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Hi, everybody.
So at some point I will take the plunge into vacuum tube audio, and according to George Lydeck on this group, the Tek 535A is the best scope ever for tube audio work.? Now, I figured out that the letter series and 1- series plug-ins, although not all of them, are the ones to plug into this mainframe.? I have that stuff on my Test Equipment Wishlist already.
OTOH, plugging directly into scope or plug-in inputs (assumed BNC, since I don't really want to go down the rabbit hole of UHF connectors) is probably not going to be productive, so I will need some probes.? Type N, SMA, 3.5 mm, BNC, and TNC are quite enough variety in my garage lab, thank you very much.
Try as I might, on TekWiki and the Internet at large, I cannot find anything specifically saying which Tek probes are appropriate for a vacuum tube scope such as the 535A.? Maybe this is tribal knowledge?? AFAIK, I have not used a scope with more than 1 tube, the CRT, (I was born in 1965, approaching 60 years old early in 2025), so the world was mostly solid-state by the time I was old enough to be playing around with scopes.? Come to think of it, all 5 of my current scopes have CRTs, and I don't think I've owned one yet with an LCD screen.? I'm in the 'tween generation, I guess.
Any recommendations for probes for a 535A?? Plug-ins also would be a good idea to know for the wishlist.
Thanks a bunch!
Jim FordLaguna Hills, California, USA
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Jim
The Tek catalog from March 1967 is what you need. I've had one for years and its one of the best single references for the 500 series stuff that you will find. I see its available on Tekwiki - lots of data on appropriate probes and plugins.
DaveB, NZ
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-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Jim Ford via groups.io Sent: Tuesday, December 31, 2024 17:33 To: TekScopes — 开云体育 Subject: [TekScopes] probes for vacuum tubes scopes Hi, everybody. So at some point I will take the plunge into vacuum tube audio, and according to George Lydeck on this group, the Tek 535A is the best scope ever for tube audio work. Now, I figured out that the letter series and 1- series plug-ins, although not all of them, are the ones to plug into this mainframe. I have that stuff on my Test Equipment Wishlist already. OTOH, plugging directly into scope or plug-in inputs (assumed BNC, since I don't really want to go down the rabbit hole of UHF connectors) is probably not going to be productive, so I will need some probes. Type N, SMA, 3.5 mm, BNC, and TNC are quite enough variety in my garage lab, thank you very much. Try as I might, on TekWiki and the Internet at large, I cannot find anything specifically saying which Tek probes are appropriate for a vacuum tube scope such as the 535A. Maybe this is tribal knowledge? AFAIK, I have not used a scope with more than 1 tube, the CRT, (I was born in 1965, approaching 60 years old early in 2025), so the world was mostly solid-state by the time I was old enough to be playing around with scopes. Come to think of it, all 5 of my current scopes have CRTs, and I don't think I've owned one yet with an LCD screen. I'm in the 'tween generation, I guess. Any recommendations for probes for a 535A? Plug-ins also would be a good idea to know for the wishlist. Thanks a bunch! Jim FordLaguna Hills, California, USA
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The handbook for the scope should tell you its input impedance which will tell you what probes it can use. Typical scopes have 1 megohm input but not all. Probes can provide voltage range extension which is accompianed with increased impedance, i.e. a 10X probe will give you 10 meg impedance. Probes usually also have some means of compensating for capacitance, usually an adjustment on the probe to optimise its square wave response. Beside scope specs also see the catalogs for probe specs.
Now, if you are going to explore vacuum tube amplifiers you absolutely need the "Radiotron Designer's Handbook" 4th edition. Available several places on the web for example:
<>
Books on this site are very well scanned and complete. They are free.
Actual hard copies are still available, do a web search. Personally, being quite old fashioned I prefer hard copy actual books but must settle for electronic versions where the originals are not available or are too expensive.
Earlier editions of the Radiotron are of historical and some practical insterest, the 3rd edition is available at the same site:
<>
There will never be another book like the 4th edition, an excellent compilation of audio design at about the end of the vacuum tube period.
BTW, I also have the original Australian edition (in hard copy) and the American edition has everything and is excellently reproduced so there is no advantage to searching out an original.
I bought a 4th when they first came out and wore it out. I have since gotten two used ones beside the PDF version.
Lots of other tube audio books at Tubebooks.org
I wonder why the Tek 535A is considered so good for audio?
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On 12/30/2024 8:33 PM, Jim Ford via groups.io wrote: Hi, everybody.
So at some point I will take the plunge into vacuum tube audio, and according to George Lydeck on this group, the Tek 535A is the best scope ever for tube audio work.? Now, I figured out that the letter series and 1- series plug-ins, although not all of them, are the ones to plug into this mainframe.? I have that stuff on my Test Equipment Wishlist already.
OTOH, plugging directly into scope or plug-in inputs (assumed BNC, since I don't really want to go down the rabbit hole of UHF connectors) is probably not going to be productive, so I will need some probes.? Type N, SMA, 3.5 mm, BNC, and TNC are quite enough variety in my garage lab, thank you very much.
Try as I might, on TekWiki and the Internet at large, I cannot find anything specifically saying which Tek probes are appropriate for a vacuum tube scope such as the 535A.? Maybe this is tribal knowledge?? AFAIK, I have not used a scope with more than 1 tube, the CRT, (I was born in 1965, approaching 60 years old early in 2025), so the world was mostly solid-state by the time I was old enough to be playing around with scopes.? Come to think of it, all 5 of my current scopes have CRTs, and I don't think I've owned one yet with an LCD screen.? I'm in the 'tween generation, I guess.
Any recommendations for probes for a 535A?? Plug-ins also would be a good idea to know for the wishlist.
Thanks a bunch!
Jim FordLaguna Hills, California, USA
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Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
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Hi Jim. Always glad to encounter someone using tube scopes in this day and age. I design and troubleshoot with tube scopes as well, although I often reach for the 2465A. Now it would be hard to find a Tek scope that could not be used for audio work. My personal preference is for the 502 or 504. The 504 is cheap, nice and portable, and offers adequate bandwidth. There is no fan so they are very quiet. On the downside they of course are single channel. The two channels of the CA are often very useful. The 530 series, the 531 and 535 both are good scopes for low frequency work, having a 15 MHZ bandwidth. However they do constitute a lot of scope for the application. They are big, heavy to move around, and noisy. They both are fairly complex, especially the 535 with delayed sweep, which I did not find very useful but it is there if you need it. It is tricky to find one that doesn’t have its problems, especially considering the age. If something goes wrong fixing a problem can be tricky. Also getting one shipped without damage can be a challenge. But with say a CA plugin they are a fine instrument. They originally came with a 6006 10X probe, which I use with most of my scopes. I have a lot of parts for these scopes, so if you do get one let me know if you need something. Best regards.
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Thank you, John, Dave, and Richard!? Now that I think about it, I did see that P6006 probe mentioned on eevblog, IIRC.
Much appreciated!
Jim
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On Monday, December 30, 2024 at 11:17:57 PM CST, John Williams via groups.io <books4you4@...> wrote:
Hi Jim.? Always glad to encounter someone using tube scopes in this day and age. I design and troubleshoot with tube scopes as well, although I often reach for the 2465A. Now it would be hard to find a Tek scope that could not be used for audio work. My personal preference is for the 502 or 504. The 504 is cheap, nice and portable, and offers adequate bandwidth. There is no fan so they are very quiet.? On the downside they of course are single channel. The two channels of the CA are often very useful. The 530 series, the 531 and 535 both are good scopes for low frequency work, having a 15 MHZ bandwidth. However they do constitute a lot of scope for the application. They are big, heavy to move around, and noisy. They both are fairly complex, especially the 535 with delayed sweep, which I did not find very useful but it is there if you need it.? It is tricky to find one that doesn’t have its problems, especially considering the age. If something goes wrong fixing a problem can be tricky. Also getting one shipped without damage can be a challenge. But with say a CA plugin they are a fine instrument. They originally came with a 6006 10X probe, which I use with most of my scopes. I have a lot of parts for these scopes, so if you do get one let me know if you need something. Best regards.
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I don't know of a reason to call the 535 best for audio work, but if so, I'd pair it with a 1A7 plug in for it's 10 uV/div sensitivity and variable bandwidth, 2nd choice 1A1 for 5 mV sensitivity with the two channels chained.? Haven't used a 500 series scope since the early1970's. For audio, I would much prefer the 5000 series scopes for solid state, large screen, and with a 5A22 plug in, the same 10 uV and variable bandwidth. 7000 series with 7A22 plug in also good. Of course this topic could be argued endlessly.
John?? KK6IL
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On 12/30/2024 8:33 PM, Jim Ford via groups.io wrote: Hi, everybody.
So at some point I will take the plunge into vacuum tube audio, and according to George Lydeck on this group, the Tek 535A is the best scope ever for tube audio work.? Now, I figured out that the letter series and 1- series plug-ins, although not all of them, are the ones to plug into this mainframe.? I have that stuff on my Test Equipment Wishlist already.
OTOH, plugging directly into scope or plug-in inputs (assumed BNC, since I don't really want to go down the rabbit hole of UHF connectors) is probably not going to be productive, so I will need some probes.? Type N, SMA, 3.5 mm, BNC, and TNC are quite enough variety in my garage lab, thank you very much.
Try as I might, on TekWiki and the Internet at large, I cannot find anything specifically saying which Tek probes are appropriate for a vacuum tube scope such as the 535A.? Maybe this is tribal knowledge?? AFAIK, I have not used a scope with more than 1 tube, the CRT, (I was born in 1965, approaching 60 years old early in 2025), so the world was mostly solid-state by the time I was old enough to be playing around with scopes.? Come to think of it, all 5 of my current scopes have CRTs, and I don't think I've owned one yet with an LCD screen.? I'm in the 'tween generation, I guess.
Any recommendations for probes for a 535A?? Plug-ins also would be a good idea to know for the wishlist.
Thanks a bunch!
Jim FordLaguna Hills, California, USA
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A few things to consider when selecting probes:
Check the probe's compensation range against the input capacitance of the scope input.
For work in tube circuits check the max input voltage spec of the probe. Also consider how safe the probe is for high voltage circuits.
Lastly consider the attenuation of the probe against the v/dev range of the scope against the voltages in the circuits you're working on.
The Tek P6006, P6008, P6009 should be considered. The first two are 10x. The latter is 100x.
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A CORRECTION
I gave the wrong links for the "Radiotron Designer's Handbook". I gave links to the table of contents only, the full text is available, it is:
Radiotron 4th Edition:
<>
Radiotron 3rd Edition:
<>
Sorry for this, I didn't notice until I reveiwed my post later.
On 12/30/2024 9:12 PM, Richard Knoppow via groups.io wrote:> wave response. Beside scope specs also see the catalogs for probe specs.
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? Now, if you are going to explore vacuum tube amplifiers you absolutely need the "Radiotron Designer's Handbook" 4th edition. Available several places on the web for example:
<>
??? Books on this site are very well scanned and complete. They are free.
??? Actual hard copies are still available, do a web search. Personally, being quite old fashioned I prefer hard copy actual books but must settle for electronic versions where the originals are not available or are too expensive.
??? Earlier editions of the Radiotron are of historical and some practical insterest, the 3rd edition is available at the same site:
<>
??? There will never be another book like the 4th edition, an excellent compilation of audio design at about the end of the vacuum tube period.
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
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Hi Jim. To be frank, it seems a bit premature to look for probe information when you don’t have a scope, and maybe don’t know what you are going to use it for exactly. It might be better to look for some help choosing and acquiring whatever type you decide on, and how you are going to get it. There are a few 535’s on eBay, but no indication of working or not. Prices seem to be around the $400 mark plus shipping. As far as probes go, I pretty much stick with the P6006. I have never had a use for 100x probes. When I was selling scopes I brought in a quantity of Chinese probes. They were pretty much the same as the Tek ones. Quality was good and they were quite inexpensive. I always use 4 foot ones, the six and nine foot cords always seemed to get in the way and snagged on everything on the bench. If you have one scope, a couple are all you need anyway.
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Bonjour à tous
In 1960s Sidney S Smith was the audio and analog engineer at Marantz, Dick Sequerra was the RF genius.
In 1971, I had the good luck to work with them at their newly formed Sequerra Co.
Sid taught me a lot about hifi and analog circuitry.
His favorite scope was the 536, which had excellent 11 Mhz XY bandwidth.
Sid would display a lissajous of the input audio vs the output or distortion product of a distortion analyzer.
Just a walk down memory lane....
Jon
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On 12/31/24 22:47, Jean-Paul via groups.io wrote: Sid would display a lissajous of the input audio vs the output or distortion product of a distortion analyzer. That's a fine looking 10 x 10 equal grid on the CRT face of the 536 on tekwiki. I see how that would be the analog purist's favorite with 11 MHz bandwidth. Much finer than a 602 monitor...and with number and letter plugins with the T timebase, (which I had never noticed before), it's better than a 504 503 or anything else without a 10 x 10 measuring grid on the CRT, (like the 535).
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“According to George Lydeck on this group, the Tek 535A is the best scope ever for tube audio work.”
Did I really say that?
I think what I meant to say is a good tube oscilloscope, like the 535A, is a good choice for dealing with the high voltages encountered in, let’s say, an audio tube amplifier since it is a little more bulletproof than a solid state scope. Although I have original probes for my 535A I tend to use more modern probes as they are less cumbersome.
Cheers and Happy New Year,
George KD6NEW
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Rebonjour
Probes, as mentioned the P600x series was used at the time.
The later probe's had wider BW but lower compensation C range.
A point of history...Stanley Kubrick's 2001: A Space Odyssey had a scene of astronauts David Bowman and Frank Poole, troubleshooting the AE -35 LNA, with a Tektronix P600x probe. No scopes though
Recommend 1980s Tektronix circuit concept books
Oscilloscope Probe Circuits and
Probe Measurements
536: a unique scope, used throughout the 1960s. So, at Marantz, Sid's , tube amp, preamplifier, tuners, 1,5,7C, 10B, were designed using 536. I was assisting Sid, later at Sequerra, I marveled at the simplicity of his technique.
Jon
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Thanks, John Kolb.? I do have a 5103N-D10 (working properly) and a 5113 parts mule, with a total of twelve 5000 series plug-ins in various states of operation.? Also a 7904 (focus problem - to be solved maybe this month) with a total of nine 7000 series plug-ins, including a 7A22 that has a problem on 0.1, 0.2, and 0.5 V/div - almost certainly an attenuator with a bad connection.? The 5000 series plug-ins include two 5A22Ns, neither of which is working (yet).? My other scopes are a 7104 which needs a bit of TLC, and a (gulp) HP 54120B that needs a new power supply.
And yes, it is probably premature to talk about probes, John Williams, before I invest in a tube scope.? But it's looking like the 536 is the one to get, when the time comes.? Thanks, Jon (Jean-Paul), for pointing out this very intriguing model with the identical horizontal and vertical paths!? And the P600X probe series needs to go on the wishlist as well.? Hey, if that great audio gear at Marantz was designed with the 536, that's plenty to recommend it.
Thanks, John Griessen, for pointing out the 10 by 10 cm grid on the 536.? That's a great feature.
John Williams, I share your dislike for long probe cords!? I have a pile of P6102As and P6106As with the long cords, and they are constantly getting tangled.? I'll have to scour eBay for ones with the more reasonable lengths like 4 foot or 1 meter.? Space here in Southern California and the wife's patience with my hobby (obsession) being limited, everything I have in my garage lab is on one 5 foot wide bench and a 13 RU + 20 RU rack, so nothing is very far from anything else.? The long cords just get in the way.
And Joe, yes, I am familiar with probe compensation.? It's difficult to determine a person's background when he posts to the group.? In my case, I've been a professional EE for over 36 years, thank God only out of work for a few months since graduating with a BSEE in 1988.? But I know next to nothing about vacuum tubes, just that they sound great!
Not sure when I'll have time to jump into the deep end of vacuum tube audio and vacuum tube scopes, but now at least I know what tools to look for.? Thank you very much, everyone!
Jim
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On Wednesday, January 1, 2025 at 10:56:49 AM CST, Jean-Paul via groups.io <jonpaul@...> wrote:
Rebonjour
Probes, as mentioned the P600x series was used at the time.
The later probe's had wider BW but lower compensation C range.
A point of history...Stanley Kubrick's 2001: A Space Odyssey had a scene of astronauts David Bowman and Frank Poole, troubleshooting the AE -35 LNA, with a Tektronix P600x probe.? No scopes though
Recommend 1980s Tektronix circuit concept books
Oscilloscope Probe Circuits and
Probe Measurements
536: a unique scope, used throughout the 1960s. So,? at? Marantz, Sid's , tube amp, preamplifier, tuners,? 1,5,7C, 10B,? were designed using 536.? I was assisting Sid, later at Sequerra, I marveled at the simplicity of his? technique.
Jon
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Hi Jim. Yes the 536 should be very useful to you. However, the problem will be where to get one. It is arguably one of the rarest of Tek models. And no, you can’t have mine! lol. However you can use any other model to do the same thing. The 536 was designed to be much more precise for phase measurements. But that doesn’t stop you from using any model with a good horizontal amplifier either. I have been looking for certain 502 sheet metal parts on eBay, and I am surprised that there are so few 500 series on there. When I was in the business there were a lot of very reasonably priced examples. Not so any more.
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Re Probes, cable legnth....
The P600x had relatively thick cables, and massive screw on probe tips, hats.
Meant for tube sockets and B+ voltages.
Compensation was by rotating the probe body.
The later probe's starting with 454 scopes were much smaller, thinner cables slip on hats and had comp box adjust.
Finally the extra long cables traded off bandwidth for legnth, so always look for the standard legnths.
Remember to check probe compensation for each probe- scope- plugins combo.
Jon
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Probing the AE-35 unit in 2001 A space odyssey
Perhaps Tektronix P6006, Kubrick was a stickler for accuracy....
Jon
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Question to Jean Paul re: x-y distortion measurements method you mentioned. I have an HP334 Distortion Analyzer, and in the HP manual, it tantalizingly mentions a way to view distortion products. BUT there are no connection details shown. I suspect it was left out in error. I’d really appreciate any info anyone has related to the x-y measurement technique with the HP 334 (or similar). This has baffled me for years. Thanks in advance, Randy Tek 555, 7834, 7633, 7623, 7D20, and a bunch of HP, Fluke, and other instrumentation. On Wed, Jan 1, 2025 at 6:28?PM Jean-Paul via groups.io <jonpaul= [email protected]> wrote: Probing the AE-35 unit in 2001 A space odyssey
Perhaps Tektronix P6006, Kubrick was a stickler for accuracy....
Jon
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John Williams
Jean-Paul
Glydeck