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Old 9th May 2022, 7:34 am   #7
Radio Wrangler
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Join Date: Mar 2012
Location: Fife, Scotland, UK.
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Default Re: Thoughts on this HiFi line amplifier?

To help many smll neons ionise and get going, there were often some radioactively frolicksome additives to their gas content. Over time, half-lives go by and their effect reduces, leaving increasing strike voltages. HP and Tek used these bulbs as voltage references in power supplies in their instruments. They are now troublesome and NOS bulbs are no better.

Also, the current flow in a gas discharge tube has long been used as a noise generator. Words you don't expect to find in a pramplifier. Care is needed over filtering BUT with much capacitance around, it's easy to kick of a relaxation oscillator. Use with caution!

David
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