Converting +4 line to -10 line level...

Discussion in 'rec.audio.pro' started by Richard Carlisle, Aug 23, 2003.

  1. I have a device with a +4 level output and need to plug this into the audio
    input (RCA) on the back of a VCR. I'm assuming the VCR is -10 since most
    consumer stuff is.

    Is there an easy way to match these up?

    Can I just use a resistor on the +4 input or is there more to it?

    Does anyone know of a website that might show schematics of a converter
    circuit?

    Thanks in advance....

    Ross
  2. Richard Carlisle wrote:

    > I have a device with a +4 level output and need to plug this into the audio
    > input (RCA) on the back of a VCR. I'm assuming the VCR is -10 since most
    > consumer stuff is.
    >
    > Is there an easy way to match these up?
    >
    > Can I just use a resistor on the +4 input or is there more to it?
    >
    > Does anyone know of a website that might show schematics of a converter
    > circuit?



    Jay Rose has a nice newbie-friendly artical on pads in his book which he
    also nicely put up on his website http://www.dplay.com/book/pgs2e/pads.pdf
  3. Ron Charles

    Ron Charles Guest

    The Aphex 124a line level matching device will work very very well.

    Let me know if you need one as I have an extra stereo unit I would sell for
    $65 plus shipping.

    RON CHARLES

    "Kurt Albershardt" <kurt@nv.net> wrote in message
    news:1061615798.983659@nnrp1.phx1.gblx.net...
    > Richard Carlisle wrote:
    >
    > > I have a device with a +4 level output and need to plug this into the

    audio
    > > input (RCA) on the back of a VCR. I'm assuming the VCR is -10 since

    most
    > > consumer stuff is.
    > >
    > > Is there an easy way to match these up?
    > >
    > > Can I just use a resistor on the +4 input or is there more to it?
    > >
    > > Does anyone know of a website that might show schematics of a converter
    > > circuit?

    >
    >
    > Jay Rose has a nice newbie-friendly artical on pads in his book which he
    > also nicely put up on his website http://www.dplay.com/book/pgs2e/pads.pdf
    >
    >
    >
  4. Ron Charles

    Ron Charles Guest

    The Aphex 124a 2 channel signal level matching device will work very very
    well for this application.

    I have one for sale at $65 USD plus shipping if you need one.

    RON
    "Richard Carlisle" <rrcarl@nhvt.net> wrote in message
    news:BB6C605E.12CA%rrcarl@nhvt.net...
    > I have a device with a +4 level output and need to plug this into the

    audio
    > input (RCA) on the back of a VCR. I'm assuming the VCR is -10 since most
    > consumer stuff is.
    >
    > Is there an easy way to match these up?
    >
    > Can I just use a resistor on the +4 input or is there more to it?
    >
    > Does anyone know of a website that might show schematics of a converter
    > circuit?
    >
    > Thanks in advance....
    >
    > Ross
    >
  5. Ben Bradley

    Ben Bradley Guest

    In rec.audio.pro, Richard Carlisle <rrcarl@nhvt.net> wrote:

    >I have a device with a +4 level output and need to plug this into the audio
    >input (RCA) on the back of a VCR. I'm assuming the VCR is -10 since most
    >consumer stuff is.


    Yes, the VCR probably is -10

    >Is there an easy way to match these up?


    If the +4 device is a mixer or similar device with an output level
    control, turning it down about 11dB would do it.

    >Can I just use a resistor on the +4 input or is there more to it?


    You said you have a +4 output and a -10 input. Anyway, yes, it's a
    little more complicated, it takes two resistors in a resistive divider
    circuit.

    >Does anyone know of a website that might show schematics of a converter
    >circuit?


    There's most likely an ASCII schematic with derivation of the
    resistor values somewhere on groups.google.com. I recall that this
    exact question has been answered to several decimal places on
    rec.audio.pro before.

    >Thanks in advance....
    >
    >Ross
    >

  6. > There's most likely an ASCII schematic with derivation of the
    > resistor values somewhere on groups.google.com. I recall that this
    > exact question has been answered to several decimal places on
    > rec.audio.pro before.
    >


    Thanks Ben. I found a nice, simple resistor pad schematic here. Just what
    I needed.

    Ross
  7. Garthrr

    Garthrr Guest

    In article <3f46fe2a_1@news.cybersurf.net>, "Ron Charles" <portugal@3web.net>
    writes:

    >I have a device with a +4 level output and need to plug this into the
    >audio
    >> > input (RCA) on the back of a VCR. I'm assuming the VCR is -10 since

    >most
    >> > consumer stuff is.
    >> >
    >> > Is there an easy way to match these up?
    >> >


    The Henry Engineering Matchbox does a good job.

    Garth~


    "I think the fact that music can come up a wire is a miracle."
    Ed Cherney
  8. Scott Dorsey

    Scott Dorsey Guest

    Richard Carlisle <rrcarl@nhvt.net> wrote:
    >I have a device with a +4 level output and need to plug this into the audio
    >input (RCA) on the back of a VCR. I'm assuming the VCR is -10 since most
    >consumer stuff is.


    With a VCR you can't really know. The levels are all over the place, and
    the automatic gain controls make it hard to tell where they really are.

    >Is there an easy way to match these up?


    I'd suggest an adjustable pad. Turn the knob until it doesn't clip.

    >Can I just use a resistor on the +4 input or is there more to it?


    Get a 10K audio-taper potentiometer. Tie the righthand leg to the input
    jack, the center slider to the output jack, and the lefthand leg to the
    ground on both. Adjust the level until it doesn't clip any more.
    --scott
    --
    "C'est un Nagra. C'est suisse, et tres, tres precis."

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