Dawn of EL34s

[David B]

That early EL34 example has some unique features not found on later metal base EL34 which I assume were found on the EL60? Such as two ribs on the plates and the two or more long support rods connecting to the mica spacers .I do see a welded plates and an interesting little ceramic washers attached to the mica spacer.

[David B]

Did find a spec sheet EL60, change the sockets on your amp and viola


http://www.mif.pg.gda.pl/homepages/fran ... e/EL60.pdf

[David B]

https://www.tubeworld.com/el60.jpg

[Jeff West]

Hey David- Yes, It's said that '49-'50 EL34 basically have an "adapter" in that "long foot" to convert EL60 into octal 8EP pinout. By '54, they had the more familiar plates (the Dutch Philips ones).

Swankmotee- I know what you mean about dating the RFTs being hard many times. I have some of the short base ones w/distributers brands where there's no clue to the specific mfr or shipping date. One thing I noticed on these awhile back , though (hadn't seen it ever mentioned anywhere else) and then told Master Keeper is that in the very early 1970s, but after the bases were longer, the shape of the mica spacers changed. The older style had points all around, including on the edge of the plates. The change added a space around the edge of the plates where teeth are "skipped", top and bottom. We looked at a bunch that could be dated, and it looked like the older style lasted approx through 1971, give or take. So of somewhat limited use, but if you get one with the older mica shapes you know it's relatively early.

Jeff