[Hydro]

I have rolled a lot of tubes in my 400 and 600R amps. NOS Mullard tubes have a great soundstage with more depth than any other tube, they also have a more "tube" sound as in lush. Gold Lion cryo tubes are more neutral but still have the huge soundstage. Sylvania are the brightest tubes that still have good bass, excellent imaging, about half of the Sylvania tubes I have tried are at least a little microphonic. Tung Sol are bright but thin on the bottom end. RCA are very neutral but don't open up like the Mullards and Gold Lions. GE JANS are really good tubes in all respects and could be a great choice in some systems, but I like the Mullards the best

[tonyptony]

I like the Valvo 6201 Blues the best.

[Hydro]

Valvo didn't  make their tubes, just sold others under the Valvo name. Where were the 6201's you have made, tonyptony? If in West Germany they are probably Siemens, Holland would be Amperex or Great Brittan would be Mullard. Valvo tended to sell premium tubes from whatever manufacturer they bought from. 

[aln]

Great stuff here-I am using the Sylvania 6201 gold pin in my 600R but want to try something different in the near future.  Thanks for the great ideas!

[tonyptony]

Valvo didn't  make their tubes, just sold others under the Valvo name. Where were the 6201's you have made, tonyptony? If in West Germany they are probably Siemens, Holland would be Amperex or Great Brittan would be Mullard. Valvo tended to sell premium tubes from whatever manufacturer they bought from.

Hydro, better late than never I guess! I’ve been putting a new house together so I’ve been away from the sites. I’m pretty sure my Blue labels were made in Germany. They are pinched waist varieties, although I know there were a number of variations in these. Most of what I have are df1 variants. A few of other dc variants.