A couple new tubes arrived in the mail today:
Below are a pair of Sylvania 6AQ6 which combines two diodes with a high-mu triode voltage amplifier. They have 150mA heaters, like the 6AK5, but an amplification factor of 70! Also notice that they have side-getters and the tops of the tubes are clear. As with the 6J4, we need to cut off pins 5 and 6 and set our LD in the EF92 mode to use these tubes.
These particular tubes are fairly old as they have green writing and came in green Sylvania boxes, maybe 1950s?
Next, a pair of Sylvania 6AV6, another two diode/high-mu triode voltage amplifier. These are essentially the same as the 6AQ6 except thay have 300mA heaters and an amplification factor of 100!!! And again, we will need to cut off pins 5 and 6 and set our LD in the EF92 mode.
Later today, I will cut pins and begin burning...
But now I want to revisit the Tung Sol 6485...
I have been a bit bothered by the fact that my experience with the TS 6485 has been so much different than that of A11 and AFB. For the most part I have substantially agreed with their impressions of all the new tubes we have been trying, and it just didn't make any sense to me that my TS 6485 sounded nothing like what they have been describing....
Last night, on a whim, I installed my 1961 Tung Sol JAN-6AH6. I didn't remember being negatively impressed while burning them in a month ago, and thought it might be interesting to listen to them again. I was shocked! I had forgotten how good these sounded! Moreover, they are nothing like my TS 6485?!
For some reason my TS 6485 do not sound like my older JAN-6AH6. And apparently, my TS 6485 do not sound like those of A11 and AFB. But this presents another mystery. Are my mid-60s TS 6485 with square getters an aberration?
Anyway, I am quite sure my JAN-6AH6 sound like Mordy's JTL-6AH6WA. And I am quite sure they sound like A11's and AFB's TS 6485. However, in order to test this further, I have ordered a second pair of TS 6485, but newer, with round halo getters. But for now, I am quite certain we have consensus that these Tung Sols are in the top tier of the best of the best we have tried.
In my mind the Sylvania 6J4/8532W are also in the top tier, but they are somewhat different than the TS 6485. I think it comes down to a matter of taste. Per AFB, the 6J4 are "musical, mellow and a little bassy" while the TS 6485 are "ultra-detailed and balanced -read occasionally treble-oriented- with a great stage." And perhaps one might say, more "analytical". Anyway, I feel that they are equally good, but different.
However, it appears that I am the only one who has listened to the Sylvania 6J4/8532W to date. AFB should be getting his soon, and after a few more people report their impressions, we will know if these Sylvanias are also a consensus top tier tube.
At this point in time, I wholeheartedly recommend the TS 6485 as long as you get the round halo getters. And I also recommend the older mil-spec TS JAN and JTL tubes. These Tung Sols are really, really good. :)
Edited to fix typing error: Should be 6485 and not 8564.
Edited by gibosi - 4/25/13 at 11:47am