BillFitzmaurice.info

My current mobile Dj rig consists of two powered Alto 12" tops and two unpowered 18” Harbinger subs. The Harbingers are rated for 400w RMS and are 8ohm, but down the road, I may replace them with some 800w 8ohm Eminence drivers. I use a Pioneer djm-707 mixer and an unbalanced Minidsp. Both have an output sensitivity rating of 1v.

So essentially, what I'm looking for is an amplifier that can drive two 800w rms 8ohm 18"s to full power with a 1v or less input signal.

this is kind of a website based on giving advice in regards to Bill Fitz Maurice gear.

so my first recomendation is sell the harbingers and build something!

Yeah... I bought the CD and some parts a while back but I never got around to building anything.

Should I forget about input voltages and just get a preamp ? If so, what kind of preamp?

You could get a simple equalizer like the behringer FBQ1502. In addition to 15 band EQ it has a built in cross over, low cut filter, and ability to increase the gain by up to 15db.

If I use a preamp, it would have to be between the minidsp and amplifier, so I wouldn't use most of those features. I was considering getting the balanced Minidsp as it is capable of 2v, but I don't think it can boost the signal, only take away from it.

The Crown XLS amps will take consumer-level input using RCA jacks, perhaps one of those?

why so hell bent on the mini dsp? they are quite pricy if I recall... :/

Just to live up to my reputation as a nitpicker:

An amp with "low input sensitivity" will require high level signals. What you're looking for is an amp with high sensitivity.

Ah yes, high sensitivity is what I meant.

The Minidsp unbalanced is $125 and $145 for the balanced version, so pretty cheap actually. I wouldn't mind having another one. I like it because it's small enough to fit in the flight case with my mixer, is powered by usb, and I can make on the fly adjustments if I need to. Only thing I wish it had was a limiter.

I think there are two xls series. There is a 5000 with balanced only inputs, 1000w @ 8ohms per channel, and an input voltage of 1.2 @ 4ohms. In the other series with the unbalanced inputs, the most powerful amp has 500w per channel, but I don't know if it will reach 400w with a 1v signal.

I think I might go with a QSC RMX 2450. It has an input sensitivity of 1.15v and can do 500w @ 8ohms per channel. I also like all the switch options on the back that I can use to combine the signals into mono without bridging, among other things.

Ah never mind, it's 1.23v. They all seem to be around the 1.2-1.4 range with the higher powered units having lower sensitivity ratings. Seems like no matter what I pick, they all seem to put out the same output voltage per input voltage.

DJ Funke wrote:Ah never mind, it's 1.23v. They all seem to be around the 1.2-1.4 range with the higher powered units having lower sensitivity ratings. Seems like no matter what I pick, they all seem to put out the same output voltage per input voltage.

That is exactly what an amplifier is. Take the input voltage and multiply it by the amps' rated gain.

Just to follow up, I talked to the people at minidsp and the balanced minidsp can produce a 2v output with a .9v input by jumpering the input sensitivity circuit. So I'm thinking I might get a qsc plx 3402 and the balanced minidsp. That way Ill have more power than I need on tap for any future changes that I might make in my setup.

whines wrote:The Crown XLS amps will take consumer-level input using RCA jacks, perhaps one of those?

By no means am I an expert in this arena, but the Crown xls 1000 drivecore that I have has the RCA inputs, but it wouldn't adequately work with the sub outs from my consumer Marantz SR5007 av receiver. Had to get an ArtBox consumer level to pro level converter.