[googleli]

Thanks - now I have decided to go for the stock SRM 727 and afterwards may place my order on the BHSE, using the 727 as a temp until the BHSE arrives.
 
Quote:

if you want to read about the rudistor amp/009 combo impression,here's the thread if you are keen on using the google translation
http://bbs.headphoneclub.com/viewthread.php?tid=158590&highlight=
apparently those guy got hold of the headphone early because someone has connection with stax from japan.
the source and headphone is good, but the amp is... but what can you do, rudistor is big over there.
 

 

 

[n3rdling]

If you know how to DIY you can google for the 727 mod.

 

[visualguy]

Quote:

Thanks - now I have decided to go for the stock SRM 727 and afterwards may place my order on the BHSE, using the 727 as a temp until the BHSE arrives.
 
 

 
The 323S sounds better than the unmodded 727 with the SR-007 in my experience.
 

 

[arnaud]

Based on intriguing comments from Visualguy and since I had to go back to Yodobashi Akiba today I did a brief comparison of the 323S and 727A (stock) amps driving the SR-009 with the same source (Marantz CDP I mentioned earlier in the thread).
 
At first, I thought I like the 323S better actually because it seemed to have a more relaxed presentation with no apparently lack of bass or bass control. However, when listening to specific tunes with low / lots of bass (such as "Tout doucement" from Feist or "Canceled Check" from Beck) I realized something was a bit strange with the 323S. In particular with "Tout doucement" it was like the bass not had no real start or end, the transients were not there in comparison with 727A amp. Also, dynamics / headroom seemed lacking in the 323S (for example listening to "Punk (DJN)" from Avishai Cohen's Trio). Soundstage also felt significantly wider with the 727 amp.
 
Now, much of this may be placebo as really the listening conditions are not good at this store (large background noise, had to change seat / rig to compare both amps). However, it does seem like both amps sounded different driving the 009. Actually, it made me curious to try other amps (like modded 727 and eventually BHSE)...
 
I think the next step will be to find a way to mod my 727 amp. If I notice improvements like has been observed with the sr-007, then I know what I will be saving for in the coming year . Like visualguy though, I am quite reluctant to spring for the BHSE due to usage of tubes, large heat / size / power consumption, long waiting time and finally high price... I will probably give in some day (that is when I digest my 009 purchase ) though, maybe by then there's a KGSSHV on the market!
 
My 2 cents, and again, to be taken very lightly, it was not proper conditions to make such comparison accurately. Visualguy, if you happen to have the tune from Feist, would you mind giving it a shot and report? Ah wait... You no longer have the KGSS I believe... Oh well.
 

 

[kiertijai]

there may be some problems with the channel imbalance of the SR009. Please be careful
here is the link
http://www.head-fi.org/forum/thread/555908/stax-sr-009-channel-imbalance-trouble-driver-problem#post_7502066 

 

[TheAttorney]

Is the SR-009 cable fixed in its vertically downward position? 
If so, has anyone experienced issues with the cable rubbing against their shoulders (resulting in vibration noise transmitted up the cable)?
 
On good thing with the O2 was the ability to turn the cable forwards slightly to remove that issue.

 

[spritzer]

The Rudistor amps were nothing more than a simple differential amp tied to a terrible PSU and built using the cheapest possible parts.   This circuit is about as simple as you can get for an electrostatic amp and for a DIY amp it is perfectly fine.  In fact, I pushed for this circuit to be used as the basis of a cheap "volksamp" back in the day since anybody can build it.  Now to sell this circuit for 4000€ or what ever he was charging is nothing short of a scam, similar to putting a SRM-252 into a new chassis and asking 5k$ for it...  Here is one I built earlier this year using this circuit but with premium parts (Mundorf coupling caps, Kiwame resistors etc.) in an old Koss ESP10 box.  Total cost was about 200$...
 

 
Quote:

Now you make me curious. Which positions did you use better resistors? Hopefully you didn't mean all of them

Most of the resistors were already PRP's but I swapped the rest for Shinkoh Tantalums and PRP's.  Z-foils would only work in series connection since they can only handle 300V... 
 

 

[visualguy]

Quote:

 
My 2 cents, and again, to be taken very lightly, it was not proper conditions to make such comparison accurately. Visualguy, if you happen to have the tune from Feist, would you mind giving it a shot and report? Ah wait... You no longer have the KGSS I believe... Oh well.
 

I still have the KGSS. I don't know about the SR-009, but the SR-007 mk1 doesn't exhibit any problems when driven by the 323S. I listened to Tout Doucement as you suggested and didn't hear a problem with the bass. I'm surprised you thought the bass on the 727 was better, but maybe the SR-009 behaves differently. On my SR-007, the 727 bass is somewhat bloated and has a tendency to dominate the mix too much. With the 323S, the bass sounds just right to me.
 
Also, I haven't noticed any problems with dynamic range or soundstage. I listen to classical orchestral music a lot, and I would have noticed such problems if they were there.
 
Bear in mind that we aren't listening to the same headphones.
 

 

[El_Doug]

He sold it for $14,000  (9500€), iirc
 
Quote:

Now to sell this circuit for 4000€ or what ever he was charging is nothing short of a scam, similar to putting a SRM-252 into a new chassis and asking 5k$ for it... 
 

 

 

[ast]

Quote:

if you want to read about the rudistor amp/009 combo impression,here's the thread if you are keen on using the google translation
http://bbs.headphoneclub.com/viewthread.php?tid=158590&highlight=
apparently those guy got hold of the headphone early because someone has connection with stax from japan.
the source and headphone is good, but the amp is... but what can you do, rudistor is big over there.
 

That Chinese forum is a scam.  The Admin "xiao bai", meaning "little white",  is a owner of a headphone shop in Shanghai and a sole dealer of Rudistor.   It is notoriously known a platform for Marketing their products.   Just ignore it.
 
 
....
 

 

[visualguy]

Quote:

 
I'm not completely done yet, but I've been doing a pretty careful analysis of the sound of the SR-007 mk1 on the 323S and I haven't heard any deficiencies so far, and nothing that sounds worse than what I remember from my KGSS. If I don't hear any differences in side-by-side listening with the KGSS, I will be ready to conclude that 323S=KGSS in terms of sound quality, and 323S>KGSS in terms of convenience.
 

I finally had a chance to do the side-by-side comparison between the 323S and KGSS with the SR-007 mk1, and indeed the KGSS is better. The main differences I noticed were that on the KGSS the highs were less strident and the soundstage was better. The 323S is a little shrill and flat-sounding when compared to the KGSS. It's not bad by any means, but it's noticeably inferior to the KGSS when I listen to them side-by-side.
 

 

[googleli]

With the SR009 now on sale, I think we should urge the manufacturer of BHSE to ramp up its production. We all understand that amps of that quality and build will take some time, but waiting for like one year is ridiculous.
 

 

[purrin]

 
Quote:

... The 323S is a little shrill and flat-sounding when compared to the KGSS. It's not bad by any means, but it's noticeably inferior to the KGSS when I listen to them side-by-side.
 

 
And you had me think I was crazy. Honestly, the differences are not that large - but they were enough to convince to not purchase an O2 (and keep my 507s) in the meantime until the SR009 arrives, which I now expect to be in July or later. (The lone USA distributor is known to suck with communications and it appears that at least one US retailer has discontinued carrying STAX because of this.)
 
Quote:

With the SR009 now on sale, I think we should urge the manufacturer of BHSE to ramp up its production. We all understand that amps of that quality and build will take some time, but waiting for like one year is ridiculous.
 

Or maybe it will become profitable enough for others to enter the market. Maybe Woo can find a way to eliminate the output caps on the WES and produce a MKII version.
 

 

[justin w.]

Quote:

With the SR009 now on sale, I think we should urge the manufacturer of BHSE to ramp up its production. We all understand that amps of that quality and build will take some time, but waiting for like one year is ridiculous.
 

I think I have posted about this on many occasions.  I'm working on a large number of amps right now, with the goal of them being all ready at about the same time.  

 

[arnaud]

 
Quote:

I am trying to figure out what Stax did with the external ear cup behind the drivers.  Am I wrong or is it somewhat more open and shallow than the 007's which seem to be recessed about 3/8 inch and have something almost like a chamber running around the edge of the driver.

Note sure the following dimensions are clear to understand but here's a shot at it, SR007mkII first / SR-009 second, all in mm:
 
- Internal ear cup depth min: ~25 / ~20
- Internal ear cup depth max: ~30 / ~30
 
- Internal ear cup diameter min: 55 / 60
- Internal ear cup diameter max: 65 / 70
 
- Frame diameter outer: 100 / 103
- Frame diameter inner (i.e. hole on the back): 78 / 81
 
- Frame depth (ear pad seam to the 90 degree bend): 12-13 / ~17 
 
- Stator perforated diameter (as seen from outside): ~55 / ~65
- Stator distance to the rear chamber opening (e.g. hole on the back): 10? / 10?
 
So, it would appear indeed that the rear chamber is more open (steel mesh a bit finer too) but the depth - although the measure I gave is quite approximate and could be +/-3mm off - is the same.
 
Also, please confirm but in regards to the "chamber running along the edge of the driver" you're referring to: isn't it just the non-perforated rim of the stator? In which case, indeed this rim is thinner in the new version with significantly larger perforated area.