Tubes Asylum

Posted by Bambi B (A) on April 21, 2007 at 06:55:02

In Reply to: SIEMENS E81CC triple mica posted by Lowrider on April 20, 2007 at 23:04:44:

Lowrider,

The Siemens E81CC is one of my three favourite 12AT7s- along with the Valvo 6201 and old Sylvania triple mica 12AT7WAs- but I've never seen a Siemens E81CC flash dramatically. I swap these in my microphone preamp for certain uses.

When two more or less identical objects in symmetrical positions behave differently, I'd first isolate the source. My suggestion would be to exchange the two positions and see if the exhibitionist tube flashes in the other socket. My impression is that tube flashing on startup is not in itself a problem, but intuitively, it seems they should behave similarly. Some tubes are enthusistic flashers while others are more circumspect. For example, it's difficult with the Sovtek 12AX7LPS to see it's even going.

Cheers,

Bambi B