Penta brand 6L6GC info?

[dgta]

Anyone familiar with these? Any info would be appreciated.

[kevinkr]

Low end Chinese coke bottle 6L6 made by Shuguang in all likelihood.. My recollection is that despite being marked GC it red plated at 20W of dissipation so was more like the original 6L6..

Penta is a rebrander/reseller of tubes made all over the place. I won't buy their products as a result of a number of not so great experiences I had with them about 20yrs ago.

[dgta]

Thanks Kevin. I was afraid of that. I had the same experience with some skinny/tall Russian tubes marked 6L6GC.

[tubelab.com]

I had a bunch (and still have a few) Penta branded 6CA7's. They all blow up even at reasonable power levels. I got some Penta branded 4-65's too. Both were gassy. I tend to avoid that brand based on previous experience.

The Shuguang sourced coke bottle 6L6GC's are also quite variable. The old ones could take serious abuse, but the recent stuf dies pretty easilly.

The old ones in the picture were "Ruby Tubes" branded and used in a Bandmaster when I got them. I use them in all my experiments where the results may be unexpected. These have glowed like this several times and they still work after over 5 years. They were dissipating 44 watts in this picture.