Film-Tech Forum ARCHIVE: Where can I find test cables?

This is topic Where can I find test cables? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=008078

Posted by Frank Dubrois (Member # 3042) on 06-13-2006, 01:32 AM:

I am considering trying to use my laptop (I know its not recommended but its all I have for now) for doing A-chain alignments. I need to pick up a set of cables or possible make a set. Any plans online? Anywhere I can just by them? I know they can be easily made, so either is fine. Thank you!

Posted by Monte L Fullmer (Member # 2797) on 06-13-2006, 02:34 AM:

Got any sound spectrum analysing programs to see any form of sound waveform in your laptop for beginners - so you can measure each side of the camera's outputs..if using LED reverse scan readers?

If so, then a USB external sound card with RCA inputs is then needed to accept the audio waveforms-since you're basically measuring voltage....

Also, goto the manuals section (if you got Dolby units) and open up the manuals...where one can use a simple headphone setup to tap across the preamp test points for left/right balance...when using a CAT-69T 1kz tone loop...

Posted by Mark Gulbrandsen (Member # 72) on 06-13-2006, 07:21 AM:

You can get your test cable adaptors from any Pomona Dealer and just buy standard length BNC cables in what ever length suits your needs. Try Allied Electronics, Newark, etc!

Mark

Posted by Frank Dubrois (Member # 3042) on 06-13-2006, 12:22 PM:

I saw a unit (I think it was a PDA with an analyzer strapped to the back) and it had a set of cables that had 3 smalle probes at one end (red, green, black) and they went into two RCA type plugs (red, white) anyone seen anything like that? If so, where. It looks like they would be easy to make if I could find the correct small tipped ends for the red, green and black. Those ends plugged into the dolby cards.... I wish I know if that set of cables had a name, it would make it easier to describe.

Posted by Gordon Burke (Member # 3370) on 06-13-2006, 01:42 PM:

Pomona and others call them "Pin Tip Plugs" and the basic diameter is .080"

Pomona's 5173 allows for crimping or soldering to 22-18AWG wire.

I use the 1431/1432 banana-to-pin tip adaptors because I have a lot of banana equipment.

The 2mm "mini" banana will work too, but I bet it stretches out the contacts on the jacks.

Posted by Marin Zorica (Member # 1716) on 06-13-2006, 03:23 PM:

I'm also using computer for A & B Chain aligments, using ESI Juli@ soundcard! For probes i use this, don't know where to buy, I made by myself and You can do it you're self, see It's easy to do! You can attact thiese crododiles to any test point!

Posted by Frank Dubrois (Member # 3042) on 06-13-2006, 08:12 PM:

To do an A-chain, don't I need a LEft and a Right input? When I say this set of cables, it had 3 cables (red, green, and black) and two RCA plugs on the other. Coud I replace the two RCA plugs with a stereo mini plug to plug into a laptop mic plug?

Thanks for the names of those plugs Gordon..gives me a great jump on finding the correct ends.

Posted by Gordon Burke (Member # 3370) on 06-14-2006, 01:13 PM:

The problem with the laptop's mic input is that the test points on dolby processors are about "line level," so unless you have a 50dB pad to insert between the leads and the laptop, the signal is too high. Just turning down the software mic "gain" won't correct this.

Better to get a USB/firewire audio interface from M-Audio or other musician oriented manufacturer. The audio interface can have analog circuits and A/D conversion that are way better than any laptop and are usually designed to handle a wide range of loading and signal conditions.

A "stereo" signal is really only necessary if you are using a 'scope program on the laptop because one of the important checks is X/Y-ing the left and right to check azimuth. If the RTA software has a two channel comparison function, then the stereo option will make it easier to get the channels to match. Doing a cross-talk test requires the ability to see a dual-trace scope display to compare both channels to each other.

Posted by Frank Dubrois (Member # 3042) on 06-14-2006, 01:38 PM:

I had anticipated using winscope on a laptop. Would I be able to use that and adequately to an A-Chain? I just dont have the equiptment, and the chain wont spring for it.