Mcintosh 250 Transformer Hum Normal

I had not noticed till today as it was very quiet here, I notice a slight hun from the unit, Nothing from the speakers.

Again I do not recall it but I had never had it on in a very quiet room and you have to be very very close (like right next to it) it could be that i just have very good hearing in that frequency range ;-)

If this is not normal what could cause it? The unit does not run warm and sounds great.
It very well could be.

Worth checking if it's responding to DC on the line. Turn off everything else in the home, via breakers, and see if it goes away. :)

Even if it is DC, it's not harmful, and the only negative effects are your level of annoyance.

Hi Escorial, you could ask a shop to borrow a dc blocker for power amps and see if it helps... This could reduce or eliminate the hum and even improve sound quality, should dc on the ac line be indeed the problem
Problem is not the wiring, have a Macintosh 6100 here also,  that is dead quiet even if you put your ear right to the cabinet.

Its the 250 transformer Im sure and annoying as heck.

I have it in my bedroom and like listening at low levels through the night. I can hear this at over 12' away.

The dealer gave it a 30 day warranty,  sadly to say its going back. Its a  beautiful example but ...

Back to the Dc blockers, its not the AC here. I have other receivers and and some tube stuff and nothing make a hum like this.

House was rewired less then 8 years ago.

This amp would be great for a loud environment but not good for my application , plus these products are supposed to be quiet. So there is something going on and perhaps on the way out.

I did check to see if the mounts were loose and nope that was not the issue.

Its either the transformer going or something else causing the transformer to act up but at this point itys under warranty and Im not screwing with it anymore

Thanks all

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Im sending it back, discussion closed...
Just wanted to clear this up. This was a Ebay purchased, seller dealer offered 30 day returns.

Dont care what transformer is in it or not ,nor about my ac here.

Have plenty of audio stuff here and have the common sence to know when something is not right and there is a issue.

Have been reading on this issue and it does happen for many different reasons.

Transformer being loose on the base, inside of the transformer loosening up and have read re- shellacking it, having it rebuilt or replaced, or something electronic wise is going south.

I did not buy this as a project , this was supposedy checked prior to the listing and the seller offered a 30 day return for faulty item.

Had they not been states away I would of ran it over and had them repair it if it was possible.

This is not the issue, there is someyhing wrong with it perood and its going back.

Its a beautiful piece but there is something wrong and for what I paid I would expect it to be working %100.

Thanks again for the thoughts and again consider this issue closed.

  • Just from a Google search

  • a lamination, winding or clamping screw in the transformer has come loose. Screws can be tightened, and you could maybe re-dip the transformer in magic lacquer.

  • the quiescent load on the transformer has increased, making it hum more (e.g. capacitor going bad, diode failing)

There are other things that can cause transformer hum, though. Within the amplifier, it may be that the transformer is running at a higher load than usual due to leaky caps or messed up biasing on the output transistors. Outside the amp, if the mains has a moderate DC bias or excessive noise, you can get hum and chatter. /u/kasonc, have you changed any heavy equipment, light dimmers, or wiring in your home recently?

Another solution is do to what this guy did where he whined that no one was willing to help him that McIntosh did not reach out to help him that contributors, posters, and users of this forum did not help him and so he was prepared to do nothing but decide to burn his amplifier because it was his right to do so it was under warantee but he was not willing to pay the shipping cost to return it to the factory!
Fyi I never had buzzing sound.

Its a annoying hum,  I live in a nice area in Chicago, its all residential homes no commercial close by.

Com Ed ran new lines not too long ago and as mentioned our home has fresh wiring from the pole in.
Have, 3 pc here, many tvs as well as audio equipment.

If there was strange stuff going on with the power  Im shure as shixx something else would of acted up by now.

Just my 2cents,  Im done