Speaker humming from a new Mcintosh MA252
 

Hi all, i just found that my ma252 having a humming sound from the speakers, not sure since day 1 or not.
humming sound when you put ur ear right next to the speakers.
both speaker and volume does not affect it.
can any of the expert help please?
I have tested all sort of things that i can test so far, nothing work.
tested:
no input.
different power cable,
different speakers,
different power point,
turn off all the power in the main except the audio power point.
test with 2 pin power plug

the humming still there as long as the speaker is connected and the amp is turned on. it's not affecting my listening, but still ignoring.....
may need to take back to Mc to service.......owned it for 3 months only from new....... any suggestion guys?

What happens if you disconnect all other equipment from the 252?
Are they all connected to the same group of outlets or do you have a power strip/power conditioner?

Hi there,
Yes i did remove all input, only power and speaker connected to the Amp MA252, speaker still hum, both channels and increase the vol doesn't make it louder.
all connected to the same power point.
i also tested plug in a headphone and play music to the headphone, the speaker connected to it still hum.
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i also asking mcintoch, but no answer from them yet.
i can only hear the hum if i put my ear right in front of the speaker closely.

If you can't hear it from your listening position, may be considered normal, remember this amp has a tube front end.

Are your interconnects and power chords running parallel? If not try running them over each other but elevated.

You must be new to tubes. In gear with tubes you always roll in new tubes first to see if one of yours is noisy. You only need to purchase 1 or 2 new ones (our own vintage_tubes is a great source for reasonably priced & fully tested tubes - tell him your problem when you purchase). Replace one tube (or one per channel) to see if the one you took out might be the offender. If not, swap the tube in the next position. Tubes have AC on their filaments and can be noisy.

Yes i am new to tube, this is my first tube amp. but this ma252 amp and it's tube, both 3 months old only. noisy from both channel too.
anyway, i am going to buy 4 new tubes to test it.
I also got feedback from other ma252 owner, few of them having the same noisy when they put their ear in front of the speaker.
Thanks

Thanks

What are the speakers you're using?

KEF LS50 and Focal 906

I purchased a 252 and had the hum since day one, took it back a week later for a refund.

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.

Which Amp did you buy?

Ma252
 

Hi, as the thread says this is about the McIntosh Ma 252

I changes the tubes, no improvement there. Also return amp for another. That one also has same exact hum as previous, and as original poster.

I guess they all just hum.....

I am surprised McIntosh do not use DC power for the heater elements - that eliminates heater hum entirely. It's been done for over 50 years now. Might be an inexpensive fix for everyone with the hum issue. Send it to a guitar amplifier technician who knows how to rebuild tube amplifiers, and tell him to add a DC tube heater supply. It's a three hour job at most.

Hello buddy, I have been in your shoes, that Ma252 Hum, cost me thousands of dollars, I blamed the AC of my Home, cables, tubes and Power conditioner. Long story short, I used the refund of the MA252 to buy a MA8900 and I have been super happy with it for more than a year now...

It's a pity that the MA252 has that problem, it´s a very good sounding integrated for the price, but that hum is a complete design and quality flaw. For what I was told, the problem is in the power transformer.

This experience ended with better sound, the new integrated, a pair of super expensive 12ax7´s and 12aT7´s (those sounded amazing installed in the Ma252, but the hum was still there), new speaker cables, a lot of new things learned in the forums when trying to do some troubleshooting and an emptier wallet.

P.S. If you ever know of a good audio product that can take profit of those NOS 12ax7 and 12aT7 tubes, just let me know... I still in love with them and it's sad to see them stored in a box.

very interesting
 

Is your MA252 dead quiet after this fix?. How does it work when using headphones?. I remember that the hum was even more noticeable when using HP.

I’m suffering with an MA8950 leaking, 6 mos old. I purchased Mac cause it’s a Mac. Nuff said. Heading for service soon.