Recommend an oscilloscope?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Jonesey, Sep 17, 2005.

  1. Jonesey

    Jonesey Member

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    What should I look for in a CHEAP, used oscilloscope? Anything I should avoid?

    Want to learn more about amplifiers as a hobby.

    Thanks!
     
  2. Slick51

    Slick51 Colonel Curmudgeon Silver Supporting Member

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    Just spend a while looking around eBay. You can find great deals there in used electronics. B&K and Fluke are top end stuff; look at the features listed on those, then look for the same features (or the ones you need) on the cheaper ones.

    Slick51
     
  3. tonezoneonline

    tonezoneonline Member

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    I would look for a Textronics scope .Dual channel is very nice to have.Anything over 20-30Mhz is fine for tube stuff.
    Some have larger screens than other and that's one of the thing's I look for .A lot of them come without probes so you will have to find one with or buy them seperate.They can range from $35 on up.Make sure you get 10X probes.
    Can usually be had for $75 to $125.Sometimes cheaper but it's always a gamble on Ebay.
     
  4. doc

    doc Member

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    Anybody ever see or use the oscilloscope cards that lets you use your PC as an oscilloscope?
     
  5. Wakarusa

    Wakarusa Member

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    Strong preference for Tektronix scopes here (I have three in the shop), but other brands should do fine for hobby work. Things to watch for:
    - Screen size - bigger is better so you can see the waveform
    - Screen sharpness - cheaper scopes give fuzzy lines
    - Voltage Resolution - some of the very cheap scopes won't show small signals well.
    - Voltage Limit - What's the maximum DC voltage that you can apply to the probe? Will you need a high voltage attenuated probe to work on tube amps?
    - Tube Scopes - great fun for the nostalgic in the bunch, but evil to maintain if you don't know what you're doing.

    Also, don't forget that you need a (or several) probes. If not included these can run large dollars.

    For a hobbyist, the laptop o-scope (and even the laptop spectrum analyzers) are a pretty good deal. IIRC a lot of them rely on the sound card (?) so response and resolution (and susceptibility to noise) will be affected by the quality of the card. The one I'm not sure of is how tolerant these devices are of high DC voltages. The down side, I'd imagine, is messing with a keyboard or mouse to adjust scope settings while you're probing a live circuit. Big knobs are easy to manipulate and less distracting so (again, I'd imagine) you're probably less likely to zap yourself using a traditional scope. Aren't these things really intended for the low-voltage solid-state crowd anyhow?
     
  6. lgehrig4

    lgehrig4 Silver Supporting Member

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  7. Wakarusa

    Wakarusa Member

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    If you're doing audio work 10MHz is more than enough bandwidth. Your link isn't working, but it looks like it points to one of the handheld units. No personal experience with these, but I like the idea.

    FWIW, the one I'm looking for is one of the small handheld signal generators :) Has to absolutely beat hell out of either running a really long cord from the bench unit, or hefting twin reverbs up onto the bench.
     
  8. lgehrig4

    lgehrig4 Silver Supporting Member

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    So would 10MHz be good enough for both tube or solid state amps? It's mentioned in a few posts above that anything over 20-30MHz can be used for tube. I assumed that anything less would not be good.


    The Ebay item # is 7548269537 if you want to check it out.

    Thanks
    Jeff
     
  9. tonezoneonline

    tonezoneonline Member

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    I use one of the handheld B&K signal generators and it works pretty good for around $70.Nice for testing crossovers and speakers too.
     
  10. lgehrig4

    lgehrig4 Silver Supporting Member

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  11. Wakarusa

    Wakarusa Member

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    Again, no personal experience with one, but the specifications would suggest that it is suitable (good sensitivity, decent resolution, and will tolerate 600V if you remember to use the 10x probe, includes probes) for your application.
     
  12. lgehrig4

    lgehrig4 Silver Supporting Member

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    Great! Thanks!
     
  13. Euthymia

    Euthymia Member

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    My favorite oscilloscope for amp (and other audio) work is the Tektronix T922.

    They use the same CRT as the famed 465 series, but are less complicated and have a smaller footprint. They fit very nicely on the smaller bench.

    Since they are less complex, they are easier to work on should the scope need adjustment, etc.

    They can usually be had for $50.00 or so at ham swaps or on eBay.

    http://www.logwell.com/tech/oscilloscopes/Tek_T922R.html
     
  14. doctord02

    doctord02 Member

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    I just picked up a Tek 453 in good working condition for $48 plus shipping on fleabay. I'm pretty happy with scoring it. Now I just gotta teach myself how to use it properly... Thanks for the apogee link earlier in the thread, Jeff - I found a cheap signal generator kit from them for a whopping $15. Nothing fancy, but together they should get me started.
     

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