Film-Tech Forum ARCHIVE: CAT 242 card

This is topic CAT 242 card in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Tom Wienholt (Member # 1510) on 05-18-2003, 12:50 AM:

In the CP55 manual, it says that the four jumpers (W5, W6, W7, and W8) on the Cat 242 card should be cut if high sensitivity power amps are used. These jumpers are all cut on my 242 card. As a result, I am having trouble getting a sufficient sound pressure level for the surround channel. My question is this. Does each jumper correspond with a certain channel? If so, could i just replace the jumper for the surround channel to get a stronger output signal from the processor?

Posted by Rick Long (Member # 213) on 05-18-2003, 01:01 AM:

Yes.

Posted by Tom Wienholt (Member # 1510) on 05-18-2003, 09:54 AM:

Does anyone know which jumpers correspond to each channel?

Posted by Christopher Seo (Member # 7) on 05-18-2003, 10:08 AM:

I would guess that you'd want to resolder all four jumpers, to improve the S/N ratio for all channels.

Posted by Tom Wienholt (Member # 1510) on 05-18-2003, 10:29 AM:

But i only need a stronger signal for the surround channel.

Posted by Gordon McLeod (Member # 33) on 05-18-2003, 11:07 AM:

You do not have to reconnect all the jumpers the output stages are independent of each other
I believe they are in order or L C R surround

Posted by Tom Wienholt (Member # 1510) on 05-18-2003, 01:37 PM:

Thanks for your help.

Posted by Christopher Seo (Member # 7) on 05-19-2003, 01:59 AM:

I meant: regardless of whether a higher CP output level is required on the other channels to obtain correct SPLs, it would probably benefit the gain structure, and therefore the S/N ratio, to have the CP output levels at normal and the amplifier gains turned down. The extra signal gain in the amplifier stage is unnecessary without high-sensitivity amplifiers and would only tend to amplify noise in the system.

Posted by Gordon McLeod (Member # 33) on 05-19-2003, 10:40 AM:

Ideally set the outputs of each channel to 300mv then adjust the gain on the power amps but that is not always possible