A while ago, a friend acquired a couple of push-pull RCA8000 amps.
The first time I saw them I said, "those top caps are exposed. They look like a death-trap to me".
I put a meter on one yesterday and sure enough, the exposed part of the top caps was at 560V. Less than I was expecting but even so.
Is anyone aware of where I could get some safe top caps for these tubes please? I've searched online and I've not been able to find any. Maybe the tubes were originally intended to be used safely enclosed.
The first time I saw them I said, "those top caps are exposed. They look like a death-trap to me".
I put a meter on one yesterday and sure enough, the exposed part of the top caps was at 560V. Less than I was expecting but even so.
Is anyone aware of where I could get some safe top caps for these tubes please? I've searched online and I've not been able to find any. Maybe the tubes were originally intended to be used safely enclosed.
Attachments
You can check the dimension of the cap before you order:Grid / Plate Anode Cap - Ceramic for tubes | Amplified Parts
http://www.tubebooks.org/tubedata/HB-3/General/Bases_Top_Caps-7_Pins.pdf
skirt medium cap jetec C1-14 for RCA 8000
skirt medium cap jetec C1-14 for RCA 8000
Attachments
Last edited:
It is a 2,000 Volt RADIO transmitter. It would be enclosed so it did not radiate crap before the output filter. And yes, to reduce deaths in the transmitter room. Even the 300V exciter box would be interlocked against live touching.
I've had worse things on my bench. Even on my coffee table for a week. But it does seem reckless.
Thanks everyone. My friend actually has 3 of them and wants be to build a 4th one to match the odd one. I'm reluctant until I have a solution for the exposed top cap.
Does indeed look like jetec C1-14 for RCA 8000.
Does indeed look like jetec C1-14 for RCA 8000.
Last edited:
Years ago I had an 811 amp that I used kerosene oil lantern glass to avoid contact with the plate cap. I have about a 3/4 inch gap at the bottom for air flow.
You may find some other suitable glass for the 8000.
With only 560 volts on the plate I would not worry about overheating the tube. The getter may be happier with the glass chimney.
You may find some other suitable glass for the 8000.
With only 560 volts on the plate I would not worry about overheating the tube. The getter may be happier with the glass chimney.
Maybe this type plate cap is more suitable? 2PCS VACUUM TUBE ANODE PLATE CAP For WE310A 807 Vintage AUDIO Amplifier DIY HiFi | eBay
Thanks. Getting close! “Medium cap JETEC No.C1-5” according to the 803 data sheet. No skirt on that one though.
Know any machinists? I'd sketch up something like a thick washer to sit below the existing plate cap and machine it from teflon. Perhaps even sculpt something from clay to be glazed and fired?
It may come to that. A ceramic skirt could be 3D printed to go under the existing caps.
