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#1
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Oscilloscope for Tube circuit analysis?
I am looking to get an oscilloscope to do tube preamp/amp circuit repair, analysis and design, and for learning. Price IS an object so I am looking at a minimum price option. I am a bit of a newbie here, but I think I need dual trace, about 100 MHz max, analog scope is OK. Hobbyist level scopes are OK. Couple things I've looked at are Tektronix 2235 or 465b which seem to be well regarded. These can be had on eBay for around $300 typically. Any other recommendations? I have also looked at a couple of PC based software scopes that work with the soundcard inputs and outputs. A couple that look promising are AudioTester at http://www.audiotester.de/ And TrueRTA at http://www.trueaudio.com/rta_abt1.htm Seems to me though that I stand a high chance of blowing out my soundcard by connecting to a signal with a DC bias or an amplifier AC signal voltage higher than a line level input would provide. Has anyone actually used either of these??? Thanks, -- Rev |
#2
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"Revolvr" wrote in message
news:YICgb.52990$vj2.19457@fed1read06... I am looking to get an oscilloscope to do tube preamp/amp circuit repair, analysis and design, and for learning. Price IS an object so I am looking at a minimum price option. I am a bit of a newbie here, but I think I need dual trace, about 100 MHz max, analog scope is OK. Hobbyist level scopes are OK. Couple things I've looked at are Tektronix 2235 or 465b which seem to be well regarded. These can be had on eBay for around $300 typically. Any other recommendations? I have also looked at a couple of PC based software scopes that work with the soundcard inputs and outputs. A couple that look promising are AudioTester at http://www.audiotester.de/ And TrueRTA at http://www.trueaudio.com/rta_abt1.htm Seems to me though that I stand a high chance of blowing out my soundcard by connecting to a signal with a DC bias or an amplifier AC signal voltage higher than a line level input would provide. Has anyone actually used either of these??? Thanks, -- Rev You don't need 100 Mhz for most audio work; 10-20 Mhz is plenty, and those should be fairly cheap. Since the signals that you'll be looking at will be in the neighborhood of 20Khz max, and allowing for a 10X bandwidth reserve, you can easily see anything that your amps/preamps will handle in a 20 Mhz spectrum. Along the lines of a PC-bases scope, I wouldn't run any signals directly into the sound card. Build a compensated attenuator, and follow it with an amplifier to get the signal up to line levels so the your sound card isn't straining to see it. You should also provide for AC and DC coupling on the input. That provides attenuation and isolation for your sound card. That's the way a real scope operates. The PC-based scopes provide several features that ordinary scopes don't; at least in the hobbyist price range. Spectrum analysis is the most noticeable of these and will prove to be quite useful if you're designing and building amps. -- Tweetldee Tweetldee at att dot net (Just subsitute the appropriate characters in the address) Never take a laxative and a sleeping pill at the same time!! |
#3
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I have been using a tektronix 2212 and it has worked out quite well for me.
Some capability for spectrum analysis WOULD be quite useful however if you can acquire it (such as a PC based ocs).. Having just built my first amp in a while, I have concluded that this capability is necessary for comprehensive debugging of a design. JamesG "Revolvr" wrote in message news:YICgb.52990$vj2.19457@fed1read06... I am looking to get an oscilloscope to do tube preamp/amp circuit repair, analysis and design, and for learning. Price IS an object so I am looking at a minimum price option. I am a bit of a newbie here, but I think I need dual trace, about 100 MHz max, analog scope is OK. Hobbyist level scopes are OK. Couple things I've looked at are Tektronix 2235 or 465b which seem to be well regarded. These can be had on eBay for around $300 typically. Any other recommendations? I have also looked at a couple of PC based software scopes that work with the soundcard inputs and outputs. A couple that look promising are AudioTester at http://www.audiotester.de/ And TrueRTA at http://www.trueaudio.com/rta_abt1.htm Seems to me though that I stand a high chance of blowing out my soundcard by connecting to a signal with a DC bias or an amplifier AC signal voltage higher than a line level input would provide. Has anyone actually used either of these??? Thanks, -- Rev |
#4
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Tektronix 453 or 454 work well.
About $100(but make sure you ask if they work). I just had some dip "imply" that it was calibrated. It turns out, he only calibrated one function. "JamesG" wrote in message ... I have been using a tektronix 2212 and it has worked out quite well for me. Some capability for spectrum analysis WOULD be quite useful however if you can acquire it (such as a PC based ocs).. Having just built my first amp in a while, I have concluded that this capability is necessary for comprehensive debugging of a design. JamesG "Revolvr" wrote in message news:YICgb.52990$vj2.19457@fed1read06... I am looking to get an oscilloscope to do tube preamp/amp circuit repair, analysis and design, and for learning. Price IS an object so I am looking at a minimum price option. I am a bit of a newbie here, but I think I need dual trace, about 100 MHz max, analog scope is OK. Hobbyist level scopes are OK. Couple things I've looked at are Tektronix 2235 or 465b which seem to be well regarded. These can be had on eBay for around $300 typically. Any other recommendations? I have also looked at a couple of PC based software scopes that work with the soundcard inputs and outputs. A couple that look promising are AudioTester at http://www.audiotester.de/ And TrueRTA at http://www.trueaudio.com/rta_abt1.htm Seems to me though that I stand a high chance of blowing out my soundcard by connecting to a signal with a DC bias or an amplifier AC signal voltage higher than a line level input would provide. Has anyone actually used either of these??? Thanks, -- Rev |
#5
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Revolvr wrote: I am looking to get an oscilloscope to do tube preamp/amp circuit repair, analysis and design, and for learning. Price IS an object so I am looking at a minimum price option. I am a bit of a newbie here, but I think I need dual trace, about 100 MHz max, analog scope is OK. Hobbyist level scopes are OK. Couple things I've looked at are Tektronix 2235 or 465b which seem to be well regarded. These can be had on eBay for around $300 typically. Any other recommendations? I have also looked at a couple of PC based software scopes that work with the soundcard inputs and outputs. A couple that look promising are AudioTester at http://www.audiotester.de/ And TrueRTA at http://www.trueaudio.com/rta_abt1.htm Seems to me though that I stand a high chance of blowing out my soundcard by connecting to a signal with a DC bias or an amplifier AC signal voltage higher than a line level input would provide. Has anyone actually used either of these??? Thanks, -- Rev I picked up a working solid state Tenma dual trace 20MHz scope for $50 from a TV shop going out of business. I got two probes and the manual. Works OK for me. Raymond |
#6
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Hi,
For strictly audio work, you could do a lot worse than an H-P 1200A. 500kHz, 100 microvolts, differential inputs on binding posts, extremely sharp trace. Mine has worked flawlessly for something like 20 years (cost me a dollar at a company auction). Cheers, Alan |
#7
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"Alan Douglas" adouglasatgis.net .... Hi, For strictly audio work, you could do a lot worse than an H-P 1200A. 500kHz, 100 microvolts, differential inputs on binding posts, extremely sharp trace. ** What's this "strictly audio work .......... 500kHz .. " business ? The minimum scope bandwidth for an "audio" technician is 20 MHz - 50 MHz is more like it. So called "audio" work includes: Mosfet power amplifiers with parasitic oscillations at up to 50 MHz. The IF signals of an FM tuner at 10.7 Mhz. The clock frequency of a uP based audio processor. Local oscillator signals from 10MHz up to 50 MHz inside radio microphone Rx and Tx units. For purely tube based circuitry a 0.5 MHz scope may be OK - but only just. ............ Phil |
#8
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Glad you offered something constructive Phil.
Oh sorry must have been someone else. why dont you try offering an answer instead of just cutting down everyone else? Doug "Phil Allison" wrote in message u... "Alan Douglas" adouglasatgis.net ... Hi, For strictly audio work, you could do a lot worse than an H-P 1200A. 500kHz, 100 microvolts, differential inputs on binding posts, extremely sharp trace. ** What's this "strictly audio work .......... 500kHz .. " business ? The minimum scope bandwidth for an "audio" technician is 20 MHz - 50 MHz is more like it. So called "audio" work includes: Mosfet power amplifiers with parasitic oscillations at up to 50 MHz. The IF signals of an FM tuner at 10.7 Mhz. The clock frequency of a uP based audio processor. Local oscillator signals from 10MHz up to 50 MHz inside radio microphone Rx and Tx units. For purely tube based circuitry a 0.5 MHz scope may be OK - but only just. ........... Phil |
#9
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"doug" Glad you offered something constructive Phil. ** All my posts are highly constructive - even my responses to mindless abuse from jerks like you Doug. Pat Turner is the master of mindless abuse and libel - as he is about to find out. ............ Phil |
#10
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Sorry Phil nothing constructive in that post
And I think I read your book How to Influence People and Make Friends that was you wasnt it? I understand why you come on to the newgroups now to spread your drivel.. Becauxe no-one will talk to you in real life. have a nice one Phil this Group will be much better whin you go away Doug "Phil Allison" wrote in message u... "doug" Glad you offered something constructive Phil. ** All my posts are highly constructive - even my responses to mindless abuse from jerks like you Doug. Pat Turner is the master of mindless abuse and libel - as he is about to find out. ........... Phil |
#11
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Wow, guess I got ripped-off. Paid $10 for mine. Awesome 'scope! Fully
differential input and extremely wide dynamic range. This 'scope plus a 3580 spectrum analyzer and you are well set up for tube audio. Ray Parkhurst "Alan Douglas" adouglasatgis.net wrote in message ... Hi, For strictly audio work, you could do a lot worse than an H-P 1200A. 500kHz, 100 microvolts, differential inputs on binding posts, extremely sharp trace. Mine has worked flawlessly for something like 20 years (cost me a dollar at a company auction). Cheers, Alan |
#12
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"doug" wrote in message news:ryKgb.41862$9l5.27859@pd7tw2no... Sorry Phil nothing constructive in that post ** You failed to see it. Since you are blind. .......... Phil |
#13
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Good ideas. Since I am only looking at tube amps and preamps, I agree 500
kHz or so will do. I'll look around on eBay for the HPs and other lower BW Tek options. -- Rev "Ray Parkhurst" wrote in message ink.net... Wow, guess I got ripped-off. Paid $10 for mine. Awesome 'scope! Fully differential input and extremely wide dynamic range. This 'scope plus a 3580 spectrum analyzer and you are well set up for tube audio. Ray Parkhurst "Alan Douglas" adouglasatgis.net wrote in message ... Hi, For strictly audio work, you could do a lot worse than an H-P 1200A. 500kHz, 100 microvolts, differential inputs on binding posts, extremely sharp trace. Mine has worked flawlessly for something like 20 years (cost me a dollar at a company auction). Cheers, Alan |
#14
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"Revolvr" wrote, inter alia,
in rec.audio.tubesYICgb.52990$vj2.19457@fed1read06: : I have also looked at a couple of PC based software scopes that work with : the soundcard inputs and outputs. A couple that look promising are : AudioTester at : : http://www.audiotester.de/ : : And TrueRTA at : : http://www.trueaudio.com/rta_abt1.htm You might also like to look at http://www.dazyweblabs.com/ I've downloaded all these, but haven't actually tried them yet. Sure are "purty" looking interfaces though, and the site seems tube-friendly, too ... [My 0.02c ... maybe others have tried their suite out?] RdM (back, after isp difficulties and changeovers ... ;=}) |
#15
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RdM wrote:
: RdM : (back, after isp difficulties and changeovers ... ;=}) OOps ... that'd be rdm@ with a reversed country code, actually! Inter alia ... several addresses now, don't want to get cut off again! Not that I've been getting much email ... and I do know I owe some ... Catching up ASAP ... apologies to those concerned! Cheers! RdM! |
#16
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Revolvr wrote:
I am looking to get an oscilloscope to do tube preamp/amp circuit repair, analysis and design, and for learning. Price IS an object so I am looking at a minimum price option. I am a bit of a newbie here, but I think I need dual trace, about 100 MHz max, analog scope is OK. Hobbyist level scopes are OK. I would look for one of the cheap 20MHz dual trace scopes. I don't think it matters much if you get a Kikusui (or however they spell it), Leader, Hameg, Philips or whatever else you can find. I bought an old Leader scope on eBay, and that works fine for me. I don't remember how much I paid for it, but it wasn't much. Best regards, Mikkel C. Simonsen |
#17
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Hi,
Good ideas. Since I am only looking at tube amps and preamps, I agree 500 kHz or so will do. I'll look around on eBay for the HPs and other lower BW Tek options. -- Rev There's no law that says you can't have two scopes: start with what you can easily find, and then you'll be in a better position to know what you need. Cheers, Alan |
#18
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"Mikkel C. Simonsen" ... I would look for one of the cheap 20MHz dual trace scopes. I don't think it matters much if you get a Kikusui (or however they spell it), Leader, Hameg, Philips or whatever else you can find. ** The Hameg and the Philips ones will have one **major advantage** - a magnetic ( mu-metal) shield on the CRT. Practically essential for working with any kind of AC powered amplifiers - no cheap Asian scopes have them fitted and the trace shimmers like crazy in the presence of an AC field. My pet hate. ............ Phil |
#19
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I would get the 2235 if the money is not too much of a problem. Some will
say 100Mhz is over kill but you will probably find other uses for it where you may need it. Lesser scopes arent that much cheaper and they are usually lesser in more ways than bandwidth. "Revolvr" wrote in message news:YICgb.52990$vj2.19457@fed1read06... I am looking to get an oscilloscope to do tube preamp/amp circuit repair, analysis and design, and for learning. Price IS an object so I am looking at a minimum price option. I am a bit of a newbie here, but I think I need dual trace, about 100 MHz max, analog scope is OK. Hobbyist level scopes are OK. Couple things I've looked at are Tektronix 2235 or 465b which seem to be well regarded. These can be had on eBay for around $300 typically. Any other recommendations? I have also looked at a couple of PC based software scopes that work with the soundcard inputs and outputs. A couple that look promising are AudioTester at http://www.audiotester.de/ And TrueRTA at http://www.trueaudio.com/rta_abt1.htm Seems to me though that I stand a high chance of blowing out my soundcard by connecting to a signal with a DC bias or an amplifier AC signal voltage higher than a line level input would provide. Has anyone actually used either of these??? Thanks, -- Rev |
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