Specifications

without compression but to pull back to a suitable continuous power for sustained

signals such as rail-to-rail feedback.

Although the long-term limiter thresholds are lower for the mid and high frequency

sections (LF +7dBu, MF +4dBu, HF +1dBu), all W8L/Longbow sections are

designed to accept full MA4.2S power on transients…

W8L/Longbow section Max continuous demand Max transient demand

Low frequency 1204W 2300W

Mid frequency 602W 2300W

High frequency 301W 2300W

How much mains power will I need?

Many touring systems are supplied with inadequate mains power causing the system to

sound like the PA equivalent of a portable radio with a flat battery!

Here are the current consumption figures for the recommended MA4.2S power

amplifier. When used with our standard crossover and limiter settings.

230Vac operation to DX1 limiter threshold, 2 W8L/Longbow sections per ch: 6A

115Vac operation to DX1 limiter threshold, 2 W8L/Longbow sections per ch: 12A

A rack with 9 MA4.2S amplifiers (each driving 2 W8L/Longbow sections per

channel for a total of 12 W8L/Longbow cabinets) will require a minimum of 54amps

at 230Vac and 108amps at 115Vac under typical live sound conditions. We would

recommend 63A at 230Vac and 120A at 115Vac.

Here are the MINIMUM figures for typical racks:

Minimum current

Number of

W8L/Longbow

cabinets

Number of

MA4.2S

amplifiers

for 230 Vac single

phase mains

for 115Vac single

phase mains

4 3 18A 36A

8 6 36A 78A

12 9 54A* 108A*

16 12 78A* 156A*

* Large racks are often supplied with 3-phase mains - e.g. a 9-amplifier rack may

be wired with three MA4.2S amplifiers per phase and a 12-amplifier rack may be

wired with four MA4.2S amplifiers per phase. The above minimum current figures

may be divided by 3 when a 3-phase mains supply is used.

How should I distribute mains power within the rack?

Normal distribution practice applies – e.g. a 230Vac inlet 63A inlet would be split

into 2 x 32A spurs which would supply the appropriate outlet strips via 32A

breakers.

Remember that, although the transient power demand will be the same for each

W8L/Longbow section (see table earlier), medium to long-term power demand will be