Stax SRM-007tII vs Stax SRM-727II
Oct 17, 2007 at 7:09 AM Thread Starter Post #1 of 40
SkiffX

SkiffX

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Hey Gents,
Im getting Sennheisers HE60 to Stax amp adapter cable, and was wondering looking for your input on which amp I should get Stax SRM-007tII / Stax SRM-727II or perhaps something else? My good friend is recommending me to get 727II because its more reliable as he states, so I was also wondering how problematic tube operated ones are?

Thanks for your help.
Skiff.
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Oct 17, 2007 at 7:23 AM Post #2 of 40
Don't know enough about the 007 vs. 727 debate (probably boils down to a personal preference of tubes vs. SS), but I do know that the HE60s will be better driven out of a more powerful amp such as a KGSS or better yet a KGBH or ES-1. Do searches for those amps and you'll see alot written about their relative merits (and about how stax amps just don't stack up).
 
Oct 17, 2007 at 7:55 AM Post #3 of 40
There are no reliability issues here as Stax tube amps last a very long time. I have one here that I restored that was made in 1968. I only had to clean a few contacts, install some new tubes and it was up and running.

The He60 isn't particularly power hungry but they do benefit from the a higher powered amp. I prefer tubes with them to tame the slight colorations in the midrange and give the bass a bit extra bloom but the solidstate amps are good as well. The WooAudio GES would also be an option and so is the Headamp KGSS.
 
Oct 17, 2007 at 7:56 AM Post #4 of 40
Quote:

Originally Posted by electrathecat /img/forum/go_quote.gif
Don't know enough about the 007 vs. 727 debate (probably boils down to a personal preference of tubes vs. SS), but I do know that the HE60s will be better driven out of a more powerful amp such as a KGSS or better yet a KGBH or ES-1. Do searches for those amps and you'll see alot written about their relative merits (and about how stax amps just don't stack up).


I found the KGSS and KGBH, can you link me to ES-1 please?
 
Oct 17, 2007 at 8:19 AM Post #5 of 40
Quote:

Originally Posted by SkiffX /img/forum/go_quote.gif
I found the KGSS and KGBH, can you link me to ES-1 please?


There isn't a link AFAIK as Single Power hasn't updated their website in years. Try searching for some information
 
Oct 17, 2007 at 8:20 AM Post #6 of 40
Also any other suggestions besides, stax are welcome, since Ive done a little more research and stax do seem a bit underpowered, Im looking for something around up to $2K range.
 
Oct 17, 2007 at 10:05 AM Post #7 of 40
Quote:

Originally Posted by spritzer /img/forum/go_quote.gif
There are no reliability issues here as Stax tube amps last a very long time. I have one here that I restored that was made in 1968. I only had to clean a few contacts, install some new tubes and it was up and running.

The He60 isn't particularly power hungry but they do benefit from the a higher powered amp. I prefer tubes with them to tame the slight colorations in the midrange and give the bass a bit extra bloom but the solidstate amps are good as well. The WooAudio GES would also be an option and so is the Headamp KGSS.


For GES it says # Signal/Noise: 100 dB, wouldnt you say its rather low?
 
Oct 17, 2007 at 10:13 AM Post #8 of 40
Quote:

Originally Posted by SkiffX /img/forum/go_quote.gif
For GES it says # Signal/Noise: 100 dB, wouldnt you say its rather low?


It is an all tube amp riddled with coupling caps but the same can be said about the Sennheiser Orpheus amp, the HEV90. Those specs are pretty meaningless.
 
Oct 17, 2007 at 10:52 AM Post #9 of 40
Quote:

Originally Posted by spritzer /img/forum/go_quote.gif
It is an all tube amp riddled with coupling caps but the same can be said about the Sennheiser Orpheus amp, the HEV90. Those specs are pretty meaningless.


hmm Im leaning toward KGSS eventhough it doesnt look as cool, it has the XLR inputs that I can connect the DAC that I will need to get.

I see that KGBH isnt available anymore, shame, and I cannot fork out 4.5K for SE version. But sure as hell would want to get me a tube one, just to experience it, so any other suggestions besides KGSS?
 
Oct 17, 2007 at 11:02 AM Post #10 of 40
i hear all this talk about Stax amps being weak, and i have this question

did anybody actually manage to CLIP them ?

did anybody drive them into serious distortion without going deaf ?

do you judge power of an amp by seeing how far you have to turn the knob ?

the stax has less gain than KGSS which is a design choice, not weakness, because it compensates by having greater maximum input voltage.

somebody please shed some light ...
 
Oct 17, 2007 at 11:03 AM Post #11 of 40
The KGSS is a pretty bland looking box but it has plenty of power for most electrostatics. The KGBH is a good upgrade but it is much more expensive to make. XLR inputs are nice to have but all electrostatic amps are push-pull so if the phase splitter is good then the amp will sound just as good with a RCA input though the gain will be slightly lower.
 
Oct 17, 2007 at 11:11 AM Post #12 of 40
Quote:

Originally Posted by g1981c /img/forum/go_quote.gif
i hear all this talk about Stax amps being weak, and i have this question

did anybody actually manage to CLIP them ?

did anybody drive them into serious distortion without going deaf ?

do you judge power of an amp by seeing how far you have to turn the knob ?

the stax has less gain than KGSS which is a design choice, not weakness, because it compensates by having greater maximum input voltage.

somebody please shed some light ...


It's not about the volume level but about the control the amp has over the elements. The more power, i.e. voltage swing and current, an amp can deliver the better and that will give you a bigger soundstage, better HF response and most importantly some real bass. The bass isn't bigger or loader but controlled and in accurate relation with the rest of the signal. There is a certain ease of delivery that the bigger amps have that the Stax stuff just can't match.

It's easy to just increase the gain of an amp or run it floating to get a more impressive voltage swing but electrostatics need current as well as voltage. It isn't much current but a few mA's are 800v is quite a bit of power.
 
Oct 17, 2007 at 11:18 AM Post #13 of 40
Quote:

Originally Posted by spritzer /img/forum/go_quote.gif
It's not about the volume level but about the control the amp has over the elements. The more power, i.e. voltage swing and current, an amp can deliver the better and that will give you a bigger soundstage, better HF response and most importantly some real bass. The bass isn't bigger or loader but controlled and in accurate relation with the rest of the signal. There is a certain ease of delivery that the bigger amps have that the Stax stuff just can't match.

It's easy to just increase the gain of an amp or run it floating to get a more impressive voltage swing but electrostatics need current as well as voltage. It isn't much current but a few mA's are 800v is quite a bit of power.


from my understanding of physics the transfer of energy from diaphragm to air will be very efficient when the mass of diaphragm is almost as low or lower than the airload mass. this means that electrostatic cans should actually be more efficient in terms of decibel per watt than dynamic ones. yet dynamic cans only need about 0.1 watt to achieve impressive output, so electrostats should only need maybe 0.01 watt ...

would you say this is wrong ?

in other words what im saying is perhaps the cans need not milliamps but microamps ?
 
Oct 17, 2007 at 11:45 AM Post #14 of 40
Quote:

Originally Posted by g1981c /img/forum/go_quote.gif
from my understanding of physics the transfer of energy from diaphragm to air will be very efficient when the mass of diaphragm is almost as low or lower than the airload mass. this means that electrostatic cans should actually be more efficient in terms of decibel per watt than dynamic ones. yet dynamic cans only need about 0.1 watt to achieve impressive output, so electrostats should only need maybe 0.01 watt ...

would you say this is wrong ?

in other words what im saying is perhaps the cans need not milliamps but microamps ?


That is wrong. You are driving the film with an electrostatic so the distance from the stators to the film has much more weight the the actual weight of the diaphragm. Since the electrostatic force diminishes by the square root of the distance a small variation can change a lot.

The phones will draw something like 8mA's of current at 20kHz and half their rated power level. Capacitors could never be considered a preferred transducer in terms of efficiency.
 
Oct 17, 2007 at 11:47 AM Post #15 of 40
Quote:

Originally Posted by spritzer /img/forum/go_quote.gif
That is wrong. You are driving the film with an electrostatic so the distance from the stators to the film has much more weight the the actual weight of the diaphragm. Since the electrostatic force diminishes by the square root of the distance a small variation can change a lot.

The phones will draw something like 8mA's of current at 20kHz and half their rated power level. Capacitors could never be considered a preferred transducer in terms of efficiency.


that square root thing i believe does not apply to infinite plane ...

so where does the power go, it must go somewhere ...

are you saying the power factor of electrostatic cans is close to zero ? so you're simply charging and discharging the capacitance without doing useful work ?

?
 
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