DNA Stratus 2A3 amplifier - first impressions
May 6, 2016 at 6:37 PM Post #2,762 of 4,510
   
They can be, but it depends on the amplifier too. With my EC 2A3 if I was tapping the case I would get an echo from the KR (and some other tube makes too). With the EC Studio, I am not getting this at all. This is using the same pair of KR with both.
 
Obviously unless someone has a hobby of tapping the case while listening this is not an issue during normal use.

 
Agreed that tapping on the case is not a normal occurrence but I haven't experienced anything so extreme before and I have a lot of 2A3 tubes (EML, Psvane WE275 and WR2A3, RCA, Sylvania, Shuguang Nature Sounds - I think that's it). I was thinking it was a good thing I listened through headphones because vibrations from a speaker in the same room might lead to a feedback loop. I'm NOT complaining - I enjoy the tubes very much and it doesn't present any real problem. It just caught me by surprise. Weird that the amp itself could play a part. So, maybe whatever causes this phenomena is also responsible for the great sound of these tubes.
 
May 6, 2016 at 7:50 PM Post #2,763 of 4,510
  Glad the KR 2A3s work for you!  How do they compare to the Shuguang Nature Sounds with your LCD-3s?


I liked the Shuguangs better when I had my Beyer T1s. Not so much with LCD3. To my ear (and after very little listening or burn-in) the KRs are more dynamic, open and airy than Shuguangs. The Nature Sounds always leave me wanting something - they are nice, full sounding tubes but kind of boring (to my ears). For a full, rich and refined tube, I much prefer the Psvane WE275 over the Shuguangs. I need to spend more time with the KRs but I know I prefer them to the Nature Sounds and, so far, I prefer them to the EML meshplates too. I just don't know yet if I prefer them to the Psvane WE275s or WR2A3s. I'm sure a lot has to do with the type of music I listen to which is mostly rock, blues, country, folk/americana and jazz - very little symphonic/orchestral music.
 
I'm not a lover of 6BQ7 driver in the Stratus but might be an interesting match with the KRs to warm them up a touch. That may be my research project for this evening.
 
May 7, 2016 at 8:55 AM Post #2,764 of 4,510
Interesting that you mention microphonics.  The KR is actually the least microphonic of all the tubes I have right now.  Just tapped on the chassis and couldn't hear a thing unless it was tapping right next to the tube.  Even then the microphonics were minimal.
 
The AVVT mesh that I currently have has the most microphonics. 
 
May 7, 2016 at 12:56 PM Post #2,766 of 4,510
  Maybe they will stop being so microphonic?? My Shuguang Naturals were really sensitive like that. My dog's barking could set them off. Seems like they have gotten better over time. Is that possible??


The microphonic isn't really and issue except that I found it very difficult to adjust the pots for each tube because just the movement of the pot caused the microphonic making it difficult to hear if I was increasing or decreasing the hum. Even more confusing to me that vc1187 says they are his least microphonic tube. Oh well. I guess hand made means differences like these. I still love the tubes - even more after listening more. At first I wondered if they might be too analytical but I also notice there is a realism I haven't experienced with other tubes.
 
May 9, 2016 at 10:20 AM Post #2,767 of 4,510
 
The microphonic isn't really and issue except that I found it very difficult to adjust the pots for each tube because just the movement of the pot caused the microphonic making it difficult to hear if I was increasing or decreasing the hum. Even more confusing to me that vc1187 says they are his least microphonic tube. Oh well. I guess hand made means differences like these. I still love the tubes - even more after listening more. At first I wondered if they might be too analytical but I also notice there is a realism I haven't experienced with other tubes.

I agree.  They sound convincingly real and gives the Stratus more clarity.  I think that the KRs do micro detail retrieval better than the other 2A3 tubes, which is why they may give the impression that they're analytical at first.  It's pretty hard to explain their sound, as they're very detailed tubes with a very spacious soundstage but yet remain musical!
 
May 9, 2016 at 11:04 AM Post #2,768 of 4,510
  Experiences with 6 headphone amps, the HD650 and HE400i
 
If you look at my audio inventory, I have 2 headphone amps, 2 power amps, 2 prs monoblocks + a headphone adapter that can turn the 4 speaker amps into headphone amps

Share your sense the horns are special, though I was in Lowther camp and have a similar amp inventory.  Would be interested in the adapter you are using, a description would be very helpful and your impression whether it affects sq.   
 
gl
 
May 9, 2016 at 11:34 AM Post #2,769 of 4,510
It's made custom by Blue Circle Audio in Canada.  It can be set four 8 and 4 ohm inputs (speaker outputs on the amp).  The output has variable impedance by attenuation.  You simply attach the cables to your speaker cables to the adapter, which will take both bananas and spades.  There will be some noise as speaker amps aren't as quiet as headphone amps as a rule.  Gilbert Yeung, the owner/designer, will make it fit your needs.  Tell him you were referred by "chowder head".  
 
May 9, 2016 at 11:40 AM Post #2,770 of 4,510
I have never experienced a microphonic output tube in SET or PP in any amp.  AVVT tubes had pretty poor QA, or so I am told.  My solid plates do not have a problem.  I've never owned a KR, but i do have some Shuggy KT88s and 300B, also no problems.  You should have mailed the tubes back as soon as you received them.  There really is no other cure.
 
May 9, 2016 at 1:44 PM Post #2,771 of 4,510
  I have never experienced a microphonic output tube in SET or PP in any amp.  AVVT tubes had pretty poor QA, or so I am told.  My solid plates do not have a problem.  I've never owned a KR, but i do have some Shuggy KT88s and 300B, also no problems.  You should have mailed the tubes back as soon as you received them.  There really is no other cure.


They have a 90 day guarantee and I have reported to the seller (Tubedepot) and awaiting a response. I may return them as you suggest.
 
May 9, 2016 at 2:14 PM Post #2,772 of 4,510
 
The microphonic isn't really and issue except that I found it very difficult to adjust the pots for each tube because just the movement of the pot caused the microphonic making it difficult to hear if I was increasing or decreasing the hum. Even more confusing to me that vc1187 says they are his least microphonic tube. Oh well. I guess hand made means differences like these. I still love the tubes - even more after listening more. At first I wondered if they might be too analytical but I also notice there is a realism I haven't experienced with other tubes.

FWIW, my issues with microphonics suddenly disappeared. It was occurring with one tube only, and has surprisingly completely vanished (knock on wood). It may be a phase tubes go through if they remain unused for a while. However, I have read in places that it's possibly the beginning stages of a tube going bad as well. Best of luck to you.
 

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