|Monitor Return Input||Balanced inputs with a range of sensitivity from -20dBu to +20dBu for loudness parity with the internal monitoring. The sensitivity is adjusted by a screwdriver preset on the base.|
|Mixing Bus Inputs||Two inputs directly into the summing amplifiers with their gain adjustable inside the mixer. Maximum sensitivity is 0dBu for +8dBu at the balanced outputs with the master gain set at 0.|
|Balanced Outputs||Two line driver amplifiers provide the output channels and each output is available on both an individual XLR and a combined Multi-way connector.|
|Output Attenuators||The level at either set of connectors can be attenuated by 50dB to provide a nominally microphone level feed.|
|Line Drivers||Floating sources (transformer coupled) with a clipping level of +20dBm into 600 Ohms. Distortion at the nominal peak level of +8dBm is less than 0.01% with a 600 Ohm load 20Hz to 20kHz. The output resistance is 60 Ohms.|
The balanced Mic-Level sends are derived from separate windings on the output transformers. Their source impedance of 200 Ohms is essentially resistive .
|Unbalanced Outputs||A SUBSIDIARY I/O connector carries separately buffered|
outputs at a line level of -10dBu.
|The SUBSIDIARY I/O connector carries four buffered|
outputs at a line level of -10dBu.
If an external link is made on the connector, the operation of the signal routing for channels three and four is changed so that they may be switched out of the mixing bus. Selecting PAN for CH3 or CH4 will now switch the channel out of the mix instead of to the PANpot. This is for the benefit of those who wish to extract the channels separately.
|Meters||Twin peak reading, logarithmic level meters with Peak Programme Meter (PPM) dynamics. Scaling may be BBC PPM, Nordic Norm, or SMPTE.|
VU meters can also be provided. The meters are normally calibrated with the mixer driving a bridging load of 10k Ohms. While the mixer is operating the meters are illuminated by low power light emitting diodes.
|Line Output Level||The nominal line level is normally set at 0dBu for PPM metered mixers and +4dBu for VU metered mixers. Peak level, which is used as a reference for the limiters, is considered to be 8dB above this setting. Other calibration levels are readily available to order.|
|Mixer Inputs||Four transformerless balanced inputs using XLR-3 type female connectors. Channels one and two also share an XLR-5 type connector. Each channel is switchable for:|
|Sensitivity||-78dBu for nominal line level (PPM4, 0VU) with the channel gain at maximum and the master gain at 0dB|
|Max Level, Mic Inputs||-20dBu (+4dBu with full attenuation)|
|Noise Figure||-130dBu (A weighted) from a 200 Ohm source.|
|Frequency Response||20Hz to 20kHz +0, -1dB, referred to 1kHz.|
|Crosstalk||Isolation, channel to unrelated channel: 75dB at 1kHz, 60dB at 15kHz.|
|Channel Configuration||The mixer has four input channels, all of which have the same input selectors, bass cuts and attenuators. The routing arrangements for CH1 & 2 differ from those for CH3 & 4.|
|Channels 1 & 2|
|The operation of the CH1, CH2 pair is controlled by the GANG 1-2 switch on the front panel. This switch has three positions:|
|Phase Switch||Channel 2 can have its phase inverted by means of a front panel switch. This has the incidental effect of interchanging left and right in an MS encoded signal.|
|Channels 3 & 4||The operation of the CH3, CH4 pair is much simpler than the CH1, CH2 pair. Each channel can be routed to LEFT, RIGHT or to a PANpot.|