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<blockquote data-quote="jeallen01" data-source="post: 1150630" data-attributes="member: 176704">About&nbsp; 40 yrs ago, I had a couple of Amstrad 5000 tuner amps (bought very cheaply from the local Currys!) and every time a local taxi cab drove past, I got the taxi radio breaking through very clearly on one of those (presumed to be via the 10.7MHz IF) - never bothered to try to fix the problem, or had similar problems with any other audio equipment.OTOH, also had a problem with intermittent cracking on the audio equipment that I tracked down to a fridge thermostat - dealt with that by fitting mains transient-suppression components to the power input to the whole audio system.Was working for HP (UK) at the time and we had a &quot;problem&quot; with a particular range of (I think) frequency generators where the internal power supply crowbar protection ccts tripped permanently the first time any such unit was plugged in on a particular MoD site. That site turned out to have a particularly high single-phase mains voltage, which regularly ran higher that the level to which the US design division had tested it, and that, + the regular high transients, tripped the crowbars. I had carefully chosen varistors fitted to the input circuits of all the units, and we never had similar problems again (and the US division learnt a hard lesson about the need for wider mains voltage-range design &amp; testing!) .</blockquote>

[QUOTE="jeallen01, post: 1150630, member: 176704"] About 40 yrs ago, I had a couple of Amstrad 5000 tuner amps (bought very cheaply from the local Currys!) and every time a local taxi cab drove past, I got the taxi radio breaking through very clearly on one of those (presumed to be via the 10.7MHz IF) - never bothered to try to fix the problem, or had similar problems with any other audio equipment. OTOH, also had a problem with intermittent cracking on the audio equipment that I tracked down to a fridge thermostat - dealt with that by fitting mains transient-suppression components to the power input to the whole audio system. Was working for HP (UK) at the time and we had a "problem" with a particular range of (I think) frequency generators where the internal power supply crowbar protection ccts tripped permanently the first time any such unit was plugged in on a particular MoD site. That site turned out to have a particularly high single-phase mains voltage, which regularly ran higher that the level to which the US design division had tested it, and that, + the regular high transients, tripped the crowbars. I had carefully chosen varistors fitted to the input circuits of all the units, and we never had similar problems again[I] (and the US division learnt a hard lesson about the need for wider mains voltage-range design & testing!) .[/I] [/QUOTE]

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