So received some preamp valves today, an old Mullard UK made 6AN8A, and new production Tung-Sol 12AX7 and Gold Lion B759. I don't really need the 6AN8A, but I'm getting myself in the habit that whenever I see a NOS one at a good price to snag it, since they don't make them anymore and I might as well start collecting them while they're still cheap. Just did a quick test over lunch time between the Tung-Sol, GL, and the old GE that was already in 2000s #2. I think I've mentioned before, the 1200s and 2000s #2 have always sounded a bit harsher than 2000 #1, though it's probably pretty subtle to anyone not really familiar with them.
Took the GE out and popped the B759 first, having heard it had pretty smooth OD characteristics, a strong midrange and solid though not overpowering lows and highs. They are also said to have good "detail", whatever that means. Took the amp up to 7, which is about the top end of where I like the breakup to be, and I have a good idea of what the GE sounds like there. So I might have actually found the point of too much mids. It honestly seemed a bit boomy in the lows and the mids seemed a bit less detailed or nuisanced than the GE. The highs were definitely tamed, which may be part of the less detail/boom, in that the sparkling highs aren't as present. It also struck me as a bit harsh sounding in the drive. Overall maybe a fuller sound than the GE, but also seemed a bit cloudy.
So next I took that out and decided what the heck, I have a few more minutes, let's try the Tung-Sol. Immediate thoughts were that it sounds much more like the GE than the GL did, and edges the amp closer to 2000s #1. Strong lows without being boomy, taut and punchy midrange, and sparkling highs, bordering on ice-picky. Overall seemed less muffled, a bit more brilliant, and less harsh than both the B759 and GE. I was pretty impressed right off the bat with this one.
I'll get to doing some more in depth comparisons either tonight or this weekend, but I'm surprised at how different they make things sound. I've never really rolled tubes before, and didn't expect that much difference in sound. I'll be interested if I get around to swapping the power valves to seeing what difference there is between KT88s and 6550s, in addition to the preamp valves. At some point I'll pool together all the preamp tubes I have and test them all out through the two different 2000s to get a better idea of how they all change the amps' sound.
