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Adding FM reception
to an AM radio

I have an old AM valve radio. Is there an FM radio kit that could be used to add FM reception to the amplifier stage with a separate tuner? (G. K., via email).

  • It is a problem isn’t it? Old valve radios look great but they don’t get FM. At present the only remedy is to modify a small AM/FM radio and feed the FM output to the amplifier stage in your radio. There is no kit to do the job.

    If you want listen to CDs, etc on your radio, why not consider building the Little Jim AM Radio Transmitter described in the January 2006 issue.

    Mosfets for
    TENS unit

    I’m trying to build the Pocket TENS Unit featured in the January 2006 issue. I am having trouble locating the STP6N60E N-channel Mosfets or similar devices, rated at 200V 1A minimum (Q1, Q2). Could you perhaps suggest a different part number? (M. C., via email).

  • You can substitute the low-cost STP4NK50ZD or STF4NK50ZD Mosfets. These are rated at 500V and 3A. You can obtain them from Farnell – see orphone 1300 361 005. Their catalog numbers are 129-1984 and 129-1974 respectively.

    HDTV sound level
    is louder than SD

    I recently purchased an LCD HDTV and when I change from a standard definition broadcast to a high definition broadcast I notice that there is an increase in sound volume. I believe this is because of the different audio system used in HD broadcasting. I have the audio output of the TV going into my stereo system and I find that I am constantly reaching for the stereo system remote control to adjust the sound down to a comfortable level again. This gets a bit annoying after awhile.

    My question is has SILICON CHIP ever thought of publishing a project for a circuit that could be plugged in between the audio output of the TV and the input of the stereo system that would keep the audio at a preset level? This device could also be useful for those commercials that seem to be very loud also. (B. A., Hobart, Tas).

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