I personally did not like KT88's in the Mini Mono's, liked the 6L6 tubes, but found the Ei KT90's were the ticket. The sound stage became huge with great depth with the KT90's. I liked the mini mono's so much, I moved up to the Mid Mono's and found KT88's were best in the mid mono's. Amps, IMO, are all different and why we roll tubes to find the sound that makes us stop and listen.
Enjoy!
Enjoy!