Question about different tubes


I have a BAT VK30 tube preamp and a VK200 SS amp. The preamp has 6-6922 tubes and presently has upgraded tubes from upscale audio that say -Russian mill gray plate. The original tubes from BAT were Sovtek 6922's. I am driving a pair of Martin Logan SL3's, and the midrange is a little lacking.

My previous gear was Parasound, and the SL3's were so bright it could make your ears bleed!! From prior recommendations on Audiogon, I picked up the BAT equipment and the SL3's are so warm, its unbelievable. The midrange now however, is a pushed back or a little lacking, if you can understand what I'm explaining.

My question is: will a tube change to the original Sovteks or another tube improve my situation? or are there any other recommendations.

I am using a Nordost red dawn xlr between the amp & pre. Speaker cables are Innersound, coaxial biwire which consists of 2 separate runs to each speaker.

I was also wondering if the BAT amp rated at 100wpc @ 8 ohms / 200 wpc @ 4 ohms, and capable of driving to 1 ohm, is enough power for the 4 ohm Martin Logans. Before, I had two Parasound amps in a horizontal biwire doing 400 wpc.

sfrounds
Try made in Holland 6dj8s,they have more mid-range,and sound very good,maybe ask manufacture if okay to run 6dj8,they will substitute a lot of 6922 and 7308,I have some if you need them $15 apiece, thank you Richard, the amp I know nothing about.
With using European tubes on your BAT preamp I would ask Kevin Deal or other Bat gear owners, as if I remember correctly, BAT gears maybe too much for European tubes, what I mean is they may not last long.
It's also worth trying to audition other IC's, changing the Nordost red dawn may just fix your midrange problem. Just a thought.
You might try one of two tubes that I have heard.A Siemens gold pin 7308 or a Lamm Audio 6922.I have the latest tube from Lamm in the front end of my M1.1s and it is very good.Good luck on your tube quest! Tom