OT: Audio on Camcorders

ScoriaMM wrote on 3/18/2002, 12:26 PM
I’m in the market for buying a camcorder, and have been looking at the Sony and Panasonic 3CCD models. Both look about the same, though Im leaning toward the Sony (DCR-TRV900).

What I don’t get, is the external audio input on the cams. It seems that all of them have external stereo mic jacks, but no line level input. What I would love to do is be able to just take a line level feed from a mixing board, or take my john hardy M1, with a pair of mics right into the camera.

What is everyone doing for this (if at all)? Are you setting up some sort of attenuator between the line level source and mic input on the camera?

Thanks for your time!
-Matt


Comments

jboy wrote on 3/18/2002, 12:58 PM
I think some outfit named Beachtek makes an under the camcorder adapter that lets you run 2 xlr mics in and control levels.
ScoriaMM wrote on 3/18/2002, 1:04 PM
>>I think some outfit named Beachtek makes an under the camcorder adapter that lets you run 2 xlr mics in and control levels. <<

Well, I've already got nice preamps I dont need a box with phantom power and a preamp. I need a device to attenuate a line level to the mic input level. It probably wouldnt be too hard to build one, just wanted to see what everyone else was doing. I guess if its that critical, I could run a couple DAT machines while filming, and pop them in Vegas too, but it would be handy to do it on the camera itself.

Matt
Chienworks wrote on 3/18/2002, 3:24 PM
What i did for mine was to buy a 12' cable with a stereo 1/8" plug on one end and two RCA/Phono plugs on the other. I cut the RCA plugs off, built attenuating circuits inside metal barrel 1/4" mono plugs, and solder these onto the cut ends of the cable. I can then plug the 1/4" ends into the line outs on the mixer and the 1/8" end into the camera. Quite serviceable, but 12' is about as long as you'll want to go. If you need greater distance than that it would be better to have the attenuation circuit as close to the camera as possible to reduce hum pickup.

Dirt simple attenuating circuit: in addition to the cable & plugs listed above you will need two 5K ohm and two 100 ohm resistors, all 1/4 watt. (Run cable through 1/4" plug barrel, strain relief, and insulator first; i always forget this step!) Solder the 5K resistor to the tip connector of the 1/4" plug with as short a lead as possible. Solder the center wire of the cable and the 100 ohm resistor to the other lead of the 5K, again keeping all leads as short as possible. Solder the other end of the 100 ohm resistor and the shield of the cable to the shield (sleeve connector) of the 1/4" plug. Cover exposed connections with electrical tape. Screw barrel onto plug. Repeat for the other channel of the cable.

These resistor values are a general starting guess. They should work in most situations. If you find the signal is too low, raise the value of the 100 ohm resistor. If it's still to low then try a lower value for the 5K ohm resistor. If it's too high then raise the value of the 5K ohm resistor. If you get lots of hum then raise both of them proportionally. The combined value of the two resistors should probably be between 500 ohms and 50K ohms. If you go outside this range you'll have problems. Going below 500 ohms or shorting the circuit inside the 1/4" plug could seriously damage your mixer.

I can post a circuit diagram and a photograph later on if anyone needs them.

ps. Should i post a disclaimer that i accept no responsibility for any damage or loss incurred by using these instructions? As always, test this BEFORE going to the big once-in-a-lifetime recital!
Caruso wrote on 3/20/2002, 3:46 AM
Am I reading correctly? I've had my eye on the Sony Cam mentioned in this post. If memory serves me correctly, this is a three-CCD machine that has a great reputation. Are you telling me a machine in this class has no audio line inputs?

Caruso
ScoriaMM wrote on 3/20/2002, 6:56 AM
>>Are you telling me a machine in this class has no audio line inputs?<<

Well, apparently not. It does have a regular L/R/V mini 1/8" analog input, but from what I can tell, this can only be used in VCR mode (for archiving old VHS and whatnot). When you're actually recording to MiniDV tape through the lens your only option is the mic input. I've found this to be true on seemingly every camera I've looked at.

Sort of a pain, and strange if you ask me, as it seems a lot of people would use this feature, but its fairly easily worked around with 5 to 10 bucks in parts from radioshack.

-Matt
BD wrote on 3/20/2002, 10:41 AM
I use Sony's TRV900 and VX2000 camcorders. The VX2000 has a switch to select either mike or line input to the stereo miniplug jack, unlike the TRV900.