Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Davidg on July 04, 2012, 12:01:38 am
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I apologize if this should be in tools sectionbut I need an oscilliscope and know nothing about them.What can I expect to pay for a decent 20mhz scope?
Can I get by with 10mhz?
Just because a scope lights up and makes a wave is it functional ? cause there are alot of cheap ones on ebay that the people say they cant test them cause they dont know how,dont have probes etc...
Anyone know a better place than ebay to get a cheap-o?
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I got an Owon PDS5022S through eBay in 2010 & it works flawlessly. http://www.owon.com.cn/eng/pdsSeries.asp (http://www.owon.com.cn/eng/pdsSeries.asp)
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Buy a Tektronix , this is one of the most tough 'scope. I have the 2215 model . Be sure they have probe in working order .
Price ? $100 to $200
Scope parts could be hard to find, so buy a good one IN working order.I see some jober's probe at my electronic store , $30 , I don't if they are good.
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Read amp tool / tech tips section on oscilloscope, there are some answer for you.
http://www.el34world.com/Forum/index.php?topic=13536.0 (http://www.el34world.com/Forum/index.php?topic=13536.0)
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Buy a Tektronix , this is one of the most tough 'scope. I have the 2215 model . Be sure they have probe in working order .
Price ? $100 to $200
+1
If you're patient you can get good deals on eBay. I got an older Tektronix 465B in good condition with 2 probes and manual for $122 + shipping cost, and I've been very happy with it. I wouldn't buy one from a seller who didn't know how to test it---that would be a crapshoot, and 'scopes are complicated critters. On the other hand, you don't have to buy a scope that has been calibrated, certified, signed by Michael Jordan, and blessed by il Papa. Look for listings where the seller has described the condition confidently and shows photos of actual trace(s) being produced on the scope by a function generator. That won't guarantee a calibrated (or even completely working) scope, but it's better than "I don't know how to test it", and far less expensive than a calibrated one. For amp use, we're mostly interested in finding p-p signal voltage and looking at distortion on sine waves anyway.
For cheaper alternatives and skipping the shipping, find a hamfest near you this summer.
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Thanks Guys! I guess I was hoping to get off too cheap and find one for $100.I have actually seen some Techtrx scopes for around $150 shipped so I guess I will go ahead and pull the trigger on one.I wish there was a hamfest near me but I am in the stix and the ones I have found are 2-5 hours away and I just dont have time.
Do the probes have to be matched to the bandwidth of the scope or something?
Is it not a good idea to buy aftermarket probesor should I be looking for one with probes just to be sure I get a good set?
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I found mine on" Craig List" close to my home so I can see it working
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> I need an oscilliscope and know nothing about them
So how can you know you "need" a 'scope?
> Can I get by with 10mhz?
I did a heap of good work with a "450KHz" (0.45MHz) 'scope. Gas-sweep!
I once, on-purpose, re-built a (junked) 'scope for 20KHz bandlimit (0.02MHz).
My current 'scope was pulled from a rain-soaked pile. Has a backhoe-bite in the top. H-P rackmount with (again) 0.45MHz bandwidth (true trig sweep, but again gas-tube calibration).
I do have a handheld. somewhere, which may be 1MHz.
While a 20MHz _might_ be useful in transistor audio, very-very few people would know what to do with those extra 19MHz.
Just in passing.... I saw this while looking for something else:
http://www.electronickits.com/gold/CKOSCOPE10MHZ_Low_Cost_10MHZ_Oscilloscope.htm (http://www.electronickits.com/gold/CKOSCOPE10MHZ_Low_Cost_10MHZ_Oscilloscope.htm)
10MHz Oscilloscope - $179.95
Single channel, and dual-channel is occasionally very useful. However X-Y mode is right there (no back-panel hacking) and will do many of the same things (plus do Lissajous, handy for entertaining stoners).
Under two-hunert from a savvy vendor fully warranted may be better than putzing around with "untested" too-fancy used 'scopes missing probes.
They also have a handheld (buck cheaper), and a dandy function generator for forty bucks kit.