separate pre-amp after DJ mixer (split from Crossover thread)

[Subvertech]

What equipment have you got between you mixer and crossover? Need more info.

[Anonymous]

Subvertech;246331 wrote:

What equipment have you got between you mixer and crossover? Need more info.

nothing.

[d.r.e.a.m]

MrAHC;246410 wrote:

nothing.

What a silly question what would you put befor a xover?do you use a compressor?

[Subvertech]

d.r.e.a.m;246590 wrote:

What a silly question what would you put befor a xover?do you use a compressor?

I use a preamp to strenghen the signal. Otherwise its a weak signal.

[elretardo87]

Subvertech;246643 wrote:

I use a preamp to strenghen the signal. Otherwise its a weak signal.

Why? If you are using the phono outs on a DJ mixer then get a new mixer with balanced outs.

If you are not then your pre amp is a waste of money.

[General Lighting]

elretardo87;246658 wrote:

Why? If you are using the phono outs on a DJ mixer then get a new mixer with balanced outs.

If you are not then your pre amp is a waste of money.

bear in mind if you live in a English county with a harsh zero tolerance policy on outdoor raves and only 3 legal venues tolerating electronic dance music events, there isn’t much incentive to spend loads of cash on a rig.

Particularly as people get older and find they have other priorities in life and crews have less chance to get together. For most people here pro audio is becoming a expensive hobby rather than a career – especially with the credit crunch.

I was once a experienced AV engineer but got laid off and have had to reskilll doing “boring” stuff like accounts databases, networking and telecoms for offices as theres way more money there and secure jobs rather than sporadic patterns of work.

So I only contribute basic info to these sorts of threads as I left the industry just before the nicer kit came on to the market, whilst I know the basics of infrastructure like cabling and power, I simply don’t know how much of the new kit works and wait for people like yourself or Biotech or Raj and Noname who do know their stuff to respond.

That said, from when I worked in pro audio for broadcast a few years back (during the big transition from analogue to digital) it was very common particularly in smaller radio stations for a bit of “consumer” hi fi with RCA outputs (usually a minidisc player/recorder) to have to feed a XLR balanced audio connection, and to deal with the obvious issues like lack of proper signal grounding on class II (double insulated) appliances

So there are many pre-amps available for this purpose which provide acceptable audio quality. it might not be the most elegant way of doing it but must work out cheaper if the mixer is normally from someones home setup when not in use for sporadic events.

[General Lighting]

I’ve split the separate discussion about pre-amps to its own thread to avoid derailing the one about how to set up a crossover..

[Subvertech]

elretardo87;246658 wrote:

Why? If you are using the phono outs on a DJ mixer then get a new mixer with balanced outs.

If you are not then your pre amp is a waste of money.

My pre-amp was only £70 so im not bothered’ its cheaper than me buying a new decent mixer and im happy with the sound thats all that matters to me.

[SUBVERSION]

Subvertech;246730 wrote:

My pre-amp was only £70 so im not bothered’ its cheaper than me buying a new decent mixer and im happy with the sound thats all that matters to me.

And its a very good sound in my opinion raaa

[cheeseweasel]

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).

[General Lighting]

I’ve not had a chance to hear subversion’s rig but from chatting to some of the crew I’ve got the impression they know what they are doing (more so than some of the more recent local crews) and are making the most of what resources they can get…

[noname]

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).

+1

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:.

[Author]

Posts