(Tung-Sol 6DN7's)
I managed to score a pack of five NOS Tung-Sol tubes which i have been looking for since i bought this amp, they are by far the rarest of all the 6DN7 tubes. I blame Doc for this due to his comment about them sounding a bit different on the forum
The construction and plates are a little bit different to regular GE/RCA tubes, the first sections have black plates, the second sections have grey plates, and they have a D shape getter mounted on the side of the first section which is unique. Every other tube i have seen has had an O ring getter behind the second section.
First thing i did was plug into into my tester and measure the output, results were a bit all over the place, for five NOS tubes from the same batch i was expecting a bit more consistency. I also noticed they all measure close to the rated 40ma for the second section as per the datasheet, where as most of my Sylvanias measure higher in the 50ma range which is interesting, and has me wondering if this contributes towards my preference for them having a slightly stronger output.
So how do they sound? They have less of the midrange tubyness the Sylvanias have, or if you like they are a little less euphoric. Low end is similar, possibly more extended, but cleaner and better defined. The high end is also clearer and more extended then the Sylvanias. Overall i think they are a more balanced sounding tube vs the Sylvanias that seem to emphasize the midrange more. There is some other quality to the Tung-Sol's i haven't been able to pin point yet, they just sound a bit different, but in a good way.
As with all the 6DN7 varietys were not talking a night & day difference, its more subtle to the extent it takes a pair of headphones and some careful listening to pin down the differences. Having said that i would confidently take the Pepsi challenge on GE/RCA vs a pair of Sylvanias or Tung-Sols, the difference is enough to be able to single them out, and enough to make them worth seeking out.
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