Dubbing Video Tapes

1/2'' VCR modes

If the source of dubbing is a 1/2'' tape, then, no matter what wiring scheme you use, make sure you configure the playing 1/2'' VCR appropriately: use the menu to set "TAPE DUBBING" to "ON". This bypasses a set of filters that the tape signal goes through before output. Yes, you do want to bypass these filter when dubbing because when the new copy is played back, then, if it was recorded with filtering, double filtering will apply, which may cause serious artifacts (extreme blur, in particular).

Cables

Most of the time, there is no need to manually rig up cable bypasses. Without cable bypasses, tape dubbing simply requires that you use the main editor switch to select where the audio and video signal comes from, and then just hit record. All four decks (1/2 play, 1/2 record, 3/4 play, 3/4 record) get the output of the editor switch.

Cable bypasses are still necessary in the following cases:

When you want to use S-VHS either in the playing or the receiving end of dubbing involving the 1/2'' VCRs.
When you (or somebody else) wants to use other equipment on the video rack while dubbing takes place. A direct hookup will free up the video rack backbone for other uses.
When you want high quality dubbing: the backbone introduces some noise in the transcription process. Now that the audio is fixed, the noise is minimal, yet not completely eliminated.

Here is information on cable bypasses; these cables should be used for dubbing only - as their installation bypasses the standard wiring of the video rack, they are inappropriate for editing.

The general steps you have to follow are:

Pick the appopriate cables depending on the type (1/2'' or 3/4'') of the source and target VCRs. Use the cable labels.
Disconnect the outputs of the source VCR. Only the left VCRs should be used as sources (i.e. for playback).
Connect the one end of the appropriate cables to the source's OUT channels. Use the cable labels to find which end fits the source VCR (the connectors usually make the choice obvious).
Disconnect the inputs of the target VCR. The right VCRs should be used as targets (i.e. for recording).
Connect the other end of the cables.

After dubbing is complete, you simply remove the auxiliary cables. So, when removing the original connections, make sure you keep track of them in order to reinstall them properly. In particular, it's easy to confuse the Right/Left audio channels.

3/4'' to 3/4''

The video channels of the 3/4'' VCRs are directly connected at all times. Two cables are needed to connect the audio channels for dubbing. In particular, you simply need to connect the AUDIO LINE OUT outputs of the left VCR to the AUDIO LINE IN inputs of the right VCR.

If you wish to monitor the recording during dubbing, use the standard switchboard on the video rack and select the TARGET VCR. As the inputs of the target VCR have been diconnected from the rack, there is no danger of feedback loops; moreover, as the outputs of the source VCR have been diconnected from the rack too, you cannot select the source VCR on the switchboard to monitor the recording.

1/2'' to 1/2''

Use the S-VHS cable to connect the video channels of the 1/2'' VCRs directly. A second cable (comprising three separate lines) is needed to connect the AUDIO OUT outputs of the left VCR to the AUDIO IN inputs of the right VCR. This cable also provides a video connection which should not be used.

As above, if you wish to monitor the recording during dubbing, use the standard switchboard on the video rack and select the target VCR.

3/4'' to 1/2'' and 1/2'' to 3/4''

The video rack should be used to transfer the video signal. Two cables should be used to carry the audio signals, connection AUDIO OUT (or AUDIO LINE OUT) of the source to AUDIO LINE IN (or AUDIO IN) of the target.

If you wish to monitor the recording during dubbing, use the standard switchboard on the video rack and select the AUDIO ONLY of the TARGET VCR. In order to transfer the video signal correctly, the video of the source VCR should be selected in the switchboard (as stated above). Use the red/green "shift" buttons to switch only audio or video channels on the switchboard.

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Last modified: Wed Oct 4 16:08:54 1995