available from most electrical supply stores.
3.3.6 Additional Load Protection
Studio Reference amplifiers can deliver very high power levels, so it’s a good idea to add protection for your loudspeakers if it is not
Thermal protection and voltage protection require dif- ferent types of fuses.
There are two common ways to install the fuses. One approach is to put a single fuse in series with each out- put. This is easy because there is only one fuse per channel to install. But if the fuse blows, power is re- moved to all of the connected loads.
Studio Reference I & II Professional Studio Amplifiers
A better approach is to fuse each driver independently. This allows you to apply the most appropriate protec- tion for the type of driver being used. In general, low- frequency drivers (woofers) are most susceptible to thermal damage and
Depending on the application, you may want to use a specialized P.I.P. module to protect your loudspeak- ers. Again, some modules are more appropriate for
Most of the other P.I.P. modules that provide signal- driven compression can be used to prevent loud- speaker damage from transient voltage. These modules include the
1.0
1.2
1.4
1.6
2
2.5
3
4
5
6
7
8
9
10
12
14
16
20
25
30
40
Example: Impedance = 8 ohms. Peak Power = 75 W
Answer: Fuse = 1.5 A
LOUDSPEAKER IMPEDANCE (ohms) | FUSE (amps) |
20
15
10
8
6
5
4
3
2
1.5
1
.8
.6
.5
.4
.3
.2
.15
.1
.08
LOUDSPEAKER RATING
3000 |
| |
2000 |
| |
1500 |
| |
1000 |
| |
800 |
| |
600 |
| |
400 |
| |
300 | power) | |
200 | ||
150 | average | |
100 | continuousthe | |
40 | ||
80 |
| |
60 |
| |
30 | 4 times | |
20 | (Typically | |
15 |
| |
10 |
| |
8 | MUSICPOWER (watts) | |
6 | ||
4 | ||
PEAK | ||
3 |
2
1.5
1
3.4 AC Mains Power
All Studio Reference amplifiers are shipped with an appropriate line cord and plug. The 120 VAC, 60 Hz North American Studio Reference I has a special TT30P plug and includes a matching receptacle. Al- ways use an isolated power receptacle whenever pos- sible with adequate voltage and current. Excessive line voltages 10% or higher above the rated voltage will cause the amplifier to activate its standby mode (see Section 4.3.2). For example, do not exceed a 132 VAC with models rated for 120 VAC operation.
Unless otherwise noted, all specifications in this manual were measured using 120 VAC, 60 Hz power mains with voltage accurate to within 0.5% and THD of less than 1.0% under all test conditions. Performance
Fig. 3.16 Loudspeaker Fuse Nomograph
Page 18
variations can occur at other AC mains voltages and line frequencies. Line regulation problems will directly
affect the output power available from the amplifier.