Tape Monitor on 500-C

Discussion in 'Fisher' started by Vinylcafe, Feb 2, 2013.

  1. Vinylcafe

    Vinylcafe Linvin' the Dream

    Messages:
    989
    Location:
    Vancouver, Canada
    I've started using the tape monitor circuit on my 500C instead of Aux In, as that now has a CD player.
    Apart from the horrible spacing of the RCA jacks, the other issue is, I need twice the output gain for the same volume when using this input as opposed to Aux.
    Is that normal? If so, what is going on.
    Would love any insight.
     

     

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  2. gsoravil

    gsoravil Fisher Fan

    Messages:
    173
    Location:
    Englewood, Florida
    I'll check my 800-C and let you know...but I'm thinking that's not normal.
     
  3. gsoravil

    gsoravil Fisher Fan

    Messages:
    173
    Location:
    Englewood, Florida
    Well son of a gun, it's the same as yours. I wonder why it does that.
     
  4. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

    Messages:
    21,760
    Location:
    Glen Burnie Md.
    It's NORMAL! Because the tape monitor is one stage after the AUX (which uses part of the EQ stage). So you get less gain on the Tape Mon. IT was originally designed to be used with "3 head" tape decks to listen to the recording thru the receiver while recording usually with a 1/4 to 1/3 second delay (basically the time differential between the Record Head and the play back head). Note that if you have something on the AUX plugs and turn on the Tape monitor the level will go down but will still play. Fisher is a strange steup this way. Other units cut the tape monitor to a separate input.

    Play the CD on the AUX. If you have more sources than plugs, use a selector box. Then plug IT into the AUX circuit.

    Larry
     
  5. audiodon

    audiodon Addicted Member

    Messages:
    9,297
    Location:
    Arlington, MA
    Play your better source on the aux, and your secondary source on the Tape Mon input.
    Since Tape Mon only uses one of the two tone amp/line stage tubes, the absolute phase of this input is inverted as well as it not having as much gain as the aux input.
    So, if you reserve your best source for aux and your other source for tape mon, all you have to do is remember to make sure the source is not playing into the aux input so there's no bleed-through.

    For my living room system, the IPOD/IPHONE male stereo connector to RCA cable for the kids goes to the tape mon switch.
    It serves two purposes:
    1. The input is not as good as my digital player and
    2. The gain is lower so the kids are less likely to make a mistake.

    Anything beyond this would involve rerouting wires inside. An alternate method would be to use an outboard line-level input switcher.
     
  6. Vinylcafe

    Vinylcafe Linvin' the Dream

    Messages:
    989
    Location:
    Vancouver, Canada
    Thanks guys!
    Think I will investigate a swiching box.
    I might be dreaming, but the tape monitor circuit seems a tad "muddy" when compared to my aux input.
    As for 3 head recorder monitoring, deck can do that in aux too.
     

     

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  7. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

    Messages:
    21,760
    Location:
    Glen Burnie Md.
    The muddiness is from the lack of 1 stage, and it being opposite phase. Nothing to fix. As AUX and Tape monitor are series'ed both will do record monitoring. The premise was that you could compare the original source with the monitored source back to the receiver. Obviously you can't record from the PHONO, and monitor from AUX, as the source being recorded from has to be selected. That's why the tape monitor with the delay. You can then flip between the original record sound on Phono, then while it's recording listen to the tape from the Tape Monitor.


    NOTE: you can do the same thing with FM but used PHONO as an Example. Haven't tried this yet, but I wouldn't try to monitor from tape monitor while recording from a source on AUX. It'll overload the circuit,due to feedback from Tape monitor.
    FISHER advises using the TAPE MONITOR ONLY while recording. For Playback the AUX-TAPE position will playback a tape deck connected to AUX or the MON jacks.

    Owners Manual for the 500C is on the WWW.FISHERCONSOLES.COM Site here http://www.fisherconsoles.com/non console manuals/fisher 500c om.pdf



    Larry
     
    Last edited: Feb 3, 2013
  8. berry1235

    berry1235 New Member

    Messages:
    5
    You say an input into tape mon will play through aux tape. How do you switch between what's on the tape monitor and aux - tape?
     
  9. dcgillespie

    dcgillespie Fisher SA-100 Clone Subscriber

    Messages:
    9,622
    Location:
    Ball Ground, GA
    That's just it, as designed, the tape monitor function and tape/aux functions are inter-mixed -- designed to accommodate either 2 head or 3 head tape recorders, which for the 500C, was about the only high level external source available (other than maybe an AM tuner) back in the day. The idea was that a 2 head deck would playback through the aux inputs (no monitoring possible), and a 3 head through the tape monitor input -- which could be accessed either by the monitor switch (for monitoring during recording) -- or by the selector tape/aux setting for normal playback. Today, the whole setup is an anachronism allowing different signals to bleed together, making the tape monitor inputs and aux inputs unusable as separate, independent inputs.

    If you would like to remove this feature (recommended), it is easy to do:

    With the receiver turned off and unplugged, turn it over and remove the bottom cover. Locate the Aux and Monitor input jacks. You will note that at these jacks, there is a 330K resistor and 120 pF cap connected between the center terminals of the jacks in each channel. Carefully clip out both of these components in each channel, and you're done. Replace the bottom cover, and now you've got two independent inputs (Aux/Tape Play and Tape Monitor) that don't interact with each other. Note however that it is normal that the Tape Monitor input will have reduced sensitivity as compared to the Aux/Tape Play input.

    I hope this helps!

    Dave
     

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