Installation, Circuit Description | Furman Sound SP-20ABE specification

SP-20AB MANUAL

Installation

For installation as a free-standing unit, attach the four adhesive rubber feet supplied with the SP-20AB to the bottom of its case.

With either the HRKIT-1 or the HRKIT-2 adaptor kits the SP-20AB may be mounted in standard 19” equipment racks. The HRKIT-1 is for mounting one SP-20AB in the center of a 19” rack. The HRKIT-2 is for mounting two units side by side in a 19” rack (or for mounting a single unit in a “half rack”). Complete installation instructions are supplied with the kits.

When installing any equipment in racks, keep in mind that standard racks come equipped with mounting rails with holes tapped for 10-32 machine screws. Be sure to use only 10-32 screws for this purpose (in particular, avoid 10-24 screws, which will ﬁ t if forced but will strip the threads). To avoid marring the panel when tightening the screws, use nylon washers under the screw heads.

For best results, the input cables plugged into the SP-20AB should be shielded. Balanced connections should use shielded, twisted-pair cable. Headphone cables and speaker cables do not need to be shielded, though no harm is done it shielded cables (such as microphone cables) are used.

Circuit Description

CAUTION! This section is intended to assist the professional user with considerable experience in electronics to achieve a better understanding of the operation of the SP-20AB. Under no circumstances should persons without

electronics troubleshooting experience and training undertake repairs on their own. There are no user serviceable parts inside the SP-20AB. All problems should be referred to the Factory or to other qualiﬁ ed service personnel.

The input connectors are XLR balanced. The inputs to the SP-20AB proceed from the input connectors to op-amp buffers wired as differential (balanced) ampliﬁ ers. If a mono signal is inserted this will convert the differential op-amp to a non- inverting amp. After the buffers, the left and right signals proceed to the two decks of the stereo Input Level control.

The SP-20AB’s power ampliﬁ cation is derived from a pair of LM1875 integrated circuits, which have internal short-circuit and thermal overload protection. They are set for a voltage gain of 26 dB and drive the speaker outputs through a standard RLC network. The network establishes the high frequency rolloff, as well as preventing voltages generated by the speakers from reaching back into the IC and causing damage. The headphone output passes through a special high-power pot wired as a volume control.

The SP-20AB’s power supply provides ±30 volts unregulated DC (with 120VAC line input) to the LM1875 stages, which may drop to ±23 volts under full load. A network of dropping resistors and zener diodes provides ±15 volts to the rest of the circuit.

Both the Overload LED’s and the Signal Present LED’s monitor signal levels at the output of the LM1875, but before the headphone volume control and the Speaker On/Off Switch.

SP-20ABE, SP-20AB specifications

Furman Sound is a name synonymous with high-quality power management solutions for professional audio, video, and broadcast systems. Among their impressive lineup, the SP-20AB and SP-20ABE power conditioners stand out as essential tools for those who demand reliability and performance in their setups.

The SP-20AB and SP-20ABE are designed to safeguard audio equipment from power surges, electrical noise, and other fluctuations that can jeopardize the integrity of a performance. One of the main features of these power conditioners is the Advanced Power Factor Correction technology. This innovation enhances the efficiency of connected equipment, ensuring optimal operation even in electrically noisy environments.

Both models come equipped with a robust circuit breaker, providing added protection against overloads. The front-panel displays include LED indicators that keep users informed about the power status and any potential issues, ensuring peace of mind during critical operations.

A significant characteristic of the SP-20ABE is its built-in Ethernet connectivity, which allows for remote management and monitoring capabilities. This feature is invaluable for sound engineers and technicians who need to manage multiple devices from a single interface. Such connectivity enhances efficiency and simplifies troubleshooting in larger setups.

The SP-20AB and SP-20ABE also incorporate Furman's proprietary Series Multi-Stage Protection. This multi-layered defense system gives users the assurance that their equipment is secured from damaging transients. The design also includes extensive filtering that minimizes electromagnetic interference (EMI) and radio frequency interference (RFI), ensuring cleaner audio signals and enhanced sound quality.

Both models feature a rugged, roadworthy chassis built to withstand the rigors of touring and on-site performances. This durability means they’re not only suitable for studio environments but also perfect for live applications where reliable power conditioning is crucial.

In summary, the Furman Sound SP-20AB and SP-20ABE power conditioners are vital assets in any audio professional's toolkit. With advanced technologies focused on efficiency, protection, and monitoring, they provide a blend of performance and reliability that ensures your audio gear operates optimally in any setting. Whether in the studio or on the road, these power conditioners represent a wise investment for safeguarding your audio investments.