Distortion- Headphones or the Source?

[Shanman]

I am completely new to dabbling with headphones and know nothing in regards to many here.

I recently acquired a new set of Sennheiser HD560S because of the decent price at the time, and reviews here. When I EQ the cans via my old Adcom preamp, a GTP-500II, bass distortion is readily heard at sane listening volumes.

How do I know if the distortion I am hearing is the headphones or my amp built into the Adcom?

The cans are 120 ohms and looking at my original manual specs on the Adcom I can't find any rating on the headphone output section. The manual does briefly mention "the jack has its own amplifier to power the headphones being used". Fairly useless info. Thanks for any help, I want to give these Senns a fair shake before I decide to return them. I don't have a dedicated headphone amp, and the other testing options I have could be a Denon AVR-X3300 or an Arcam AVR 350. Any help greatly appreciated!

 

[Katji]

It's probably the headphones. How much bass boost is there? You could try doing the EQ with EAPO, adjust the bass boost until it isn't so distorted.

 

[Shanman]

Thanks, I keep flip flopping between the 560S and some ancient Fostex headphones I snagged from my father to have something to compare the Senns to. I can’t get the Fostex T20's to distort, but they don’t have the bass extension or the comfort the Sennheisers have.

I am listening to them flat on the Arcam preamp by the way.

 

[freemansteve]

What is the source of your music? Are you certain it's not already distorted and just being made more obvious by EQ? For example, rips without mp3gain or replaygain can sometimes clip.

Also, what output on the amp are you using? One that is not intended for phones, such as a line out, may not have enough current to drive 120ohm ? phones....

 

[Katji]

...well, i'm going have to assume/guess the source is not computer and the Adcom preamp has some sort of 5-band equalizer.

 

[Shanman]

5 band EQ? Sheesh, I haven't thought of that in 35 years when the eq "booster" was popular in car audio. No, I am using a legacy Adcom preamp, specs to the headphone output are not in the actual spec sheet I have. My source material is cd and vinyl. Sometimesultra HD files from Amazon Prime via Chromecast Audio.

 

[Katji]

So where is the EQ happening then?

 

[Shanman]

Tone controls on the Adcom itself.

 

[twsecrest]

Tone controls on the Adcom itself.

Headphone jacks with a high output impedance, can cause a bloated (louder, less detailed) base.
Have you tried plugging the headphones into a smartphone?
Modern headphones seem to be designed to work well with smartphones, so using less voltage, but might require more current.
The old Adcom's headphone jack might be great for voltage, but not so much for current (guessing).

 

[Robbo99999]

I'll just add that I've got 3 units of HD560s, they are super good in the bass after EQ in terms of definition.....better than all of my open backed headphones and about on par with my planar open back HE4XX for bass definition after EQ. Either you listen super loud and are at the same time putting huge amounts of bass EQ through them too....or it's something else in your chain.....that would be my intuition because HD560s is good for bass in my experience & also from the low distortion measurements. Oratory measured one of my HD560s units and it has low distortion in the bass (& everywhere else):