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Amplifiers shootout for Stax 009 (Eddie Current Electra, AudioValve RKV + WooAudio Wee, Stax SRM727 / SRM007t2) - Page 7

post #91 of 98
Quote:
Originally Posted by eric65 View Post
 

Hello,

 

Thank you for your opinion on this test of the combo EC445 / Woo Wee.

 

One note: the succession of two series of transformers: step-down (that of the EC445) followed by step-up transformers (1:50 of the Wee) is not recommended (interference between transformers and degradation of sound quality) .

 

To improve your combo EC445 / Wee it would be better to remove the output transformers step-down from 445 amp to operate in OTL mode, and replace the step-up transformers 1:50 of the Wee by the step-up transformers 1:5.9 of better quality (like that of the Verto) with lower ratio of voltage amplification, which can only be beneficial to the sound quality.

 

If I said something inaccurate thing, prove me otherwise ...

 

Quote:
Originally Posted by georgep View Post
 

 

... and then remove all the internals of the EC445 and place a RKV mkII into the empty chassis... then say "Audiovalve, you are my master and I love thee", three times in the mirror.. swallow the red pill... and voila... you are part of an elite group of audiophiles fighting the "man"....

 

 

Otherwise, I'm not talking about RKV-II amp, but the EC-445 amp which would have withdrawn its output transformers step-down voltage for operation in OTL mode.

post #92 of 98

It does beg the question though: What's the difference between a regular tube amp and an electrostatic one? Is it possible to make anything (transformer coupled) work as long as you have the right output transformer?


Edited by Tachikoma - 11/15/14 at 6:32am
post #93 of 98
Quote:
Originally Posted by Tachikoma View Post
 

It does beg the question though: What's the difference between a regular tube amp and an electrostatic one? Is it possible to make anything (transformer coupled) work as long as you have the right output transformer?

 

Essentially, a larger gain with electrostatic amplifier (about 50 dB gain) and the presence of a bias voltage generator (580 V DC for headphones Stax Pro bias)

In the case of a OTL tube amplifier with step-up voltage transformers (ratio 1:5.9)  : 50 dB gain is obtained as follows: gain 34.5 dB, mode OTL (related amplification tubes in OTL mode) + 15.5 dB additional gain related with the step-up transformers voltage (ratio of 1: 5.9)

post #94 of 98
All. Will the energiser from woo Audio through a Leben cs300 drive the sr009?
post #95 of 98
Quote:
Originally Posted by deuter View Post

All. Will the energiser from woo Audio through a Leben cs300 drive the sr009?

 

Hello Deuter,

 

It is always possible with the Wee box (and its step-up voltage transformers of ratio 1:50) (gain : +34 dB) (need min 4-5 Watts on 8 Ohms for the amp).

 

However, with a tube amplifier of 2 x 30 Watt (Class A) you will have better results with the box Verto (of the AudioValve brand) (http://www.audiovalve.info/to/verto.php), and his step-up voltage transformers of smaller ratio (1:21) (gain : +26.5 dB) using the speaker input/output 8 Ohms teminal in reverse mode of the Verto box (NB : need 20-30 Watts amp on 8 Ohms).

 

Finally, the best results will be obtained with a tube amplifier without step-down transformer (amplifier OTL) (such as for example RKV mk2) and using the box Verto and his step-up voltage transformers of low ratio of only 1: 5.9 (gain : +15.5 dB) (with the input Jack of the Verto).

 

In general, it is better to avoid the succession of a step-down transformer followed by a step-up  transformer (interference among transformers and degradation of sound quality).

So must choose the step-up transformers of the smallest ratio possible (see link reading: http://www.homecinema-fr.com/forum/post178323342.html#p178323342 ) (in French)

 

and relevant forums: http://www.head-fi.org/t/727630/audiovalve-rkv-ii-otl-amp-2014-version-audiovalve-box-adapter-verto-for-stax-headphone-and-for-low-impedance-orthodynamic-eletrodynamic-headphone

 

and http://www.homecinema-fr.com/forum/casques-haute-fidelite/verto-et-luminare-des-produits-audiovalve-atypiques-t30052030.html


Edited by eric65 - 11/19/14 at 3:00am
post #96 of 98


Hi there. I have a Stax sr009 and a SRM007 and SRM727. I bought SH the SRM007 with the intention to see whether I could feel the difference between solid state and valve. And I cannot! I listen mostly to HD classic music, Linn in particular, through my Imac and using Sony PHA3 as a DAC (I use Audirvana as well).

 

Maybe at 51 I am too old to feel the difference! But I was surprised: both sound very well and OK to me. Maybe I can feel the SR007 being, how could I say it, more round or soft around corners (not sure if this makes sense). But that´s it.....

 

So well, I will save a lot of money in pursuing the "perfect" amplifier for the Stax SR009.....

post #97 of 98

The differences between amplifiers (at a certain level) are often very small, on subtle domain; they are often exaggerated ; the differences between headphones are much larger.

post #98 of 98
Quote:
Originally Posted by angeche View Post
 


Hi there. I have a Stax sr009 and a SRM007 and SRM727. I bought SH the SRM007 with the intention to see whether I could feel the difference between solid state and valve. And I cannot! I listen mostly to HD classic music, Linn in particular, through my Imac and using Sony PHA3 as a DAC (I use Audirvana as well).

 

Maybe at 51 I am too old to feel the difference! But I was surprised: both sound very well and OK to me. Maybe I can feel the SR007 being, how could I say it, more round or soft around corners (not sure if this makes sense). But that´s it.....

 

So well, I will save a lot of money in pursuing the "perfect" amplifier for the Stax SR009.....

 

The difference between the SRM-007A and SRM-727A to me, though small, were quite noticeable. especially from the perspective of the width, and imaging (where the SRM-727A to me had greater width whilst the SRM-007A had the imaging), but also in terms of "speed". Not too sure why an amp would have any part to play (usually I just listen, I don't try to explain...I'm not an audio electronics engineer), but the SRM-007A was noticeably "slower" than the SRM-727A for "speedy" tracks.

 

I've had the owner os the SRM-007A and another colleague come by to have a listen even.

 

Then the Electra is on a different level from both aforementioned amps.

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