Speaker humming from a new Mcintosh MA252

[ps7256]

Which Amp did you buy?

[Jim B]

Originally Posted by ps7256

Which Amp did you buy?

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.....

[cheater]

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.

[AudioFi]

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.

[AudioFi]

Originally Posted by cheater

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.

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.

[Xtraheadroom]

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