavours, as it's always nice to see estats aren't quite dead yet. 

 

cheers,

arnaud

post #212 of 348
Thread Starter 
Quote:
Originally Posted by cucera View Post


The luminare is allready sold via ebay germany and the seller is using your pocture Eric, but via photoshop enhanced to a T2 and bhse. And in a German forum a seller tried to persuade me the Luminare is better than my BHSE with technical nonsense. But he didn't expect me to be an engineer.

It is unbelievable how this Stuff is pushed and makes me resent the whole story even if it is good. Guerrilla Marketing of the annoying sort.

 

Hi cucera,

 

I am not responsible for this photomontage (with the BHSE and T2 amp). ;)

 

My picture (see below) showed only an amplifier AudioValve RKV-II, a Verto box (before its amendment and his improvement),a  SRM 727, a SRM 007t, a Wee box (original) and a Wee box doctored (transformers 1:50 disconnected).

 

The best listening in this roundup (with headphones Stax SR-009) was the combo RKV-Verto (in direct comparison with other amps).

 

Thereafter, the enhanced version of Verto (by deleting two resistors) we seemed even better (more transparent).

 

Regarding Luminare when the final version will be released (at the end of 2014), very clever who can say how the sound quality will be compared to the competition, including the best electrostatic amplifiers direct-drive of the moment, for listening to the 009.

(NB: the low ratio (1:5.9) step-up transformer of the Luminare amp do not bring only that pitfalls of ; it can in order to make it more enjoyable listening electrostatic headphones like the 009 giving it more thick and a natural sense of sound and more fun to hear).

 

 

 

Winner of the comparison: combo RKV-Verto

 

http://www.head-fi.org/t/677809/the-stax-thread-iii/3135#post_10863960

 

Eric

post #213 of 348
Thread Starter 
Quote:
Originally Posted by arnaud View Post
 


I actually sent an email to Mr. Becker about the false advertising / usage of image that does not belong to him (I am the one who made the mock up picture with T2 and BHSE).

 

Suffice to say I never received a reply.

 

So the intent is certainly to blur the lines between the reality and the world some are dreaming.

 

My post was to highlight how ridiculous the statement was. The designer's response was to use the image without explanation, in order further promote his product, whatever, it doesn't affect me.

 

In the end, I wish audio valve all the best with their endeavours, as it's always nice to see estats aren't quite dead yet. 

 

cheers,

arnaud

 

Hi Arnaud,

 

I have restored your picture of the SRM-T2 amp; indeed, this legendary Stax amplifier, that unfortunately no longer in production, might never to be exceeded (this is a myth); moreover, it is a bit more powerful than the Luminare amp (1785 Vpp for the T2, against 1700 Vpp for the Luminare) ; it deserves to be on the podium of the best electrostatic amps to associate with the Stax SR-009   ;)

 

 

 

Eric


Edited by eric65 - 11/23/14 at 11:00am
post #214 of 348
Dear eric you need to learn much young Padavan. :oVoltage swing is only one measure and it alone means nothing for The quality of an electrostatic amp. Otherwise this one would be king but it is verry mediocre:

2400 volts peak to peak stator to stator (+/-600 power supplies)
koss esp950
post #215 of 348

Sounds like nobody is falling for this amp...they seem so desperate. :frown:

 

RIP Virgo

Aug., 2014 - Nov., 2014

post #216 of 348
That's why they have a shill like Eric posting these strange posts here.
post #217 of 348
Thread Starter 
Quote:
Originally Posted by cucera View Post

Dear eric you need to learn much young Padavan. :oVoltage swing is only one measure and it alone means nothing for The quality of an electrostatic amp. Otherwise this one would be king but it is verry mediocre:

2400 volts peak to peak stator to stator (+/-600 power supplies)
koss esp950

 

Hi cucera,

 

For Luminare amplifier, we will soon see; for now we only know that he is very powerful.


For the combo RKV-Verto, we already know that it is very powerful and it is also excellent for the sound quality (for all audio criteria) with headphones Stax SR-009 (see our comparative listening); this is obvious; it delighted me every day when listening to my audio system (with a very good source (DAC Audiomat Maestro Reference), it must be said).


Eric

 

 

PS: 

Wie St. Thomas, glauben Sie, was Sie hören.

Sie haben Recht; Sie werden nicht enttäuscht (in Kürze) ;) 

 

Eine Empfehlung, schauen Sie nicht form dieses Thread, aber das Fundament, und innovative Idee, die gezogen werden können, und welche draußen sind des tretenen Pfade.

 

Andernfalls können Sie auch lesen Sie diese (in Französisch):

http://www.homecinema-fr.com/forum/post178334214.html#p178334214


Edited by eric65 - 11/25/14 at 7:23am
post #218 of 348
Thread Starter 

Hello,

 

Here are some measured performance of the combo RKV2-Verto (and Luminare which incorporates the basics and step-up 1:5.9 transformers of Verto) : 

 

Max output voltage (OTL mode) (load> 2000 Ohm) = 102 V rms (measured)


Max output voltage (stax mode) (with step-up 1: 5.9 transformer): 102 x 5.9 = 600 Vrms (1700 Vpp)

 

Slew rate (SR) (load: 470 pf) = 2 * Pi * F * Vp = 2 x 3.14 x 250 Vp (500 Vpp / 2) x 10,000 Hz = 15,700,000 V / s = 15.7 V / us

 

source:http://www.audiovalve.info/to/verto.php

 

Current I (max) = SR x C (load pf) 
(link: http://www.head-fi.org/t/582518/electrostatic-amplifiers-voltage-ratings#post_7926541)
I max = 15.7 V / us x 470 pf = 7.379 uA = 7.38 mA

 

Slew rate (SR) (load: 110 pf) (= Stax SR-009) = I max / C = 7.38 mA / 110 pf = 67 V / us.

 

Slew rate (SR) (load: 50 pf = load C chosen by KG to measure his amps whose T2): link: http://www.head-fi.org/t/582518/electrostatic-amplifiers-voltage-ratings/15#post_7927298) = I max / C = 7.37 mA / 50 pf = 148 V / us.

 

(NB: the slew rate of the T2 measured by KG on a C = 50 pf load would be situed between 150 and 200 V / us)

 

Conclusion: with Vpp max 1700 and Slew rate 148 V / us (load = 50 pf) (or 67 V / us (load = 110 pf = Stax SR-009)), the combo RKV2-Verto (and soon Luminare which incorporates the basics and step-up 1:5.9 transformers) are amplifiers for electrostatic headphones (among others) extremely fast and powerful.

 

Eric


Edited by eric65 - 11/25/14 at 4:19pm
post #219 of 348

Eric I will bet you put a fair amount of work into that.

Trouble is your complete lack of understanding on how electrostatic amps work.

 

Just about every electrostatic amp out there is balanced push pull.

(frank's amp is one of the exceptions)

 

That means that the active element (top element kgss,kgsshv and all late model stax solid state)

(bottom element stax tube, kgst,T2)

is capable of way more than 9 ma of current. The 9ma of current is just the class A bias.

So it is possible that the amplifier is much faster than your calculations.

 

But why the 470pf. Don't want to show what a 10khz square wave actually looks like with 120pf.

Could it be the massive ringing of the waveform because with that transformer and a 120pf

load, the resonant frequency is way to close to 10khz?

 

But lets look again at that 9ma number. into a 1:5.9 transformer the primary current is

54ma. Way over the tube limit of 10.5ma. Which means the amplifier is going to be pushed

way over its power limit, and the result will be significant amounts of distortion.

post #220 of 348
Thread Starter 
Quote:
Originally Posted by kevin gilmore View Post
 

 

But lets look again at that 9ma number. into a 1:5.9 transformer the primary current is

54ma. Way over the tube limit of 10.5ma. Which means the amplifier is going to be pushed

way over its power limit, and the result will be significant amounts of distortion.

 

Load 1200 Ohms (Luminare amp or RKV2 amp ; OTL mode): P max = 5,5 Watts (THD 1 % at 1 KHz) ; V max = 81 Volts rms (OTL mode)

 

P= UI

I = P/U

 

I max = P max (THD 1 % ; 1 KHz) / V max

 

I max (RKV2 or Luminare) = 5.5 Watts / 81 Vrms =0.068 A = 68 mA (THD 1 % ; 1 KHz) (OTL mode)

 

 

I max (with step up 1:5.9 transformers of Luminare amp or combo RKV2-Verto) = 68 mA / 5.9 = 11,5 mA (Nb : this number is > 7,38 mA or 9 mA) (Stax mode with step-up 1:5.9 transformers)


Edited by eric65 - 11/26/14 at 8:09am
post #221 of 348

First, repeated disclaimer : I am not affiliated with anybody - on this thread or otherwise.

 

It is a classic situation when a long time established status quo is being seriously challenged - similar to CD vs SACD wars that flushed much of the dirty laundry on either side for the public to see for the first time - which is good.

 

It is being presented in somewhat - to say the least - questionable way by Eric65 . It is perfectly clear to anyone who knows what it is all about that technical/electrical background of Eric65 is not exactly his forte. Furthermore, it is that his (or mine for that matter ) native language is not English. 

 

On the last oscillograme posted by Eric65 is not a SQUARE wave of 10 kHz, but TRIANGLE wave ( source - link provided by Eric65 ) at that frequency driving a much above normal load - 470 pF, an equivalent of approx 4 pairs of Stax headphones. It is next to perfect. So what KG wrote regarding transformer output inductance  resonating with the capacitive load "around 10 kHz " when reproducing "square wave"  is WAY off and misleading - but yes, if that had actually been the case, resonance at 10 kHz might look very similar to that picture. The response of 10 kHz SQUARE wave at the same level using the same load is also shown - and although not perfect, it IS better than most direct drive amps can provide using SINGLE Stax headphone or load approx 120 or so pF. 

 

What I would like to see are the true unretouched measurements of all competing amps into known specified load at precisely specified frequencies, levels and distortion limits. Particularly is of interest the power response limit - or frequency to which is the amplifier still capable of driving the load to full voltage as attained at low frequencies < 1kHz. But take care - any output transformers HAVE to be rated for CONTINOUOS  output power under such conditions, or else damage or complete failure of the output transformer WILL occur. Obviously, direct drive amplifiers share no such limitations - but in a well designed transformer it should also not be an issue.

 

If a set of meaningful tests for testing amplifiers for electrostatic transducers could be devised and agreed upon, there would be no waxing either way possible anymore. The amp that performs better in real world conditions wins - end of story. This is NOT comparable to amps for dynamic phones, where amp can exceed the driving needs of the load ad libitum,  micro minute differences can be make or break; compared to those are electrostatic amps barely alive, and can not afford to care about make up, toenails, eyelashes, etc - to merely survive driving the nasty purely capacitive load WELL is already extremely close to the win.

 

I do not like the word "shill" ( which I learned of first on head-fi ...) - with behaviour of Eric65 being a hair thin line from it, it is a situation one can not be exactly comfortable with. 

 

The same can be said regarding the misleading (mis)interpreatation by KG regarding the 10 kHz oscillogram as posted above by Eric65.

 

I am perfectly aware here is money/bussiness interest at stake, jostling for position in the marketplace, but please try to be fair - me personally would far more prefer "he/they is/are good, please allow me/us the opportunity to show I/we are better" than trying to badmouth ( in this case "badpicture" ) the other party or use (consciuosly or unconsciuously) misleading interpretations. To my knowledge to this day, the only openly published measurements of "anything driving electrostatics" were DIY designs of Mr. Heyser and Mr. Sanders in 70s in The Audio Amateur ( later reprinted in The Speaker Builder ) magazine. Everything else, at least what I am familiar with, was hear>say>claim>prove-me-wrong-if- you-can; and even that mostly on subjective basis. To highlight only the pros and remain completely silent regarding the cons does not qualify for open publication in my book.

 

I am the last to say that subjective evaluations are meaningless, but if a device does not measure at least "sound", it is not a good device no matter how much might I like it subjectively. Problem with ESLs is high voltage : the probes that are specified for voltages required and still having low capacitance/extended frequency response do exist, but are ANYTHING but cheap and common even in highly specialized labs. And yes, here the necessary precautions regarding lethally dangerous voltages/current are to be repeated: in order to measure anything, one has to gain access to exactly what should NEVER be touched. Regardless if it is coming from a direct drive or transformer coupled amp. All this means I have NEVER seen an objective test with measurements of a commercially available device designed to drive ESLs in any commercially available magazine - only circumstantial evidence, if you will, of acoustic output of ESLs being driven by said device.

 

I think it is about time to "pour some pure wine" ( as we say around here ) in these murky waters ESLs are forced to swim due to the technical difficulties that result from the purely capacitive load characteristics of the transducers themselves. But whatever one might wish do : this is not + - 15 V preamplifier - so use this caution seriously.

post #222 of 348

I was referring to the square wave graph linked to here

http://www.audiovalve.info/to/verto.php

(pic3)

 

because a triangle wave is useless for measuring rise times.

in fact triangle waves are usually very sharp at the top and bottom

peaks, something that looks very rounded in the graph above.

 

And yes I own 100x Tektronix probes suitable for making accurate

measurements at 1kv levels. 20pf loads.


Edited by kevin gilmore - 11/26/14 at 12:24pm
post #223 of 348
Quote:
Originally Posted by kevin gilmore View Post
 

I was referring to the square wave graph linked to here

http://www.audiovalve.info/to/verto.php

(pic3)

 

because a triangle wave is useless for measuring rise times.

in fact triangle waves are usually very sharp at the top and bottom

peaks, something that looks very rounded in the graph above.

 

And yes I own 100x Tektronix probes suitable for making accurate

measurements at 1kv levels. 20pf loads.

Pic 3 is OF LOUDSPEAKER OUTPUT - and Verto driven in reverse. It is adequate, it means approx - 3 db @ 30-40 kHz, which is good enough. The ringing seen would be at higher frequency and of lesser amplitude with the load of 120 pF or so ( one pair of Stax ). Remember, this are all square waves at 10 kHz, usual 1 khz would appear 10 times more "squarer/non rounded" - actually kudos to RKV/Verto for publishing them at so high frequency to highlight as much detail as possible

 

The REAL treat of this ( amp + low step up ratio transformer ) is pic 1 - where there is a very clean square wave without any ringing and with a very fast rise time. It clearly extends - 3dB beyond 50 kHz - but unfortunately no voltage level is given.

 

I never doubted you not to have probes capable of measuring direct drive ESL amps - at least those to 1 kv, which is good enough for Stax. You are designer and manufacturer - how could you do without them?

 

Jecklin Float unfortunately require at least 1.5 kV for comparable performance of Stax at its maximum levels - and ESL speakers extend that to almost 10 kV.

post #224 of 348
Thread Starter 
Quote:
Originally Posted by kevin gilmore View Post
 

I was referring to the square wave graph linked to here

http://www.audiovalve.info/to/verto.php

(pic3)

 

 

Pic3 (see below)

 

That has nothing to do with the combo RKV2-Verto because:

1: use here of a transistor amplifier Hi-Fi connected to the output teminal speaker  8 Ohm (in reverse mode) of the Verto box.

2: use transformers step-up with much higher ratio on this path: 1:21 ratio (against 1:5.9 in Input Jack of the Verto, for the RKV2 amplifier)

 

 

 

 

 

 

 

pic 1 : M. Becker said "show you the excellent transmission properties of the VERTO used on a STAX headphone connected to the output of the RKV Mark 2 as driver"

 

 

pic 2 : triangle signal at 10 KHZ, load 470 pF (= 4 x load Stax SR-009), combo RKV2- Verto with step up 1:5.9 transformers

 

 

pic 3 : square signal at 10 KHz ; load 470 pF ; transistor (Hi-Fi) amp on the speaker terminal (in mode reverse) of the Verto Box (use 1:21 step-up transformers on this input SPK terminal (mode reverse)

 

http://www.audiovalve.info/to/verto.php


Edited by eric65 - 11/26/14 at 1:47pm
post #225 of 348
first picture has no voltge levels. could be 10 volts
lots of conflicting published information, but no
picture of 10khz at 500vac

why?

piles of misrepresentation here.
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