Power Tube Find EL34 / 8417

[plexi50]

A friend has acquired a box of tubes. Preamp and power tubes of various makes. Anyone have any particular opinions on the CEI EL34 power tubes made in Germany? I have read the 8417 tubes had there problems and impedance differences between 6L6GC/5881 .

[PRR]

8417 is not much like 6L6. While you might be able to make it work in a 6L6 socket, this makes no sense.

8417 came in two flavors: fine, and fragile. I forget if we liked GE or Sylvania(?). However "ECG" tells nothing unless the real maker-mark is on it. "CEI" is another re-boxer?

8417 was invented for a Fisher hi-fi monster-amp as a high-gain (low driver strain) 6550 in the 100W output range. Dyna's biggest amp used them. One of the mega-Hi-Fi brands used bucketfuls. Bogen used a bunch in a 75W PA pair (I once had three 2*150W amps, 24 tall bottles.) Some guitar amps used them; mostly 'lost' over the years when good 8417 vanished. In this range, 6550 or parallel 6L6/EL34 make more sense today.

[pdf64]

Here’s some interesting info about the Philips ECG valve brand https://www.thegearpage.net/board/index.php?threads/tube-questions.2276140/#post-32974157
Dunno how accurate it is, but it seems plausible.

The ‘Made in Germany’ EL34 might be Siemens, RFT etc. Assuming it’s good, it may be worth looking into that.

[plexi50]

Well the EL34 tubes i can definitlely use. Lot's of reading on the Hi-Fi aspect of the 8417 use.