12AX7/ECC83,Mullard CV4004 Mil Spec Box Plates

[Bassmec]

I am sort of finished with playing dual triode swopsies again for a while, I have made my brain go numb. I have good sets of rare Mullard and STC Mil spec Box plates that are surplus to my requirements having gone a bit RCA JAN 6J7 pentode crazy of late.
What are these valves worth anybody, cos I see stupid high prices for these on Ebay. For instance a pair halo getter Mullard 7710, CV4004 KB,QDD Military rugedised copper laced Boxplates in a matched pair (huge low mid). Also a pair of very bright clean sounding STC CV4004's with offsett Boxplates.
I bought a load of rare 12AX7 equivalents from a collectors estate about twenty years ago. Any ideas guys. I would like these to go to pro audio rather than audiofile hi fi anoraks.
Regards.•:*¨¨*:•. ¸¸.•´¯`•.Mark Fairfax-Harwood, Engineer Springvale Studios
http://www.springvalestudios.com