RACK/ELECTRICAL
70/100 V70/100\,\mathrm{V}

70 V / 100 V systems

Add up the taps. Leave room to breathe.

Inputs

YOUR SYSTEM
Line voltage
W
1100
1100
%
050

Result

METER
Minimum amplifier rating
225W
Including the selected capacity reserve
Total tapped power
180W
Equivalent line load
55.6Ω
Nominal line current
1.80A
PARALLEL TRANSFORMER TAPSAMP+-15 W15 W15 W15 W12 transformer-equipped speakers on the lineMINIMUM AMPLIFIER RATING : 225 W
Distributed loudspeaker line: Constant-voltage system

How it works

A simpler way to distribute sound.

In a constant-voltage system, transformer-equipped loudspeakers are connected in parallel. Add their tap ratings, then choose an amplifier with enough unused capacity.

The formula

Pamp=Ptap⋅N1−R/100P_{\text{amp}} = \frac{P_{\text{tap}} \cdot N}{1 - R/100}
  • PtapP_{\text{tap}} — selected power per speaker
  • NN — number of speakers
  • ZlineZ_{\text{line}} — Zline=Vline2/PtotalZ_{\text{line}} = V_{\text{line}}^2 / P_{\text{total}}

Worth knowing

Use matching line-voltage taps throughout the installation. A 70 V tap driven at 100 V does not draw the power printed for 70 V.

Assumptions

Transformer insertion loss, cable loss and manufacturer-specific capacity recommendations are not included. Line outputs can carry hazardous voltage; use qualified installation practices.

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