A high-end, CLASS-A output amp that offers the basic features required in a smaller mixer configuration. Adding the optional AUX master unit provides all routings plus further output functions. The two L / R master faders attenuate or amplify the L and R signals from all input units. Resulting signals can be seen on the VU meters. These show the amount of signal being sent to the XLR output connectors (LEFT OUT and RIGHT OUT) and onwards to other audio devices, or a PA system. Note: Arthur features a headroom of 30 dB, so its electronics and output amps are rarely likely to clip. The purpose of the VU meters, therefore, is mainly to monitor the level of signal flow to successive audio devices. The ON/OFF buttons connect faders with output amps. These are similar to the MUTE buttons used on other mixers, but their functionality is reversed. When the ON/OFF buttons are depressed, the L and/or R outputs are connected (whereas a MUTE button disconnects the output in its depressed position). The L /R master unit also has a single AUX send and FX return, enabling the connection of a reverb unit. Note: With larger mixers, the reverb / effects unit is probably connected to an additional stereo input unit, where frequency corrections and routings such as “reverb to monitors” can easily be set. This isn't possible in a basic “all through one L / R master unit” configuration. The reverb unit’s input will be connected to the AUX 1 OUT and its output to the FX RET (effect return). This enables the amount of reverb for every input unit (for example the mic units) to be controlled via the AUX 1 knob. This must be set to “post-fade” (orange light on the post/pre button), making the reverb amount dependent on the channel fader position. The FX RET fader controls the amount of reverb mixed in (in the same proportion) to the Left and Right signals on the L/R master output. The L/R master unit also features a switch (positioned on the circuit board) that deactivates the summing function of its AUX 1 section. Changing this switch from its default setting (AUX 1 on) to AUX 1 off means that AUX 1 on the L/R master unit stops running and the reverb unit “takes over” the AUX 1 signals from all channels. The summed AUX 1 signal from the reverb unit can however be picked up for external use. The mixer’s power supply is connected to the DC IN connector. From this 48 Volt DC input, all other units attached to the L/R master unit will also be served via this power supply. For more information on available power supplies, maximum unit numbers etc, please consult the manual. (Chapter: Power Supply and Starting the Mixing Console.)
Combining L/R master units
The Arthur concept enables the combination of a quasi-infinite number of outputs, which can prove useful in a range of situations. The mixer’s structure only allows for one summing amp, which will sum all L and R signals coming from the BUS. The L/R master unit features a switch - positioned on the circuit board - to deactivate that summing function. If more than one L / R master unit is used, only one unit should be left as per its default setting (i.e. with summing on). All additional L/R master units must be switched from their default settings to “summing off”. If using the Master EQ unit together with the L/R master units, this unit will do the “summing job”. In this case, all L/R master units on the mixer must be switched to “summing off”, even if there is only one L/R master unit involved. For more information, please consult the manual. (Chapter: Master EQ Unit)
A high-end, CLASS-A output amp, designed to function as an additional output unit for the L/R master. It provides all routings as well as additional output functions. Installing the AUX master unit to the right of the L/R master unit means that all AUX faders will then go from left to right in numerical order (AUX 1 on the L / R master, AUX 2 and AUX 3 on the AUX master). The unit includes six output amps. Note: All six phone plugs are designed to send balanced signals via space-saving stereo phone plugs. Phone plugs also allow an unbalanced music signal to be connected to any of the outputs via a mono jack. The unit’s PFL (pre fade listen) function is similar to that of other mixers. But, as well as being a traditional PFL, this also serves as a fourth AUX send, (without the possibility to independently set levels on channels.) Signals from any input units that have their PFL buttons depressed (red light), will be controlled via the PFL fader and sent to the output via the PFL OUT. (The headphones’ PFL functionality is not affected by this fader). AUX 2 and AUX 3 faders control the amount of signal on the AUX 2 OUT and AUX 3 OUT respectively. The unit also includes a talkback section with integrated condenser microphone. Depressing the TB ON button (yellow light) activates the talkback section. The preamplified signal from the microphone can be connected from the TB OUT to any (active) loudspeaker system (in the recording room). Or it can be sent directly to the AUX 2 OUT by depressing the TO AUX 2 button. The correct talkback level can be set using the dedicated VOLUME knob. Headphone section. Headphones are connected to the HP OUT, with the VOLUME knob used to adjust level. Music signals from the L/R master will be heard independently from the signal level determined by the master faders’ position. Depressing the PFL to HP button (red light) causes the PFL signal to appear on headphones, provided that the PFL button is depressed on at least one input channel. The control room section is an additional stereo L/R output for driving devices such as room monitors in a recording studio. Other devices can also receive a stereo signal from this output, e.g. a subsidiary PA, side fills, a second recording device etc. The MONO button is useful when listening to a stereo program reproduced in mono, in order to evaluate its “mono compatibility”.
The ARTHUR Subgroup is a high-end, CLASS-A summing amp. It functions as an additional unit for configuring a group of input modules that are to be controlled via a single pair of faders.
Two Subgroup units can be directly mounted in the ARTHUR Format 48 mixer - along with a theoretically infinite number of other sub group units that must be cabled to either a Stereo In or Multiple In unit.
Let’s see how this works in detail: Figure 1 (see below) shows an example of how to mount the Subgroup unit(s). If you are only using two Subgroup units, which in most of cases should be sufficient, the mounting process is very simple: One Subgroup should be positioned to the left of the L/R master and the other sub group to the right. The first step in mounting a sub group is to set the Master Side Switch, which you will find inside the module on the circuit board, near the BUS connector. If the L/R Master is to the right of the Subgroup, do not depress the Master Side Switch. If it is to the left, then depress it. This obviously has to be done before the sub group is connected to the other units.
Once the mixer is put together, one of two LEDs will light up showing which side has been ed. The group of units being controlled via the Subgroup should be positioned “before” the sub group unit, i.e. on the opposite side from the L/R Master unit. Depress the back to L/R button to let the summed signal flow back to the L/R BUS. Any other input units that are next to the L/R master on its left or right sides will be summed by the L/R master and will not be affected by the Subgroup unit(s). An ARTHUR mixer using two Subgroup could therefore be configured as follows, working from the mixer’s left hand side: Input units controlled by the first sub group - the Subgroup itself (master side switch not depressed) - the independent inputs not affected by the sub group - the master L/R unit - another set of independent inputs (if necessary) - the second Subgroup (master side switch depressed) - the input units controlled by that second sub group
The architecture of ARTHUR’s SPRING unit reverb offers the best of both worlds: digital delay and analog decay. Digital delay provides a simple and efficient solution for delay lines that retard or echo the signal before being sent to the spring. However, when it comes to the more complex matter of reverberation, the good old spring still provides a more “natural” and musical solution. The spring unit includes six springs to give a rich reverb effect that also has a time-adjustable decay.
In addition to its function as an ARTHUR mixer module, the spring unit can also be used as a stand-alone unit, providing reverb for a signal from another mixer, or a guitar pedal, for example.
The Arthur master EQ unit is a multi-band parametric equalizer. Many sound engineers look to avoid filters on their main stereo output signals, knowing that these color and flatten the dynamic of the original signal. This becomes audible in the loss of freshness and attack.
The master EQ unit’s architecture avoids any NFB circuitry. Instead it contains straightforward high-voltage Class-A circuits with no negative feedback loops to have a slowing effect. This is very rarely found in a filter configuration and you will need extremely good ears to notice any difference in sound quality between the signal bypassing or passing through these particular filters. Good to know!