First post, my “new” 18W

18watt-specific Tech Talk - Building, Fixing, Parts, Mods...

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Skydog6653
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Re: First post, my “new” 18W

Post by Skydog6653 »

Are the 200v sprague caps sufficient?
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geoff 1965
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Re: First post, my “new” 18W

Post by geoff 1965 »

the one next to the sozo blocks your DC voltage from the V1 plates so if you've got 150-60 volts on your plates it's not much of a safety margin,i would be happier seeing a higher voltage rated cap like the sozo or mallory's then if you do any mods in future that raise your plate voltage you know it's safe. i.e. i had around 150 on my plates but then i did a cascade mod which brought the plate voltage up to over 200 volts.
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colossal
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Re: First post, my “new” 18W

Post by colossal »

Yeah, you definitely want any coupling cap to be rated for at least the full B+ at no load condition.
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Skydog6653
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Re: First post, my “new” 18W

Post by Skydog6653 »

Hello again, everyone! Apologies for my absence, but I was presented an opportunity to come out of retirement briefly, and couldn't afford to say no! Unfortunately, it manifested into more than anyone ever expected. I still have about two weeks of wrapping things up, but just ordered the F&T dual can cap, the higher voltage caps, several resistors, a tube socket, and a few incidentals. I can't wait to get back to working on my amp. Any available free time I've had lately has had to go towards keeping my chops sharp (otherwise, what's the point)!
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Skydog6653
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Re: First post, my “new” 18W

Post by Skydog6653 »

I can't believe how the days turn to weeks to months! Last week, I finally made the time to solder in several more components. I replaced the two 5W 1K resistors with like cement ones and replaced the two caps with the Zosos. I reused one of the 1K resistors and replaced the old Dale one when I replaced the dual can cap. The amp is much quieter now. It still has a low hum, but so does our other two amps, the Siegmund MS, and a new SFDR. I believe this is a power issue. I'm going to look at power conditioners next. Anyway, here's the chassis as it looks now.
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