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Hello,I would like to know if these are real RCA's I have. I cannot post a photo at this time but will describe. They have the bold block "RCA" logos and below that is the letters "EU". There is no Octagon and there is:
8 usa
_HI
...Any opinions ? Thanks for your help.
Follow Ups:
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PRM,I'm looking at a black plate RCA- old style, thin red "RCA" label with "HV" code (I think). I have 5- RCA 6GH8As of which two are grey plate. All of these have the etched octagon very clearly.
The common feature of these 5- RCAs is that the upper and lower micas have are round but with one side cut into a flat. This is similar to the traditional RCA 12AX7 except those have to flat parallel sides.
RCA did relabel some European tubes and later East Eurpoean tubes though I haven't heard of 6GH8s in that category, it's possible it's by someone else. If you've ended up with Tungsram of RFT it's possible, thought the "8 usa" suggest of course something from the US! The vast majority of the US 6GH8As I've seen have been RCA with GE a close second.
By the way, my interest in 6GH8A is to use it instead of the 6U8 in various tuner sections- McIntosh MR67, Mcintosh MX110, Fisher 800, Scott 330D. The 6GH8 has the highest gain of the 6U8 world and Modaferri recommends it for the MPX section of his tuner designs:
6GH8, 6U8, 6BL8, 6EA8 ratings:
tube....pentode Trans.....power.....triode Trans....power
6GH8....8500 umhos......2.5W......7500 umhos....2.5W
6U8........7500 umhos......2.5W......5000 umhos....3W
6BL8......5000 umhos......1.5W......6200 umhos....1.7W
6EA8.....6400 umhos..... 3.1W..... 8500 umhos... 2.5WA photo would be most helpful and you're welcome to email one through Asylum post. It happens I've been looking a lot at this type just lately.
Cheers,
As far as the 6gh8 goes,almost every manufacturer made a version of it and sylvania made the most from the days of tube color tvs.RCA did make their own 6gh8a as they had the CTC 24 color tv chasis which used 7 of them in that set alone.
The EU is the date code of manufacturer.I believe its the 21st week of 1977 or 1978 but not totally sure because its been years.
DEAR S.N.
I'm bulding new boards for my mk-3 and want to use the best risistors and mica capicitors...whats the best I can buy?
Tell me a little about K42Y-2 PIO caps.
OUT
Hi Michael,Thanks for your input. These are black plates and I am used to seeing the octagon on the tubes. Thanks again.
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