5u4gb rattling / rustling from valve itself.

grog · Post by **grog** » Tue Dec 10, 2013 2:52 pm

i powered up the kit1 tonight, all seems ok, voltages all near enough.
only problem is a rattling/rustling/tinkling from the rectifier itself.
it's the same sound as light bulbs sometimes make when they are on their way out.
should i be concerned?
it's audible from near the amp but i'd describe it as reasonably quiet.
circuit is ..
tx-rectifier-(2x47u in series)-10H choke -220uf.

grog · Post by **grog** » Wed Dec 11, 2013 2:10 pm

after some googling it seems that its not so uncommon for 5u4gb's to rattle.
i also noticed that the tx secondary is 100 ohms, this might be a bit low? i found the min resistance for 5u4 (non gb) is 170r.
current rectifier is EH,
options are, add series resistors, 39r to each anode, or new rectifier the same or different type

pre65 · Post by **pre65** » Wed Dec 11, 2013 2:32 pm

I'd try adding the series resistance first.

Mike H · Post by **Mike H** » Wed Dec 11, 2013 4:23 pm

My 5U4G buzzes, last time I used it, so I put the U54 back in. (Or can also use GZ37)

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5u4gb rattling / rustling from valve itself.

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