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
You might try some NOS Mullard 6922's. They tend to push the midrange forward, but since I don't know your preamp circuit, I can only guess as to how they will sound in your unit. They may also brighter than the tube you are using now, so you might not get exactly what you are looking for.