new to tubes

+++ The 84's are usually transferable with 6550's and KT 88's +++

Not sure how a KT88 or 6550 will fit into an EL84's socket or vice versa. The EL84 is a much smaller tube. They [KT88 & 6550] use identical tube sockets to EL34s, 6L6s etc and these tubes are interchangeable in many amps.

KT88, 6559, EL34 are NOT interchangeable with 300Bs

Regards
Paul

Sorry, but you cannot use teh PX25 or 300Bs in your system. I was just using the 300B and PX25 as an example of tubes that have generally acknowleged sonic signatures, because the previous comments stated that the sonic signatures were totally equipment dependent, and that is not true. With the tubes that you have mentioned, the EL34s will give you the best mids, the KT88s the biggest soundstage and a technicolor presentation, and I am not familiar enough with the 6550s to give you a fair assessment.

Thanks again guys for your feedback and clarifications. Saki70 the amp is Sound Quest SQ88, my first foray into tubes. I have only listened to it for about 10 hours so far and already enjoy it. Though I am keeping my Plinius 8200 and Portal Panche, the more I listen to the SQ it may have me hooked on tube amps going forward. The amp comes with Shuguang (Chinese Military tubes), seem good across the range; but I will be interested in hearing other tubes after the amp break-in awhile.

My bust , sorry for the incorrect info .

Facten ; welcome to the tube side !
Enjoy .

I'm late to this thread, but wanted to ask what brand of KT88 people like the most. I'm sure each brand has a different sound.