[mulveling]

  I don't like to "voice" systems or paying tons of money for a tube dac/amp with 10% distortion above 1khz.
In my opinion, amplifiers should be neutral and powerful, I like balanced solid states designs, pure class A with no feedback, like Gryphon amps for example.
 
For example "009 sounds harsh", solution: get 007 or another headphone, the problem is 009 not the partnering equipment.
 
That's my opinion of course, not the universal truth.

The BHSE (and I presume DIY T2) has extremely low distortion across the audio band. Justin published some BHSE (though a tube/SS hybrid) distortion numbers a while back -- even without comparison to other amps, they were extremely impressive numbers; no 10% THD in sight. Very impressive especially considering the 54-60dB of gain in an electrostatic amp:
 

Originally Posted by justin w. 
 
I have measured the first BHSE produced in the current batch (not under test in the photo)
 

 
Equipment for THD testing: Tektronix TS-4353/U distortion test set (SG505 MOD WQ, SG505 MOD WR, AA501A MOD WQ)
 
Results @ 100Vrms w/ SR-404 load, RCA input to amp w/ 1.55Vrms sine wave
the 30khz low pass filter was enabled, the 400hz high pass filter was not enabled, which would have improved the results 
Don't remember if this was the left or right channel however both were near identical
 
100hz - .003%
1khz - .0032%
5khz - .0058%
7.5khz - .007%
10khz - .0078%
15khz - .0049%
20khz - .0051%
20khz - .015% (with 30khz low pass filter disabled)
 
Results not comparable to any other amp measured by any other equipment at any other time.

And I've found that I do much prefer to have tube amplification somewhere in my 009 chain. And no harshness in the BHSE/009 with British/Mullard EL34 tubes. But I have heard harshness w/ the 009 in certain other all-SS amps, which I'm pretty sure would measure higher in THD than the BHSE.

 

[ToroFiestaSol]

  The BHSE (and I presume DIY T2) has extremely low distortion across the audio band. Justin published some BHSE (though a tube/SS hybrid) distortion numbers a while back -- even without comparison to other amps, they were extremely impressive numbers; no 10% THD in sight. Very impressive especially considering the 54-60dB of gain in an electrostatic amp:
 
And I've found that I do much prefer to have tube amplification somewhere in my 009 chain. And no harshness in the BHSE/009 with British/Mullard EL34 tubes. But I have heard harshness w/ the 009 in certain other all-SS amps, which I'm pretty sure would measure higher in THD than the BHSE.

 
I know, I wasn't talking about BHSE/T2 (which are hybrid and not full tube amps), I was talking about tube DACs, set tube amps, etc, like the Audio Note level 5 DAC for example.

 

[JimL11]

  The BHSE (and I presume DIY T2) has extremely low distortion across the audio band. Justin published some BHSE (though a tube/SS hybrid) distortion numbers a while back -- even without comparison to other amps, they were extremely impressive numbers; no 10% THD in sight. Very impressive especially considering the 54-60dB of gain in an electrostatic amp:
 
And I've found that I do much prefer to have tube amplification somewhere in my 009 chain. And no harshness in the BHSE/009 with British/Mullard EL34 tubes. But I have heard harshness w/ the 009 in certain other all-SS amps, which I'm pretty sure would measure higher in THD than the BHSE.

I wouldn't be so quick to draw a correlation between distortion and harshness.  When solid state amps first came out, the meter readers were astonished at the low distortion readings they generated, but the ear told a different story.  Now some of that was due to high feedback in those early amps, but even today with low feedback or no feedback designs, solid state designs generally have lower distortion readings than tube designs (check out a few issues of Stereophile, where they regularly measure amp distortion).  IIRC, KG posted that his Megatron, which basically uses tubes for all signal processing, with solid state elements in support roles (e.g. current sources), had around 0.1% distortion, which is 10-30-fold higher than the BHSE, and I haven't heard of anyone complaining it sounds harsh.  And I would be willing to bet that my SRX Plus, which also uses tubes for signal processing and solid state current sources, would measure in the same ballpark.  Now for a little history, back in the 30s to 50s when tubes were the only amplifying devices, the consensus was that THD < 0.1% was inaudible.  Distortion, at least the crude total harmonic distortion, doesn't really seem to correlate with sound quality unless it's really bad.

 

[zolkis]

Is there correlation data between total odd harmonic distortion and subjective sound quality of amps?

Also, there is an opinion that tube amps tend to have mostly even harmonic distortion, and most transistor amps have mostly odd harmonic distortion, but I wonder what actual data we have on this, and also on the correlation with subjective SQ.

 

[zolkis]

 
There is an Omega for sale, 9000 euros. 

 
That is completely out of reality. That Polish guy is known for testing the market on how much crazy guys are ready to pay for an available rarity.
 
The last SR-Omega sold for 4.454,86 euros + 13 euros shipping on ebay Germany, and that's European price, i.e. higher than usual. Even that is half of what this guy is asking, and he keeps fishing. 

 

[3X0]

I think the most recent listing for the Omega that sold in the classifieds was actually asking for $8000US. No idea whether it sold for that much but it was spoken for within a week or two.

TBH it should certainly be worth more than the R10 or HE90 (on the basis of rarity and performance), either of which are fetching absurd prices right now.

 

[Blackmore]

Stax should release them again.

 

[zolkis]

  Stax should release them again.

 
I agree... I guess that's what the 009 was meant for. But I think the SR-Omega diaphragm cannot be made anymore?
For what it's possible in reality, I'd be very interested in a 009 with tonality closer to the 007, or the SR-Omega. 
Perhaps using slightly thicker diaphragm would help achieve that, but I am pretty sure Stax did their homework on that .
 
BTW the 009 pads can be modded to do something like that, in two ways:
- change the white styrol part of the pads stuffing to wool felt ring, or
- add a crescent moon shaped thin foam strip to elevate the back of the stuffing a bit more.
 
Both will make the sound stage larger and the bass more prominent,  cut some of the 4K peak, and tame the treble (the first will tame the treble a bit more than the second).
Materials do matter: wool felt density and make, or foam density and rigidity.
 
However, after a while I reverted to the original pads, as overall I found they were closer to neutral with classical music. However, for other genres (jazz, instrumental, electronica etc), or just for more fun, the mods did make a positive impact.

 

[purk]

I think the most recent listing for the Omega that sold in the classifieds was actually asking for $8000US. No idea whether it sold for that much but it was spoken for within a week or two.

TBH it should certainly be worth more than the R10 or HE90 (on the basis of rarity and performance), either of which are fetching absurd prices right now.

I once had a chance to buy one for around $2000 on ebay....what a major mistake!

 

[Tinkerer]

  I once had a chance to buy one for around $2000 on ebay....what a major mistake!

There were three that went for a little more than $3k on yahoo.japan just this last year. And original T2 #33 for similar money.

 

[Blackmore]

The link I found, yahoo I mean, T2+Omega were sold for USD 23k just a little over a month ago.

 

[yates7592]

Any other thoughts on Omega vs 009 out there?

 

[Pale Rider]

I heard an Omega years ago, but not in a comparative setting, and certainly have not been able to recently. 
 
I have an SR-007 Mk1 [serial number 71xxx], and I have been listening to it quite a bit on my Carbon CC amp. I don't know that I like it better than my 009, but I like it different. A touch more lush, less hyper-resolving. I know that many refer to the 007 as "dark," but that's not a word I would choose.
 
I have another set inbound with a lower serial number to see if there is a discernible difference. And in the meantime, I will be on the lookout for an original Omega.

 

[Tinkerer]

  The link I found, yahoo I mean, T2+Omega were sold for USD 23k just a little over a month ago.

Yeah, prices are a little high the last few months. Used to be you could grab all sorts of lambda frame headphones for under $200. You can still get some of the old amps like the SRM1, SRA 8,10S,12S for pretty cheap though.
 
Oh, saw one of those 4070 TV station special edition closed lambda up right now. It's about $2k. Always cool to see the oddballs pop up.

 

[Tinkerer]

  I heard an Omega years ago, but not in a comparative setting, and certainly have not been able to recently. 
 
I have an SR-007 Mk1 [serial number 71xxx], and I have been listening to it quite a bit on my Carbon CC amp. I don't know that I like it better than my 009, but I like it different. A touch more lush, less hyper-resolving. I know that many refer to the 007 as "dark," but that's not a word I would choose.
 
I have another set inbound with a lower serial number to see if there is a discernible difference. And in the meantime, I will be on the lookout for an original Omega.

Let us know the comparison between both when you get it in. Always interested in hearing the impressions between the 007 versions.