Extended Audition: Fascinating Tango and Tamura transformer shootout

Fascinating Tango and Tamura transformer shootout
(From an article that initiated the thread here, on 09/05/01)

"...Sunday 6 pm, just back from the USA, I gave Andy L a call. Guess what, a significant event was taking place at his house, with Thomas, and also Mr and Mrs 徐偉強.

They had been testing various output transformers on Andy's DIY 300B amp. Or more accurately, 300B tubes in Andy's barely modified 2A3 amp. Working condition was ~240V, 70mA. 3.5 wpc by Andy's estimate. Tannoy Canterbury against the wall of course... DIY
6SN7 (using RCA 5692) preamp. Marantz CD7 cdp.

I missed the first contestant, the top-of-the-line (TOTL) Tango 2.7k outputs. Thanks to the ferrying by Thomas, I caught the next contestant, the TOTL Tamura 3.0k outputs. Compared to the next contestant, sound was more musical in the midrange, with silky treble. But the bass was loose, indeed watery. Next was the TOTL Tango 3.5k outputs, which no doubt tighten the sound, with more sharply etched midrange and MUCH stronger bass. However this came at the cost of less subtlety and less elasticity. According to Thomas and Tsui and Andy, the Tango 3.5k was more balanced and extended than the Tango 2.7k.

The important thing is that the difference between the impedance (same grade; 3.5k vs 2.7k) as well as between brands (Tamura and Tango) were CLEARLY and EASILY audible. So much for those people who say only tube matters. I should add the difference between the Tamura and Tango was TOO BIG to be explained by the small difference in impedance.

Which would I prefer? Hard to say. I think Tamura is more musical. With the wroking voltage of 240V, indeed too low for 300B, I'm not sure the results can be extrapolated to a more typical working condition of, say, 450V and 70 mA. Would like to find out though.

Overall, Andy's sound was more musical than before, when I heard the amp as 2A3 (RCA double plate). Of course I was not surprised to find out the tubes used were a pair of 1951 WE 300B. Hmmm...And well maybe sometimes there are multiple sweet spots in operating a tube, and
using lower dissipation should not automatically be ruled out (as people do today, in general working tubes towards the fringe).

I should add that before all this the new DIGNITY AUDIO million dollar 300B amp prototype sounded. These used the REALLY expensive iron, and had been previously reported in Audioboard. Many of us, including me, Captain, Richard Mui, TKL etc have heard the previous incarnation, a good machine that never seemed to saturate. Superior iron no doubt.
According to accounts, the results this time were super-transparency, speedy and detailed, but somewhat lean in Andy's system. Rumor has it that JUST the transformers MAY be available for trial in Andy's amp. THAT would be interesting.“