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Sound City Concord Question

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  • Sound City Concord Question

    Anyone familiar with the Concord amp?

    I have a Sound City Concord that has a bad power transformer
    (heater shorted to frame/core and blows the fuse with all secondary connections removed).
    I replaced it with a Hammond 276X and added a borrowed bias (which was easier than it sounds).
    Originally, the power indicator was connected to the 245V primary tap and the amp was configured for 115V input.
    I am using the the Hammond 115V input winding. The Hammond I selected (for use in the US only) does not have the 245V tap.

    Question:
    Can I connect the power indicator to the 115V primary connection without burning the indicator out?
    It looks like it could handle the 245 volts (if you were to use the 245V taps). Also, I did not see and
    specs/ratings on the indicator, although I did not remove it from the amp for an up close inspection.

    I think it would work, but thought I would check with the experts.
    I attached the power supply portion of the schematic as a reference.

    I realize they are somewhat rare (exist in small numbers; not highly desirable).

    All replies are welcome!
    Attached Files

  • #2
    I can only assume that the indicator is a neon lamp with a dropping resistor so that it would work at 245vac. If you connect it to the 120vac line it may not have enough voltage to fire the neon lamp.

    Is there a resistor on the outside of the indicator assembly or is it all self-contained?

    Comment


    • #3
      Agree and add: IF it's just a plain neon bulb and a series resistor, it will still glow on nominal 120V , neon trigger voltage is around 90V (DC) and 120VAC still goes way higher.
      Now the resistor sized for 240V may be too large and the bulb will glow weakly ... but it "should" anyway.

      In the old times I used to open dead or very weak neon panel indicators and glue inside a new bulb and proper sized resistor.

      Today it's harder to get the spare bulbs than the ready made indicator.
      Juan Manuel Fahey

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