ROYAL OPERA HOUSE CALREC REFURB

[Richard Lumb]

Hi,
Simple schematic seems to explain it.
You have 36 channels which ties up with the routing buttons.
Looks like the Sub group button would take the routing mix and feed to chan sep output
The aux's feed chan 33-40 when their sub group button is selected.
Auxes 1-4 can mix with routing 33-36
So either channels are in chan mode or sub group, mix return. Just like in line mixing on a music desk

There doesn't appear to be a stereo mix, so just choose a pair of channels you want as a stereo mix and VCA group them together so they track.

Does that make sense.

Richard

[brianroth]

Gentlemen,

I have been reading this thread with interest, even though I have no Calrec experience.

I am curious...are the meters LED, or did they use the Borroughs "plasma" bar graph elements? MCI offered them as an option, but they required a HV power supply (250 VDC, as I recall), since they used an unusual neon gas design.

Vishay still sells the "neon modules".

Best,

Bri

[Matt Syson]

Hi Brian.
This desk and the UA8000s used a HP 101 segment LED display in either red or in a few cases, green.
As far as I know only a very few Calrec desks used the gas plasma displays. I can think of one desk only (might have been one of a pair for the same customer) but that was in test at the time I joined Calrec so there may have been a few more but on the other hand Calrec were not 'into' multitrack recording desks with the need for many channels of metering.
The gas plasmas use a 5 phase clock and multiplexing to get the display, with as you say about 240 Volts DC HT supply.
If the drive electronics was kept cool they could be quite reliable but of the several implementations I have seen the need for this heat removal was not taken seriously enough. One or two watts of heat in a small space gets darn warm!
Matt S