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I strayed over into the audio threads...
and came across a cool thread about heat. Dear to my heart it is, and so I paste my response here fer u'all:
Intriguing thread idea... Although my high-power tube audio days are over (Citation IV and V), and have shifted to vintage color TV (36 tubes in a CT-100; 410 watts at 115 Vac) I do get concerned about stress on the old sets anytime I run one for more than a few minutes, summer or winter. Never worried about the 12AX7's in my Citation preamp, but like the Citation V then, I still gauge equipment stress indirectly by the warmth of the power transformer: if it's quite hot to the touch, it's been on too long in that given environment. It's a subjective assessment to be sure, but one I've used over the years to coddle important tube-based electronics. My philosophy here is steeped in troubleshooting high reliability tube-based military electronic systems in my youth; you could grab any power transformer that was in 24/7 service and just have it warm to the touch. Two basic reasons: it was designed (over-designed) to run that way and there was forced-air cooling everywhere (even refrigerated when necessary). HK Citation amps and preamps were very well designed and built, as they used late fifties-style military terminal-board construction and IIRC the PA stages ran in AB, so the load on the power transformer and supply components was not constant. Nevertheless, in the heat of summer or a hot apartment or home, I did and still do the transformer-heat touch test. And finally, the RCA CT-100 was not designed to mil-spec by a long shot, and so the touch test is more useful today than it was for my Citations. Pete |
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Hi Pete: I know what you mean. I run three tube stereo systems, and the McIntosh C-20 needs new 12AX7's. Checking costs, I find that the tubes I would like to use are way expensive, so I will use others. 6SN7's are also VERY dear. I am also now spending more of my hobby funds on vintage TV restoration. I have a blonde "7" to restore, and a recapped DeLuxe 5 to put back together. Great therapy.
BTW, I have seen your post about the video input interface article, and only have the first page. I am wondering if the same circuit that works with the CTC-2, and 2B will also work with a CTC-4, etc. Loved the pix from the ETV convention. All the best, Kevin
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stromberg6 |
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why not install fans?
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Last edited by andy; 12-07-2021 at 02:07 PM. |
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Quote:
Pete |
Audiokarma |
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Thanks Pete. I will go over the schematics for all three chassis to compare the video detector and first video stages. Perhaps the circuit in the article you have can work with the 4 if the output of the interface circuit can be matched to the 6CL6 1st video stage. It could be a rewarding project. Even though the 4 is narrow band, the color of the 21AX is super. I can't post a screen shot here, but can send one to your address if that's ok.
Kevin
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stromberg6 |
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