I recently had the same problems with my KR8000 monos, which use KR KT88 tubes (I believe that these are the same tubes used in CARY amps as they had a partnership with KR Audio).
Within, the next few weeks, expect the popping sound to magnify and reach a point where you will feel as if your woofers will explode.
KR factory, with whom I have good relationship, informed me that they have stopped producing KT88 tubes and amps using these tubes as they were consistently having reliability problems with these tubes. Check their website and you'll see no trace of KR KT88 tubes.
You have to change the tubes ASAP.
Within, the next few weeks, expect the popping sound to magnify and reach a point where you will feel as if your woofers will explode.
KR factory, with whom I have good relationship, informed me that they have stopped producing KT88 tubes and amps using these tubes as they were consistently having reliability problems with these tubes. Check their website and you'll see no trace of KR KT88 tubes.
You have to change the tubes ASAP.