6922 Recommendation for my BAT VK-3iX Preamp

Can someone recommend a set of good 6922s for my BAT VK-3iX? Currently, I have NOS Tesla goldpin ECC88s. They sound good especially for piano music. However, violin music still has room to improve. I am wondering if getting a set of different 6922s will improve the violin, without degrading piano of course. :-)

Thanks.