Question about analog oscilloscopes vs digital oscilloscopes

[Wuerstchenhund]

The thread wasn't about who still makes analogue scopes.

No, the thread was about if there are any advantages in buying an analog scope in addition to a decent DSO, and some of the analog proponents claimed that an analog scope still maintains various advantages over a modern digital scope.

The point is that if that were true, then this would raise the question why no-one makes analog scopes any more. Something which of course so far none of the analog scope proponents has answered.

It's about how fluid the display is when looking at fast changing waveforms.

Can you suggest an affordable DSO that will provide me with a display as visually fluid as my Tek 465? The Tek 465 cost me about £50 back in the 1990s.

If staring at waveforms is your thing then one nice example would be the HP 54645A, which was HP's first DSO with MegaZoom ASIC and pretty much the first DSO with high waveform rates and does intensity grading. It has the same BW (100MHz) as the Tek 465, and replicates the 'analog' feel very well IMHO (much better than many other DSOs).

Ebay UK tells me that these days Tek 465s sell for somewhere in the region of £80 to £190. It only found one HP 54645 on ebay UK, which went for £216, but that was the 'D' version (the MSO version), and it came with the logic cable+pod (which alone go for quite a bit of money).

I'd expect a 54645A to fetch something around £120 to £150 in the UK in good, fully working condition. With some patience, you could probably even get one of the later Agilent 54600 scopes, which offer a few advantages over their HP predecessors, for similar money.

Wuerstchenhund: Besides, I wouldn't exactly consider clinging to yesteryear's test gear a sign of intelligence 

G0HZU:That probably places me into the moron category because I still have (and use) a 50 year old HP8405A 1GHz vector voltmeter and a 50 year old HP431C/HP478A 10MHz-10GHz RF power meter.

Wuerstchenhund: Great for you. So you really wanna suggest that this is a sign of intelligence?

Maybe you need to email the people of low intelligence at Keysight and the various NIST calibration houses that still use the HP478A power sensor (designed in the 1960s) as a transfer standard to calibrate modern RF power meters.

AFAIK some NIST calibration houses use the HP8405A vector voltmeter (designed in 1965?)  to cross check various atomic frequency standards over time. They may use something newer today but up until recently the old VVM was a classic tool for stuff like this. I bought it to measure/verify negative impedances for some study work but maybe you also need to email the people who use 1960s VVM technology (to cross check atomic standards) to tell them how dumb they are.

Talking about dumb people, you know that reading comprehension is generally considered a sign of intelligence?

So let me just repeat what I said in my last post (the part you didn't quote):

Just to make it clear: there's nothing wrong with using old or even antique test gear if it suits you. But there's a lot wrong in talking beginners into sinking money into archaic pieces of test equipment no-one makes any more despite it's aleged aleged superiority, which is what happens pretty much every time the question re. analog scopes comes up. It's poor advice by any standards, and while it might massage your ego that another 'young one' could be saved to follow the old paths, it only serves to hurt beginners.

The relevant part is highlighted, and the part you should have paid more attention to is underlined.

So your blathering about what old kit calibration houses use is completely irrelevant, because they're not the ones who try to talk beginners to sink money in antique test gear. 

[Rupunzell]

Most amazing discover in this pile of text...

Laws of Physics and how this electronics stuff has changed to accept and discover the newest and latest IS the greatest. 

Imagine that...


Bernice

[G0HZU]

So your blathering about what old kit calibration houses use is completely irrelevant

No it wasn't. It gave me an opportunity to demonstrate your ignorance about 50 year old test gear and how even the top RF companies still use tech this old.

Wuerstchenhund: Besides, I wouldn't exactly consider clinging to yesteryear's test gear a sign of intelligence 

Come on, admit it... you had a rush of blood and went into 'put down' mode and then typed out the drivel above.

[Rupunzell]

This was the intro from years ago, Aerospace engineer, Really-Honest ?

https://www.eevblog.com/forum/chat/new-member-please-introduce-yourself/msg182870/#msg182870


Bernice

The relevant part is highlighted, and the part you should have paid more attention to is underlined.

So your blathering about what old kit calibration houses use is completely irrelevant, because they're not the ones who try to talk beginners to sink money in antique test gear. 

[Rupunzell]

Appears that way, have a look at history of post.


Bernice

So your blathering about what old kit calibration houses use is completely irrelevant

No it wasn't. It gave me an opportunity to demonstrate your ignorance about 50 year old test gear and how even the top RF companies still use tech this old.

Wuerstchenhund: Besides, I wouldn't exactly consider clinging to yesteryear's test gear a sign of intelligence 

Come on, admit it... you had a rush of blood and went into 'put down' mode and then typed out the drivel above.

[tautech]

Facts are folks, both have their place depending on the specific needs. Using the correct tool for the requirement IS what should be done, not falling into the fantasy one is always better than the other.

If these older machines are so indispensable for certain applications, I wonder why nobody makes them any more? You would think there would be a market for them.

They do. Many obscure Asian manufacturers still have new CRO's on their websites but I've not seen any over 100 Mhz BW and I'd still choose a DSO over a new low BW CRO.

[rsjsouza]

From my point of view there are a few common denominators across these discussions of oscilloscopes:
- a used analog oscilloscope is nowadays not recommended for a beginner to invest a somewhat large sum of money (=their "oscilloscope money") given the risk of getting a worn out (=close to failure) or faulty equipment. Conversely, if the price is low and/or the availability is restricted =(nothing else can be had), then the principle of "something is better than nothing" prevails
- a used analog oscilloscope may be a great second equipment for hobbyists above a minimum level of experience, given the opportunity they bring to learn about improve the process of interpreting waveforms and improving the skills to get a "feel" for what is shown on the screen.
- a used digital oscilloscope is trickier for a beginner to get it right, given there are additional specifications (other than bandwidth/channels) that play an important role in the usability of the instrument. These specifications (SPS, resolution, acquisition memory, waveforms/s, etc.) are added to other less obvious but still important usability treats, such as interface responsiveness, startup times, etc. All are related to the built-in processing speed of the equipment - after all, they became actual computers in an oscilloscope's skin.
- despite that, a digital oscilloscope for a beginner is closer to what they will face in the marketplace, therefore it may leap they learning curve.
- a new digital oscilloscope can be bought today with some decent specifications at a reasonable price. That reduces the risk beginners investing a larger sum of money.
- no matter how you look at it, digital oscilloscopes are almost hopeless to be repaired (certain analog scopes are easier, but you frequently need part donors) - that is mostly applicable to dedicated and programmed ICs

Well, hopefully the overall idea is here, but additions are welcome.

[Fungus]

They do. Many obscure Asian manufacturers still have new CRO's on their websites but I've not seen any over 100 Mhz BW and I'd still choose a DSO over a new low BW CRO.

Farnell lists 12 of them.

GW Instek will sell you a 20MHz analog scope for $530:

http://www.newark.com/gw-instek/gos-620fg/oscilloscope-bench-2ch-20mhz/dp/64M4798

[nctnico]

- no matter how you look at it, digital oscilloscopes are almost hopeless to be repaired (certain analog scopes are easier, but you frequently need part donors)

IMHO this a myth. Any higher end oscilloscope analog or digital will contain proprietary parts. I have run into this problem when trying to repair both analog and digital scopes.

[tggzzz]

That is pretty sane and sensible, with the caveat below.

From my point of view there are a few common denominators across these discussions of oscilloscopes:
- a used analog oscilloscope is nowadays not recommended for a beginner to invest a somewhat large sum of money (=their "oscilloscope money") given the risk of getting a worn out (=close to failure) or faulty equipment. Conversely, if the price is low and/or the availability is restricted =(nothing else can be had), then the principle of "something is better than nothing" prevails
- a used analog oscilloscope may be a great second equipment for hobbyists above a minimum level of experience, given the opportunity they bring to learn about the process of interpreting waveforms and improving the skills to get a "feel" for what is shown on the screen.

I don't understand what you mean there, unless you are thinking of just voltage / time / frequency measurements. Interpreting an oscillogram to understand what's happening in a circuit doesn't change too much between analogue and digital.

- a used digital oscilloscope is trickier for a beginner to get it right, given there are additional specifications (other than bandwidth/channels) that play an important role in the usability of the instrument. These specifications (SPS, resolution, acquisition memory, waveforms/s, etc.) are added to other less obvious but still important usability treats, such as interface responsiveness, startup times, etc. All are related to the built-in processing speed of the equipment - after all, they became actual computers in an oscilloscope's skin.
- despite that, a digital oscilloscope for a beginner is closer to what they will face in the marketplace, therefore it may leap they learning curve.
- a new digital oscilloscope can be bought today with some decent specifications at a reasonable price. That reduces the risk beginners investing a larger sum of money.
- no matter how you look at it, digital oscilloscopes are almost hopeless to be repaired (certain analog scopes are easier, but you frequently need part donors) - that is mostly applicable to dedicated and programmed ICs

Well, hopefully the overall idea is here, but additions are welcome.

[Jwalling]

GW Instek will sell you a 20MHz analog scope for $530:

  

Jay

[tautech]

- no matter how you look at it, digital oscilloscopes are almost hopeless to be repaired (certain analog scopes are easier, but you frequently need part donors)

IMHO this a myth. Any higher end oscilloscope analog or digital will contain proprietary parts. I have run into this problem when trying to repair both analog and digital scopes.

In your opinion maybe, but all must acknowledge that for DSO's of today, schematics are generally not available whereas most scopes (CRO's and DSO's) of yesteryear they are.
For the novice with very limited understanding of the basic building blocks involved schematics are very important if one has to have any hope of repairing a scope.
The beginner really only has PCB swap options to repair a busted scope and those with modular construction are then a big plus. 
For those with repair experience and the "tools" this in not such an issue if parts can still be sourced, most but not all can.

Therefore best advice for those without scope experience that can't/won't buy a modern DSO is to ensure schematics are available and there is a minimum (preferably 0)of unobtainium parts required if/when they might be needed.

[nctnico]

- no matter how you look at it, digital oscilloscopes are almost hopeless to be repaired (certain analog scopes are easier, but you frequently need part donors)

IMHO this a myth. Any higher end oscilloscope analog or digital will contain proprietary parts. I have run into this problem when trying to repair both analog and digital scopes.

In your opinion maybe, but all must acknowledge that for DSO's of today, schematics are generally not available whereas most scopes (CRO's and DSO's) of yesteryear they are.
For the novice with very limited understanding of the basic building blocks involved schematics are very important if one has to have any hope of repairing a scope.

IMHO a novice shouldn't get a (likely) broken scope (or any gear) other than for the purpose of fixing it while using a scope which works and is reliable. Sure I like to have schematic of my gear but the reality is that in many cases proprietary parts for older equipment can not be bought so schematics aren't helping much. Also service manuals for newer equipment usually contains a detailed block diagram which is just as usefull as a schematic. Sure a block diagram doesn't have the part values but on the other hand it clarifies how the signal flows through a piece of equipment more clearly than a schematic does.

[David Hess]

In your opinion maybe, but all must acknowledge that for DSO's of today, schematics are generally not available whereas most scopes (CRO's and DSO's) of yesteryear they are.

Service manuals with schematics vanished sometimes in the early 1990s.  I have heard various justifications for this but the best was that detailed design documentation was fueling an increase in patent lawsuits.

Therefore best advice for those without scope experience that can't/won't buy a modern DSO is to ensure schematics are available and there is a minimum (preferably 0)of unobtainium parts required if/when they might be needed.

I would not go quite that far.  Only a minority of problems involve custom parts and even with them, it will almost always be significantly less expensive to buy a parts mule if necessary than a new instrument with equivalent capability.

[joeqsmith]

I was hoping to get a PM showing where I had crossed the line as I really don't know.   I was a thinking he was in sales,  never would have guessed Aerospace engineer.   I did a quick google search and found this:

horsemeatburger  3/29/13   
That's actually written by me ;-) I'm glad you liked it.
. . .
    Hello folks,

    I just saw a nice review of a LT224 scope on the EEVBLOG
    forum site here:

    https://www.eevblog.com/forum/testgear/lecroy-waverunner-lt-224-review-and-%28partial%29-teardown/

I suspected it was the same person by their tone.   This was basically part of what I had posted.  Let's see if it gets pulled.

This was the intro from years ago, Aerospace engineer, Really-Honest ?

https://www.eevblog.com/forum/chat/new-member-please-introduce-yourself/msg182870/#msg182870


Bernice

The relevant part is highlighted, and the part you should have paid more attention to is underlined.

So your blathering about what old kit calibration houses use is completely irrelevant, because they're not the ones who try to talk beginners to sink money in antique test gear. 

[joeqsmith]

Wuerstchenhund,  I was curious why you never post about anything you have actually done.   This is partly why I was guessing you were in sales.   I had watched your video and had not realized you sold the 64xi.   So you never tried the SSD or repairing it?


 
This was basically part of my post.  Was this the problem?

[GK]

Mr W seems to be in a special world where Lecroy products are available at huge discounts to the open market, not that they'd share with us how to get these amazing bargains.

Geography is important. I spent some time scourging the domestic second hand market down here to no avail before deciding to buy a new Rigol 1202CA (200MHz/2GSa/a) a few years ago. That cost me a little over a grand AUD and was a much better $/performance deal than anything I could find used, even without factoring in that the Rigol was new and warranted.

My 500MHz BW 7904 goes down to 1nS/div. There is currently a (local to me) Lecroy 7200A 500MHz/1GSs/s DSO boat anchor listed on ebay for a rich $900. This is typical. I wouldn't consider this dinosaur to be a significant advance over my Rigol and even so the sampling rate satisfies Nyquist for the 500MHz bandwidth it is still far from the equivalent real time performance of my 7904; 1 sample per division at 1ns/div sweep time just wouldn't cut it.

To match the 7904, 500MHz/5GSa/s would be the minimum required spec. The "entry level" new DSO bracket has not technically progressed this much since I bought my 200MHz/2GSa/s 1202CA and the options for sensibly priced second hand DSOs in this performance bracket on the local market are generally non existent.
The only worse thing is trying to find a decent used spectrum analyser.

Buying from the US from a private seller is an uncomfortable gamble for anything upwards of $1k for a whole host of reasons. You can of course buy used but "guaranteed and operationally checked" from a test equipment reseller with the assurance that you're not going to be sent a dud or something packaged for international shipping in butchers paper, but you will typically pay through the nose for the privilege. That is often enough to make the used option economically unviable even before factoring in often stupid "handling" and shipping charges.     

[joeqsmith]

The last comment I had made was about still running the SSDs in the two old DSOs along with the 1G Ethernet for well over a year now contrary to Wuerstchenhund's advice of the potential problems.   Getting the data off that old 8K at a decent speed has been great. 

Maybe this is what did it?   

[joeqsmith]

Buying from the US from a private seller is an uncomfortable gamble for anything upwards of $1k for a whole host of reasons. You can of course buy used but "guaranteed and operationally checked" from a test equipment reseller with the assurance that you're not going to be set a dud or something packaged for international shipping in butchers paper, but you will typically pay through the nose for the privilege.

Buying in the US can be a bit of a gamble.  I always assume the seller is not capable of fully testing the device and it will be bad.  I've bid on some fairly high priced equipment but have always made sure there was something written down about a trial period and such.   Normally, the higher end stuff was not a problem.

I think pretty much every peace of TE I purchased used off eBay had a problem.   Relays, caps, mechanical connections and switches were by far the most common problems.     

[tautech]

I was hoping to get a PM showing where I had crossed the line as I really don't know.   

Offensive or personal comments that a moderator agrees are such will get a response and get deleted.
It all stems from a "Report to Moderator" action unless a moderator is closely watching the thread.
Unles the moderator "deems" it's serious you won't get notified.

Some discussion of moderators actions get discussed here:
https://www.eevblog.com/forum/chat/moderation-reports/

[Rupunzell]

For those who are entrenched in the belief and idea that there is zero value to repairing great classic test gear, try designing a O'scope from scratch. This would include designing the CRT, mechanicals along with each and every aspect of the instrument. Much will be learned in this process. What is not often appreciated by the current generation of "electronics" folks is just how much can be learned from what has been done in the past to push the absolute limits of device technology and laws of physics.

Try this and be humbled by how cleaver great designers from the golden era of test gear really were. Much of what is done today even in the absolute state of the art instrumentation is really an extension of what was done and established in the past. Gaining a deep and complete understanding of these fundamental designs have extremely great value to anyone wanting to learn electronics.

Many if not most of the very best circuit designers I have met, known, conversed with and shared with have all studied stuff like this and all have learned a great deal from them. Much of this knowledge and expertise is NOT found in any text book or academia based education.

This is why one of the very best things any novice or anyone interested in electronics should learn from history.


Bernice

IMHO a novice shouldn't get a (likely) broken scope (or any gear) other than for the purpose of fixing it while using a scope which works and is reliable. Sure I like to have schematic of my gear but the reality is that in many cases proprietary parts for older equipment can not be bought so schematics aren't helping much. Also service manuals for newer equipment usually contains a detailed block diagram which is just as usefull as a schematic. Sure a block diagram doesn't have the part values but on the other hand it clarifies how the signal flows through a piece of equipment more clearly than a schematic does.

[Rupunzell]

Wuerstchenhund intro'ed  as Aerospace Engineer doing Radar and etc...


EE bud has not been having good results with new LeCroy stuff, They fail a lot and too many software bugs complete with quirks.


Bernice

Wuerstchenhund,  I was curious why you never post about anything you have actually done.   This is partly why I was guessing you were in sales.   I had watched your video and had not realized you sold the 64xi.   So you never tried the SSD or repairing it?


 
This was basically part of my post.  Was this the problem?

[joeqsmith]

I guess everything I write could be offensive to the right person.   Not sure why Wuerstchenhund would have a problem with me pointing out other public materials they have posted or for stating the changes I had made to my DSOs were still working fine.     Or why anyone else would have reported the post.   

Then again, I have seen a few members accounts get banned and after reading the threads could not figure out why.   Kiriakos-GR was similar to Wuerstchenhund.  Both provided some good info.  Both had strong opinions.   One gets kicked. 

Really strange. 

Spam
posts that are vulgar or otherwise inappropriate
anything you deem to be illegal or for ill intent (but don't go jumping over the mere mention of something like a possible harmless prank)
Direct attacks on members (naming people)

[Wuerstchenhund]

The last comment I had made was about still running the SSDs in the two old DSOs along with the 1G Ethernet for well over a year now contrary to Wuerstchenhund's advice of the potential problems.   Getting the data off that old 8K at a decent speed has been great.

All I can say is that I don't know why your posts have been removed, and pointing out that you haven't seen any of the problems I said could happen when plugging in the network card and older revisions of a certain Transcend SSD certainly isn't something I'd report (nor is it anything that should be removed!).

I've reported posts a few times in the past, but most all of them were just for off-topic threads with a request to move it to the appropriate forum, and two instances because a certain member was specifically trying to provoke dissent.

I certainly would never report a posting just disagreeing with me.

Wuerstchenhund,  I was curious why you never post about anything you have actually done.   This is partly why I was guessing you were in sales.   I had watched your video and had not realized you sold the 64xi.   So you never tried the SSD or repairing it?

No, I'm not in sales, although I happen to spend a big part of my professional time buying loads of test gear, in addition to more managerial stuff these days. As to what I do, one of my and my employers' rules are that important work stuff stays at work, and that includes details about the projects I work on, or where they are located.

I'd gladly talk about more mundane and general stuff (i.e. buying test gear in general, or not work related technical things), though.

As to the WR64Xi, as stated the last time we discussed the SSD topic I did put one of the newer Transcends with the 44pin UDMA fix in the scope, and like yours it ran fine (but then, as stated back then this was a problem with older versions of that SSD and the 44pin cabling of the WRXi which doesn't support higher UDMA modes). I also had the acquisition board connectors fixed, I shot the shoddy video when the scope was back in fully working condition.

Unfortunately a former colleague saw the scope when visiting, and talked me into selling it to him. That bastard! 

Buying in the US can be a bit of a gamble.  I always assume the seller is not capable of fully testing the device and it will be bad.  I've bid on some fairly high priced equipment but have always made sure there was something written down about a trial period and such.   Normally, the higher end stuff was not a problem.

I think pretty much every peace of TE I purchased used off eBay had a problem.   Relays, caps, mechanical connections and switches were by far the most common problems.     

Pretty much all my personal test gear was bought from the US via ebay, simply because prices and availability were so much better than here in the UK or in mainland Europe. The only things I bought in the UK were my Agilent E3632A PSU and my Agilent E4406A VSA. Never had a problem, but I check feedback and what else the seller has sold. But buyer protection on ebay works very well in general, if an item fails then you've 45 days to complain, and if the seller doesn't return your money then ebay will do so forcibly.

Kiriakos-GR was similar to Wuerstchenhund.

Hey, no reason to get offensive!   

[Someone]

Mr W seems to be in a special world where Lecroy products are available at huge discounts to the open market, not that they'd share with us how to get these amazing bargains.

Geography is important. I spent some time scourging the domestic second hand market down here to no avail before deciding to buy a new Rigol 1202CA (200MHz/2GSa/a) a few years ago. That cost me a little over a grand AUD and was a much better $/performance deal than anything I could find used, even without factoring in that the Rigol was new and warranted.

International shipping isn't cheap like it used to be but its still viable for dealing with the US and many European nations, but we've got some examples from Mr W now to show whats around.