DNA Stratus 2A3 amplifier - first impressions
Mar 7, 2017 at 7:28 PM Post #3,241 of 4,456
  Purely out of curiosity, why use the WE275 when they make a direct 2A3 replica? 
 
I agree that Shuguang tubes stride on the warm side.
The Psvane treasure mkii series is on the opposite pretty bright, but exceptional resolution (imo ymmv).


The WE275s have a very liquid smooth sound - more so than their 2A3s - and less problems.
 
Mar 8, 2017 at 2:56 PM Post #3,242 of 4,456
Let me add a couple comment's on my recent post's.
 
I spoke to Sue from Sophia and she said to let anyone interested that the current 5Z3PA production does not sound good. Only the vintage one (no later than 1985). The sound of the 5Z3PA in my system has been changing. Last night, paired with the 300B's the sound proved to be to bright for my HD800's. This morning I rolled in the U52 and next, 40's Sylvania and both toned the sound down to an acceptable level. With all thing's audio it's never a free lunch. The 5z3pa has it's short coming's but so do the other's. I will try it next with the WE275's.
 
On the amount of time it take's the Sophia 300B's to break in, Sue said this, "the tubes will improve gradually until they are fully broken in – big sonic character changes for the first 100 hours, then the improvement will be much subdue for next 200 hours, but still continue to improve." I don't know if the 5Z3PA, being a rectifier, will break in like a power tube or not. But right now it's so bright, it's causing me some ear pain after prolonged listening. The Sophia's themselves have some serious treble response. I may have to re-think this.
 
Mar 8, 2017 at 6:33 PM Post #3,243 of 4,456
Tube rolling and Flagship headphones are just two ways to find the sound you like best.  Another option is to work inside the Stratus and improve the quality of some of the components.  I use very average headphones and I have found that replacing some existing components has a big impact.  The Stellaris goes several steps further.  It has a better power supply, and much better caps and resistors, and OPTs.  I would have liked to have changed the OPTs inside the Stratus, but their design is somewhat unique and hard (and expensive) to improve without shipping the amp off to a custom transformer builder to copy the general design and change the core and winding wires to better materials. As is, I focused on the coupling caps, the 2A3 cathode bypass caps and a small number of resistors. I spent as much on this as I would have on flagship headphones, but the good results are general, while finding the right headphones can vary a lot, depending  on personal preferences for "sound" and the type of music one listens to.  
 
Mar 10, 2017 at 10:40 AM Post #3,244 of 4,456
Here's a couple pictures of the Sophia Princess 300B's. Please forgive poor picture quality.
 

 
Note the new, raised ceramic socket's. They make it harder to put the tubes in wrong.
 

 
Still a great looking amp, the socket's don't detract from it's beauty. That's the 40's Sylvania rectifier and a version of the Voskhod 6N1P driver tube. The Sophia's may be the last power tubes I buy. I don't disagree with Friehd89, and maybe Donald will upgrade the Stratus with some better part's if possible. Knowing Donald he wouldn't do it unless it's a step in the right direction. Tube's are expensive, and so are part's. I like tubes because I get to raise the level of performance in gradual steps. This also make's the Stratus the most versatile amp I could ever want.
 
Mar 17, 2017 at 4:24 PM Post #3,248 of 4,456
  I have a question - has anyone compared the KR's and the Carbon Princess'?  Most specifically, the new KR 2A3's with the white base.

I can only comment on the existing KR audio 2a3 tubes which I've had for a while. First pair failed and second pair are working, but distractingly microphonic. In view of the staggering price of the revised KR 2a3 tubes (I assume you are referring to their new reference HP tubes?)....I personally would not take the risk with them based on my experience with their tubes. The sophia 300B carbons out perform the KR 2a3's on every level and the build looks to be vastly superior.
 
Again, I can't comment on the new KR HP 2a3's , but the older ones weren't exactly cheap and are now expensive ornaments. At close to 2x the price of the existing tubes, they'd also need to make espresso!
 
sbb
 
Mar 17, 2017 at 4:26 PM Post #3,249 of 4,456
  I can only comment on the existing KR audio 2a3 tubes which I've had for a while. First pair failed and second pair are working, but distractingly microphonic. In view of the staggering price of the revised KR 2a3 tubes (I assume you are referring to their new reference HP tubes?)....I personally would not take the risk with them based on my experience with their tubes. The sophia 300B carbons out perform the KR 2a3's on every level and the build looks to be vastly superior.
 
Again, I can't comment on the new KR HP 2a3's , but the older ones weren't exactly cheap and are now expensive ornaments. At close to 2x the price of the existing tubes, they'd also need to make espresso!
 
sbb

 
 
That's fantastic - thank you.  That makes my decision.
 
Mar 17, 2017 at 4:40 PM Post #3,250 of 4,456
I haven't seen too many comments or impressions on the forum regarding Mr Speakers Ether flow headphones with the stratus.
 
I've had the flows for a few months now and I can say this is also a superb match with the stratus. In some ways I think it might even be better than the HD800's. 
 
The 800HD's still come out top for ultimate soundstage and resolution, but the Flows are so close in these areas, whilst improving on a number of others (Bass response and treble) that they have essentially replaced the HD800's for the majority of my listening. It's probably 80/20 (flows/HD800)
 
 
I'll never sell the HD800's and they are still my go-to for classical recordings, but the Ether flow is such a superb all round headphone with none of the weaknesses that the HD800 is known for.
 
For anyone looking for a superb open headphone I think the Ether flow is one of the best, and a great match with the Stratus.
 
Mar 17, 2017 at 4:43 PM Post #3,251 of 4,456
  After much, much ado I am so thrilled to say this landed today!
 
 

 
I remember that feeling! Enjoy!
 
sbb
 
 
More to come on the other thread...

 
Mar 17, 2017 at 4:49 PM Post #3,253 of 4,456
Mar 17, 2017 at 5:08 PM Post #3,254 of 4,456
   
I stand by my previous description of the Sophia 300b sound and my love for it.  I didn't notice much change after the first 20-30 hours, but perhaps that was because I was too busy enjoying the music.  Maybe Stuart will chime in with his experience. 
 
I will remind you that Sophia removes most of the tube rolling risk by offering you return privileges if you do not like the sound.  You are only responsible for shipping costs in the event of a return.
 
Separately, I recently switched playback software from JRiver to Signalyst HQPlayer because I was unhappy with the way JRiver performed with my microRendu.  I grew frustrated with JRiver's inability to consistently find the microRendu on my network. I was SHOCKED at the improvement in sound quality with HQPlayer using only the default settings and no upsampling.  Once I started upsampling and tweaking the settings, the sound improved even further.  I also found that I am able to set my DAC to use the most precise clock setting for the first time ever.  Typically, it only locks on to low- jitter sources, especially at higher sampling rates, implying that I have eliminated most jitter in my system.  I upsample all of my files to 352.8/32, 384/32, or DSD 256 using only PCM to PCM and native DSD to DSD conversions.  Nowadays, I have a hard time pulling myself away from the music. 
 
HQPlayer offers a 30-day free trial if anyone is interested. 
 
Caveats:
 
1.  I have done a lot to isolate my system from digital noise with the microRendu, a JS-2 LPS, and high-quality CAT-5b and USB cables, so it is possible the improvement from HQPlayer is more perceptible starting from a very quiet environment.  YMMV.
2.  The HQPlayer feature set and user interface is not as robust as JRiver.  It is something between Foobar and JRiver.
3.  HQPlayer does not read mp3 and mp4 files.  I used JRiver to mass convert those files to the aiff format.  I found that the 'composer' field in the JRiver tag had to be manually deleted prior to conversion for files containing that information in order for them to be properly displayed in HQPlayer.
 
Links:
 
http://www.signalyst.com/consumer.html
 
http://www.computeraudiophile.com/f26-sonore-sponsored/signalyst-hq-player-101-a-29494/
 
http://www.computeraudiophile.com/f8-general-forum/hqplayer-resampling-filter-setup-guide-ordinary-person-13298/
 
http://www.computeraudiophile.com/f11-software/hq-player-20293/

Sorry guys. I've been travelling for quite a few weeks so missed a few posts. My experience with the Sophia 300b's are similar in that I didn't notice too much change in the first 10-30 hrs. I probably have more than 100hrs now and have switched out a couple of times to compare again with KR audio 2a3's, my original Sophia 2a3 globes and my Nos GE dual mono plates from 1944. 
 
I still come back to the Sophia 300b's for their overall balance, which is exceptional. As the hrs have progressed, I have noticed a slight added weight to the bass....subtle, but welcome as I originally thought they sounded just a touch lean in the bass. Now they sound perfect to me. 
 
The only thing I want to do now is to swap rectifier....I currently have a U52 in place, but want to try the WE 422a again as I haven't tried this with the sophia 300b's yet.
 
Now all is I need is a nice free weekend to do some listening!
 
Mar 17, 2017 at 5:50 PM Post #3,255 of 4,456
I can't recall how my KRs (black base) sound compared to 300Bs. I only remember that swapped out the KRs for the 300Bs and have had no desire to switch back. The KRs are great sounding tubes but I continue to prefer the 300Bs. As said previously they have a more natural cohesive balance. 
 

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