Some good information about buying oscilloscopes from ebay can be found here:
http://reviews.ebay.com/A-Guide-to-...0001406477?ssPageName=BUYGD:CAT:-1:LISTINGS:2
And if you'r interested in the Tektronix 2000 series here is some good information:
http://reviews.ebay.com/Buying-an-Oscilloscope-on-ebay_W0QQugidZ10000000001568756
http://reviews.ebay.com/A-Guide-to-...0001406477?ssPageName=BUYGD:CAT:-1:LISTINGS:2
And if you'r interested in the Tektronix 2000 series here is some good information:
http://reviews.ebay.com/Buying-an-Oscilloscope-on-ebay_W0QQugidZ10000000001568756
Hands down finest scope ever made by anybody is the Tek 2465B. Available on Ebay for less than a grand... With a little luck. Iffy part is getting one with good jug without being able to directly check it out. I picked up a 2465 plain for $300. Not as fancy but a dang fine home bench unit. Doc
Have you considered the brand new Agilent budget series DSO-X 200?A? At my work at a university we bought some DSO-X 2002A (70MHz, 2 GSa, 100k memory) for teaching purposes. They are probably slighly more expensiv than 1000$ (list price on agilent homepage 1230$) but I think they seems to be very good value for the money compared to the competitors in the similar price range right now. User friendly, Larger-than-normal screen, probes included and decent performance for most purposes. They have FFT-capabilities as well which is very useful for audio purposes.
Jim Williams could afford any scope he wanted. Prominent on his home bench is Tek 2465B
I rest my case.
Doc
http://i1112.photobucket.com/albums/k485/machinebuilderdoc/jim_williams_home_lab_bench-1.jpg
I rest my case.
Doc
http://i1112.photobucket.com/albums/k485/machinebuilderdoc/jim_williams_home_lab_bench-1.jpg
60 Bucks : http://www.diyaudio.com/forums/solid-state/92952-make-up-laboratory-scratch-2.html#post1095884
(problem with secondhand scopes, once you start buying it's hard to resist the next one that comes along)
(problem with secondhand scopes, once you start buying it's hard to resist the next one that comes along)
RIGOL DS1052E 5.6" TFT LCD 50MHz 2-Channel Digital Color Storage Oscilloscope - Free Shipping - DealExtreme
This is a 50MHz scope that is easy hacked to 100MHz with software.
You can buy 3 for 1000USD!!!
This is a 50MHz scope that is easy hacked to 100MHz with software.
You can buy 3 for 1000USD!!!
[warning class="rant"]
Having worked extensively with DSO's in the 90's (mostly Lecroy) I got spoiled by the 810 x 796 vector displays of the 935x series (the 9450A was 4096 x 4096), so the thing that turns me dead off about this class of inexpensive 'scope is the 320 x 234 ("1/4 VGA") display resolution that has been about since the early days of the Tek TDS series.
I realise that the ADCs in these units are probably only really good for 7-bits (high-end scopes use 9 or 10-bit ADCs with 8-bit outputs), leaving plenty of room for the trace and some parameters on the 234 pixel high display. However to my eye the result remains looking like a Fisher-Price My First Scope from 'Scopes R Us"...
[/warning]
If you are a beginner, skip the PC scope stuff. a GOOD scope is available cheap. and do yourself a favor and get a real scope until you understand what you are doing better and then you can play around with PC scopes! that's just my .02 cents but...
Analog VS. Digital. for audio work. - One of the things i DON'T like about digital scopes is when you are trying to look at noise. digital scopes are not real good at that. when you get down to the real real low resolution stuff, you never know if what you are seeing is real noise or a digital artifact or dithering or what? even the cheapest analog scope is better in this regard. maybe some of the mega mega buck scopes are better but at work we have some pretty expensive Tektronix digital scopes that we wont use for that exact reason!
My all time favorite el cheapo scope is the Tektronix 5103N series of scopes. gotta love that GIANT 6.5" screen! very low bandwidth. I think 10mhz but if you shop well you can buy these for under $100 EZ to use.
my 2nd fav, and the one i own, is the Sencore SC61 scopes. these are a sort of hidden secret! a fav of TV servicemen, 60mhz, usable to 100mhz, tons of features and a very solid and reliable performer! these are on eBay all the time. the scope probes are the hard part. buy one with genuine sencore probes! they have an extra lead for the DVM functions and are hard to come by. you can buy these for $100-150 all day long! EZ to use.
I too am looking at the Tek 2465/A/B series of scopes. BUT, they have some issues to be aware of that's for sure! bad caps in the SMPS power supply, and several proprietary IC's that are very hard to come by! buy one you know works! a 2465 (300mhz) can be had for under $500, a 2465B(400mhz) is around $600 or more. these are on eBay often. shop wisely on these! complicated to use.
Oh yeah, I 2nd that you can't go wrong with the Tek 465B scopes! LOT's of them out there! lots of service info and they are pretty decent scopes. you cannot go wrong with one of these. They do have a lot of functions and features and for a beginner that may be a bit overwhelming at first. but should you buy one, you will own it for a long time! your money would be spent wisely!
Analog VS. Digital. for audio work. - One of the things i DON'T like about digital scopes is when you are trying to look at noise. digital scopes are not real good at that. when you get down to the real real low resolution stuff, you never know if what you are seeing is real noise or a digital artifact or dithering or what? even the cheapest analog scope is better in this regard. maybe some of the mega mega buck scopes are better but at work we have some pretty expensive Tektronix digital scopes that we wont use for that exact reason!
My all time favorite el cheapo scope is the Tektronix 5103N series of scopes. gotta love that GIANT 6.5" screen! very low bandwidth. I think 10mhz but if you shop well you can buy these for under $100 EZ to use.
my 2nd fav, and the one i own, is the Sencore SC61 scopes. these are a sort of hidden secret! a fav of TV servicemen, 60mhz, usable to 100mhz, tons of features and a very solid and reliable performer! these are on eBay all the time. the scope probes are the hard part. buy one with genuine sencore probes! they have an extra lead for the DVM functions and are hard to come by. you can buy these for $100-150 all day long! EZ to use.
I too am looking at the Tek 2465/A/B series of scopes. BUT, they have some issues to be aware of that's for sure! bad caps in the SMPS power supply, and several proprietary IC's that are very hard to come by! buy one you know works! a 2465 (300mhz) can be had for under $500, a 2465B(400mhz) is around $600 or more. these are on eBay often. shop wisely on these! complicated to use.
Oh yeah, I 2nd that you can't go wrong with the Tek 465B scopes! LOT's of them out there! lots of service info and they are pretty decent scopes. you cannot go wrong with one of these. They do have a lot of functions and features and for a beginner that may be a bit overwhelming at first. but should you buy one, you will own it for a long time! your money would be spent wisely!
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It all depends on just what you want a scope for. If it is trouble shooting electronics, buy an analog. If it is looking at digital signals that you don't particularly care the exact shape of buy a DSO. As Zero Cool so wisely pointed out, digital scopes are the pits for looking for noise problems. The sampled waveform inherently looks just like the kind of crap I'm usually trying to find while trouble shooting. Digital scopes have come a long way and I wouldn't mind owning one. The Rigol looks to be a steal.... But I will never give up my 2465 for trouble shooting. Having repaired just about ever form of electronic instrumentation and broadcast equipment for over thirty-five years, I think I know what I'm talking about. I'm not alone in my preferences. Take a look back in this subject at the picture of Jim Williams home bench. That man could afford any scope he wanted. A 2465B is promenent along with another really old analog scope he had configured with dual-quad input plugins giving him eight channels.
Yes, the best analog scopes are beginning to have age issues. You have to be careful when buying one. The trace should be clearly visible with the time base at full crank with the 10x multiplier on. This is an indicator of sufficient cathode material in CRT. Trace should be sharp withouth any cloud or glow around it. A fuzzy trace or especially readout characters are evidence of a gassy CRT. Defocus the trace and run the verticle position pot up and down to iluminate every portion of the screen. Look for spots that don't iluminate; those are burn spots in the phosphor.
The 24xx series does contain some expensive hybrids that are no longer made by Tek, but they are still available. The 22xx series is far cheaper (and slower) but has more problems with caps in their switching supplies. But thats an easy fix with readily available parts. Just recap the entire supply and you're done.
465's are great, but are now so old that getting one with a good jug is very iffy. Likewise the HP 1740A. For a good cheap scope don't discount the Japanese offerings. For a time I got along fine with a 100mhz Iwatsu. Controls were laid out just like a 465. If you can sit down and play with whatever you intend to buy. Change the controls. Get a feel for the ergonomics of their layout. Individual controls are far faster to work with than a single knob does all. (I was once given free use of a brand new HP1980 with the one knob concept. After working with it a while I sent it back in favor of a 465.)
My favorite of them all is a 2465B. There is a good reason why a professionally refurbished and cal'd version still goes for almost $1700.
As a last note on DSO's, unless things have changed radically with them, they still won't do what a good analog scope will. I have one freind who is an AM broadcast engineer. At one time he tried every single DSO on the market and not one of them would show him an AM modulation envelope on an RF signal. Maybe that's changed, or maybe not.
DSO's are very convenient and damn cute... I'd maybe buy one if I already had a good analog. 3 DSO's for the same price won't do you much good if they won't do what you need.
For the record I own a 2465, a 454 with a good spare jug and full set of spare Nuvistors, a Tek SC504 for the TM mainframe and a really old HP120BR tube model. I also have two Hitachi scopes I haven't gotten around to trouble shooting as yet. If the 2465's are too pricey for you I'd next look at a 2445.
Doc
Yes, the best analog scopes are beginning to have age issues. You have to be careful when buying one. The trace should be clearly visible with the time base at full crank with the 10x multiplier on. This is an indicator of sufficient cathode material in CRT. Trace should be sharp withouth any cloud or glow around it. A fuzzy trace or especially readout characters are evidence of a gassy CRT. Defocus the trace and run the verticle position pot up and down to iluminate every portion of the screen. Look for spots that don't iluminate; those are burn spots in the phosphor.
The 24xx series does contain some expensive hybrids that are no longer made by Tek, but they are still available. The 22xx series is far cheaper (and slower) but has more problems with caps in their switching supplies. But thats an easy fix with readily available parts. Just recap the entire supply and you're done.
465's are great, but are now so old that getting one with a good jug is very iffy. Likewise the HP 1740A. For a good cheap scope don't discount the Japanese offerings. For a time I got along fine with a 100mhz Iwatsu. Controls were laid out just like a 465. If you can sit down and play with whatever you intend to buy. Change the controls. Get a feel for the ergonomics of their layout. Individual controls are far faster to work with than a single knob does all. (I was once given free use of a brand new HP1980 with the one knob concept. After working with it a while I sent it back in favor of a 465.)
My favorite of them all is a 2465B. There is a good reason why a professionally refurbished and cal'd version still goes for almost $1700.
As a last note on DSO's, unless things have changed radically with them, they still won't do what a good analog scope will. I have one freind who is an AM broadcast engineer. At one time he tried every single DSO on the market and not one of them would show him an AM modulation envelope on an RF signal. Maybe that's changed, or maybe not.
DSO's are very convenient and damn cute... I'd maybe buy one if I already had a good analog. 3 DSO's for the same price won't do you much good if they won't do what you need.
For the record I own a 2465, a 454 with a good spare jug and full set of spare Nuvistors, a Tek SC504 for the TM mainframe and a really old HP120BR tube model. I also have two Hitachi scopes I haven't gotten around to trouble shooting as yet. If the 2465's are too pricey for you I'd next look at a 2445.
Doc
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I think the somewhat older low-price range Agilent scopes were made by Rigol, but the new DSO-X2000 series from last spring/winter is something very different. They are more expensive then the Rigols, the cheapest model is just above the $1000 range going upwards depending on performance and abilities. They have a large really good screen, 8.5" with a 800x480 pixel resolution. I have been using digital scopes in a variety of price classes for a long time but this is the first cheap type I liked this far. The noise is quite ok for being a digital scope. The FFT-function is very useful. I think in most ways the DSO-X is better then ~a 10yr old TEK TDS3012 which I have used a lot. This scope was ~5 times as expensive at that time. Some versions is still availible and they still seems to be significantly more expensive,. The TDS3012 really suffers from having only ~7 effective bits on the screen even though the AD-converter uses more bits (9?). Maybe this has changed with later versions. I don't know.
I think cheap (not the cheapest though...) digital scopes starts to become really useful nowadays, from beeing quite crappy just a some years ago. At my job we have a five years old cheapo scope (do not remember the brand). The screen resolution is crappy, image quality is bad, the viewing angle bad and it is in general a pain to use it, even though it on paper has good specs.. It is definitely not so with the DSO-X2000 series (I am in no way connected to Agilent)
I think cheap (not the cheapest though...) digital scopes starts to become really useful nowadays, from beeing quite crappy just a some years ago. At my job we have a five years old cheapo scope (do not remember the brand). The screen resolution is crappy, image quality is bad, the viewing angle bad and it is in general a pain to use it, even though it on paper has good specs.. It is definitely not so with the DSO-X2000 series (I am in no way connected to Agilent)
It must have been over 16+ years ago, the live display below was just now created on a 1994 Lecroy 9254L¹. It is an analysis of a 780 kHz carrier, 50% modulated by a 5 kHz sine wave:
Note: The plotter emulator resolution created the dark overlayed aliases and unevenness in [2] and [A], they are very much less visible on the 'scope display.
Trace [2] is the raw input;
Trace [A] is a full wave peak detection obtained by applying the ABSsolute() function to the raw input [2];
Trace is the envelope of the detected signal ([A]) obtained by digitally filtering out the carrier;
Trace [D] is an averaged FFT power spectrum of the input signal, showing a cursor at the 780 kHz carrier, and the 5 kHz sidebands;
Below is an simple analysis of the detected signal envelope ( above):
The maximum (774 mV) and minimum (261 mV) envelope voltages are displayed as gathered parameters. The modulation factor is calculated as mod = (max - min) / (max + min) = (0.774 - 0.261) / (0.774 + 0.261) = 0.4956522 = 49.56% = pretty darn close to 50%
I don't know what else more one would care to know about an AM broadcast signal?
Then of course both setups can be saved as named "front panel" configurations for future use...
Sure is "convenient and damned cute"...
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¹ - In the interest of "being fair" I must admit that the 9354L equipped as used above was a $50k+ machine in 1994. They can however be now readily had on eBay, in top notch condition, for $1200 to $1500.
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I have one too. Hacked it to 100MHz. Great VFM. Fan sounds like a hairdrier though. I got a bigger silent one to substitute right from the start for months now, but haven't bothered undoing the case's torx yet.
"It" is there on an analog scope (bandwidth/vertical slew rate)--it's just that that the absurdly high persistence of the phosphor masks it. In fact a lot of newer DSOs have "persistence" modes to make us geezers happy--not all bad because there is info to be had there.
Here's a neat screenshot from my Lecroy WJ 322 with persistence off, but a "color gradation mode" ON:
An externally hosted image should be here but it was not working when we last tested it.
It shows the X-Y "hit" times of the observed signal with cooler colours indicating more X-Y coordinate hits than warmer colours. The jitter is created by the 50 Mhz clock of the (unnamed) PAL based DDS generator, and that the PAL is being asked to do so much.
I only have once analog scope left, an HP 1726A 275 MHz device, that I use to look at detected/demodulated IF/AF signals--and as an X-Y display for my old Leader 905 and a modern single-board Huntron emulator. The other five are digital--20 to 500 Mhz front-ends, 50 MS/s to 5 GS/s.
It is the real-time sample rate that separates the "wheat from the chaff"--if it is not at least 10X the claimed front-end band width then expect to be disappointed.
What kind of probes should be essential for our purposes. -Sorry if that's too generic a question, but I'm just getting into this. My copy of Horowitz & Hill has just recently arrived and I've already put a bid on a TEK458B....with no probes.
Thanks in advance for your candor.
If you're in Canada (or USA ... shipping would be a problem to EU + elsewhere), check out Sphere Research (Vancouver), lots of cal'd, 100% working scopes with probes. Not eBay prices, but only slightly more for much better certainty. Tek, HP, Phillips/Fluke.
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