The Stax Thread III

[Ali-Pacha]

Stax amp's are great value for the money...looking at US prices, and of course japanese prices.
In France, think about a ridiculous 3000 € (3850 $) for an official SRM-727II 

 
BTW, when I compare this last one to my old (but re-capped) SRM-1/mk2 pro, everything is better (dynamics, details, extension, power, soundstage, etc...), except two things :
- Linearity. When pushing the SRM-727II, high-mids can become shouty. Noticeable on acoustic music with low recording volume
- Bass texture. Bass on the SRM-727II is a kind of over-the-top / bloating mixture, when it remains very tight (but one-could-find-it-meager) on the SRM-1/mk2 pro
 
Ali

 

[astrostar59]

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.

Wrong. The max Ma for the on-board KGSShv is 5.5Ma due to the heat dissipation. The Off-board as standard is 10Ma, but many have tweaked it up to 14Ma.
 
Not sure if the 727 is better than the 717, but it would need to be WAY better IMO. I am not saying the Stax amps are not any good, they are for the price point, I am saying a Stax amp built to a budget of £1800 - 50% dealer commission and you are talking a £900 amp. So yes, the 727 is really good for a £900 amp! BTW many DIY KGSShv's have been bought for round £1600 with good quality parts. If you are brave, you can do one for a lot less than that.
 
The KGSS is similar in design, but I am informed by those who heard both the Justin amp is better, probably as it has better parts quality.
 
I wish there were more demo's available to spread the word. It is too difficult to do this with words, your ears will tell you more than this forum. However, the Stat amp world is quite small and if outside of the states, not much chance to hear alternatives. 
 
Don't you know anyone with a BHSE or KGSShv to try out?

 

[jcx]

  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.

 
 
 
there's always EQ - much cheaper to get one decent, mostly flat full range response with low distortion headphone - then make it sound like you want
 
EQ can be done at a much higher quality and level of sophistication than many appreciate - just doesn't get you the name dropping, conspicuous consumption, audiophile connoisseur points
 
http://www.head-fi.org/t/612665/how-far-can-eq-really-go-towards-truly-equalizing-headphones#post_8429154 below
 
Quote:

   
FYI:
http://www.cpt.univ-mrs.fr/~briolle/11thAESpart1.pdf
http://www.cpt.univ-mrs.fr/~briolle/11thAESpart2.pdf
 
Indeed, we can certainly save some money.

 
 
for more fun think about what the Smyth SVS Realizer is doing when it makes your headphones sound like the loudspeaker/room system you calibrated in - you can also calibrate, use different headphones with the same personal HRTF room calibrations
 
http://smyth-research.com/
 
what makes you think "the headphone's soundstage" can't be manipulated?
 
 
 

  "minimum phase" linear filters - like most analog EQ, and DSP IIR filters actually compensate for the minimum phase shift associated with amplitude variations in the transducer - EQ for flat frequency response and you improve the phase response
 
multi-driver transducers and the output above cone breakup at higher frequencies aren't "minimum phase" so linear EQ doesn't fully correct the "excess phase" part of the response
 
the "excess phase" response can in principle be fixed by more complex filters with all-pass phase EQ sections or in DSP FIR filters - usually you need automated measurement - our ears really aren't sensitive to phase above a few kHz
 
I do think the SVS Realizer is relevant to the discussion of what EQ can in principle do - even if you want to make distinctions between increasingly general "EQ"
 
1st order - a single frequency response adjustment curve - common to both R,L channels
 
next - custom per channel - even manufacturers bragging about matching their transducers only claim "1 dB" matching - clearly above ABX DBT detectable difference thresholds
 
cross-feed is simply "matrix EQ" - uses signals from both channels, cross-feed is the start of hrtf simulation, allows aproximating your hearing free field sounds with both ears
 
Dolby Headphone, some other SW adds simple idealized models of speaker separation, room reverb
 
the SVS system skips the modeling and measures the sound at your ears in the sweetspot of a real room and loudpseaker setup - including surround systems up to 7.1, adds angular response with the head tracking
and uses the in-ear mics to measure the headphones you're using, applying EQ for each channel - you can have separate headphone corrections in addition to multiple loudspeaker+room personal calibrations
 
 
for me all of the above are fundamentally related - we are multiplying the input channels by frequency/phase correcting filter transfer functions, possibly in in a full matrix and calculating the corrected 2-channel output to the headphones, only the head angle tracking of the SVS takes in any "new" information - and that just allows interpolation between transfer functions measured during the in room personal calibration

 

[paradoxper]

Quote:

  Wrong. The max Ma for the on-board KGSShv is 5.5Ma due to the heat dissipation. The Off-board as standard is 10Ma, but many have tweaked it up to 14Ma.
 

 
You can build out the HV to whatever flavor you truly desire. As Kevin has said that's the beauty of DIY you can use the overpriced RK50 and silver wire or
crank the bias to all hell. So there's no real standard.

 

[doyouknowSBmean]

What's the price of a pair of omega I?

 

[georgep]

Wrong. The max Ma for the on-board KGSShv is 5.5Ma due to the heat dissipation. The Off-board as standard is 10Ma, but many have tweaked it up to 14Ma.
 
..... 
 
Don't you know anyone with a BHSE or KGSShv to try out?

 


Sorry, could you tell me how many KGSSHVs you have built? I have built two off-board and one on-board (uncased). I have also built a DIY-T2. I think I know what I am talking about when I tell you that 10ma is not the "standard" for the offboard - it is a modification, though a very easy modification any diy-er can do as they build. Diy'ers were encouraged not to up the curent for the on-board because of heat dissipation issues. And for the most part the parts quality is the same for these diy builds as most people tend to use the same resistors and caps as everyone else (the pot being the only real differentiator). I get the sense you are just parroting inaccuracies. As well, I did not get the sense that you have heard the 727, yet you keep making statements about it.

 

[negura]

Quote:

You can build out the HV to whatever flavor you truly desire. As Kevin has said that's the beauty of DIY you can use the overpriced RK50 and silver wire or
crank the bias to all hell. So there's no real standard.

Agreed re the beauty of DIY. As per a couple of pages ago Kevin himself is rocking a 20mA 600v supplies HV. I would not say no to hearing one of those if however possible.

 

[carbonfet]

What's the price of a pair of omega I?

Anywhere from $3k to $6k (give or take), depending on the condition.

 

[Ali-Pacha]

What's the price of a pair of omega I?

Ask wiktor 

 
Ali

 

[kevin gilmore]

Agreed re the beauty of DIY. As per a couple of pages ago Kevin himself is rocking a 20mA 600v supplies HV. I would not say no to hearing one of those if however possible.

 
That is a completely different gain and output stage. Off board only and very large heatsinks

 

[complin]

Sorry I just don't get it !!
So you criticise an amp for clipping at volumes way way above normal listening levels that would damage your hearing 

 
Its like playing a speaker amp so you can annoy the neighbours 1/2  a mile away and then complaining thats clipping too
 
Sorry but I just don't hear and have never heard the Stax amplifiers you list being at their limits on dynamic music at normal listening levels. You must have issues elsewhere in your audio chain or are playing music at insanely high levels.
 
I don't dispute the KGSShv with outboard power supply can handle musical dynamics much better, but then we are comparing apples with oranges, not apples with apples, so an unfair comparison
 
 
 
Quote:

  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.

 

[NoPants]

there is a bit too much hyperbole thrown around when mentioning current delivery numbers, not to mention voltages

 

[complin]

Yes the voltage swing is lower
However; you keep trying to compare stuff that is not comparable in both topology and technology. Its very important to compare like with like.
I would sure hope the KGSShv off-board is superior but then Stax only ever produced a very few amps like this the T2 being one of them
You are entitled to your opinion but I doubt you will find many Stax users here who would describe the 717 as crude, cold and sterile. However; I would agree that the Stax SS amps don't help with the bright top end of the 009.  
  
Quote:

  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.

 

[complin]

Well I would be the first to say that a decent power supply and good "power" delivery will make a huge difference to any audio system
If you have been around audio for any length of time, especially in two channel speaker audio its often the quality of the power supply which is the differentiating factor in terms of providing top audio quality and being able to reproduce something like the dynamics of the original music. 
 
Quote:

  there is a bit too much hyperbole thrown around when mentioning current delivery numbers, not to mention voltages

 

[jackskelly]

Astrostar

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

Read this

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

 
This is a very important topic. I always try to be conscious of the volume level when listening to my rig, but sometimes inevitably I find myself listening to my system too loud (especially when I'm really enjoying the music of course). The problem (maybe not really a problem) I've found with STAX rigs (and maybe this goes for most or all high-end headphones rigs) is that you can easily turn the volume up to dangerous levels without realizing it at first, just because the distortion is so low and the sound is so crystal clear.