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Help reading the scale on my Heathkit IG-18 Signal Generator

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  • Help reading the scale on my Heathkit IG-18 Signal Generator

    So, I have this Heathkit signal generator that I have been meaning to use in some trouble shooting. I have the original assembly and operation manual, but can't figure out how to interpret the meter readings for setting the amplitude for my test.

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  • #2
    You set the amplitude control for max. voltage the range can produce. It will be a multiple of 3 or 10. Then you use the appropriate scale (3 or 10) adjusting the decimal place as required.
    So, for example, on the .3V range, you would read the top scale (3), and a '2' reading would be .2V
    "Everything is better with a tube. I have a customer with an all-tube pacemaker. His heartbeat is steady, reassuring and dependable, not like a modern heartbeat. And if it goes wrong he can fix it himself. You can't do that with SMD." - Mick Bailey

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    • #3
      Originally posted by g1 View Post
      You set the amplitude control for max. voltage the range can produce. It will be a multiple of 3 or 10. Then you use the appropriate scale (3 or 10) adjusting the decimal place as required.
      So, for example, on the .3V range, you would read the top scale (3), and a '2' reading would be .2V
      Thanks, G1. I didn't read the manual carefully. Do you have a sine wave frequency that you use when trouble shooting preamps?

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      • #4
        I've been using 400Hz forever, mostly I find it much less annoying than 1K.
        "Everything is better with a tube. I have a customer with an all-tube pacemaker. His heartbeat is steady, reassuring and dependable, not like a modern heartbeat. And if it goes wrong he can fix it himself. You can't do that with SMD." - Mick Bailey

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        • #5
          I tend to use 100Hz for the same reason. But way more than sine waves, I just use music - like from a CD player.
          Education is what you're left with after you have forgotten what you have learned.

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          • #6
            Originally posted by g1 View Post
            I've been using 400Hz forever, mostly I find it much less annoying than 1K.
            Juan had given me some reason to use 400hz but I don't remember what it was,

            nosaj
            Binkie McFartnuggets‏:If we really wanted to know the meaning of life we would have fed Stephen Hawking shrooms a long time ago.

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            • #7
              Originally posted by Enzo View Post
              I tend to use 100Hz for the same reason. But way more than sine waves, I just use music - like from a CD player.
              100 Hz here too for larger amps. 200 Hz for smaller ones where 100 would challenge dinky output transformers. And with that in mind 500 Hz for Champs and Champ-like SE amps. All guitar amps get a guitar played thru them as a final test, bass for bass amps. This final test often reveals problems that don't show with single frequency or sweep sin wave tests.

              And yes, these lower frequencies are a lot easier on the ears.
              Enjoy. Every. Sandwich.

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              • #8
                Originally posted by g1 View Post
                I've been using 400Hz forever, mostly I find it much less annoying than 1K.
                it certainly is if you have to listen to it (output transformer "singing" not withstanding). IkHz make mathematical sense as a mid band freq., but it is NOT what you'd consider mids if you listen to it.
                Regardless, I still use it as a default for signal testing
                If I have a 50% chance of guessing the right answer, I guess wrong 80% of the time.

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                • #9
                  Originally posted by SoulFetish View Post
                  IkHz make mathematical sense as a mid band freq., but it is NOT what you'd consider mids if you listen to it.
                  I'd agree with 1K as midrange for Hi-fi or PA, but not for the guitar amp world. 440Hz is high E string fretted at 5th fret (standard pitch). So everything else is below that.
                  "Everything is better with a tube. I have a customer with an all-tube pacemaker. His heartbeat is steady, reassuring and dependable, not like a modern heartbeat. And if it goes wrong he can fix it himself. You can't do that with SMD." - Mick Bailey

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