[eric65]

  I liked Frank 845 amp much more than the bhse, although I only listen to the bhse through the sr-009 and did not use the sr-007

 
Hello,
 
Currently there are three very good amplifier to listen to the Stax SR-009 and, also, the JPS Abyss and Audeze LCD3-F headphones.
 
To listen to the JPS Abyss and the LCD-3F headphones, go see the side of Viva Egoista
 

http://vivaaudio.com/en/products/egoista/
 
To listen to the SR-009, well, the DHT Franck Cooter amp, with 845 tubes, does not leave unmoved (ask to jude,

) .
 

 

 
 
To listen to both the JPS-Abyss, the LCD3-F, but also the Stax SR-009, go to Munich (in 1 month) at the HIGH-END and listen to the amazing Audiovalve Luminare amp built by Mr. Becker.
 

 

 
 
Finally, to do justice to the SR-007 mk1 headphone (which is no longer produced), the BHSE amp is a good choice to those who wait two years (or more) of waiting for the order.
 

 

[kevin gilmore]

my guess eric is that the viva is WAY out of your required price range.
 
yep, 9000 euros, about $10k.
 
if I was going to do a dht dynamic amp, this is how I would do it.
(except with high frequency filament supply)

 

[eric65]

Maybe, in some time, Viva will commercialize, in addition to the Viva Egoista amp (845 dynamic headphone amp), a similar version of the 845 DHT of Frank Cooter (for electrostatic headphone); like this, for the modest sum of 20 K USD (10 + 10 K ?) (estimate) you can buy the two best headphone amp in the world for your favorite high-end headphone (JPS  Abyss and Stax SR-009). 
When we love, we do not look at the cost...

 

[kevin gilmore]

you do realize that anything involving an 845 tube without feedback is at least 5% distortion...

but its a really sweet distortion

 

[eric65]

Probably, this is what makes the charm and musicality of these 845 amp ... but ask to Frank what he thinks about; he is the Expert of this fabulous tube.

 

[arnaud]

At least Eric, one can say you have good aesthetic tastes. The lumination was pretty already but this viva egoista takes the bunch with its subdued yellow tint

 

[eric65]

It would seem that this beautiful Italian headphone amplifier has been chosen by one of the bosses of Audeze (Alex Rosson); the aesthetics of headphones Audeze worth what it's worth, the pairing with this amplifier is perhaps not a bad choice (Nb: also, you can read this review : http://parttimeaudiophile.com/2014/10/25/review-viva-audio-egoista-headphone-amplifier/)

 

[FrankCooter]

you do realize that anything involving an 845 tube without feedback is at least 5% distortion...

but its a really sweet distortion

Although I've worked a lot with tubes of this type, I've never actually measured the distortion.
 
According to RCA the 5% figure is at 10W  output.
 
In neither application discussed  here is the output power anywhere near that level.
 
I could be wrong, but I would expect the distortion characteristics of an 845 to drop substantially as  the output power decreases.
 
Of course, no matter how low the actual measurements might be, they will still be poor  by modern standards. Whether or not this disqualifies the amp from consideration is a matter of personal choice.

 

[FrankCooter]

  Probably, this is what makes the charm and musicality of these 845 amp ... but ask to Frank what he thinks about; he is the Expert of this fabulous tube.

I appreciate the compliment, but I am not an expert on the 845, amplifier design, or electronics in general. I'm a pretty decent technician, and I've built a fair amount of audio equipment, but in the end I'm an amateur hobbyist.

 

[wink]

http://www.ebay.com.au/itm/Stax-headphone-amp-electrostatic-step-up-transformer-/131490998959?pt=LH_DefaultDomain_0&hash=item1e9d796aaf

 

[eric65]

No comments

 or rather read the additional information (about the operation of the Verto box) at the following link: 
 
http://www.homecinema-fr.com/forum/post178505962.html#p178505962
and
http://www.homecinema-fr.com/forum/post178506104.html#p178506104

 

[kevin gilmore]

the viva is a 15 watt amp, so the distortion is probably close to 5% with no feedback.
The 845 is a class A Modulator/amplifier, and actually works at lower distortion at
much higher power levels with much higher plate voltages. Can actually get down
to 1% at 50 watts.
 
Here are a few more entertaining numbers, asked by a person on an island off the
coast of spain.
 
Singlepower MPX3 with 6sn7 tubes...  Actual measured distortion 5.4% into 300 ohms
at 2 volts peak to peak. (this definitely surprised me)
 
Singlepower Extreme with 6as7 output tubes, 2% into 300 ohms at 2 volts peak to peak
 
MPX3 with 6as7 output tubes and appropriate plate resistor, point 2% (.2%)  into 300 ohms...

 

[cladane]

  my guess eric is that the viva is WAY out of your required price range.
 
yep, 9000 euros, about $10k.
 
if I was going to do a dht dynamic amp, this is how I would do it.
(except with high frequency filament supply)

Could you elaborate why with high frequency filament supply ?

 

[kevin gilmore]

in the higher power DHT tubes, DC ends up taking many hours off
the life of the filament due to hotspotting. 
And 60hz AC supplies no matter how hard you try always
have a slight bit of hum.  So pure sinewave drive at 40khz
is much better. Also much more complicated.

 

[cladane]

Thank you for the answer.
I should understand that the 845 tubes in the Viva  will have a small life time ? Comments say that they heat very much as a matter of fact.
Remains musicality and impressive spatiality. Is it the 845 tube or question of design and output transformers ??