Please help me pick a preamp

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I have 2 qsc 1400 amps running bridged into Bose 901 series 1.

I need a preamp to get more juice out of the amps, I have read amps like this do not respond well with home audio preamps.

Can someone please guide me int he right direction?

I heard NAD had one that pit out 15 volts
 
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A simple mixer will do the job as these have stage gain and top channel gain as well, just remember also try not to drive your amps in to clipping...there are many mixers to choose for your given needs even citronic/pioneer will do. If you know what to do and have a pre-amp it's straight forwards to tweak the op-amp gains via changing resistors to boost level but only if you know how..
 
Frequency Response 20 Hz - 25 kHz
Number Of Channels 2
Tech Details
Audio SNR 100 dB
RMS Power per channel at 2 ohms 550 Watt
RMS Power per channel at 8 ohms 200 Watt
RMS Power per channel at 4 ohms 400 Watt


8 Ohm Bridge mono

THD (Total Harmonic Distortion)



600 Watt

0.1 %
just found this on line.. them qsc's are 800 mono bridge use... so good pre-amps will drive with ease...
 
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I wouldn't mind a 2.1 Pre Amp - if they make such a thing.
A Y-adaptor which is just 2 or 3 resistors blending both channel signals to drive a third preamplifier output is commonly used. That still requires a low pass filter incorpoated into its amplifier circuit, in the same way as any powered sub. A new socket on the rear and a couple of resistors and wires and that's it!

The filtering, level control and auto power switching could all be performed in the preamplifier too but it seems pointless when the sub. amplifier or plate amp. is a more universal and ready-built location.
 
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Those little boxes appear to be passive (unpowered) since no other features are offered so how much more than a few cents worth of parts might be inside the +$22 box? Use one if you wish but it seems like a waste of money. All you need to do what is claimed in the descriptions, is 2-3 10k resistors. That's all you see as a blending circuit inside powered subs that have inputs for both channels anyway.

A 2.1 integrated amp may incorporate an inbuilt low-pass filter, matched to a particular recommended speaker. There are a few old designs by Onkyo, for example, that had powered or unpowered 2.1 adapters inbuilt. Unless it is independently adjustable though, the filter settings will be matched to the driver specified or included in that product so it won't be a simple or attractive solution for compatibility with other products. I can't imagine that remaining commercially viable for long. Generally now though, 2.1 systems are inexpensive desk-top PC audio systems whilst preamps are largish high-end or audiophile products for conventional 2 channel stereo. You don't see much lasting change or innovation in that convention other than by a complete change to active crossover speakers but a Y adaptor is still needed for a single driver bass box.

What you see on the web described as a Y adaptor, is just a cheap paralleled socket or split cable but for proper audio termination, a 10k resistor in series with each channel input, before they are connected and a third resistor to ground from that junction are advisable before simply joining in the single lead to the sub. amp.

Like I said, if you want to do it with the filter in a separate preamp, for a straight, separate bass amplifier and a passive speaker box then that's also possible but a bit pointless when an active sub or just its plate amplifier does it all, just as in any 5.1, 6.1, 7.1 etc. surround system. Preamplifiers may not switch the whole system on/off unless a dedicated switching system like a 12V control lead is fitted so something needs to be incorporated to ensure that 1-off = all-off, for a degree of safety. That's where powered subs and subwoofer controllers become useful.

You can purchase DIY subwoofer controller PCB kits to retrofit in a full size preamp that incorporate the (likely necessary) adjustable filter and power-up/down controls to manage the system for setup and in daily use. This is DIY though, as you would expect here and you need to assemble and get out a schematic of your preamp to plan and fit the circuit board, controls and route power and signal wiring properly. Given that you may now have a particular signal termination like the suggested 10k, it won't be difficult to calculate the RC values for a simple 6 or 12 dB/octave LP filter, if that's all you want to tackle.
 
So I can use a regular home preamp and it will allow for the amps to open all the way up?

With direct line in from cd palyer full blast they are not any where full cap. My 110watt channel receiver is about as loud, but the amps are more clear with no distortion at all.

I was thinking maybe the preamp gave the signal a boost and allowed the amps to be louder.

Am I correct? if it is the same output level with or without a preamp that sucks. If that is the case no way these are rated accurately and many said they were that is why I bought them.
 
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These QSC amps (I assume stereo version) are good for a massive amount of PA power, bridged or not. They should literally vaporise Bose 901s with 800W/8R when driven hard. This is a real case of overkill but if that's what you want, this is one way to make certain of the result.

Something that hasn't been commented on yet is that, according to a few versions of the schematic, input connections are via an unspecified "jack plate". They are balanced line inputs, such as you use XLR connectors for on most equipment nowadays. You don't see many hi-fi preamps with balanced line outputs unless they at least have pretences to high-end quality and a matching price tag.

So, as you mention distorted and low volume sound, just how are you connecting signal input to the +/- and ground connections? Does your current preamp actually have a balanced line output?
 
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