Clipping in headphones

[parker_muse]

My brand spanking new ball of excitement arrived today - my first head, an Ashdown Superfly 500. I'm buying a cab for it post xmas, so for now i gave it a trial through headphones, and i found it was clipping a lot. After hearing dodgy things about the chinese powerboards i'm paranoid - is this because of the amp or the headphones? Will it be fine run through a cab?

The headphones are plugged into the line out. The volume on the bass is max, and the input volume on the amp is to the top of the green bars on the digital read out, which is where Ashdown advise it to be. To have any real volume on the master though means you get quite regular clipping, i.e, for it to be more then a modest volume through the headphones.

Sorry, i'm a complete amp noob, as stated this is my first head. Can anyone shed any light on this and help me out?

[crez5150]

Doesn't matter how loud it is through the headphones really.... may be an impedance miss match.... which headphones?


J

[parker_muse]

They're 12.99 big ones, i can't really tell you more then that! So is it probably the headphones not the amp?

[LawrenceH]

[quote name='parker_muse' post='674526' date='Dec 4 2009, 09:48 PM']They're 12.99 big ones, i can't really tell you more then that! So is it probably the headphones not the amp?[/quote]

Hi parker_muse

Short answer:
it is probably both the headphones and the amp, but don't worry, it's not a fault.

Long answer:
I don't know if you saw my reply to this in the other superfly thread. But if you are trying to drive headphones from a line-level output that is not designed to double as a headphone amp then you can expect clipping. The line-out is designed to drive a line-level desk input, which will typically 'show' a very high impedance to the line-out on your amp in comparison to a pair of headphones. Looking at the manual, your superfly has an output impedance of 600ohms. A typical desk input is about 10-50 thousand ohms.
Typical headphone impedances are 150 ohms or less. Broadly speaking, driving a low impedance input with a higher impedance output results in signal degradation. This is what is likely happening here. Apart from the sound quality I would also be wary of doing this in case it put too much stress on the superfly and you end up knackering the line out (someone else correct me if in practice this is not going to be a problem?).

The other aspect is the headphones. It is really difficulty to get cheap headphones that will accurately reproduce the raw sound of a bass guitar at a high level without distorting/generally sounding horrible. You'd need to run the bass through EQ and a compressor to get a more controlled signal level like that you hear on a decent recording.

A cheap headphone amp is probably the solution for you, Behringer do one that runs off a line out for about £25 or you could get one that has a dedicated guitar input, though you'd probably want to avoid those which have amp modelling/distortion built in. Alternatively if you have a hi-fi with a spare input (tape, CD or aux) then just buy a cable that connects the line-out of your superfly to that and use the headphone out from the hi-fi. If you do this and it still sounds crap, that is the point at which new headphones with better bass handling become necessary. You're probably looking at £50 there.

Hope that helps!
Lawrence

[parker_muse]

Fantastic, i presumed it might be to do with the ohms after seeing the line out was 600 myself. That's eased my fears, thank you very much!