Supratek Tubes and Tube Swappin' for Everybody

Larry,
Sorry I forgot to address your vibration question. I was using the Symposium Super Plus Platform alone and in conjunction with both Aurios and Final Labs roller bearings (only one brand at a time of course). Surprisingly the roller bearings actually exacerbated the microphonics in my rack but as always YMMV. I then tried the Gingko with and without the roller bearings and after all the smoke cleared the Cloud 11 alone works best. My power supply is sitting on a 2" maple platform from Timbernation which sits on a set of Final Labs Daruma 3; no problems there. Don't give up and you'll find the right piece(s) or combination thereof.
Congrats on the 7308; you're going to flip. They're that good.

Hi Larry. A tough call on the choice of either the 76 or the 6sn7. The 6sn7 uses an octal base whereby the 76 uses a UX type base so there is no substitution option for comparison. The 76 is also a single triode whereby the 6sn7 is a dual triode. The single triode equivalent of the 6sn7 is the 6j5 which is electrically very similiar to the 76 with a slightly higher amplification factor. There are different flavours to be sampled in both choices however my only bone to pick with the 6sn7 is that there are really only 3 or 4 examples of the 6sn7 that will sonically compete with a 76 as well as many other single triodes like the 37,56,7168,6j5,6c5,6p5. The few that do will cost you a small fortune. The only down side to the 76 is it's a 50 year old tube and somewhat difficult to source these days and even then it's only a fraction of the cost of a tungsol round.

Hi Larry. I am not at all surprised that the Grange is sensitive to microphonics when using the meshplate examples of these directly heated triodes.Most of my experience with these DHT triodes is from repairing vintage amplifiers that used them.The early amplifiers that employed these tubes had to deal with the same issue common to DHT tubes. Most of the better amplifiers of the day employed a hum pot in the circuit to trim away the hum and microphony from the amp. A single triode like the 6j5,56 or 76 was also commonly employed as the driver for the DHT output tube in most of these amplifiers. In most cases, the meshplate examples of these triodes are generally far more prone to microphony than the solid plate examples of the same tube,and the same can be said for the driver tube as well. I would think one would have more success using a solid plate version of these tubes in a preamplifier circuit. The old nos RCA 45 is a fabulous tube and far less prone to microphony. I seriously doubt you can find a better sounding tube anyway. The same can be said for the Western Electric 300b for those that can afford them.Hey, it's a great option to have the ability to voice the grange with the different DTH's if one has various a examples of each type laying around.... but if it were me I would lose the microphonic prone meshies like the px4 and be done with it. Hey,I really love the sound of the early nos 6c5 meshie in my cortese, the 6c5 is basically the octal base equivalent to the 76. I had to sort through no less than 16 examples to find a pair that were acceptable for duty in the preamp. With the metal envelope versions of the same tube, not one of them were the least bit microphonic.Unfortunatly, they don't sound the same either.

A dissenting opinion on 76. I'm not a big fan. I have many pairs for my personal use and have sold quite a few in the past, but in terms of sonic attributes, I'd much rather use 6SN7 then 76 tubes myself.

>>I'd much rather use 6SN7 then 76 tubes myself<<

Which is not a bad thing. However Mick prefers the 76 or 37 in the Grange at least. Mine sounds much nicer with a pair of NOS VT-37 (RCA) than the factory supplied Italian made 76. "Different strokes", as Sly used to sing.