Film-Tech Forum ARCHIVE: CP65 cards

This is topic CP65 cards in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Antonio Marcheselli (Member # 373) on 01-12-2003, 07:15 PM:

Hi everyone!

As someone will remember, I'm going to try an EQ to a my friend's theater (a little theater, not commercial) using not conventional tools (Pink Noise from PC, no cat 85c card, no Cat 64 extensions) so I need some tips from you.

1. Can I Plug/Unplug Cat 64 EQ cards without turn off the CP but just lowering to zero the volume?
2. I've read somewhere that there is an "optimal" position for trimpots that set the channel's gain. Like Cp500/650 (that are best at 70% if I remember correctly) is there an optimal position for CP65's trimpot?

Thanks for your help!

P.S. What "cat" means?? [Smile]

Posted by Jon Bartow (Member # 241) on 01-12-2003, 07:37 PM:

Dolby "cat" #xxx equals Dolby catalogue #xxx.
Dolby processors usually handle the 64 cards being pligged/unplugged while hot, but don't tempt fate. The power switch is right there on the front of the cp65, please use it.
Is the RTA on the computer as well?
Jonathan

Posted by Antonio Marcheselli (Member # 373) on 01-12-2003, 07:43 PM:

Thanks Jon

Yes, the RTA is on the PC. But I made a mistake, the PN will be on a CD (not on PC). I'll check that the output level of that PN from that CD Player will be the right one.

Can I turn off the CP by "bypass" button without turn off amplifiers? Can set the fader to zero be enough? Just to avoid ampli on/off continuously...

Bye

Posted by Gordon McLeod (Member # 33) on 01-12-2003, 08:40 PM:

All I ever do is flip to bypass and I have yet to see a power switch on the front of a CP65 Ideally for noise the output level should be 300mv at 50% mod

Posted by Jon Bartow (Member # 241) on 01-12-2003, 08:59 PM:

Sorry, yes, I meant the bypass switch on the front of the power supply [Embarrassed]

Posted by Antonio Marcheselli (Member # 373) on 01-13-2003, 06:00 AM:

Gordon,

How can I measure 300mV at the ouptuts? 1Khz tone for channels and 100Hz subwoofer? Pink noise?

An Italian's Dolby technician said that 5 turns of the trimpot are the right solution. Is it right?

Bye

Posted by Gordon McLeod (Member # 33) on 01-13-2003, 09:58 PM:

With the cat 85c on the out put with the fader at 7 should be set to 300 mv
A solution would be play dolby tone and set the out put of the center channel (when in stereo A) to 300 mv
The inject your pinknoise source and adjust it's level to match that output then do the rest of the channels

Posted by Tom Wienholt (Member # 1510) on 01-13-2003, 11:42 PM:

What equipment is needed to adjust the output of each channel to 300mv? How do you measure this?

Posted by Antonio Marcheselli (Member # 373) on 01-14-2003, 07:24 AM:

Gordon,

Thanks for the useful tip!!

But how can I measure the mV of Pink noise? The usual RMS meter? I had a conversation with one of film-techers once about setting the level of PN. Is a "normal" RMS meter able to display true 20-20.000 response of the PN? Or should I need a special meter?

In other words, can I just connect my meter to the PN output and watch for "300mV"?

Thanks!!