Unplugging the headphones or not?

Hi everybody
I have a little query... When you all are done with a listening session do you keep the headphones plugged into the amp or do you unplug them leaving the amp without a load? I have the UL and (coupled with Grados at least) the background hiss is quite noticeable when silent or without input signal.
What are you're thoughts about this, could it in length be harmful for the headphones to never have the transducers rest, or could it even be benefitial?
Lately I've been unplugging my cans and then it actually seems that they're a bit smoother when I'm using them the next time, but it's hard to tell since the comparing sessions are so many hours apart.

Also, on another subject completely, how much does speaker cables vary in quality? I have a pair of semi thick jenving cables that cost about £1 a foot. Could there be much real improvement there or are the more expensive cables just for show?

Grateful for any input or views on this!



Johan

I'll just add that with other headphone amps it is probably a good idea to unplug them.

This is because with many, the output coupling is direct - a DC level (DC coupling).

A DC coupled output should be 0V but can vary slightly with input offset - this in itself won't damage your headphones.

However, some DC coupled amps have been known to go unstable and flip to one voltage rail or another. When this happens, the DC voltage will "fry" the transducers, thus destroying your very expensive headphones.

I would never design a DC coupled amp in this age on that precept alone! Headphones are too expensive for a company to survive with damages claims.

So, with our headphone amps, I AC couple them, which means an output capacitor, and everybody goes ape when they hear that, because they have been fed misinformation (this IS the misinformation age after all).

True, an output capacitor on a dual supply amp design will distort crazily at its turnover frequency, but the thing they don't understand is all that distortion disappears once the capacitor has a bias voltage (didn't John Linsley Hood make that clear enough?), and all our unipolar supply amp designs (Solo, Voyager, Novo) provide that bias voltage by default.

Therefore, because there is no likelihood of any DC with our amps, your headphones are safe left connected.

Yes, and the tweeter is the most important for the stereo "projection" etc.

franklin wrote: Irony all those ape have a capacitor on their tweeter. I don't know they don't know that or ...

Edited by Fatmangolf - 27 Sep 2011 at 11:22pm