Film-Tech Forum ARCHIVE: Cat 64 question

This is topic Cat 64 question in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Matthew Taylor (Member # 2310) on 12-18-2005, 10:54 AM:

What is the relationship between the gain , input and output adjustments on the cat 64 card?

I have set the centre channel levels using dolby tone and ensured output level from the cat 64 was 210mv but the centre channel is really distorting. I have played around with the gain and the input controls but I don't really understand what they do.

[ 12-18-2005, 12:00 PM: Message edited by: Matthew Taylor ]

Posted by Brad Miller (Member # 2) on 12-18-2005, 12:15 PM:

Download the Dolby CP50 manual. It explains the settings in there.

Posted by Gordon McLeod (Member # 33) on 12-18-2005, 12:25 PM:

Matthew From the number of topic you have started relating to this CP50 I think you need to get someone who is experienced with it to deal with the unit

Posted by Matthew Taylor (Member # 2310) on 12-18-2005, 12:49 PM:

Yes, I probably could do with that, but it's a learning curve for me. Im not in the trade and this is the first processor I've had and I'm trying to deal with the (many) issues as I come to them. Because this is only for my hobby (and my hobby is financially constricted), there's not an urgency to get these things sorted. I've got some good advice on here, but if I'm bugging the FT community too much, then I'll try to desist.

I must admit, I reckon I'm due to get the 'mosts posts pertaining to the CP50' award though :-)

Posted by Richard May (Member # 2627) on 12-18-2005, 01:18 PM:

Nothing wrong with asking questions. That's what this site is supposed to be for.

Posted by Ben Wales (Member # 92) on 12-18-2005, 02:59 PM:

Matthew: You will need to set the Imputs on the Cat64 (fully counterwise) and set the imput gain to min gain, you can adjust if required the ouput gain on the Cat64 card measured from the Output card, but have to bear that this card would have be correctly adjusted, I found with my CP50 I set all the four output channels (output card) at 5 turns each on the Trim pots as a starter.

I assume you have the correct test equipment required for alignment of your CP50?.

Posted by Marin Zorica (Member # 1716) on 12-18-2005, 04:02 PM:

I think first you must discover is problem in Cat 64 (EQ) or in cat 150 (matrix decoder).
Is left and right channel distorted, as you don't mentioned this i assume they are ok. So swap other cat 64 from L or R channel and put it on Center channel, if them sound isn't distorted then problem is in that Cat 64 (may be some OP amp is bad), or if problem remain, then i think failure is in Cat 150 decoder.

Posted by Matthew Taylor (Member # 2310) on 12-18-2005, 04:50 PM:

Thanks Ben and Marin.

All I have for test equipment is the Cat 69 tone, multimeter and scope. I don't have the pink noise generator or RTA. I am relying on it sounding reasonable to the ear rather than set up perfectly.

Thanks for the advice, I will try to have a go tomorrow.