The Stax Thread III

[complin]

I believe the 727 and 717 are both 450 volts which is a comparable amp to the KGSS/hv
 
Quote:

  Err, the KGSS and KGSShv all run at higher voltage swing and have more amps in the PS than the 007t and 727.
 
The KGSShv (most examples) use 450v rails not Stax 350v rails.

 

[Golfnutz]

No I've never heard the NOS Mullard's but I'd like to, however I've got two quads of PH's, a quad of SED's and those stock Mullard's that came with the BHSE, so if I did decide to get any NOS Mullard's it won't be for quite along time, but by the time I'd be ready to get some there might be none available.

Another tube I'd like to try is the NOS Philips Holland Metal Base.

One of the reasons I would do the 2-for-1 swap is the first quad of PH tubes I had (very reliable) started to fail after 10 months (2500 hours). My feeling is the Mullards would probably out last 2 quads of PH's. I also think the better the source, the better one would hear the difference between the two. Not that my source is end game, but I think it's good enough to allow me to hear enough of a difference to know which one is clearly better. As a reference, when I first heard the PH tubes I had the same experience that David has been posting. However, with the Mullards, I had even more of the same experience. So ShuguangTreasures (6CA7) to PH = WOW what a difference, then PH to Mullard = holy crap, I've been an idiot.

 

[astrostar59]

 

Err wrong dude:
 
http://www.head-fi.org/t/582518/electrostatic-amplifiers-voltage-ratings

 

[complin]

All I can say is that Stax state 450 volts in their specification for the 727.
Also as Kevin also says "For solid state amplifiers, the output voltage is usually very close to the power supply rails"
 
Quote:

  Err wrong dude:
 
http://www.head-fi.org/t/582518/electrostatic-amplifiers-voltage-ratings

 

[astrostar59]

Kevin also states the swing is much lower on the Stax amps. And then we have the amps reserves in the power supply, the 727 is around 4 MA, the off-board KGSShv 10Ma and can go up to 14Ma. I can hear myself that my 717 is on the limit with even the 009s, never mind the 007s. Wind it up a bit and loose bass and edgy treble are the norm. The sound changes in pitch, it just sounds rough on any material with decent bass and dynamics in.
 
Aside from all this, are you saying the 727 is a great sounding amp that is as good as say a KGSShv off-board, or the BHSE? I don't see the logic in this discussion. I have the 717 here, and used it last week on my same system, and let say for the last time, it sounds crude, cold and sterile compared to the KGSShv. It doesn't suck, but it is night and day. Well behind IMO, on both the 007 MK2s and the 009s. These phones sound lame on the 717/727 sorry. With the 507s however, that is a decent system, and makes nice music and costs a sensible amount for the phones and amp. A pair of 009s powered by the 727, it is not good value for the SQ on offer.

 

[David1961]

One of the reasons I would do the 2-for-1 swap is the first quad of PH tubes I had (very reliable) started to fail after 10 months (2500 hours). My feeling is the Mullards would probably out last 2 quads of PH's. I also think the better the source, the better one would hear the difference between the two. Not that my source is end game, but I think it's good enough to allow me to hear enough of a difference to know which one is clearly better. As a reference, when I first heard the PH tubes I had the same experience that David has been posting. However, with the Mullards, I had even more of the same experience. So ShuguangTreasures (6CA7) to PH = WOW what a difference, then PH to Mullard = holy crap, I've been an idiot.

As I say, I'd very much like to try the NOS Mullard's and especially the NOS Philips Holland Metal Base, but just supposing I did get to try them both with my BHSE and preferred them to the Psvane PH's, either still wouldn't be the next audio gear I'd get after my new kitchen and conservatory are done, that next piece of audio equipment would be a new headphone amp, assuming the builder was to do that amp because at the moment it's only in the pipeline.

 

[greggf]

astrostar,
 
I have a simple question for you:
 
At what volume levels do you listen to music on STAX headphones? 

 

[astrostar59]

Quiet, loud, it depends how I feel and the material type. My point is the way to test (review) stat amps has always been to listen to the upper level of normal, as Inner Fidelity realised (and was recommended technique by the head-fi community they talked to at the time of that big review). Tyler kinda thought the 007t was well behind the other amps ....

 

[Moonhead]

Astrostar

Be carefull Playing too loud, eventually you will damage your hearing.

Read this
http://www.innerfidelity.com/content/loud-music-sucks

 

[Michgelsen]

I have a question. I feel like a sinner because of it, and don't let the mafia know:
 
What dynamic cans most closely resemble the SR-007 in tonal balance and presentation? Must be relatively easy to drive, in production and open (not closed). Price should not exceed that of an SR-007.
 
I'm thinking of building a compact (backup) rig around my m903, which has a decent dynamic amp inside, but it's obviously not K1000 capable or anything like that. It does have crossfeed however, which I would like to try.
 
Would something like the HD600 or HD650 be an option? I have little experience with dynamic cans, so I could use some advice. I did own the HD650 years ago, but remember thinking it had a bit too much bass. Any ideas would be greatly appreciated.

 

[georgep]

Kevin also states the swing is much lower on the Stax amps. And then we have the amps reserves in the power supply, the 727 is around 4 MA, the off-board KGSShv 10Ma and can go up to 14Ma. I can hear myself that my 717 is on the limit with even the 009s, never mind the 007s. Wind it up a bit and loose bass and edgy treble are the norm. The sound changes in pitch, it just sounds rough on any material with decent bass and dynamics in.


 


Aside from all this, are you saying the 727 is a great sounding amp that is as good as say a KGSShv off-board, or the BHSE? I don't see the logic in this discussion. I have the 717 here, and used it last week on my same system, and let say for the last time, it sounds crude, cold and sterile compared to the KGSShv. It doesn't suck, but it is night and day. Well behind IMO, on both the 007 MK2s and the 009s. These phones sound lame on the 717/727 sorry. With the 507s however, that is a decent system, and makes nice music and costs a sensible amount for the phones and amp. A pair of 009s powered by the 727, it is not good value for the SQ on offer.

 


Just a few comments:

Don't know the current rating for the 727, but the KGSSHV outboard is not 10ma without modification. Besides, Spritzer has commented numerous times that there is no audible difference between stock (which I believe is 5.5ma) and higher current ratings.

The 727 with the feedback mod (changing two resistors) has received Stax mafia approval and is a bit better than the 717 post-mod. With the transistor mod (slightly more intensive work), the 727 is essentially a lower powered KGSSHV. Justin of HeadAmp has also commented (either here or at the other site) that the current Stax amps are great value for the money and that he could not compete with the prices they charge. That is not to say that a KGSSHV might not be better for a greater premium, but the 009 does not sound lame on a 727 (modded or un-modded) or a 323s. As well the KGSS and 717 are very similar amps.

I think Milosz in an earlier post was quite spot on about the differences between the Stax branded amps and the cottage/diy amps. The solid-state Stax amps are a great bang for the buck (I cannot speak about the tubed ones though as I have never heard them).

 

[Moonhead]

I have a question. I feel like a sinner because of it, and don't let the mafia know:

What dynamic cans most closely resemble the SR-007 in tonal balance and presentation? Must be relatively easy to drive, in production and open (not closed). Price should not exceed that of an SR-007.

I'm thinking of building a compact (backup) rig around my m903, which has a decent dynamic amp inside, but it's obviously not K1000 capable or anything like that. It does have crossfeed however, which I would like to try.

Would something like the HD600 or HD650 be an option? I have little experience with dynamic cans, so I could use some advice. I did own the HD650 years ago, but remember thinking it had a bit too much bass. Any ideas would be greatly appreciated.

HD650 with a neutral AMP or ortho if you are willing to go in that direction.
Alternatives could be LCD2 or HE500.

 

[kevin gilmore]

srm-007t, srm-006t,srm717,srm727  are all +/-350V power supplies
caps are usually 400V caps and the supply is unregulated, so there
has to be room for high line.
 
The stax spec is Volts RMS stator to stator
 
kgsshv is either +/-450v or +/-500v power supplies
 
T2 is +/-500V power supplies
 
koss is +/-600V power supplies

 

[astrostar59]

Great post. I had read that article before. A friend of mine got Tinnitis during the years of being a DJ
in his left ear (mixing ear).
 
My point was Tyler tried the stat amps at higher volume levels to check if they could handle the dynamics
and started clipping. It wasn't a normal listening recommendation. Listen to the 007s are 'normal'
listening levels, and you will still hear the 717/727 or 323 amp at it's limits on dynamic music. It is quite obvious.
 
I can hear it at 12 o'clock on an RCA line input with 2v max line feed from a source.
 
I would not recommend anyone to listen at high volume on any headphones.
 
Another point on this subject, a cheap or poor sounding speaker or headphone system can do more damage
due to 2nd order distortion and artefacts, especially in the higher frequency region as we often get with low budget
IEMs.

 

[greggf]

So, as I quoted earlier, spritzer says that most stat amps are idling at "normal" listening levels.  And Tyll says that he was advised to crank up the volume beyond "normal" listening levels in order to hear any differences between the amps.
 
And, therefore, the STAX amps sound as good as anything else at "normal" listening levels, eh?
 
Cool.  So boutique amps only sound better when you're deliberately going out of your way to damage your hearing in a systematic fashion?