What should I look for in an oscilloscope?

[jaycee]

I have £100 to blow

Unfortunately, in the UK even second hand 'scope's ain't cheap.

I'm looking at two at the moment - a Hitachi V212, and a Philips PM3216, both in good condition. The Philips is 35MHz versus the Hitachi's 20MHz. However, I can't find a manual anywhere for the Philips, while I can find the Hitachi's manual which even includes a schematic.

Forget Tek stuff - it all goes for over £200 even second hand, unless it's broken.

I've just spotted another Philips scope, a PM3217 which is 50MHz. Are Philips 'scopes any good?

[Conrad Hoffman]

Philips and Hitachi are ok, and I'd go with the one I could find a schematic for. You can do almost any analog audio task with a 20 MHz scope. More is good for bragging rights, but it isn't like a 20 MHz scope is going to hold you back in any serious way. We used to have some Philips and Hitachi scope where I used to work, and they did eventually have some problems, but so did the Teks.

[aardvarkash10]

A vote for the 212. We had them in a polytechnic I taught in where we trained automotive electrical students. They were not new when I got there, and they lasted the eight years I was there. If they can survive that, they could survive anything...

SImple, reliable, clear, basic. I'd buy one.

[barrymagrec]

Philips scopes of that age were very good in my experience, second only to Tektronix and generally quite reliable. My PM3212 is rated at 25 Mhz but the measured response went to 35Mhz when I checked it soon after I aquired it.

Barry

[jaycee]

Im leaning towards the PM3217 now even though it costs a bit more. I've found a service manual for it, and one of the neat things is that the PSU uses a 28V transformer to power the rest of the circuit - it can even operate from a 24V battery. While the battery option wouldn't be used, the transformer would provide isolation from the line.

Looking at the schematic too, most of the transistors and such are standard things such as BC548/558 and BF469/70 - all stuff that still exists or can be easily substituted, unlike some of the old Japanese devices used in the Hitachi.

20MHz is enough for audio work, but I do plan to dabble with digital stuff as well.

[burbeck]

hi jaycee
have a look here Stewart of Reading

these guys have been in business awile and im sure that they can supply a suitable scope for you.

i have no connection with the company only as a satified customer

kind regards
bob

[5th element]

The only thing I would mention is that a 50Mghz scope will allow you to look at the majority of digital master clocks. Quite how useful you will find this is debatable however.

[jaycee]

Originally Posted by 5th element

The only thing I would mention is that a 50Mghz scope will allow you to look at the majority of digital master clocks. Quite how useful you will find this is debatable however.

Very - I plan to build a DAC

[5th element]

Yeah, but I've built my fair share of digital stuff and seeing the master clock is great to look at, because it's there and working, but it's not wonderfully useful beyond that point.

The trouble with the higher frequency stuff is that you have to be careful of what it is your seeing, because cable capacitance and probe capacitance will easily alter the way the signal looks.

Although having said that I would consider saving up a bit more money and perhaps splurging on a more expensive model. I have found that since getting my scope (a tek 2225 that I got for free ) that it is the one tool I would rather keep out of all the others.

You do have to be somewhat wary when buying second hand, but something like this looks like a fairly good deal (pure coincidence that it's the model I've got >.<) . The scope has a clear picture taken of it functioning in a well lit room. Lots of the time you can see the scope working in the dark... why? Because the screen is going? And lots of the time you don't see them with anything other then the trace going from left to right and nowt else. Why? Most tek scopes come with a build in square wave generator so you can calibrate your probes, is the scope broken in some way?

[amc184]

My simple advice for buying an oscilloscope for audio is:

- get something analog
- get something of at least 20MHz bandwidth
- the more bandwidth the better

It's also worth getting one whose service manual is available. I've got a Philips PM3267, which is somewhat similar to the PM3217 you're looking at, and I've been happy with it.