Slight Tone Oscillator Drift upon Shoot set-up?

V

vicrattlehead

Well-known member
Hi Everyone,
I have an unusual experience everytime I use my 4-channel mixer with my DVX100b. When I'm getting ready to shoot with my mixer connected (PSC Alphamix w/ PSC Betasnake breakaway cable) I notice that the audio meter will drift slightly after I have set the dials up to -12dB with 400khz reference tone.

Even after disabling the Auto limiting feature, the camera's meters will drift up or down (+/-) 2-4db if I just leave the DVX sitting there with tone running in to it. This is with mixer outs set to line-level and camera in also set to line-level (also does the same thing with everything set to mic level).

It's not a BIG deal, but it makes me wonder if the DVX is wavering on input levels at all times.

Oh, and I have hooked the mixer up to Betacams, and the tone reads constant.

Any ideas on what's going on???
 
I don't have a clue. MAYBE it could be static interference in the cables??....causing them to get a false signal?

i honestly don't know crap when it comes to these really technical things....its just my guess.
 
I am not familiar with this camcorder, but in general, when electronic attenuators are used in automatic gain control (feedback) circuits they don't have to be very stable because they are constantly corrected by the feedback voltage. If the same DC (electronic) attenuator is used in open loop by applying a given DC voltage for attenuation, they can drift. Normally they drift in one direction. If they drift slowly up and down and/or both channels drift differently, I think there is something wrong...Other DVX users same results?
 
Hi and thanks for the thoughts thus far,
Jan- Here is an excerpt from the PSC Alphamix manual upon the subject of mixer output levels: "At the line livel setting, the mixer outputs deliver a nominal +0dBv signal into 10K Ohm loads. When set to microphone level, the outputs supply -50dBv signal levels. Please note that 10K Ohm loads are typical of the loads imposed on the mixer by most Betacams, and other recording devices. Additionally, the Alphamix's outputs are capable of driving 600-Ohm loads."

Does that help any?
 
I think you should probably take it to your dealer and have them evaluate what you are doing. Mostly from here it looks like we do not understand why you are having the problem.

Sorry,

Jan
 
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