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DNA Stratus 2A3 amplifier - first impressions - Page 4

post #46 of 2013
Quote:
What's the weight of this thing?

It's pretty substantial. Donald will have to chime in on the exact number, but my guess is around 20 pounds.

 

Physical size 17" W x 13" D" x 9" H with tubes. In my opinion it's a fairly large amp.

post #47 of 2013

I have not yet measured the amplifier weight directly. Fully packed in the shipping carton, it weighs 32 pounds (14.5kg). Subtract a few pounds for the packaging material and I estimate the amplifier alone weighs 27-28 pounds (around 12.5kg).

post #48 of 2013

I hope one of these somehow makes its way to RMAF!

post #49 of 2013
Thread Starter 
Quote:
Originally Posted by daigo View Post

Thanks for the initial impressions.  Looking forward to seeing more thoughts with other genres of music though :P

 

diago, what genres of music are you interested in?

post #50 of 2013

It looks nice.  I'm looking forward to more reviews.  It's not a hybrid amplifier is it ?


Edited by Audio-Omega - 5/28/12 at 8:04am
post #51 of 2013

No, the audio power supply and amplification is purely tube. The only solid state components are the diodes on the bridge rectifiers for the low voltage DC heater supplies.

post #52 of 2013
Thread Starter 

EDIT - new paragraph --- sorry, I forgot a very important news item --- I replaced the 6N1P driver tube with a cryo'd 1960s NOS RCA 6BQ7a, after receiving the OK from Donald that this tube matched his design parameters and pin assignments. No adapter needed. And the effect was stunning and marvelous - the music became much more clear, actually a step improvement in clarity, a big step. In fact, it now sounds 99% as clear and transparent as my modded Sonnet (in which I installed solid silver Dueland signal wires), which I felt on direct comparison is just as clear as the Apex Pinnacle. And the very special emotional presence of the Stratus remains. This tube cost me $25, and together with the NOS 5U4G and 2A3s, it made the Stratus a top-of-the-line amplifier. And that is why ... [end of edit]

 

I have switched over now completely for instrumental music -- the Stratus with NOS tubes is simply outstanding driving my T1 on a DHC RSC cable.

 

Last night I enjoyed listening to Brahms 3rd Symphony with Claudio Abbado on DG - this time it was clearly a moving, stupendous performance --- crystal clear, noise-free, each section (voice) in its own location within a big soundstage, powerful (the timpani and pizzicato on the double bass were tuneful, controlled, and visceral), and the strings were liquid with incredible timbre and real resin. I could just hear someone breathe occasionally (quite close on the right in the cello or bass section), which I have never heard before on this recording, and, for the first time, I could hear the small timbral differences and place the different violin clusters in that fast fugal section in the first movement - extraordinary!!

 

A truly wonderful headphone rig!

 

So I took the plunge and ordered the Emission Labs tubes - rectifier and 2A3 pair, all meshplate, $862.83 from George at tubeusa (and a deep breath). Hard to believe this will make it even better, but I will let you know.

 

(I will be happy to be rid of the smidgen of gas discharge in the right 1960s NOS RCA 2A3 that remains even after >100hrs.)

 

beyersmile.png


Edited by budx3385 - 5/27/12 at 2:37pm
post #53 of 2013
Quote:
Originally Posted by budx3385 View Post

EDIT - new paragraph --- sorry, I forgot a very important news item --- I replaced the 6N1P driver tube with a cryo'd 1960s NOS RCA 6BQ7a, after receiving the OK from Donald that this tube matched his design parameters and pin assignments. No adapter needed. And the effect was stunning and marvelous - the music became much more clear, actually a step improvement in clarity, a big step. In fact, it now sounds 99% as clear and transparent as my modded Sonnet (in which I installed solid silver Dueland signal wires), which I felt on direct comparison is just as clear as the Apex Pinnacle. And the very special emotional presence of the Stratus remains. This tube cost me $25, and together with the NOS 5U4G and 2A3s, it made the Stratus a top-of-the-line amplifier. And that is why ... [end of edit]

 

 

beyersmile.png

Interesting development on the driver side.  It's good there are inquisitive people like you out there.

 

Next, we need to find out from Donald if the 5U4G can be replaced with the 5U4GB, which has a higher voltage swing.  Now, the results from comparing 2 tubes in one amp does not necessarily apply to another amp.  However, in 2 different pieces of gear, a preamp and power amp, I have found the 5U4GB to produce music that sounds more real and alive than the 5U4G.  

 

BUT, do not substitute this tube unless Donald gives his approval.

 

By the way, did you try Jac Music for those EMLs?  Are the prices really that high?  Also with JAC you get the benefit of the higher exchange rate (for the dollar vs. the €) these days.

 

In my own musical world, I am in the middle - really the start - of a 45 project for a speaker amp and more sensitive speakers.  That got a higher priority after recently hearing 45's in my own system (in which the amps can use the 45 but the OPs are not optimal for various reasons that require a true 45-based amp).

post #54 of 2013

Looking forward to your review of EML mesh vs the black plate RCA!

post #55 of 2013

Nice Bud, thanks for the continued impressions. I dug up some 6BQ7a's from my stash, and look forward to trying them out.

 

I put in some Black Treasure 2A3's last night, but didn't get much listening time in. Hopefully I'll get some more time in the next few days so that I can report back.

post #56 of 2013
Thread Starter 
Quote:
Originally Posted by santacore View Post

Nice Bud, thanks for the continued impressions. I dug up some 6BQ7a's from my stash, and look forward to trying them out.

 

I put in some Black Treasure 2A3's last night, but didn't get much listening time in. Hopefully I'll get some more time in the next few days so that I can report back.

 

I will be looking forward to hearing your description. The EML meshplates have arrived, and they are slowly burning in - they recommend 4 hrs on, then full cool-down, so it will take some days to get 100 hrs on them.


Edited by budx3385 - 6/8/12 at 1:56pm
post #57 of 2013

Has anyone been able to compare the Stratus with the EC 2A3 or does anyone at least have experience with both? I don't have much insight into tube circuit design so I can't even evaluate them from a technical standpoint though I see they use different driver and rectifier tubes and probably different transformer technology. One of the appealing aspects (to me, anyway) of the EC is its speaker outputs. At any rate, any feedback about this?

post #58 of 2013
Quote:
Originally Posted by budx3385 View Post

 

I will be looking forward to hearing your description. The EML meshplates have arrived, and they are slowly burning in - they recommend 4 hrs on, then full coll-down, so it will take some days to get 100 hrs on them.


Although the Black Treasures seems better in some areas, I feel I have lost some dynamics and bass control. From the mid range up the Black Treasures are better, with a warmer mid range and better high frequency detail. Unfortunately to my ears the cons out way the pros, so I will be putting the stock tubes back in.

post #59 of 2013
Thread Starter 
Quote:
Originally Posted by davidross View Post

Has anyone been able to compare the Stratus with the EC 2A3 or does anyone at least have experience with both? I don't have much insight into tube circuit design so I can't even evaluate them from a technical standpoint though I see they use different driver and rectifier tubes and probably different transformer technology. One of the appealing aspects (to me, anyway) of the EC is its speaker outputs. At any rate, any feedback about this?

 

davidross, I haven't heard the EC 2A3, but I have heard the EC Balancing Act with KR PX4s, which produced a mighty clean and juicy sound on LCD-2, but really did not work as well with any other headphone we had on hand to try. I feel quite comfortable in saying that the Stratus with NOS RCA 2A3s, a cryo'd NOS 5U4G and 6BQ7a produces a very comparable, clean, powerful, fully extended, and emotional sound image with every headphone I've tried. My favorite is still the T1.


Edited by budx3385 - 6/4/12 at 8:40am
post #60 of 2013
Thread Starter 
Quote:
Originally Posted by santacore View Post


Although the Black Treasures seems better in some areas, I feel I have lost some dynamics and bass control. From the mid range up the Black Treasures are better, with a warmer mid range and better high frequency detail. Unfortunately to my ears the cons out way the pros, so I will be putting the stock tubes back in.

santacore, thank you very much. I won't be tempted by those any longer.

 

The EML meshplates have about 80 hrs now, and they have changed a bit. They are controlled, fast, very clean and accurate - but dry. They sounded lifeless at first, so they have gained a bit of emotional juice, but they still need to loosen up and relax. When I replace them with the RCAs, the presence returns in spades. Same with the rectifier. I will keep on burning.

 

I'm very tempted to order a pair of Sophia Electric Princess 2A3s. If you have any experience with those, please let me know.

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