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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
retiredaudioguy OP
330 posts
 

@posbwp55 I did some experiments a while ago.  I generated various mono .WAV files (e.g. square, sin) to provide steady SPLs for a few minutes.  After putting on my hearing protectors I played files, adjusting the volume to give  with 2.83 volts at the speakers.  That is 2 watts (2.83x2.83/4).  At my listening position that yielded 84dB.  

At 4 watts I get 87dB.  That is close to any peak that I want (and above the 85dB safe level) - and 90dB needs just 8 watts.  Listening to Mahler, at the greatest volume I need, I just see 90dB brief peaks.

Live chamber music is, perhaps, 75dB to 85dB - reproducible with about 3 watts.

The PP 2A3s are rated at 14 watts, enough to drive the Atrias to volumes far above a safe level.

At 82 years I am perhaps fortunate in my hearing. Yes, I have lost significant very high frequency hearing but up to A7 - key 88 on a piano (plus a bit) my hearing is "normal".

The sound of my system is exquisite and the sense of air and space is outstanding.  I listen exclusively to "classical" music at reasonable volumes and the power is ample.  There may be musical genres for which the setup does not work - but that is irrelevant.  For people who routinely listen above 90dB - enjoy it while you can.

 

jacklynn's avatar
jacklynn
42 posts
 

Another pump and dump post.Ho hum.

posbwp55
24 posts
 

If you have done the measurements and you’re enjoying the sound, congrats.

I had a pair of Avalon Ascents for 13 years that had the same specs as your Atrias, 87db sensitivity and 4 ohms. I ran them with Manley 350’s. I now have PBN 2!5s at 4 ohms and 96db sensitivity. I use two different pairs of monos, not biamped. I use a Cayin M-845 monos and Symphonic Line 300 monos. The Cayin rated at 60W the SL rated at 300W. I have been swapping them out seasonally. Run the Cayin in winter and the SL in summer. They both drive the speakers but I think the SL better controls the speakers. I have used and preferred primarily tubed gear most of the last 40 years. I think I have now flipped to the SL as being my preferred sound in this system. I use the Einstein Mk2 preamp. It was a gradual 4 years of swapping these amps back and forth, I initially preferred the Cayin but have come to the conclusion that the SL is not just very different sounding but better. What ever works for you. I was surprised to come to this conclusion after 40 years of using tubes almost exclusively. 

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
6,090 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.

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