Best M8080 NOS tube for CJ preamp line stage?

Jeffrey, on the MET-1, how did you determine which tube goes with which channel? Is it something I missed in the manual?
Thanks.

Billimbriale, no, you didn't miss it. I suggested years ago to c-j that they include that info; apparently they're still not.

Looking at the face of the unit, the front row, left to right, is LF, RF, LR, RR. Rear row is C and SW, left-to-right.

You have one? And enjoy its sound? I LOVE mine, and it sounds even better after I replaced the front-L/R channels' coupling caps* with SoniCap Platinums (Teflon-film) and the PS small-bypasses** with Platinums and Jupiter HTs. E-mail me (address in 4th post above) if you'd like pics.

* Originally, large 'propylenes bypassed with small 'styrenes
** Originally small 'styrenes.
.

Dre, Here is how the tube reads, top to bottom:

000-458
CV-4058
KQDD/K
80-45

Dre, just discovered this online:

6C4 tubes are available from Watford Valves of England as the Mullard CV4058 (military number) which is also known as a KQDD/K or M8080. These tubes are the best 6C4 variant that money can buy, and Conrad-Johnson uses them in their new PV-14L audiophile preamp. They told me they have never found a better 6C4 tube. They were made for Britsh military mobile radios and can really take a thrashing, as well as a minimum 10,000 hour useful life.

http://www.rickresource.com/forum/viewtopic.php?f=1&t=13899

Looks like CJ did me right. Wondering what they recommend for the phono stage--but the genalex sound better than those electro-harmonix 12ax7's that were in there initially.

Sometimes I feel like I need two amps--one for acoustic and the other for electronic music. The CJ MF2250 has never sounded better on acoustic folk and jazz, thanks to the tube replacement in the PV-15. And it's not even the "a" version. I'm driving Dali Helicon 400's, and have a Rega DAC with a Cayin CD-t23 transport, and a VPI Scout with an ortofon 2m black. looks like i can wait a while before I upgrade my amp. Still thinking about a butler or a moscode, a VTL or a Cyber or a Rogue, or a Cary or a Cayin. lol. i just don't think a 2500a would be a significant enough upgrade for a larger living space. But right now I'm happy with this set-up in my tiny 12x11 bedroom.