[bcg27]

SR007s are not the only stax headphone that uses pro bias.

 

[driggs]

Yes, I know, but the question still stands!!??  Why are there 2 outputs on these amps?

 

[Amarphael]

It's so you could connect the Omegas in super-balanced configuration with a seperate cable to each channel and turn into an OMeGAWD!

 
No seriously, Just beacuse it's marketed for the O2's doesn;t mean you can't buy it seperatley and use it with any 'stat phone that you'd want.

 

[Sim1]

Quote:

Yes, I know, but the question still stands!!??  Why are there 2 outputs on these amps?

Some users (h-f forum is just a tiny part of all stax owners) do not show such orthodox attitude and want to use 2 pairs of headphones (like O2 / Lambdas) and not bother with constant headphones switching
Some might want to use extention cord in one socket and listen to the music in bed or such, while the other socket is for direct use close to the amplifier... and some want to have possibility to compare directly headphones... so what's the difference 1 or 2 sockets?
In the past Stax must have had such demand (look here -> http://earsp.web.fc2.com/kakosonota/sreb3/sreb3.htm#SRE-B3) so why not? Does it really matter if you have 1 or 2 sockets?
 

 

[edstrelow]

Quote:

 
 
That maintenance cost does seem ridiculous though. That's almost the same price as I paid for my 007 mk1 used. All headphones fail eventually though =/

Short of serious abuse,most Stax phones are good for decades if not a lifetime.  The phones are very simple in construction and unless you actually burn out a diaphragm, and that is rare on the newer phones, most other problems are cables and connections which many people can fix on their own.
 

 

[Clarkmc2]

Quote:

So, can anyone tell me why there are 2 headphones in in the Stax 007tII amp when it is designed to be paired with the higher-end Stax phones which are power hungry and need all the power of the amp (and some here say that its not even enough to drive one pair of 007's, incl. me).  I understand in some of the other Stax amps one out is normal and the other is pro, but here we have 2 pro outs!  This is the 3rd time i've posted this but no response.... it probably is a very stupid question!

With my first Stax setup I had one phone for my girlfriend and one for myself. We liked it better than speakers - better sound and it didn't interfere with kissing.
 
All these years later I still think women who share one's passion for music are the best!

 

[WilCox]

Quote:

So, can anyone tell me why there are 2 headphones in in the Stax 007tII amp when it is designed to be paired with the higher-end Stax phones which are power hungry and need all the power of the amp (and some here say that its not even enough to drive one pair of 007's, incl. me).  I understand in some of the other Stax amps one out is normal and the other is pro, but here we have 2 pro outs!  This is the 3rd time i've posted this but no response.... it probably is a very stupid question!

Adding a second pair of earspeakers doesn't appreciably degrade the sound.  Electostats need only voltage, not much current, to do their thing, so running two in parallel is not a big deal.  Also, in regards to the SRM-007 being under powered, you are right that many here say that and I agree they could use more voltage swing for greater headroom.  I can't help but think though, that many new owners confuse power and gain.  Some Stax amps, like the 007 have only moderate gain requiring the volume to be turned past 12:00 to get any reasonable sound.  This is wrongly interpreted as being under powered.  In fact, I believe Stax increased the gain on some of their more recent amps so people could believe they have more power available since they can now operate at 9:00 or 10:00 on the volume pot.  Truth is that the volume control is more linear in its later stages of travel.

 

[jgazal]

This is certainly the best explanation. Sometimes you want to share your passion.

 
Quote:

With my first Stax setup I had one phone for my girlfriend and one for myself. We liked it better than speakers - better sound and it didn't interfere with kissing.
 
All these years later I still think women who share one's passion for music are the best!

 

 

[driggs]

Quote:

Some users (h-f forum is just a tiny part of all stax owners) do not show such orthodox attitude and want to use 2 pairs of headphones (like O2 / Lambdas) and not bother with constant headphones switching
Some might want to use extention cord in one socket and listen to the music in bed or such, while the other socket is for direct use close to the amplifier... and some want to have possibility to compare directly headphones... so what's the difference 1 or 2 sockets?
In the past Stax must have had such demand (look here -> http://earsp.web.fc2.com/kakosonota/sreb3/sreb3.htm#SRE-B3) so why not? Does it really matter if you have 1 or 2 sockets?
 

 
Ok, that's a good explanation.  I have 007mk2's and am waiting for my 009's.  I hate to think what'll happen with both connected to the 007tII in parallel (don't want to leave my wife out), but I will try...  let's see exactly what this voltage vs. current thing is really about... 
 
 

 

[DaveBSC]

Quote:

Adding a second pair of earspeakers doesn't appreciably degrade the sound.  Electostats need only voltage, not much current, to do their thing, so running two in parallel is not a big deal.  Also, in regards to the SRM-007 being under powered, you are right that many here say that and I agree they could use more voltage swing for greater headroom.  I can't help but think though, that many new owners confuse power and gain.  Some Stax amps, like the 007 have only moderate gain requiring the volume to be turned past 12:00 to get any reasonable sound.  This is wrongly interpreted as being under powered.  In fact, I believe Stax increased the gain on some of their more recent amps so people could believe they have more power available since they can now operate at 9:00 or 10:00 on the volume pot.  Truth is that the volume control is more linear in its later stages of travel.

The SRM-007Tii is fine with the SR-507 and below, and may even be ok with the 009 if those are indeed much more efficient as I've heard around here. The Omega 2 is not efficient though, it needs voltage and with the SRM-007Tii it just isn't there. It's got significantly less voltage swing than the half as expensive 323S, less than even the original SRM-1 from 1979. The T2 was the amazing amp it was with the O2 in part because it swung 630V, which no other Stax amp to date can even touch.

 

[driggs]

Quote:

The T2 was the amazing amp it was with the O2 in part because it swung 630V, which no other Stax amp to date can even touch.

Since I am relatively new in this game (long in hi end home audio but new in head-fi audio!), I dont quite understand this..
 

 

[deadlylover]

The T2 was the best stat amp you could get for Stax. Nothing they have released since then has even approached the amount of insanity the T2 was packing.

 

[WilCox]

Just to be clear, all of the current Stax amps can be considered to be somewhat underpowered, whether they have 350 or 450 volt swing.  To play twice as loud as a typical Stax amp, you would need approximately 1200 volt swing.  Justin's amps (HeadAmp) are the only current commercially available amps that can do that as far as I know.
 
 

dB Change	Voltage	Power	Loudness
3	1.4X	2X	1.23X
6	2.0	4.0	1.52
10	3.16	10	2
20	10	100	4
40	100	10,000	16

Looking at the chart, and starting at the left, we can see than an increase of 3dB results in a voltage increase 1.4 times the original, a doubling of power, and yields only a subjective increase in loudness only 1.23 times the original. To get a doubling of loudness, it is important to note that an increase of 10dB is necessary. And to reproduce that volume through our loudspeakers, note that we require ten times more power from the amplifier! 

 

[deadlylover]

If I recall correctly, you'd only need something like 800Vp-p for a 106db or so output from an O2. Now say a normal listening level of 90db, you won't need thaaat much voltage swing.
 
Those Stax amps are outputting 350vrms or 450vrms, not voltage swing. Even the little 252 has more than enough voltage swing/gain that one would need. How an amp handles the load is far more important.
 
If you plug a second headphone in, the amp won't need to swing twice the voltage, the amp would only have to throw in some more current. I could be very wrong though =P.

 

[livewire]

@ WilCox - where did you come up with that? Sumpin aint right...
 
Also FYI, HeadAmp's KGSS has 350V rail to rail, so 700V RMS swing. BHSE - 400V rails / 800V RMS swing, IIRC.