Anyone make their own cage or “protective” cover?
I have been looking at a couple of circuits using top cap tubes like the 807, but having pets and such would like to have the plate cap inaccessible to some degree. Most the circuits I’ve been expiring are SE, so some sort of cover for just the output tube would be nice.
One I’ve seen is the one Pete Millet did. He used a borosilicate glass tube with a machined vent cover which is very slick. I didn’t know how well it would do for heat dissipation though.
http://www.pmillett.com/PL177.html
Let’s hear your ideas and especially see any cages and such you’ve made for inspiration please.
I have been looking at a couple of circuits using top cap tubes like the 807, but having pets and such would like to have the plate cap inaccessible to some degree. Most the circuits I’ve been expiring are SE, so some sort of cover for just the output tube would be nice.
One I’ve seen is the one Pete Millet did. He used a borosilicate glass tube with a machined vent cover which is very slick. I didn’t know how well it would do for heat dissipation though.
http://www.pmillett.com/PL177.html
Let’s hear your ideas and especially see any cages and such you’ve made for inspiration please.
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You can make a cage out of perforated steel that is more hole than solid. Either cover the whole top of the amp with the cage or just around the output tubes giving as much room as possible from the tubes surface to the cage. If you make an open topped screen around the tubes like 3 inches longer than the tube itself you won’t really need a top, just leave it open. That 3 inches is far enough to avoid animal noses from getting to the top cap of the tube. The other option it let them learn the hard way!
From the linked article by Pete Millet : "Notice the two large fans. They are 12V low-noise fans, running off of the 6V filament supply. They are very quiet, and draw air from the rear of the amp. The air is exhausted through the tube sockets into the glass chimneys, which direct air over the tubes and the heat dissipating plate caps. "
Lateral thinking - you only have to stop the top caps coming off. So you can use a U channel piece of aluminium which goes between and covers both top caps when they are on. This can be secured in the centre, between the tubes, by a piece of threaded rod.
Is this clear or do you need a diagram?
Is this clear or do you need a diagram?
That could work!
I also have thought about the typical ornamental tube cages only with a cap on the top.
I used a pyrex cylinder with powder-coated house eave vent covers on top to make my 833C amp safe. 2.3kV on the plate top cap, so it's been torture-tested for sure!
No electrocutions yet...see below for details.
https://www.diyaudio.com/community/...my-833c-amp-build.232484/page-34#post-3832648
No electrocutions yet...see below for details.
https://www.diyaudio.com/community/...my-833c-amp-build.232484/page-34#post-3832648
If the power tubes are all in a line I like a classic rectangular cage, fabricated of brushed perforated aluminum, bend the sheet stock in a "U" shape, walnut sides with the aluminum set in routed grooves. Clips can secure it to be liftable off. Kind of like a Dynaco ST70 cage but prettier and narrower to only cover the row of power tubes. No fan or anything needed.
The ones I’m planning are monoblocks with a single power tube per chassis. But could still do the same thing I think?
You don't need the fan to run very fast. I used a separate small power supply for the fan and ended up dialing down the fan voltage quite a bit as I optimized the amps. Basically you just want to keep the air moving up the chimney, so there is very little "moving air noise" from the fan, and with the separate transformer and PS there is no noticeable electrical noise.
The Noctua fans I used are very quiet to begin with.