Best 6JN6 for Berning ZH-270

What is stock?
It doesn't really matter because tube cliches always are true. For instance the oldest version is better than the latter production.
The European brands if not under some communist or dictator's government are better than the U.S. versions.
If you like a clean strong signal which to many may seem sterile use West German Siemans or even better fine filament Telefunkens.
If you want warmth and musicality then use the oldest Blackburn Mullards you can find.
If you want detail and holographic imaging the the Heerlen early 60s Amperex will be your best choice.
The American tubes are the sleepers here, try the RCA clear top or Sylvania Gold Brand. The black glass tubes are best however and they were all made by Tung Sol no matter what the label says.
If there is a choice always get the gold pin version.
The industrial or military tubes are rugged/durable and less prone to microphonics .
The mislabled Japanese Matsushitas are great for the money.
The JAN from the 80s are cheap and sound thin.
The NOS Russian version is better than all of them but avoid the new production like the plague.
The obscure drop in replacement was half the price until the supply dried up.

I've found only slight differences between 6JN6 in any Berning amplifier application (well, in either the EA230 or the ZH270). There are subtle differences to be sure, and a cryoed tube will most likely be slightly quieter than an uncryoed tube. I've used GE, RCA, Sylvania, Amperex and Zenith, and they all perform well.

The key in the ZH270 is the driver tubes - these will have a much larger sonic impact IMO than changing the output tubes.

Mechans, I appreciate your information regarding tubes in general, but to my knowledge, there is no Russian or JAN version of the 6JN6 from the 80's, nor is there a gold-pinned iteration, nor was it ever manufactured by Siemans or Telefunken, nor was there a black-glass Tung Sol. As a horizontal output amplifer (Compactron) for TV sets, this tube pretty much ceased production in the mid-70's, and being an American invention, I am not aware of many foreign sources for this tube.

Good listening,

-Richard

My experience with Milbert(Berning designed) is that Sylvania is the best 6JN6. Like most amps they are much more sensitive to input tube selection than power tube.

Most of the other 6JN6 are rebranded Sylvania.

6JN6 was originaly a TV sweep tube. I have never seen any foreign examples or gold pin versions.

John C.

Mechans just summarized every tube post that I've ever read. Cheers,

Spencer

Thanks for all the very informative responses. I also feel that Mechans is commenting also on the 12at7 and 5965, and it is very helpful. I am doing the tube switchings for my ZH-270, so any suggestions on tube switchings for ZH-270 are very welcome.