[Peter Wieck]

On Friday, November 13, 2015 at 2:36:18 AM UTC-5, Big Bad Bob wrote:



are these tubes mounted vertically or horizontally? I've seen 5V
rectifiers mounted horizontally before, in an old hifi from the 50's.
That might affect how long the tubes live, depending on whether they're
designed to take it or not.


They are mounted conventionally (base-down).

Quite a bit of eequipment mounts tubes horizontally, a very few upside down.. Hickok mounts its tester tubes horizontally - specifically against handbook instructions for the 83 as it happens. Zenith and Motorola have a line of radios with the chassis mounted 'upside down' and Lafayette (amongst a few others) has a line of audio components with the tubes mounted horizontally.

I keep a big Hickok tester, but I have replaced the rectifiers with SS equivalents to remove the issue. The whole process takes about an hour (and a few bucks for the tube bases, resistors and diodes) most of which is the recalbration process.

But cutting to the chase - Chinese tubes carry a risk that, as measured against the value of the equipment, seems unreasonable to me. Screening and testing gives only momentary results. The long-term behavior is of much greater interest to me, and observed failure modes if available. As I work mostly in vintage equipment reaching back to the '20s, I have had more than the usual few opportunities to observe failure modes. And those observations have served me well.

Peter Wieck
Melrose Park, PA