Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => AmpTools/Tech Tips => Topic started by: hdave on January 04, 2009, 04:21:02 pm
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Hey,
Where can I find a good oscilliscope at a decent price?
I know there is stuf on eBay but you never know what you are getting.
Thanks,
Dave
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I bought a fully functional Tek 465B for $180 on eBay. No issues at all. The trace is brighter and sharper than the one I have at work. You need to be familiar with scopes to buy smart on eBay. There are some good deals. Cross your fingers and hope for good packing/shipping.
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google "used test equipment". Talk to the dealer directly. It they know what they are talking about and back up their product, then all is good. If they says phrase like "well it is used" or "sold as is" - try someone else.
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if i needed a scope, i'd bid on the one in the link below... more than you'll ever need, and very well built ... bid at $150-200
http://cgi.ebay.com/Tektronix-Tek-465-Oscilloscope-Special-Features_W0QQitemZ270326132873QQihZ017QQcategoryZ104247QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
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another pair...
http://cgi.ebay.com/TEKTRONIX-465-OSCILLOSCOPE-100MHz-DUAL-TRACE-TESTED_W0QQitemZ280299670459QQihZ018QQcategoryZ104247QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.com/Tektronix-TEK-465-100-MHz-Oscilloscope-GOOD-w-CAL_W0QQitemZ260342294232QQihZ016QQcategoryZ104247QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
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if i needed a scope, i'd bid on the one in the link below... more than you'll ever need, and very well built ... bid at $150-200
http://cgi.ebay.com/Tektronix-Tek-465-Oscilloscope-Special-Features_W0QQitemZ270326132873QQihZ017QQcategoryZ104247QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
Yeah, this one is OK. Buyer has sold a lot of scopes with 100% feedback and also claims that it has a good sharp trace and operates within specs. Two probes too!
The other ones are from sellers with short selling history and states that the scope will only pass "power on test".
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Thanks for the tips and the links guys!
Dave
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Is there any reason not to consider a digital scope? I have found an older Fluke 200MHz at a reasonable price with a full, albeit short warranty.
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I used a bitscope with some success, then replaced with a high resolution pico scope. They are very good for some things - like one shot captures, FFT and save to disk. But I find I still use my old tek scope for 95% of my amp/scope work. These are computer based scopes so my screen size is quite large.
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I use a Fluke 190C daily. It's a very good scope. Does some stuff that you can't do on a conventional analog scope. Takes some getting used to if you were raised on analog.
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The one I am looking at is a model PM3320A Philips / Fluke 200 MHz, 2 channel if anyone might be familiar with the model.
Sluckey, I was raised on analogue but have not used my electronics, or touched any equipment in many years. I am jumping back in not quite ice cold, but at best lukewarm. Tube amps other than playing thru them is a new thing for me. I have been reading and just starting to assemble some equipment.
I have a meter and Bias probes, guess I need the scope and maybe a signal generator now.
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How much are you getting it for? The ones I am seeing on the net are about $1000. You might be much better served from a nice analog scope or a better PC based scope that has better vertical/horizontal resolution and buffer memory.
What reasons do you have for wanting a digital scope? For this audio work it might not meet you needs or be too much money.
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Hi ToN,
How goes it?
It's selling for under $200.00 US and is fairly "local". Just seemed like the price was right and the condition good compared to some of the analogue ones I've seen so far.
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guess I need the scope and maybe a signal generator now.
I built my own signal generator according to the attached schematic. It's a simple circuit that offers enough features for messing with amps and is a fun and educational project.
I added a 3-way rotary switch for selecting the wave shape, a buffer op-amp with a "volume pot" after the selector switch and a power supply with a tiny transformer. Built it into a hand-held plastic case with an RCA jack at the front.
Depending on your collection of "stuff" you may have all the components and a piece of perf-board at hand. It's certainly a very inexpensive solution.
I borrowed a professional HP signal generator from work some time later, but I keep using my own device since it is so much smaller and simpler.
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Thanks Heinz,
I may have the parts in my old kit from College (if I can ever find it). Looks like a fun little build. :)
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How does a Tektronix 465M (I believe M is for Military so it should in theory be more rugged) tested to work at $250.00 US and I can pick it up locally sound?
Good, bad, or avearge deal? ::)
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They seem to go for about $150 on eBay with manual, probes and guaranteed not DOA.
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If it is the same shape as that one on ebay for $315 - I'd take a serious look. That looked like a real clean scope with a sharp focus. I have had a few scope that were crap, but were not DOA so I could do nothing about it.
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Yes. It's better to buy test equipment form a reputable seller who refurbishes & re-sells equipment, with the Item guaranteed to be in good working order and a return policy.
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How does a Tektronix 465M (I believe M is for Military so it should in theory be more rugged) tested to work at $250.00 US and I can pick it up locally sound?
Good, bad, or avearge deal? ::)
test it! make sure it has a nice sharp trace, both vertical channels and the horizontal time base have no issues, all the knobs are there and not broken. 250.00 is not bad for a local sale if it comes with a pair of probes. offer him 200.00. ::)
don't get buyers bug, if it looks like junk, beat up, etc., then walk away. ;)
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Good points! Take a signal generator with you if you have one, or can borrow one.
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Hey Dave, just wanted to pass along a few things I like about my scope.
(1) I use if for tuning distortion all the time. I quickly see when I play a guitar or with a signal genertaor what stage is causing distortion and what type (cut off or saturation). Then I just tweak the gain stage under test and get what I am after.
(2) Oscillations. A scope is great for this cause sometimes you cant really hear them, or sometimes they sound like a speaker or cabinet rattle. With a scope, I can see these right away.
Dying to hear what you got...
ToN
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guess I need the scope and maybe a signal generator now.
I built my own signal generator according to the attached schematic. It's a simple circuit that offers enough features for messing with amps and is a fun and educational project.
I added a 3-way rotary switch for selecting the wave shape, a buffer op-amp with a "volume pot" after the selector switch and a power supply with a tiny transformer. Built it into a hand-held plastic case with an RCA jack at the front.
Depending on your collection of "stuff" you may have all the components and a piece of perf-board at hand. It's certainly a very inexpensive solution.
I borrowed a professional HP signal generator from work some time later, but I keep using my own device since it is so much smaller and simpler.
Elemco has some cheap signal generators. simple..just turn them off when not using them or they will eat batteries...mine looks like this...
http://www.alfaelectronics.com/RC555.htm (http://www.alfaelectronics.com/RC555.htm)
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Hi ToN,
Have not done it yet but I will likely go for the Textronix 465M.. They offered it at $250.00 US. Dollars are beyond tight for me at the moment so I am going to offer $200.00 US and will likely go for it if they accept.
I know I am distorted and in oscillation all the time. Wonder if the scope will help there as well?? Not likely unfortunately! LOL
Greasehorse,
That seems like a reasonably priced unit. Must be Made in China?
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I hook the scope up to my head all the time! Doesn't help me any, but sure makes the kids laugh.
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I have been using the same old Heathkit Model 10-12 since 1966. I replaced the capacitors a few years ago. Anything old will need new capacitors.