Best Oscilloscope for the money - Page 1
Forum section: electronics / testgear

author: impalacustom
author_rank: Newbie
timestamp: April 04, 2019, 04:06:47 am
content: Hi everyone, I am a first time poster here but have been lurking for a while. I am breaking down and going to buy a oscilloscope and need some guidance. I have a Siglent SDG 2042X, a Variac, a DMM, and a Hickok 6000 tube tester. I use this stuff to work on old tube radios from the 30's and 40's and I am honestly wanting to buy an oscilloscope to add to my tools. I have read and looked at quite a few on here in the forum post above and I am completely overwhelmed at what to buy. I don't want to spend a lot of money because I wouldn't be using it everyday for hardcore use. I have found someone local who has an Owon DS7102V for $200 but I am scared of it because of a lot of reviews I read are bad about it dying. Another concern of mine is I've read that some scopes aren't able to handle the high voltages that old radios can put out because of grounding issues and noise issues.I would appreciate any help and foresight anyone has.Thank youEric

author: 0culus
author_rank: Super Contributor
timestamp: April 04, 2019, 04:16:23 am
content: Disclaimer: I don't work with old tube equipment. However, I've heard numerous times that older analog scopes which were basically designed when vacuum tube electronics were a thing are better suited for that kind of work than modern DSOs. If I were you working purely on old analog tube electronics (and not afraid of having to do a little work replacing tantalum caps) I'd look for a 400 series Tek, like a 465 or 485. Classic scopes, and a number of members here collect them, and might be able to provide more direct advice.

author: Old Printer
author_rank: Frequent Contributor
timestamp: April 04, 2019, 03:11:21 pm
content: Not sure about radio & TV but for tube guitar amps all you nee is a reliable 20Mhz analog scope like a Leader, Kikisui or one of the simpler Tek 2000 series like a 2225 or 2235. They will be easier to work on than a 465-485. Sooner or later they will need work, usually power supply electrolytic caps and balky contact/switches. Sound like you have the background to do that. I wouldn't pay more than $150 for a nice old analog and make sure you can get a good factory service manual before you buy it. Sooner or later you will need it. Haunt Craigslist, they show up all the time here in south Florida.

author: Fungus
author_rank: Super Contributor
timestamp: April 04, 2019, 03:51:58 pm
content: If you're working on tube amps you should probably get a fixed 100x probe or, better, build a big 10x voltage attenuator.Even a cheap DSO should be safe with a decent attenuator in the middle. Bandwidth won't be a problem at the frequencies you're interested in, in fact you might want to permanently enable the 20MHz limiter that these 'scopes provide.If you own a Siglent SDG 2042X then itmightbe able to interface with a Siglent SDS1202X-E oscilloscope and do basic Bode plots. You'll have to ask the Siglent experts if that combination will work though, I'm not the right person to ask.

author: particleman
author_rank: Regular Contributor
timestamp: April 04, 2019, 04:27:36 pm
content: Quote from: 0culus on April 04, 2019, 04:16:23 amI agree on the 4 series scopes. For working on vintage gear I would get a 465, 465B, 468, 453. 485 is a great scope I have 2 of them but parts are expensive, they were very advanced for the time and not as easy to fix or calibrate. Although the 468 can be hard to fix also due to the digital portion. I love the 453 for vintage audio work.

author: alpher
author_rank: Frequent Contributor
timestamp: April 04, 2019, 04:51:51 pm
content: While I don't disagree on suitability of older Tektronix scopes for tube work, you may want to look for a different brand of older analog scope to avoid paying "tek tax" .Somehow people think that everything with Tektronix name on the front is made of solid gold insideOlder japanese stuff is nice and often dirt cheap.

author: Old Printer
author_rank: Frequent Contributor
timestamp: April 04, 2019, 05:13:12 pm
content: Quote from: alpher on April 04, 2019, 04:51:51 pmThis is very true, but the other side of the coin is parts availability. Non Jellybean parts for 30 year old scopes are usually going to be salvaged from a donor scope. Tek put a lot of scopes on the market and I think donors will be easier to find for the most popular scopes as will user groups for troubleshooting help.

author: AG6QR
author_rank: Frequent Contributor
timestamp: April 04, 2019, 05:14:39 pm
content: I've done a fair bit of repair on tube radios with my local ham radio club. The older analog scopes can work well, but most are old enough to start needing repair, and many types of scope repair can require a known good scope for diagnosis. So you may have to start a collection if you go that route.What I personally find most useful is a Rigol 1054z with at least a couple of fixed 100:1 probes. Tube radios are full of high voltage, high impedance circuits, hence the 100:1 probes to bring the voltage down and avoid loading the circuits.The modern Rigol will do many tricks the old analog scopes wouldn't do, and it has enough bandwidth to directly see RF throughout the HF range, where the old guys would settle for using an RF probe that could merely detect the presence and magnitude of a signal, without seeing its frequency or waveform.Having said that, the guy in our club I most respect really prefers older analog gear. He learned with it, and finds it faster and easier to work with. He detests the menus and overloaded buttons/knobs of a computerized UI. I see his point, even though I find the features of a modern scope worth the trouble of a few menus.

author: particleman
author_rank: Regular Contributor
timestamp: April 04, 2019, 05:28:29 pm
content: Quote from: alpher on April 04, 2019, 04:51:51 pmSome are

author: exe
author_rank: Unknown
timestamp: April 04, 2019, 05:46:44 pm
content: Quote from: AG6QR on April 04, 2019, 05:14:39 pmYeah, I'm on the same boat. Didn't want to start a holywar, but you did it. When someone says "analog is better than digital" do not hesitate to ask "why". Without proper arguments the aforementioned statement worth nothing. It's also not granted that reasons not to buy a digital o'scope apply to you. One common argument is "it's easy to screw settings" and "step learning curve". Well, if you are not afraid to learn, I don't see how it applies to you.Other common arguments are "more bandwidth for the same price". I leave it to you guys to discuss this, as well "how many channels it should be on the o'scope", "XY mode on digital scopes" and other hot topics.In my opinion it's worth investing into a reasonably good digital o'scope. It wins hands down any analog except some very specific cases and much more versatile. Do you really want to miss automated measurements, ability to save waveforms, serial decoding, math functions, capturing of single-shot events and limit yourself to only repeated waveforms? Not to say many other features related to signal recording and processing, sophisticated triggering, fft, etc

author: nctnico
author_rank: Super Contributor
timestamp: April 04, 2019, 09:01:18 pm
content: One of the best things when I switched from an analog scope to a digital scope was the ability to look at low frequency signals without flickering. Roll mode is also something which is very useful on a digital scope.

author: tautech
author_rank: Super Contributor
timestamp: April 04, 2019, 09:02:16 pm
content: Quote from: Fungus on April 04, 2019, 03:51:58 pmYepQuoteAt this time SDS1202X-E doesn't offer Bode plot capability, but for 2ch entry level DSO's, SDS2000X-E models do.They are 2 GSa/s and 28 Mpts models of 200 and 350 MHz.For better Bode plot capability where a DUT can be characterized with up to 3 Bode plot sweeps only the 4ch X-E's can do this......at this time.

author: rsjsouza
author_rank: Super Contributor
timestamp: April 04, 2019, 09:39:32 pm
content: Tautech, don't Siglents feature 300V CAT I inputs? This can certainly give extra reassurance to work on vaccuum tube systems.

author: nctnico
author_rank: Super Contributor
timestamp: April 04, 2019, 09:48:19 pm
content: Quote from: rsjsouza on April 04, 2019, 09:39:32 pm300V CAT I is pretty standard. I just checked a few of my scopes.

author: tautech
author_rank: Super Contributor
timestamp: April 04, 2019, 10:05:10 pm
content: Quote from: rsjsouza on April 04, 2019, 09:39:32 pmAll Siglent scopes have 400V p-p rated inputs however we must consider the whole measurement system for use in a mains environment so you should factor in probe ratings also as this is where the greatest risk to the operator is.We also know that componentry used in the front end is 500V rated.Most of the supplied probes are rated as:1 X: 150V RMS CAT II10 X: 300V RMS CAT IIhttps://www.siglentamerica.com/wp-content/uploads/dlm_uploads/2017/10/SIGLENT_Probe_Datasheet_201812_E.pdf

author: Fungus
author_rank: Super Contributor
timestamp: April 04, 2019, 10:36:01 pm
content: Quote from: nctnico on April 04, 2019, 09:48:19 pmNothing special, Rigols have it, too.Realistically you should never work on tubes without a 10x or 100x attenuator of some sort. Depending on your voltage a simple 10x probe might be enough to make it safe for the hardware. I wouldn't work on tubes with a switchable 1x/10x probe though, just in case.(anybody know why they don't sell 'scopes with a mix of switchable/non switchable probes? It would make more sense...)

author: bd139
author_rank: Super Contributor
timestamp: April 04, 2019, 10:47:22 pm
content: Main risk with tube stuff is path to ground. Use any old 20MHz+ scope, get a decent 100X probe - they are usually rated up to 2KV peak or so.If the chassis is earthed, stay off the primary side of the main trainsformer and make sure scope is attached to the same ground. Don't probe live above 50V.if the chassis is floating, ground it and do the above.If the chassis is a live chassis or has no transformer then take the DUT outside and beat it with a sledgehammer until it exists only as powder while shaking your fist as the cheap arse who designed it. Some stuff shouldn't exist any more.

author: JoeO
author_rank: Frequent Contributor
timestamp: April 11, 2019, 12:34:49 pm
content: There is nothing wrong with the Owon 7102V for what you want to do. In fact it may be the perfect scope for you for 2 reasons.There is a VGA port on the scope. This is nice to use if you need to see a larger view of the scope face.The 7102V also runs on battery power. This means you can take it places and you don't need to be looking for a power cord, extension or a power plug to use it.When using it in battery mode, the scope is floating so you don't have to worry as much about grounding problems, except when you are also using it with a VGA display.$200 is a great price for that scope. New they are going for $350. I own 2 of them.Just make sure that it works when you buy it.