SPL Volume 8 - Eight-Channel Monitor Volume Controller

The Volume 8 is a fully analog, 8-channel, active stereo volume controller and a puristic surround preamplifier.

Features:

• High end volume potentiometer and illuminated mute switch; the potentiometer controls signals directly (without VCA or DAC circuitry)
• The mute switch allows for very fast reaction times in cases where loud speakers or ears should be protected (for example, with computer crashes)
• In contrast to digital volume controls which reduce the bit resolution at lower listening levels thus there is no degradation in sound with an analog volume control 
• In contrast to passive volume controls which alter the phase and frequency response there is no alteration in sound with an active volume control 
• Users of analog summing without monitoring facilities can cost effectively improve their systems
• High quality balancing stages with extremely good common mode rejection minimize interferences and disturbances in the signal paths
• Balanced DB25 input and output connectors (Tascam-Standard)
• A high quality power supply with toroidal transformer
• Massive, 45 mm diameter aluminum knobs ensure consistent, refined handling
• The elegant, compact housing allows for flexible desktop positioning near or under a computer monitor.
• Made in Germany

As a cost-effective alternative to the full-featured Stereo and Surround Monitoring Controllers MTC and SMC,  the Volume 8 focuses on high quality active volume control. Users who do not need additional monitoring functionality provided by the SMC will find the Volume 8 an cost-effective solution without compromises. The Volume 8's design is based on active circuitries to avoid nonlinear frequency response introduced by impedance changes with passive designs when changing levels.

The Volume 8 serves as a system-independent analog volume regulator in all areas of audio processing and playback, including 

• Stereo- and Surround Music production
• Multichannel movie and video post production
• Multichannel video computer games production
• Multichannel Hi-fidelity applications

Analog Volume Control - Why?
The majority of D/A converters and sound cards provide nothing in the way of analog level control, and this means the necessity of varying signal levels at the converter outputs. The result is a lowered bit rate in the monitoring signal, which can lead to commensurate loss of audio quality.

Compared to passive volume controls which affect the frequency and phase response each time the volume is changed the active design of the Volume 2 is stable in phase and frequency, which is important to always be sure to monitor the same signal.

A further, very interesting application area is in the construction of a straight, audiophile-quality stereo playback chain, where the Volume2 is situated between the playback machine and either power amp and speakers or simply active speaker system. In such cases, the playback machine must offer analog outputs. This provides for minimal financial and electronic efforts through the most direct possible playback path. 

Multichannel Configurations
The electrical pin configuration of the balanced DB25 input and output sockets comply with the TASCAM standard (see graphic below). The nominal input level is +4dB, other levels are transmitted 1:1. 

DB25 to XLR, TRS or RCA multicore cables are required for connection of input and output signals. The eight channels of the DB25 connector at one side are routed to eight single XLR, TRS or RCA connectors on the other side.

The channel configuration is free (input=output). Here are some common multi-channel configurations:

SMPTE/ITU: L/R/C/LFE/LS/RS/L(t/o)/R(t/0) 
DTS: L/R/LS/RS/C/LFE/L(t/o)/R(t/0)
Film: L/LS/C/RS/R/LFE/L(t/o)/R(t/0)
SDDS: L/LC/C/RC/R/LFE/LS/RS