Heathkit Station

Discussion in 'Amplitude Modulation' started by KA5SDC, Apr 23, 2019.

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  1. K5UJ

    K5UJ Ham Member QRZ Page

    Last fall, W9SWR was on 75 m. one night and he had three D104 heads, one with an Astatic xtal element, one with the Astatic ceramic element and a third with a Kobitone xtal element. He did an ABC test swapping the heads on a G stand. the Astatic xtal element sounded great; the ceramic element almost as good but not quite. If he had not mentioned anything about it being ceramic, one might have not noticed anything. The Kobitone was comparatively abysmal, just awful. No where near the clean clear sound of the Astatics. The two or three of us on frequency told him to pull it out of the D104 head and throw it in the trash.
  2. W2VW

    W2VW Ham Member QRZ Page

    Rob, you can post audio clips, frequency response charts and reviews by people who know good from awful.

    In a few weeks internet folklore will take over like nothing ever happened.

    Same for a variety of pet subjects.

  3. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page


    I wonder if the Kobitone element was the 25LM022 or the 25LM025. The 25LM025 was available for quite some time after the 25LM022 was discontinued. When both elements were still available from Mouser, I tried both of them and the reports using the 25LM025 were no where as good as when the 25LM022 was used.

    In the past, I made a kit to convert D-104 microphones with blown microphone cartridges to the 25LM022. This kit had a styrofoam disc, with a center hole in which the Kobitone cartridge was mounted, that fit inside the D-104 head. The connecting wires were unsoldered from the original cartridge and then soldered to the Kobitone element. During the time I was selling these kits, I never got a single complaint and got several very complimentary comments about the audio quality.

    I found a hole saw at Home Depot that produced a "perfect" sized disc. The disc would push into the D-104 head providing the support to hold it in place. Another hole saw produced the center hole in which the 25LM022 was pushed and the cartridge was well supported as well. I still have both hole saws! I don't really use them. But, if the 25LM022 ever comes back, they will be ready to make more conversion kits!

    The microphone that uses the 25LM022 element is an old Radio Shack "end fire" type. The Kobitone element was just slightly smaller in diameter so I use a piece of double-back "sticky" foam to hold the cartridge in place. The microphone is mounted on a "goose neck" attached to the first shelf in my main operating console. I have had that microphone for over 40-years!


    Glen, K9STH
  4. K4KYV

    K4KYV Subscriber QRZ Page

    What I hate is when I hear of someone gutting a perfectly good D-104 to put in some kind of crappy "modern" cartridge, and then throwing away the original, or tearing it apart to see what's inside. There are only a finite number of working cartridges left, now that Astatic has discontinued producing them and no-one else has attempted to make an authentic after-market replacement. Every time one is foolishly destroyed, that's one fewer in existence on the planet.
    AF7XT and N2EY like this.

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