Jadis DA50 blown tube

I have used my DA50 for many years without problems. Recently one of the KT88 tubes blew out and there was no sound from the left channel. I took the amp in for repair and it came back working fine with two of the four KT88s replaced.
However, on closer listening, it turns out that the sound from the left tweeter is at a lower level than the right channel. The rest of the mids and bass sound the same. I switched the speakers around and made sure the problem was not with the speakers. I even switched the cables to make sure the cables are ok. The sound especially with vocals, is now skewed to one side. Any idea what could be wrong with the amp, or anything I can try to resolve this? Thanks for any advice.