The API 500-6B, also commonly called "lunchbox" is a 6-slot rack designed to accept all API standard 5.25" X 1.5" modules.
The standard established by API (VPR alliance) allows an engineer the flexibility to bring along specialized EQ effects to any situation: 550A, 550b or 560. The lunchbox has an internal power supply with a rear panel selected AC voltage switch and a removable power cord. The input/output jacks are XLR. The lunchbox comes standard with a +48 volt internal phantom power supply, bussed to pin 15 for interface with the API 512c Mic Preamplifier.
API makes several modules for the 500-6B, including the 512c Mic Preamplifier, the 525 Compressor, the 527 Compressor, the 550A 3-band EQ, the 550b 4-band EQ and the 560 Graphic EQ. Combinations of these modules make perfect stereo recording packages (two 512cs and two 550bs) or vocalist's box (one 512c, two EQs and one 527).
Other uses for the versatile lunchbox include:
Multi-track recording of acoustic and electronic audio sources
Sound reinforcement systems and recording to multi-track formats
Multiple facility projects where portability is a plus
Broadcast and audio for video production
Custom channel input strips
Holds 6 API standard modules
Rack Ears available for rack mounting
6 Slots with 250 mA of current per slot
DB-25 connectors for easy input and output connection (see diagram)
XLRs to access channels 7 and 8 of the multipins
Power rail LED indication
Internal power supply; 100 to 250 Volts switchable, 47 to 63 Hz
Rubber feet & carrying handle for portability
Rugged steel chassis
Perfect for remote recording of vocalist and instruments