February 4, 2011

Multi channel Power Amps & Crossover

This project contains 4 power amp channels and a digital active crossover module in one box:

Above: power amp modules and MiniDSP sitting in place, not yet connected.

This is a simple low cost project that challenges two criticisms made of active speakers in the past:

  • they are more expensive
  • they clutter up a rack with many extra boxes
Low cost

The MiniDSP crossover costs $100. This is comparable to the cost of a decent passive crossover for a 2 way speaker. It's easy to spend more, and this is excluding the "development cost" where multiple versions of the crossover are built. 

The amp channels only cost $200. The case which is shown above only cost $52. The total cost is around $400, or less for those spoilt individuals in the US who get everything cheap! 

In the past, a more typical choice would have cost around $500 for the lowest cost crossover (Behringer DCX), then around $600 for a pair of Behringer A500 studio amps. This option would also cost considerably more once a host of XLR cables and connectors were purchased. 

It isn't too difficult to find power amp modules such as these on ebay, which come pre-built and only require inputs and outputs to be wired up.

Single box solution

This option is far neater and more compact with no Vegas-style flashing lights. Cable runs are minimised and kept shorter, and the need for many different connectors is eliminated. This is the ideal situation. Traditionally, audiophiles have been led to believe that separates are better. Often this will be true, but only where better quality parts and design are used at a much greater price. All other things being equal, a single box is better due to shorter cable runs. It is certainly a more cost effective solution.

This project will feature two RCA inputs and two 4 pole speakon speaker outputs. This prevents accidental wiring mistakes where the tweeter and mid outputs are mixed up. 

More details and photos to come when complete. 


  1. They are a Sinewave OEM module which are unfortunately only available if you want to buy 100. Got a spare $10 grand?!


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