Jack has released numerous non-slip-stream items, and even let friends play with even more that were never sold. I wouldn't be surprised at all if he had a clamp on device.
Wonder how Scott's (okay, okay AD in partnership with someone else) USB analyzer does here?
I'd try using the same duplex outlet.
It can also be confounding with an iso if the safety bond travels through (as it should).
This safety thing is such a bother...
John
ok - here goes.
I'm using the same duplex mains outlet for both the Tek and the Rigol.
Rigol shows about 10-20mV pk to pk at ~70 kHz no matter where I locate its probe.
The Tek can show up to 1V pk to pk when I locate the probe near the PSU on the rear, and about 100mV with the probe on the bench, about 1" from the scope.
Turn the Tek off - silence - problem has gone away.
Pic 1 - Rigol and Tek are on and noise is displayed
Pic 2 - Tek is turned off - no noise on Rigol
Pic 3 - Rigol probe placed under the Tek
Pic 4 - SMPSU hash picked up by coil placed close to Tek LCD screen
Pic 5 - noise from Tek measured by Rigol with 10k resistor across probe. Probe located under Tek about 1" from case
I'm using the same duplex mains outlet for both the Tek and the Rigol.
Rigol shows about 10-20mV pk to pk at ~70 kHz no matter where I locate its probe.
The Tek can show up to 1V pk to pk when I locate the probe near the PSU on the rear, and about 100mV with the probe on the bench, about 1" from the scope.
Turn the Tek off - silence - problem has gone away.
Pic 1 - Rigol and Tek are on and noise is displayed
Pic 2 - Tek is turned off - no noise on Rigol
Pic 3 - Rigol probe placed under the Tek
Pic 4 - SMPSU hash picked up by coil placed close to Tek LCD screen
Pic 5 - noise from Tek measured by Rigol with 10k resistor across probe. Probe located under Tek about 1" from case
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Do you get any radiation from the Rigol? If its the main switcher there may be an internal problem? Someone left part of the ferrite off the main transformer?
The mid-market Keysight scopes are made by Rigol, maybe they are a decent alternative. I would only be looking at Tek for the ultra high speed samplers and then its a toss up between them and LeCroy. The other curious think about the top of theline scopes is the 3-4 year service life before they are obsoleted by the market needs. I asked Agilent, LeCroy and Tek about this before specifying a DSA fro Tek. Essentialy they said just by a new one (for $150K).
The mid-market Keysight scopes are made by Rigol, maybe they are a decent alternative. I would only be looking at Tek for the ultra high speed samplers and then its a toss up between them and LeCroy. The other curious think about the top of theline scopes is the 3-4 year service life before they are obsoleted by the market needs. I asked Agilent, LeCroy and Tek about this before specifying a DSA fro Tek. Essentialy they said just by a new one (for $150K).
Both the Tek and Agilent scopes due this to some extent on an AP especially our new 525 AP with its low noise floor. I keep a good old Tek 2245 4 ch 200 Mhz scope around. I leave the fancy one for decoding serial bus lines and other things it is great for.
I have a funny story on monitors and AP's from years ago at Threshold.
I have a funny story on monitors and AP's from years ago at Threshold.
No radiation from the Rigol - zip. I did open it up just to take a look about 6 months ago. The whole PSU section is enclosed in a metal frame. From what I can see through the slots in the housing, the Tek PSU is not encased.
I will email Tek tomorrow to see what the story is.
Id rather get my money back and try to get a good 2nd hand analog scope. This Tek BTW was a replacement after the storage company trashed my Philips analog scope.
I really need a scope with a good 2mV/Div performance
I will email Tek tomorrow to see what the story is.
Id rather get my money back and try to get a good 2nd hand analog scope. This Tek BTW was a replacement after the storage company trashed my Philips analog scope.
I really need a scope with a good 2mV/Div performance
IIRC, a guy on usenet group sci.electronics.design also complained
about a Tek scope where a lot of radiation came out of the LCD.
I have an 3 GHz Anritsu pulse generator that makes soo beautiful pulses:
flat, fast risetime, absolutely no ringing when watched on a 50 GHz scope;
I don't think I could produce those that nice.
But at the same time it generates conducted noise that one cannot measure
anything. I used the 30m lawn mover cable to power it from a distant socket
somewhere else in the house.
I need an isolation transformer but the ones I looked at have toroid cores,
they may be safe, but I don't expect much noise suppression from them.
Also, my 4 channel 200 MHz analog Iwatsu scope failed for the 2nd time
in maybe 30 vears. First time it was a transistor in the x deflection, now it
does not focus any more. At least all the circuits are in the manual.
regards, Gerhard
Hammond sells EI-core isolation transformers, put 3 of them in series inside your own enclosure and puff out your chest proudly.
I've mentioned before that I cornered Hofer at an AES event to ask him about the SMPS in the new Aps. I forgot that I should have worn my "Pardon me, I'm from California" badge as my dialogue was somewhat profane, and he winced noticeably. But so it goes.
He said he had been skeptical about the departure from the classical toroid-based mains supply, and that it had required a lot of work with vendors and spending a good deal more money, but that the SMPS in the new beasts was good enough that one could no longer see line-frequency-related stuff in the DFTs. In addition to substantial shielding, the secret sauce was a very good common mode choke.
The occasion for the profanity was when I said I'd seen a post (in another forum) alleging that switching supplies now had output noise in the low microvolt region, and that I had declared Bull$hit about this. Bruce said No, theirs was in the low millivolt region, with the good circuitry it supplied having plenty of power supply rejection. I said that sounded quite reasonable.
He said he had been skeptical about the departure from the classical toroid-based mains supply, and that it had required a lot of work with vendors and spending a good deal more money, but that the SMPS in the new beasts was good enough that one could no longer see line-frequency-related stuff in the DFTs. In addition to substantial shielding, the secret sauce was a very good common mode choke.
The occasion for the profanity was when I said I'd seen a post (in another forum) alleging that switching supplies now had output noise in the low microvolt region, and that I had declared Bull$hit about this. Bruce said No, theirs was in the low millivolt region, with the good circuitry it supplied having plenty of power supply rejection. I said that sounded quite reasonable.
A pretty good deal, but you may need the optional power supply.
Tektronix ADA400A Differential Preamplifier
http://www.bellnw.com/manufacturer/Tektronix/1103.htm?gclid=CNWJ2uSQqc4CFdcXgQodz_4OPw
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Yes, we have a bunch of shoebox sized Tek TDS2114 and 3114 scopes that nobody wants to use, precisely for that reason: the LCD CFL inverter radiates like crazy. That, and the absurdly small sample memory (4k, if memory serves). Not sure what industry segment Tek targeted with these scopes, they are not even upgradeable for a price.
Our favorite for general test purposes is the Tek754 500MHz scope. Some prefer the LeCroys, in the same class, for their superb math processing features and deeper memory, but are otherwise considered awkward from an usability perpective.
My favorite scope is a TEK 485. Kind of a small screen, but it is a well focused one. Heard about it first from one of its designers at a UCB seminar, and thought it was extra special. I also have a 100MHz 7000 series memory scope. I have virtually forgotten how to use the memory function, but I used the same series back in 1978 when I wrote my IEEE paper on MC phono cartridge mistracking. Today's scopes could be a lot easier to use, I would presume, for the testing I had to do back then. I have a couple of other scopes as well.
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