100% truth .Yes! Keph they are matching & sound very well. That is the ‘’magic’’ possibility of vacum tube amps you can easily change the amp sound signature by simple tube roll off as for the solid stage amplifier could be a bit difficult.
Getting one of the custom mods will be my next step definitely! for now I have to save some funds for summer holiday but after that who knows?
In the meantime I gonna try some other signal tubes ...
The adapter added to LF339 to replace the stock OTK6*4 tube with EF80, it will also works with those pentodes: EF860, E810F and 7778? I think it will but I’m not 100% sure. Keph can you confirm it with Yuking09 also the two 3A fuses in LF339 marked (F)3A/250V which mean (F) fast-blow but for primary side(input) of transformer it should be slow-blow IMO. I’m a bit confused witch type of fuse could be used for further upgrade.
P.S
The gap between the socket and the Tube... sorted out! 
Quote:
Originally Posted by
keph 
The 5998 and the red hots really match well i like the bass out of it..i wish you could here the 5998 with the GEC CV1067 its like the 5693 with better and thicker mids and makes the sound more warm and Tubey hehe..but yeah the downside is that you need to mod the 339 like mine to get the sound i have..I see in ur 3rd pic that you didn't install the right 5998 well enough..seems like there is still a gap between the socket and the Tube..anyways great pic and setup..glad that you like the combo that i suggest...
let me know when u got the audio grade Fuse installed in ur 339..