Expensive lab gear vs cheap and cheerful

Discussion in 'Test & Measurement Forum' started by smooth_jamie, Feb 23, 2018.

If I spend more money on an lab instrument am I likely to get a better instrument?

  1. True

    76.5%
  2. False

    17.6%
  3. Undecided

    5.9%
  1. smooth_jamie

    Thread Starter Member

    Jan 4, 2017
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    Hi All,

    I was having a lively discussion in this post and I thought it best to seperate it into this poll instead. The subject questions is; does paying more for a piece of lab equipment such a s a soldering iron or oscilloscope mean you get a better product? Or does paying less give you exactly the same or better?

    I am fully in favour of cheaper lab gear, but I think paying less still gets you less in general and it often depends on what you need to accomplish in your project. In the post in question the arguement was between using an $8 soldering iron and an $80 soldering station with temperature control.

    I'd be interested to see what people think, not just about who is right, but in general does paying more give you more? yes or no?
     
  2. WBahn

    Moderator

    Mar 31, 2012
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    It all depends on the two pieces of equipment you are talking about. As with most things, you can easily find examples where the more expensive item is actually inferior to the less expensive item. In many markets you can find the "snob appeal" affect in which raising the cost actually increases sales because people believe that paying more means they are getting more value and actual value doesn't matter very much.

    Also, for a given purpose, there almost always comes a point of diminishing returns where spending more money adds negligible benefit no matter how much "better" the more expensive item is.

    Your goal should almost never (never say never) be to buy the "best" equipment, or even the best that your budget can afford, but rather to buy the least expensive equipment that fully satisfies your current and projected needs over the planned life of the equipment (which is the time you plan to use it, not the actual useful life of the equipment).
     
    -live wire- likes this.
  3. Papabravo

    Expert

    Feb 24, 2006
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    If you are an amateur dabbler, then by all means go the cheapest route. If you are doing serious product development work or research there is no substitute for capable instrumentation. When I was young, and had limited means, I did as you suggest and very quickly bumped up against the limitations of low cost equipment. My solution was to get a bank loan to buy my Tektronics #2236 in 1981 (~ $2500.00). I never regretted that decision.
     
    -live wire- and panic mode like this.
  4. smooth_jamie

    Thread Starter Member

    Jan 4, 2017
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    I agree on both the above. I can appreciate both sides of the coin since I am a hobbyist, but I am also a certification engineer so I get to buy equipment I can never afford at home.

    From the hobbyist side I've bought alot of cheap equipment, and occasionally I have come undone when relying on the limitations of such items. (wire strippers that fall apart after a week, counterfeit IC's and batteries) That isn't to say some of the cheap stuff is in fact rubbish, because I have a DMM that performs as well as my Fluke 287 in work. However with oscilloscopes you seem to get what you pay for and all scopes are manufactured to a price point.

    I think in any market there is "snob appeal", where you are paying for the label. I recall the "ALBA" branded walkman being manufactured by Sony if I remember correctly, which had a lower price simply because it was branded differently.
     
  5. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    In general the answer is true but there are specific items that may be cheaper and function identical to the more expensive brand..

    China has knocked off many pieces of equipment.. But you likely won't get the warranty service nor technical support nor will it be built with the same higher quality materials nor may it hold its calibration as well,etc...
    And the biggest part is that the may have skimped on over overlooked some of the safety features..
    Its not uncommon at all to find components under rated/creepage and clearance distance violations,etc.... None of that matters until it does and it will all be invisible to many until that fire starts or the shock occurs,etc...

    But there are also some things they have built that work just fine..
    There are also quite a few companies that are simply having China private label the products for them and its an identical product just with a 500-1000% markup because of the branded name on it.. This happens quite often..
    China isn't the only country doing this but they are likely the biggest player in the game..
     
  6. OBW0549

    Distinguished Member

    Mar 2, 2015
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    Likely, yes; certain, no. My view is, "pay what you must, to get what you need."

    I finally reached a point in my life where I could afford to pay for some decent equipment (soldering iron, oscilloscope, function generator, DMM, and so forth). Electronics as a hobby is a LOT more fun once you remove the limitations and frustrations caused by inferior gear.
     
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  7. dl324

    AAC Fanatic!

    Mar 30, 2015
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    My opinion is maybe. It depends on the equipment in question.

    There are times where you could spend less and get something better (features and/or quality). The last time I checked, Jameco was selling a 20MHz 2 channel analog scope for around $500. I could pick up a 40 year old used Tek 7000 series scope, e.g. 200MHz 4 channels, for less and end up with a better scope. For around $100 you could add a 70MHz digital scope plug-in.

    EDIT: Jameco also sells a 30MHz digital scope for $400. That scope would have more bells and whistles than a 7D20. So you'd need to decide how much those bells and whistles were worth to you.
     
    Last edited: Feb 23, 2018
  8. ebp

    Well-Known Member

    Feb 8, 2018
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    Some of the cheap stuff is pretty good. Much of it looks pretty good even if it is not. Differences in performance often are not apparent to many users.

    Example: There are a zillion cheap DMMs on the market and a much small number of expensive ones. The expensive ones are better - full stop. Better is not necessarily required.
    At the core of any DMM is a voltage reference. You can pay under a dollar for a mediocre reference to tens of dollars for a pretty good one to hundreds for a really good one. Clearly you can spend more for just a voltage reference than you can for a complete meter. Generally, better references have tighter initial accuracy and lower drift with time and temperature. There are exceptions: the venerable LM3999 has dismal initial accuracy but very good temperature performance because it has a heater to keep the temperature constant - to use it you need to do voltage trim with fairly wide range, which probably means you'll degrade performance with the trimmer. It's a long way from micropower.
    DMMs require voltage attenuators. The ratios of the resistors must be very precise and remain so with time and temperature. You can build an attenuator with 1% tolerance 100 ppm/°C tempco resistors. It will be rubbish. The current sense resistor needs to have a very low tempo.
    If your 3 1/2 digit meter has a poor quality reference and/or a poor quality attenuator, it will still show you 3 1/2 digits of resolution - but anything beyond the most significant 2 digits may fantasy in terms of absolute accuracy. Unfortunately, lots of people don't understand this limitation.

    I have some cheap meters because I used to do power supply design and often needed meters on four different things at once and 1% accuracy was good enough. My good meter is 6 1/2 digits, has a very good voltage reference, Kelvin connection capability, ultra-high input impedance on part of the range, USB & ethernet interfaces, graphic display, memory & assorted other bells & whistles - but it also has a power cord and a fan. And unlike my moderately priced Fluke, it won't be at all happy if dropped.

    Some other examples:
    - Frequency counters - cheap time bases use an ordinary crystal that might be less accurate and stable than a $3 wristwatch; better time bases use a temperature compensated crystal oscillator or an ovenized crystal oscillator
    - Cheap oscilloscope probes - poor flatness of response, especially at higher frequencies; higher capacitance at the tip (lots of scope users don't understand the importance of the latter)
    - Cheap soldering irons - vinyl insulation instead of silicone, temperature sensing knows more about what the heater is doing than what the working part of the tip is doing; tips seem OK but may be skimpy with the iron plating which is necessary for longevity
    - Cheap tweezers - buttery soft steel, bad fit and finish (I have some quite cheap ones that are really pretty decent quality & I don't need sedation and 3 days in a dark quiet room if I drop them tip-down onto a concrete floor); same goes for all manner of small hand tools
    - Cheap power supplies - can be pretty good, but stability may be compromised due to poor choice of panel potentiometers, they may be noisy, dynamics may be poor. For much digital work, you don't need low noise and excellent stability but you may need good dynamic performance. For analog work noise can be a big issue. I have one power supply that is really noisy - but it's the fans. It is an 80 V 15 A CV/CC linear supply. I think I paid about $900 for it, used.
    - Cheap drill presses - horrible awful frustrating junk, too awkward to use as boat anchors

    Cheap oscilloscopes - I have little experience with cheap ones. A friend works at a place where they have a fairly high-end Rigol. He hates it, mostly because of incompetent triggering, and takes his own Tek scope to work. He's used a range of good scopes and knows what they'll do and how to make them do it. He owns active probes. Most hobbyists don't even know they exist or why you'd spend several hundred dollars for a probe (prices for GHz bandwidth probes nearly make me fall off my chair).

    The more you know about instruments and tools, the better position you'll be in to decided if the cheap tools will do what you require of them. If you've never used or at least learned about good instruments, you won't likely appreciate how bad some of the cheap stuff is.
     
  9. ebp

    Well-Known Member

    Feb 8, 2018
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    " ... Tek 7000 series scope ..."

    There were some very fine oscilloscopes in that series. One that would take four plug-ins would have so many knobs and buttons lots of users of modern scopes would probably just sit quietly sobbing for awhile if confronted with having to use one. One problem with buying a used one is that if it doesn't come with probes you could be looking at over a $1000 for a set of four that are of quality suitable for the scope.

    The Tekprobe interface on the newer Tek scopes is awfully nice when you need to use a current probe or active probes.

    I don't remember the model number, but Jim Williams, best known for his prolific work during his time at Linear Tech, had an ancient Tek scope that I believe would do up to 8 vertical channels. Of course he was extremely expert with it and used it for almost all of the excellent ap notes he wrote. It has an odd little "signature" of dots that appear in the lower centre of the screen. You can identify Jim's work from his days at National by those dots in screen photos, even if his name doesn't appear on the ap notes.
     
  10. dl324

    AAC Fanatic!

    Mar 30, 2015
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    I think the only video I saw of him using a scope was a Tek 4xx series ("portable"); 2 channels, 60-100MHz.

    Any Tek 7000 series mainframe will accept two 4 channel vertical amplifiers giving 8 channels.

    I picked up a dozen or so Tek and HP scope probes on eBay about a decade ago for a good price.

    Prices for used test equipment wax and wane. Currently, they're on the high side. A decade ago, you could get a used Tek scope for $50. Now they're going for hundreds more. 7D20 digital scope plug-ins are going for $200 or so. I've picked them up for less than $50.
     
  11. ebp

    Well-Known Member

    Feb 8, 2018
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    The scope Jim Williams used for much of his work was an old wheelbarrow-portable one with very high bandwidth. He does identify the model in at least one ap note. He wrote quite a bit about scopes, probes and probing.

    Interesting that older Tek scopes are going up in price. I suspect that people are finding that the low cost digitals, though very good in many ways, are just inferior to a good analog scope for some work. I'm always somewhat amused by how hard digital scope makers have worked to try to emulate the extra information provided by trace brightness.

    I once tracked down digital glitch problem with a pulsewidth of nanoseconds and a very low rep rate with a 7000 series (don't remember the model number) with a 350 MHz (iirc) vertical module. Get the triggering set up on an easier signal, turn up the brightness, turn off the room lights and sit there staring at the screen. The glitch was easy to fix once I identified its existence (interrupt grant arbitration on Unibus in a PDP-11/44).

    I have an Tek function generator that goes up to 40 MHz, which is pretty good for an analog generator. The thing that distinguishes it from a lot of newer ones is that it will drive ±15 volts into a 50 ohm load, twice that into high-z.
     
  12. MrChips

    Moderator

    Oct 2, 2009
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    I think this thread belongs to Test & Measurement Forum. Anyone objects?
     
  13. dl324

    AAC Fanatic!

    Mar 30, 2015
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    78xx had a 400MHz bandwidth, 7904 was 500MHz, 7104 was 1GHz.
     
  14. ebp

    Well-Known Member

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    MrChips, the recent direction is T&M, but the original intent was for discussion of cheap v. expensive equipment in general and was spawned by a discussion of soldering irons. I have no objection to moving it.

    I wonder if a "tools" or "tools and methods" or something like that forum might have merit, but I haven't been around long enough.
     
  15. nsaspook

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  16. dl324

    AAC Fanatic!

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    When I was working at HP Labs, we wanted a 7104 for a project, but we were only allowed to use HP scopes. I had to use a sampling scope instead. This was late 70's.

    But our lab probably had at least one of every piece of test gear HP made.
     
  17. KeepItSimpleStupid

    AAC Fanatic!

    Mar 4, 2014
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    Home stuff wierd. Work stuff even wierder.

    Even though I worked nearly 30 years at one place, a lot of the stuff was bought before my time. It was very difficult to buy general purpose stuff because stuff had to be tied to contracts.

    1. There were lots of Sorenson power supplies for running lamps until we got a 1 kW Solar simulator Xenon bulb and consolodated testing. They eventually all failed the same way and were easily fixed. It was important to be able to replace failed equipment quickly with a spare.
    The same was true for vacuum gauges. Nearly all were the same model. An 843 Varian. They were easy to fix. Main problems were the filter caps on the -15 V supply, or spilled acetone on the plastic meters, bad relays because of the ripple on the -15 v supply and re-lamping)

    kronos thickness monitors I didn't fix. They were all TTL.

    We had a number of HP x-y recorders and again, they were easy to fix. The problems were slide wire lubercation and pot replacement. An occasional electrostatic hold down.

    Fluke multimeter were mostly display replacements.

    The Keithley stuff seemed to be better. One voltage source I fixed by writing a program to exercise a relay every 10s overnight.
    An electrometer, I burned out a 100 ohm protection resistor. I also found a serious design flaw. Keithley had a $200 minimum order, so a simple part was tough to get.

    I worked with Oriel a number of times and got stuff repaired (sometimes re-engineered) for free. I made changes myself until they made much better solutions. The spark gap was a normal thing to replace.

    Repair of Keithely stuff almost ended up being 1/2 the cost of the instrument.

    A schematic always helped. I added parts to a thermocouple scanner, I converted digital thermometers to analog out, I modified a bunch of Eurotherm temp controllers so they all had the same pin-outs. I had access to a sense resistor in a Kikisui power supply. I had to sign an NDA to get a power supply schematic. I wont mention the name.

    Stuff that was difficult to fix or send away I had to fix like a 100 kV 0.1A, 1948 X-ray power supply or a 10 kV 1.5 E-gun power supply.

    The last manager I had did not believe in my style and nano-managed. The one prior knew that I helped the organization overall and i could keep things running smoothly and running safely. In one case one professional and a graduate student spent the entire weekend trying to fix an measuring system that was sparking. When I came in on Monday, I had the problem identified in 5 minutes. A bad ground in an outlet strip.

    At home, we can look at me being a little kid with a Micronta (radio Shack) meter, then an Eico FET TVM kit, then a fluke 77 and now a bunch of meters. One DVM I got free from Circuit Specialists. Scopes were the same way. I got one from High School free, then a hugh tube/transistor HP military scope, then a Kikasui scope and then a Tek TDS series scope.

    I have a bunch of test equipment from ebay that needs minor repairs that i still haven't done. The price was right, e.g.
    A voltage source with a bad IEEE board (sold as non-working and really cheap). I disconnected the board and it works fine. A dead current source that needs some work, three Keithley 480 picoammeters. two had the same problem, just not 100% fixed. A Keithley frequency couter that has buttons that need replacing. A nanovoltmeter that just needs some mechanical stuff. I want to make a low-thermal adapter, but the company hasn't responded. A few Keithley 5 digit DVM's.

    The TDS scope really needs the NVRAM replaced and a floppy emulator installed.

    So, there is a lot of work involved with used older stuff.

    Now, it appears you have to spend time reverse engineering stuff to even try to fix it. That's an area I need to work on. I have two simple cordless phone charger bases. One I fixed easily. the other is much harder. They aren't really chargers. They just provide a current limited source and an indicator of some sort.

    I need to work on better reverse engineering techniques.
     
  18. ebp

    Well-Known Member

    Feb 8, 2018
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    I was disgusted when the Hewlett-Packard name went with the computer division and the T&M div got named Agilent, which was marketing committee enough. Now Keysight. Keysight!?! It sounds to me like some outfit that helps you find the best place to put your advertising billboard. I have an Agilent DMM that is very nice. If I'd bought it just a bit later it would have been a Keysight product. I'd put a tatty piece of black tape over the name to show my contempt.

    Those Tek scopes really were astounding pieces of engineering.
     
    Last edited: Feb 23, 2018
  19. ebp

    Well-Known Member

    Feb 8, 2018
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    Schematics? Youse want schematics? With some of the stuff you're lucky to get a comprehensible user manual, though the big-name products still seem to have good manuals. All the Tek stuff I ever bought new just came with those great long fold-out schematics in the back of the always-included service manual.

    One problem with some of the old gear is getting parts other than by buying more of the same to sacrifice for parts. My Tek function generator has a PNP RF transistor in the output stage that hasn't been made for years, and there is nothing even remotely close still available. Since I don't actually do electronics anymore I no longer fuss about such matters.
     
  20. ebp

    Well-Known Member

    Feb 8, 2018
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    At this point I will state that at no time in my life have I tied an onion to my belt.
     
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