Lab12 Melto 2 - tube rolling

i have literally a couple hundred 6dj8/6922 type tubes from years of running c-j and arc gear, mostly collected in the 80s 90s 00s - usa western eastern european as well as japanese origins

happy to help if there are some varieties folks here may want to try

Audphile, were those all new in box tubes you compared?  Differences can be due to age of the tube. Tubes lose transconductance as they age.  But I certainly do not doubt you hear what you hear. I hear differences between a 12AU7 and a 12FQ7 used as a CF in my Quicksilver preamp, even though those tubes have identical specs.  The FQ does draw twice the filament current of the AU, so somewhere in there may be a key to the sonic differences.  The difference is decidedly in favor of the FQ way over the AU, in this case.  My other point was that the sonic difference probably would be lessened in the presence of a CCS, and for the overall better than eithr tube without a CCS.

@lewm the tubes I borrowed from my buddy: Siemens are from 1976, the Russian 6H23P EB are between 20-30 years old.
The EH tubes that came stock with the phono stage are from 2022.

I ordered the current production Gold Lions to baseline against the NOS and help with the decision making process on how to proceed. 

@audphile1 

Not a Melto owner, but standard EH tubes are junk and their best tubes are Junque.  I have 6dj8/6922 in a few things and I have had great luck with NOS Amperex gold pins and even the Bugle boys are are pretty darn good. 
All the best.

Thanks @curiousjim 

Looks like Brent Jesse sold his business when he retired so the new owner will be restarting the orders soon. I’ll investigate the amperex and bugle boy. Plenty of variations there at different prices for this tube. I used to run ARC preamp with Bugle Boy years ago. They were definitely an improvement over the sovtek and EH.