Slight hum/buzz in right headphone when using NAD Int amp but not Marantz Int Amp

[pinger]

Just got new AKG K371 phones. Also have AKG K240 phones. I get a very slight hum or buzz in right ear with the 371 phones hooked up to the NAD 316B but not when hooked to the Marantz 6007. The 240 phones have no issues with either amp. Not a big deal i just make sure i use the 371's with the Marantz. Both phones sound the same to me. Just curious what could cause this and what could "fix" it

 

[staticV3]

Most traditional Int amps don't have dedicated headphone amps, but instead tap into the power amp via a 300-500Ω resistor for current limiting.

This is a poor solution with audible power supply hum as a likely consequence.

To fix it, you can try buying an external headphone Amp and plugging that into the int Amp's Line/Pre out. Set that to full volume and use the headphone Amp for attenuation.

Some good, inexpensive headphone Amps are:
Schiit Magni
JDS Atom Amp
Topping L30II

 

[pinger]

How come it only happens with one of the phones and not the other though?

 

[staticV3]

How come it only happens with one of the phones and not the other though?

The K371 is 10dB more sensitive than the K240 Studio.

The same noise on the Amp's output will sound twice as loud on the K371.

 

[pinger]

The K371 is 10dB more sensitive than the K240 Studio.

The same noise on the Amp's output will sound twice as loud on the K371.

Awesome. Thanks for explaining