Slight humming noise coming from Mark Levinson 331

I was changing an LP last night and noticed a very slight hum coming from my amplifier. I have owned this amp for about six months now, and just noticed the noise. It is not noticeable while listening to music, but you can hear the faint hum from a few feet away provided the room is super quiet. Is this normal, or should i be concerned? I bought this amp used from a authorized Levinson dealer and have not had any problems with this amp at all! Just wondering if this is normal, or am I going to see smoke and flames in the near future? There is no buzzing or hum from the speakers at all, just the amplifier. The amp is plugged into a Transparent Power-Wave 10 power conditioner. I have tried plugging the amp strait into the wall and it still makes the humming sound! Thanks for any input on this issue!
A ground lifter plug will probably take care of that. They are available in any decent hardware or electrical store.
Its most likely transformer hum which is a mechanical/vibrational thing. Sometimes it can be "cured" by tightening the transformer hold downs. Your dealer should be able to help you out. AKAIK, its not going to make it go up in flames.
Are you using XLR or RCA?
Transparent Ultra XLR's
Might want to check the connectors and make sure they are tight (inside and out). A buddy of mine has a 334 and he was getting some hum on his rca's and it ended up being a loose connection.
He also had a ML 38 preamp that hummed. He sold it with the hum so not sure what of the outcome? I have owned several ML amps with no problems.


The noise you are hearing is the transformer buzzing. You may want to check the power at the wall outlet with a volt meter...if possible. If it is 110-120v you are good...even 125v is ok, but the transfoemr will start to become noisey. I think around 130v the amp will shut down. Pay attention to the noise, it will probably change at different times of the day depending on the load on the main grid for the area.
Thanks for the information! What are my options if my voltage is irregular or over 130 volts?
Hey again, If the voltage is nearing 130v you need to contact your electric company ASAP. Once they come out to check the problem and see that it is high, they'll make the necessary adjustments at the main grid. Unfortunately, if the power is on the high side but still in range (+/- 10%) there maybe nothing they or you can do. The only thing then would be to get a good voltage stabilizer...of course it would need to be able to meet the demands of your current hungry Levinson. It's frustrating, I know, I'm living it. If you are only able to hear the buzz by puttig your ear up to the amp, you are fine. If it is to the point where you walk in the room and can make it out...there are some serious issues. Only other thing you can try is just what the other post says...check the bolt/nut that holds down the transformer. That's about it. FYI, my incoming power is 127v, if I put my ear up to my Levinson no.333 I hear a slight buzz. Before the Elect. CO. corrected the problem the power was 131v and boy was the amp loud!!
One more thing...All of the other amps I was using Krell, Parasound/Halo, Rotel, 127v, they all buzzed! it's not just the Levinson.
In my equipment ML 331 is very nice and never lsten noise o humming!
Is better that somebody checking his power line at home!