MeToo2 said:
I then bought a ~30 year old second hand Tektronix 2445B 4 channel 150MHz scope on evilbay for far less including probes. It's really fantastic for what I use it for. The 10megohm 400V peak input and 50V/division (with 10:1 probe) is absolutely ideal for hooking up directly to tube circuits. On the finest trace setting I find you can actually see better resolution and with less artifacts than on a digital scope. You can really see if something has small HF oscillations or low frequency motor boating. No chance of calibration or spares, but you can probably measure levels better with a modern true rms voltmeter than with a scope. So my scope is more important to me for fault tracing and quickly looking at wave shapes along the signal path. I also got some Wandel and Goltermann audio test sets really cheap (25 euros!) from an army surplus depot. I combine these with PC software via a standard sound card if I ever want to look at audio spectra and harmonics.
When you do find oscillation with your oscilloscope, even minute, what is the usual fix for it? Is it to replace components or is it a matter of trimmer adjustments?
Thanks for the info, I was about to consider an OWON.
Can Oscillsoscopes get damaged from the units they test, I am concerned about buying those USB/PC oscilloscope units and damaging my laptop with my inexperience.
I just want to callibrate my EQN, NV73, 1176 and La2a and maybe some form of SSL type compressor and Tube preamp in the future.
Thanks for the response.