Oscilloscopes - teach me pls.

[pula58]

I am in the market for an o-scope.

One thing I am trying to understand is the issues that might, or might not., come-up in terms of working on amplifiers with voltages up around 450V or even as high as 470V.


One digital scope I was looking at (Rigol 1052E) can only accept up to 400V, with a 10X probe! So, I would need a 100X probe, wouldn't I?

So, I looked towards getting an old Tectronix scope (Craigslist)...but got confused in terms of getting the right probes.

Tektronics specs their probes in terms of max RMS voltage. For example, one probe (the P3010), 10X, 100MHz, is spec'd to 300V RMS, does this imply a max voltage of 300V * 1.414 = 424V? If so, I would need one of their probes spec'd at 400V RMS (565V peak)...The thing, new, would cost $171..

This seems way more pricey than I would have expected. Am I missing something here?

Teach me please!

Thanks.

P

[selloutrr]

most 20mhz dual trace scopes will do what you need.

http://www.doctronics.co.uk/scope.htm

[pula58]

If I got the old Analog scope route, most of the used scopes around here don't seem to come with probes.

How much $$ would I expect to spend on 10X probes good to 500V probes? and, where to purchase them?

Thanks!

P.

[The New Steve H]

It never occurred to me to worry about the input voltage of an oscilloscope. I have an old Hitachi V-1050F, and I just checked the manual. I was cutting it pretty close at 452 volts!

[frankeg]

For most of the signal tracing you'd do in a tube amp it's low voltage. I just use a dvm for the power supply stuff. They do make high voltage probes (we have them at work) but I don't know the cost. I found a good deal for 1x and 10x probes at amazon.com. You could also make you own hi volts tester using a few resistors to form a voltage divider. In the military we had in line (coax) reducers rated in db but I never felt the need to get them for amp work. Since you have a scope, you should look for a cheap audio signal generator. I found one on ebay which was mailed from the far east. Those two tools together (scope & sig gen) are worth having if you do a lot of building/reparing...

[The New Steve H]

I guess this will sound crazy, but I built a frequency generator as a kit a few years back, and I also bought an old professional model on Ebay.

[boots]

I wouldn't be surprised to pay more for a good probe than for an old used o-scope!

[frankeg]

I guess this will sound crazy, but I built a frequency generator as a kit a few years back, and I also bought an old professional model on Ebay.

I was thinking about doing that as well but then found one on ebay for $56 which is a lot like the old hp I used in the service.

[The New Steve H]

It's funny how much wonderful old equipment is selling cheap on Ebay. I'm pretty sure the $50 Hitachi I have is considerably better than the Tektronix jobs I used in college.

I don't know what model my used frequency generator is. I should get it out and play with it. I don't even remember if it works. I think it's an HP.

[tubeswell]

Teach me please!

http://www.google.com/search?q=using+an+oscilloscope

[The New Steve H]

Ebay has tons of used probes, plus new Chinese.