Driving signal quality @ 0Db

Hey guys;

Can anyone tell me if they have noticed distortion at 0Db signal levels on their empeg? I have a MK2a and I have noticed that the audio seems like its clipping or distorting when the volume is at its peak. I am definitely not 'overdriving' to +Db levels, and I'm listening at low amplifier levels so remember Im talking line levels here.

Im sure its not the source files, but I have found that the driving causes clipping when plugged into a stereo amp, my soundcard, a tape adapter in other cars etc. Can't tell in my own car, cause 0Db would probably pop my ears !

I havea few theories, and I'd love any debunking of them so I can understand why this is the case.

A) the live level outputs are 4V - I rmember that the mk1 had the option of 1v or 4v outputs; maybe this is just too much line level signal for most devices @ 0db? even if it is 1v, is this still too powerful for some hardware eg soundcards?
B) not enough source power: Im running 2 x 60Gb, and a insufficinent power supplpy might stop full driving of the DAC?
C) Some hardware gremlin I dont know of?

Is it wrong to expect that 0Db should be great quality, with the highest signal/noise ratio you can get from the empeg?

If you are using any EQ settings in the + territory, it will push your signal past 0dB when you have the main volume turned up to 0dB. This may also be true (I'm not sure) if you are using the Treble and Bass adjustments in HiJack.

If this is the case, use your EQ to "cut" unwanted frequencies rather than boost "wanted" ones.

You didn't say which outputs you were using, home or car? The car outputs (well, the sled outputs specifically) are definitely 4v.

As far as the home outputs are concerned, I drive those all the time at exactly 0db and never have any trouble with most amplification equipment. Occasionally I'll run into a receiver that clips a tad and then I have to bring the player's volume down a couple of DB, but otherwise it's not a problem.

Check to make sure your EQ is flat or below 0 on all bands, and that you haven't used the Hijack bass/treble commands to increase, only to decrease. If you increase any of those settings above 0db, you'll get clipping at the DAC on very loud songs.

Hmm ok; definitely not EQing in the + using a flat eq line. Good point about the line-levels Im using: I have been using the dock (which == car) levels for my soundcard, so if they really are 4v then that could be it, but I am pretty sure I have seen the same behaviour on the RCA (non-dock) connectors but I'm gonna have to go and try now.

Ok; I put in a voltage divider on the 4v line so my soundcard gets approx 1v driving levels (using a 10k/39k drop), and this works at 0db fine. the 1v outputs are too much for a tape adapter, but I guess that they need less then a 1v drive, as it needs to be at around -12dB.

Still havent tried on a proper stereo input (to test the full 1v driving) but I suspec this will be Ok too. thanks guys for your advice

Quote:
the 1v outputs are too much for a tape adapter (...) Still havent tried on a proper stereo input

What are you talking about, tape adapter, proper stereo input? What are you trying to plug the player into?

You wouldn't happen to be trying to plug it into a phono input, would you? That would explain everything.