Limiters
The FP24 has two
The FP24's limiters can operate in either either
•In the middle position, the limiters are turned off.
•In dual mono operation (ON switch position), the limiters work independently, responding only to their input signals.
•In
When the limiters activate, the Peak/Limiter LED on the front panel illuminates amber in proportion to the amount of limiting for each channel.
Tone Oscillator and Slate Microphone
The switch labeled 1 kHz/SLATE on the front panel controls two functions. The 1 kHz position (left) mutes all inputs and sends a 1 kHz sine wave calibration tone at +4 dBu to all outputs. The tone oscillator can be used to verify connections and set nominal levels on recording and transmission equipment.
The SLATE position (right) is a momentary switch position that activates the
Metering and Clip-Indicators
Three
1.Above each input gain control, a
2.A
3.The
When the limiter is activated, these input LEDs glow amber in proportion to the amount of limiting.
The FP24 has a seven segment LED output meter that shows peak output level in dBu. From left to right, the first three LEDs are separated by 15 dB and the remaining LEDs are separated by 4 dB. This calibration provides a 46
The meter uses premium Gallium Nitride (GaN) LEDs which are visible even in direct sunlight. A
CAUTION ± When set to
Power Sources and Battery-Life
The FP24 operates from either two internal AA alkaline cells or an external 5±14 VDC battery supply or AC to DC transformer (such as the Shure PS20). The power connector is a locking, threaded coaxial connector. Center pin = positive, sleeve = nega- tive. Use the supplied threaded power connector if necessary (see Figure 5).
The external DC input supply is galvanically isolated (floating) from the chassis and the rest of the circuitry. The isolation provides
Two AA, 1.5 Volt lithium cells can power the FP24 for up to approximately 11 hours. However, several factors affect how long a given pair of batteries will last. These factors include battery chemistry, ambient temperature, use of phantom power, output meter brightness, and the output drive level of the FP24. The chart below provides estimates of battery life in different kinds of circum- stances. Experimentation can determine expected battery life for specific setups and environments.
NOTE: AA carbon cells and AA
Battery | Microphone Type and | Battery | |
Type | FP24 Settings | Life | |
|
|
| |
Eveready AA | 2 dynamic handheld microphones, low | 11 hrs. | |
No. L91 (lithium) | meter brightness, no headphones | ||
| |||
|
|
| |
| 2 dynamic handheld microphones, low | 6 hrs. | |
| meter, low headphone level | ||
|
| ||
|
|
| |
Duracell AA MN | 2 condenser, |
| |
ered microphones, normal meter in- | 4 hrs. | ||
1500 (alkaline) | |||
tensity, normal headphone level |
| ||
|
| ||
|
|
| |
| 2 studio condenser, |
| |
| powered microphones, super bright | 2 hrs. | |
| meter intensity, high headphone level |
| |
|
|
|
Test conditions: 70 degrees F, 42 dB of gain with an acoustic music source, 600 ohm load, +4 dBu output
Interconnecting the FP24 and FP33
You can connect the balanced, line level XLR outputs of the FP24 to the mix bus of the FP33 using the Shure A33LK accessory kit (or construct a cable assembly as shown in Figure 4 on the fol- lowing page).
Combining an FP24 and a Shure FP33 (or FP32A) mixer yields a flexible,
•Simultaneously accepts a stereo microphone,
•
•Limiters on the FP24 inputs
•Input assignment switches on the FP24 and pan pots on the FP33 inputs
•Two output busesÐassignable to mic or line level output.
•Master volume and headphone monitoring for all five inputs controlled from the FP33.
•CompactÐFP24 adds little bulk to an existing FP33 package.
•The FP24's isolated external DC input jack eliminates ground related interference problems.
5