Bought Mark Levinson 433 on 2/9/24 and immediately noticed noisy center channel. Took to Precision Sound & Services, per Davids request, which could not fix problem. David took it to The Tone Garage in Oxnard for repair and returned to me with clean center channel but new popping sound on startup and shutoff. When asked for service report at time of pick up from David, David stated, "I'll see what I can get from them." Popping not a normal sound from high quality amp. David insisted it was a normal sound until I told him I wanted a refund. David offered to pick up amp, service it and return to me to which I agreed. Returned to me with same popping sound and now thumping on startup and turnoff. Stated is was worked on by authorized Mark Levinson repair facility and DC offset was adjusted and everything was "good as new." Returned for a refund on 6/25/24. 4.5 month waste of time, felt David did not want to spend money on a full repair. Amp is in need of input to output repair/probable re-capping. I offered to take amp to George Meyer for repair since my Krell 600c was repaired there 7 years ago and they did a great job. He refused stating he has his, "personal" reasons. Amp was in and out of my system 3 times during the 4.5 month time frame. Amp is now on Audiogon listing "lisb78ae" with him stating the amp noise is normal. I have all communications with David along with videos/recordings of the popping sounds the amp makes as evidence. David will tell you "it was repaired by authorized repair facility and everything is perfect," "that is a normal sound." I never saw a service report from The Tone Garage. Happy to share all communications and videos I made of the amp. read more