DNA Stratus 2A3 amplifier - first impressions - Page 9

Quote:

Originally Posted by Donald North 

I would be suspicious and cautious towards the AVVT 2A3 meshplates. A couple years ago I bought a NOS quad set in beautiful blue glass with the intention of using them in my speaker amps. Before installation I tested them on my Amplitrex and found that they drew substantially higher plate current than the textbook 2A3. In a normal amplifier with auto (self) bias, the tubes would been burnt through quickly. I ended up selling them with the disclosure that they measured different from normal 2A3s and should be used in an amplifier with fixed (adjustable) bias.
 

Thank you very much, Donald. My enthusiasm certainly got the better of me, and I forgot the rule that we have all stated clearly earlier, namely, to be sure to check with you about compatibility before doing any tube-rolling.

Besides, I really cannot believe that I will ever hear headphone music any more beautiful than what I am listening to right now ---  Emil Gilels and his daughter Elena playing Mozart's Concerto for Two Pianos and Schubert's fantastic two piano Fantasie D940 on DG --- through my Bricasti, Stratus and T1. 

Just plain AWESOME.

Thanks again, Donald !!!!!!

Quote:

Originally Posted by Frihed89 

Yes, AVVT had some reliability problems.  There are certain runs that have proven to be fault-free over the years, but I never researched it.  Instead I paid a premium price and trusted my source, who has sold them all.  Other than my previous reference, I have no additional information.  Dennis claims the tubes he bought are fault-free.  He has some comments on AA in the SET forum.

He told me he tests each and finds ~80% good (I think that was the number he gave). Nevertheless, he explicitly said that he will not sell any without them being installed in one of his hand-built monoblock 2A3 amplifiers (~$16K ea).

Like I wrote above, I am VERY happy with the SQ I have now from my M1 > Stratus > T1 using the EML 2A3-S tubes, which keep getting better. And with the Marigo Mystery Feet that Rdr. Seraphim recommended in this thread installed under every component, the SQ is better than any headphone music I have ever heard.

Cross my heart.

Thanks again, Mark!

Quote:

Originally Posted by madbull 

 

Don't you have a less expensive option to suggest?

I'll bet Rdr. Seraphim has some suggestions.

I made one earlier -- the Isoblocks from Mapleshade

http://shop.mapleshadestore.com/Original-Isoblock-1s/productinfo/ISOBLOCK1-ST/

work better than most other feet. If you place a PointPod under each one, then they get much better.

http://store.acousticsounds.com/d/29215/Symposium_Acoustics-Point_Pods_Set_of_4-Isolation_Devices

But IMHO the Mystery Feet really do produce a delicate realignment of phase relationships that simply makes the sound image fall magically right into place!

My tube recommendation list has changed again.

I finally swapped the EML 2A3-S solid plate tubes out for the Shuguang 2A3C-T “Nature Sound” pair that I had purchased from the “shuguangs” store on ebay. (I think they probably mean to call them “Natural Sound”.) On first hearing, I was impressed with their presence on the Stratus, so I left them in place. Now, after only ~30 hrs burn-in, they sound nearly as wonderful as the EML solids. They are detailed, balanced, extended, and full of life. They lack that last iota of realism provided by the solid power of the EMLs, but I have listened to them for >2 hrs in 3 different sittings and I have experienced almost as much musical enjoyment as with the EMLs.

In back-to-back comparison, they have a very slight enhancement in the upper midrange and a very slight reduction in the lower midrange, so that a piano sounds just a smidgen bright, but on the other hand, an oboe sounds more immediately real than on the EMLs.  That small difference in voicing also results in slightly different emphasis, so that particular background instruments (voices) can be more noticeable on the Shuguangs than on the EMLs, and for certain portions of particular tracks, I actually prefer them, but not overall.

I also compared them back-to-back to the Sophia Princess 2A3s on my Stratus, and they won hands down. I found the SQ of the Sophia’s more recessed, somewhat less detailed, and slightly more congested than the SQ of the Shuguangs. Sweet and enjoyable, but not as harmonious, not as convincing. This comparison also revealed the slight voicing difference of the Shuguangs noted above, a factor to the good for the Sophia’s, but in clarity, presence and stage presentation the Shuguangs are simply “mo’ better”, IMHO.

The Shuguang NATURAL SOUND 2A3C-Ts are definitely my second choice for the Stratus now.  Since Donald provides the basic Shuguang 2A3 stock on the Stratus, I wonder if they might let him offer them as an upgrade for a discounted price. I suppose they might require that he sell at least 100 units/month --- but then they certainly wouldn’t be hand-built and tested by Donald, and I for one wouldn’t give that up! Anyways, at $298 a pair they are already a bargain compared to both the EMLs and the Sophia’s!

BTW, in this month’s issue of Stereophile, John Marks recommends quite a few less well-known classical pieces that can be heard on youtube. I’ve never surfed there for classical – I found a dynamite video of Yuja Wang playing Flight of the Bumblebee – wow -- lots more music to discover!