Scope Usage at chez Atwood: Main work bench: 561A with 3A6 or 3A74 and 3B4 plug-ins. I do mainly audio or low HF work here. No fan! Second bench: 502A - again, mostly audio work. I like the sensitivit

FWI: Antique Electronic Supply (tubesandmore.com <http://tubesandmore.com/>) sells new manufacture twist-lock electrolytics under their “CE Manufacturing" brand. They bought the tooling and equipment

Since you mention compactrons, it should be remembered that Tektronix did use them - in the 556 scope: three 6M11 and two 6GF5. Did any other Tek equipment use compactrons? - John Atwood

In virtually all CRTs, the cathode is made up of a metal cup with one end coated with a mixture of barium and strontium carbonates. While the tube is being evacuated, the cathode is heated much hotter

A friend of mine just purchased an old Tek 570 Vacuum Tube Curve Tracer that hadn't been used in decades. He is a competent technical guy, but wasn't too familiar with old tube scopes. I made up a lis

Both the GeigerCounterEnthusiasts group and the GammaSpectroscopy group were shut down by the owner, George Dowell, in September. In their places, new groups were started on Yahoo. I'm not a member of

I'm a member of the GeigerCounters Yahoo group, and it went silent from Nov. 19 to Nov. 24. A post I made around Nov. 22 showed up as one of the first posts on Nov. 24. So, something is going on at Ya

I've also got a 570. I'm also involved in vacuum tube audio design. I bought it from a retired engineer in Silicon Valley in the mid-1980s. I think I paid $220 for it. These are quite scarce now, sinc

The 556 dual-beam scope uses several 6M11 tubes (dual triode + pentode) as well as two 6GF5 tubes (beam power tube). As far as I know, this is the only Tek scope that uses compactrons. I've got a 556,