We have had very good luck with the 561B Scopes. The
mainframes are transistorized and don't seem to have
power supply problems like the tube models, especially
the HV. They also have very good traces on the CRT.
Don't let the tubes in the plugins scare you.
E55L/8233's aren't worth much. I have good used ones
(I have a tube tester that tests the duo-decar type
tubes) in abundance and more plugins to get them from.

The scopes are very good for audio type work and
general service. I got about 12 561B's that were like
new in consecutive S/N order about 10 years ago and
the ones left always seem to work when powered up
(except for some dirty switches). I have some of them
left with plenty of plugins available. Also have
manuals.

The 3A6 dual trace vertical plug has the delay line
built in so you can see the leading trigger edge of
the signal. The 3A1 does not.

Sampling plugins will take the bandwidth higher but
the sampling heads usually cost more than the plugins
or scope.

Let me know if you need any info on certain plugins.
Either I have it or can get it out of an old Tucker
catalog. Jim Tucker's catalog had nice listing of
most of the plugins with specs.

Regards

Jim
--- "Steve B." <baldy3823@yahoo.com> wrote:

--- In TekScopes@y..., "Steve B." <baldy3823@y...>
wrote:

1: The fastest amp P-I's (3A1 & 3A3) use expensive

and failure-

prone E55L tubes.

That is 3A1 and 3A6 10 mHz D-T amps that use E55L
(3A3 is a D-T
500kHz diff amp w/different dfl driver tube).

Rgds; Steve Bringhurst

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--- In TekScopes@y..., "Steve B." <baldy3823@y...> wrote:

1: The fastest amp P-I's (3A1 & 3A3) use expensive and failure-
prone E55L tubes.

That is 3A1 and 3A6 10 mHz D-T amps that use E55L (3A3 is a D-T
500kHz diff amp w/different dfl driver tube).

Rgds; Steve Bringhurst