Forums Music Sound Equipment separate pre-amp after DJ mixer (split from Crossover thread) Re: separate pre-amp after DJ mixer (split from Crossover thread)

    cheeseweasel;246793 wrote:
    A general rule in anything audio is to keep the signal path as clean as possible and use decent components. Any boxes you put between the mixer and crossover are going to add a certain amount of noise and distortion to the signal.

    I would just connect the mixer straight to the crossover, and set the gain structure so that the crossover is receiving a healthy level. There should be no need to put extra amplifiers and stuff in there. If there are discrepancies between the level coming out of your mixer and the level going into the crossover it’s probably because the crossover is expecting professional line level (+4dBu) and the mixer is outputting at the consumer level of -10dBu, in which case there could be a small switch on the crossover or mixer somewhere to change this. Alternatively buy a better mixer, or connect the mixer to a desk (though a desk will invariably add some noise to the signal depending on how good the desk is).

    I’m not sure what the pre-amps are that people are talking about, do they simply boost consumer line level to professional line level, or are they phono preamps? A phono pre-amp would be unsuitable for this use.

    If you’re using the mixer with your rig you might want to put a limiter before the crossover as a safety measure (it has no sonic benefits here and should not be limiting the signal in normal operation).


    The less shite in your signal path the better usually (as a point of interest, there are a good few crossovers that have limiters built in too saving you needing another box)…

    Having said that, I like to put a desk between any DJ’s and my rig – partly because DJ’s are generally not to be trusted and giving the engineer a bit of control over their levels is essential IMO, and partly because I like the colouration Soundcraft desks give to the sound (not terribly good engineering in theory, but I’ve always trusted my ears and the colouration the desk gives is worth it IMO)…

    As for pre-amps – unless you’re relying on passive crossovers, an active will have gain controls for both attenuating the input, and attenuating each frequency band – use that to deal with the -10dBv/+4dBv difference (on my cx3400’s, I would set the input attenuation to +12dB if I was using a consumer level (-10dBv) feed…

    If you’re using passives then the preamp is useful if you’ve only got a -10dBv feed – and doing what you think sounds best is always a good way to engineer – your ears are always your most important test tool :wink:.