Ed's AV Handbook.com
Home Theater & High Fidelity Stereo Audio

Chapter Five
The AV System Sequence

Page 2

Batting practice for the audio/video pro and a primer for the novice 

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The Alternate Route
The Record Output Input Loop

          Stereo receivers, audio preamps, plus many AV pre/pros and AV receivers include a useful diverting exit and re-entrance point called the record or tape loop.  The loop is primarily intended for recording devices.  
          Think of the record loop as an off-ramp with a quick on-ramp.  
When a source is selected it begins its path towards the preamp output.  Prior to entering the volume or any other manipulating processing, the source is simultaneously routed to the record output as it also continues on its 'normal' path to the preamp output.  
          The record output level is fixed.  It is not affected by pre-amp controls such as the volume or tone controls.
 Its unaffected output can be fed to the input of a recording device.

          The tape input is a re-entry point still prior to any manipulating process.  Engaging its corresponding front panel tape button (tape monitor) allows the audio from the recording device to re-enter the preamp.  (This button overrides all other input selections.)  Disengaging the tape button allows a normally selected source to pass.
          Many preamps include a record output selector.  It offers the option of routing a source to the main output, while routing a different source to the record output.

Handbook Note:
Many tape recorders provide 'The 3rd head'.  A 1st tape head prepares-erases-biases the tape.  A 2nd tape head records the audio.  The next in the path 3rd head is the playback head.  It allows users to compare their recording to the source in real time by engaging/disengaging (monitoring) the 3rd head with a tape monitor button on the recorder.   Then the 'tape monitor button' on the preamp can choose to listen to the tape deck's 3rd head or the source.

Record Loop Processing Options
          A record loop can also be used as an audio processing loop for inserting an equalizer, reverb, mixer, or surround sound decoder.  The audio is routed to the device, processed and re-engaged via the tape monitor button.

          Many manufactures have re-labeled the 'record output' as the multi-room output and the 'record output selector' as the multi-source selector.  This feature promotes the routing of sources to an amplifier with speakers in another room/zone.

Video Routes
          The video source component determines the video cable path to the video display. Contemporary product is now widely limited to only HDMI.  However many legacy products
employ composite video, S-video, component video, RGB, or DVI.  
          The issue -- If you start the sequence with composite video you must continue to the TV with a composite cable; if you start with component video then you must continue with component cabling, and so on.  If you install multiple video sources with different types of outputs; then you must run multiple types of cabling and accordingly change the TV inputs for each.  This is true unless you employ an AV receiver or preamp/processor that offers video trans-coding.   Typical
transcoding converts:
      a.  Composite video to component video.
      b.  Composite video AND component video to HDMI.
The transcoding feature has dissapeared from many new AV receivers.  If required, be careful with your component selection.

Handbook Note:
If the tape monitor is accidently engaged it mutes the audio.  Only the playback - if attached - of a tape deck can be heard.  This is a common problem for consumers with a stereo receiver.  If the record loop is not used; 'close-the-loop' by inserting an audio interconnect from the tape output to the tape input.

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Ed's AV Handbook.com
Batting Practice for the AV Pro and a Primer for the Novice.
Copyright 2007 Txu1-598-288   Revised 2018