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I think I have found the End Game Amp

For the past couple of years I have been searching for a power amp that plays well with the highly resolving nature of the Esoteric K-01XDSE source and the Rockport Atria II speakers.

How do I get a mid-range to captivate without losing the sense of air and space?

The K-01 and the Atrias deserved something great in between but I could not bring myself to spend $25k - $50k if I went all out on both pre and power.  Building an amp is surely easier than building transducers?

The closest I came was with a Cary SLP-98 pre - with NOS RCA 6SN7s and the Elekit 8900 running Black Plate 2A3s.  There was not quite enough power, slight sounds of strain at fff and not quite the warmth in the mids.

I was enamored of the 2A3 sound and wondered if there exists a PP or PSET 2A3 amp, so I discovered and contacted Frank Ng at Triode Labs.  He had recently found a pair of Tamura OPTs and Tango chokes and had built a pair of the PP 2A3 GT-C amps that I could have immediately!  Working with Frank was an absolute joy, getting a story of his constant search for the Tamura OPTs, and seeing his views on various tubes.

He gave me great price (he supplied only the 6SQ7s) and I was able to pay through PayPal - I rounded up (dividing by .96) to cover the fees.  I got him to autograph the base plates!

The shipping boxes were superbly protective but easy to unpack.

Even cold out of the box I could hear something special; there is just a natural quality to the sound.  The amps now have about 30 hours and Frank expects break in to be about 200.

Everything I play sounds - I am not sure of the word - but "right" seems to fit.  I have played everything, from Angela Hewitt's Goldbergs - you can clearly her management of tone from her Fazioli piano - to Simon Rattle's Mahler 7 (Bavarian Rundfunk).  Also the Borodin recording of Shostakovitch quartet 9, the Beethoven op.132, the Sveshnikov Rachmaninov Vespers with Klara Korkan's haunting mezzo, Hilary Hahn playing Bach.  AMAZING!

There will be some tube rolling to fine tune (!) everything but at this time the SLP 98 has coin base a 6SN7 gain stage, Tung Sol buffers.  The GT-C has Motorola branded 6SQ7s, Smoked glass RCA 6SN7s, JAN Black Plate 2A3s and Sophia 274B rectifiers in the main amp..

 

 

 

retiredaudioguy
markw1951
55 posts
 

I'm also a tube guy.  I build my own.  No solid state device I've ever heard comes close but my experience is somewhat limited.  

curiousjim's avatar
curiousjim
6,095 posts
 

Congratulations!

How cool is that, to have something like an amplifier made just for you.

Keep us posted when it’s fully broken in and what tube rolling you do.

All the best.

retiredaudioguy OP
330 posts
 

Probably not fully broken in, 60 hours so far, but I spent yesterday pm playing with tubes.  My preamp is the Cary SLP-98 so that features in the quest.

What sounds best (so far) is:

SLP-98 Gain JAN RCA Smoked Glass 6SN7
SLP-98 Buffer TungSol 6SN7
GT-C Gain JAN Sylvania NOS 6SQ7
GT-C Splitter-Driver LinLai Sapphire 6SN7
GT-C Output JAN RCA Black Plate 2A3
GT-C Rectifier Sophia Aqua III 274B


For fun I fed this combination to Google AI and got approval (others did not).  In particular it recommended NOT to use NOS tubes in the Buffer positions of the SLP 98 as they are driven quite hard and could die prematurely - also make the sound too syrupy (agreed).  When I state that I listen at fairly low volume the AI response is (just) approving of the total system - even my Atria II speakers. Tongue in cheek here, but the AI summaries did give useful hints.

The JAN Smoked Glass tubes (how I had a pair I do not know - they are about as common as hen's teeth - but I have found a pair for spares) these do magic in the mid range.

The TungSols are meaty - both in sound and construction and so can handle the demands as buffers.

The 6SQ7, transparent and musical

The LinLais, airy, extended.  These made the sense of space much more real than NOS tubes.  I cannot try these in any SLP-98 position as the bases are too big.

RCA 2A3s, seem liquid and natural, I do not have a quad of any other variety.

The resulting sound, within volume limits, is as good as I have heard.  I did play Rattle's Mahler 3 (CBSO)  with 92dB peaks which is loud enough for me! The Sveshnikov Rachmaninov Vespers' a cappella voices are sublime.  In every work, in good recordings, pianos, strings, brass and woodwinds just sound real.

Bad recordings stay bad.

 

 

lumakuu
8 posts
 

I haven’t been around those speakers nor the amps but I’ll reiterate another poster’s sentiments….2A3 not the best pair up with those inefficient Rockports

pindac's avatar
pindac
4,072 posts
 

 The 6SN7's will find a very special synergy if worked with Power Amp Input Tubes, as the investigation.

Not cheap, but 1950's RCA 12BH7A Long Black Plate Valves receiving a signal from a 6SN7 Line Stage could become substantially more than the sum of the parts.

The idea of all four 6SN7's not having to be a matched quad helps, as 2 x matched pairs is an option as well. 

Whatever the permutation, I have about $600 as the price if Vintage Valves are the selected models. How does proving Valve purchases made are measuring near factory spec after receiving any purchased Input Valves get managed??     

 

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