Name: Steve Kennedy
Email: steve@pacair.com
Subject: Ei-Yugo 6CA7 copies...
Thread: 79
Time: Sun, 27 Jan 2002 18:40:46 UTC
I am a glutton for punishment and try new and weird things out from time to time. I just got a matched pair of Ei-Yugo 6CA7 "big-bottle" tubes sold under the "Orion" logo (from Triode Electronics... $34.95/pr).
I was curious to see how they were physically constructed. Physical construction of the output tubes is important to Music Man amplifier owners because the larger the tube diameter, the less likely that the 700Vdc plate voltage will arc-over to other tube elements inside the tube.
A tightly-constructed EL34 can survive with no problem but the cheap EL34 may arc-over internally at these voltages.
The Ei-Yugo 6CA7 definitely has a large envelope as compared to a typical EL34 type. Their "wimpy"-looking base seems stout but looks cheap when compared to a Sylvania 6CA7. The bottle has a "nipple" on top like a 12AX7 (unlike the smooth Sylvania bottle)
I compared these physically to a Sylvania 6CA7 and an Electro-Harmonix EL34EH (Sovtek)
and surprise,surprise....
The Ei-Yugo 6CA7 internal construction looks like a close physical copy of the Sylvania 6CA7 in many respects.. the larger plate area, dual getters, and bulb size (same diameter and height). They even copied the number of holes in the plate sides!
This tube doesn't appear to be an EL34 stretched to fit the new glass, it looks like a 6CA7 (at least from the outside).
Next time I have one of my amps opened up I'll try these out! (I don't want to just throw them in... I want to make sure they bias correctly first!) That may be awhile but I thought I would post a heads-up on another tube possibility for the Music Man amps.
Steve