Just to add my personal experience, my new Ma252 is dead silent, ear to speakers, with a silent test track playing 100% volume. I will keep an eye on it for this hum.

If you own an MA252 and like everything but the hum, try rolling in a set of Gold Lion tubes that have been tested by the seller (Tube Depot, whomever). Would not be the first time an OEM provided a noisy set of tubes to their customers.

I emailed McIntosh about this.Their answer is that it is to be expected with tubes running the pre amp functions....anyway I have this in my system but you have to place your ear within a centimeter of the active speaker drivers.

Gabe

Speaker humming from a new Mcintosh MA252
 

Just had tube issue, significant hum and fizz. Replaced my Tubes and audioquest interconnects and PS Audio AC3 Power cable. Now back to velvet blackness.

I also have buzzing MA252.... Speakers emit 60Hz buzz even when volume is set to 0%.
Moving volume to 100% just adds extra low "Shhh", but the buzz is still there...
I have Panamax M5300 to filter AC noise and Emotiva CMX-2 to block possible DC.. Still buzz... Not very loud, you have to be within 1-2 feet from speakers to hear it, but it is there..always...

Sounds like McIntosh has a QC problem with this line. How are they letting those units out the door? :scratch2: For them to reply via email that a hum/buzz is to be expected (just the nature of tubes) is a blow off statement IMHO.

I feel bad for the members who trusted the brand and then have to put up with that annoyance. If it were me, I would have sent the unit back ASAP and demanded either a non-buzzing unit or a refund.

Had the hum/buzz issue last June with new MC452, Non-Tube. Took it back to dealer and ordered a new MC462. The MC462 was dead after 3 weeks of use. Exchanged for another new MC462. This one has been working well since October 2018.

Just incredible! What's happening to this company? Not good, no matter how they try to spin it. :no:

It is a great question. Do not know what is going on. I remember hearing that it was maybe a ‘bad batch’ of parts, but QC does come to mind.

Any update on this? I just bought an amp with identical issue. About to change tubes to see if that corrects hum.