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I was asked to help sort a problem with a Bradford system based electronic three manual organ installed in a church. Plate on the organ said it was Bradford system, but not exactly who built it.
Anyway, it seems to be all working but there is an issue over the connections to the speakers. There are two signal cables from the console, one to each of two amplifiers, which are set up in the original organ loft, next to an older pipe organ.
Amplifiers and cables appear to be identical. The black box amplifiers each have four pairs of bannana/4mm push in connectors on the back, one row for positive and one negative. I opened one of the amps to check out why there was no output, and I see it is actually three amplifier channels. The two centre outputs are simply wired in parallel.
The speaker wiring for one amp had been disconnected and there is a question how it should be reconnected.
There are four high frequency speakers and three bass speakers in the setup. The other (undisturbed) amplifier has high frequency speakers connected using white cabling to the extreme left and right sockets on the amplifier, with two bass speakers connected to the two centre connectors using grey wiring. The disturbed wiring has two white cabled hf speakers and one grey bass speaker.
Does anyone recognise this setup so could advise how its is meant to be wired?
Thinking about it, I am guessing the two amplifiers are identical and standardised. The treble and bass speakers are each seemingly identical. That it makes sense to have the bass speakers doubled up to give the physical speaker area to give that punch to the sound. So, it would be logical for the system to have been designed with a left and right channel and a doubled up bass speaker on each channel. Everything would then be simple to install without mixups given a little knowledge.
Does anyone know how the sound output is divided up, as there are three manuals and a pedalboard and assorted stops being reproduced on these two output channels?
Internally the organ has two main processing boards each with two Z80 microprocessors. So that might create four signal channels. There are additional post-processing boards which seem to modify the signals from the main boards. The boards seem nicely finished with all socketed chips. The whole is around 30 years old.
Anyway, it seems to be all working but there is an issue over the connections to the speakers. There are two signal cables from the console, one to each of two amplifiers, which are set up in the original organ loft, next to an older pipe organ.
Amplifiers and cables appear to be identical. The black box amplifiers each have four pairs of bannana/4mm push in connectors on the back, one row for positive and one negative. I opened one of the amps to check out why there was no output, and I see it is actually three amplifier channels. The two centre outputs are simply wired in parallel.
The speaker wiring for one amp had been disconnected and there is a question how it should be reconnected.
There are four high frequency speakers and three bass speakers in the setup. The other (undisturbed) amplifier has high frequency speakers connected using white cabling to the extreme left and right sockets on the amplifier, with two bass speakers connected to the two centre connectors using grey wiring. The disturbed wiring has two white cabled hf speakers and one grey bass speaker.
Does anyone recognise this setup so could advise how its is meant to be wired?
Thinking about it, I am guessing the two amplifiers are identical and standardised. The treble and bass speakers are each seemingly identical. That it makes sense to have the bass speakers doubled up to give the physical speaker area to give that punch to the sound. So, it would be logical for the system to have been designed with a left and right channel and a doubled up bass speaker on each channel. Everything would then be simple to install without mixups given a little knowledge.
Does anyone know how the sound output is divided up, as there are three manuals and a pedalboard and assorted stops being reproduced on these two output channels?
Internally the organ has two main processing boards each with two Z80 microprocessors. So that might create four signal channels. There are additional post-processing boards which seem to modify the signals from the main boards. The boards seem nicely finished with all socketed chips. The whole is around 30 years old.
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