So -- if AC power worries you, power your audio off of LiPo battery packs... How long would an ex-Tesla pack run a system? And those are not expensive comapared to some Audiogonzo prices?
Mr Barr barely made it beyond 60.
Eric Tabarly sailed around the globe many times, drowned at age 66 because he could neither swim nor sim.
https://en.wikipedia.org/wiki/%C3%89ric_Tabarly
Jacco
He was sailing alone away from a coastal line. Don’t be that hard a judge (skip the sim).
I can only recollect the “bang” on my young scalp and the immediate flooding of my mouth with a taste of iron.
A side kick from the boom on the head during a turn sent me away into the sea.
Cold water brought me back into consciousness soon enough (*), some 10 m from the capsized Lazer boat. I was bleeding a lot in the water and I had to turn the boat back on top. When back in the boat, winter wind stopped the bleeding and due to my stubbornness I continued sailing.
George
(*)back at the dock, the instructor told me he spotted me through the binoculars and he was about to come to rescue with the Zodiac. But when he confirmed the ‘back to action’ he left me to learn by myself .
The sim referred to a life jacket
Eric Tabarly, 66, Ocean Sailor Known for His Solo Exploits - NYTimes.com
(some say my long term memory defies christian belief, as goes for my lack of humor)
I see.
He wasn’t sailing alone
Most probably he lost his senses from the slam. Had he wore a life jacket, it would have kept him afloat.
(but then, what about the fate?)
George
He wasn’t sailing alone
Most probably he lost his senses from the slam. Had he wore a life jacket, it would have kept him afloat.
(but then, what about the fate?)
George
Sigh,
Every few years I remind all to try placing one of the cords through a toroidal transformer and sweep a sine through the toroid with the system on and playing.
Be very careful at upper audio frequencies as tweeters may not like it much.
Try the pc or line input, doesn't matter.
Iirc, it's depicted in my gallery here. (Very weird, when I put iirc, it replaced it with Kirchhoff...go figure
John
Ps. If you hear nothing, your equipment has no ground loop sensitivity. If you do, you are typical.
Every few years I remind all to try placing one of the cords through a toroidal transformer and sweep a sine through the toroid with the system on and playing.
Be very careful at upper audio frequencies as tweeters may not like it much.
Try the pc or line input, doesn't matter.
Iirc, it's depicted in my gallery here. (Very weird, when I put iirc, it replaced it with Kirchhoff...go figure
John
Ps. If you hear nothing, your equipment has no ground loop sensitivity. If you do, you are typical.
here? where is here? Checked the galleries but couldn't see it, unless it's filed under an odd name. Re-reading you ground loop stuff tho...
In my ground loop theory,test gallery as gpapag linked to. I've put several incursion paths in as starters for the search for coupling mechanisms and how they react.
Some day I will detail how the chassis structure path is frequency dependent due to proximity effect and pinch.
John
Same same for Mr. Morinix.
(I had classes plus training in circuit simulation tools in the late '80s at delft-u. Not the absolute truth, imho, but keeps the mind afloat. On the other hand, merely following pokemon instructions pushes the blind over the edge of a cliff)
Did news of the guys here in SD that walked straight over a beach cliff make it all the way to Europe? If so, I'm laughing. If there've been other occurrences of that, than I'm even more dumbfounded.
Okay, I'm laughing period. Do hope they're okay (think it was bumps and bruises).
As far as getting people out of the house and walking around, though, it's good. 🙂
Okay, I'm laughing period. Do hope they're okay (think it was bumps and bruises).
As far as getting people out of the house and walking around, though, it's good. 🙂
I meant the bear's inquisition, I shall instead seek a comfy chair and listen to my hopelessly compromised stereo.
No, I'm only really laughing because of people's lack of foresight, especially with two of them. In the SD case, they were mostly okay with some bumps and bruises. Yes, I appreciate that's a bit callous, and acknowledge that the injuries themselves aren't funny in the least.
Was doing some late night work on my power amp and could not get a clean - i.e noise free signal from my new Tektronix scope while monitoring the output of my amp. I've got ~72 kHz at c. 100mV pk-pk coming out of my power amp - both channels. I'm sure its not a stability issue - the square wave plots are well behaved and the bias current and offset are stable. When I unplug the input, its quiet. The cable from my sig gen to my amp is about 500mm long and not of a particularly good quality.
Anyway, with the Tek plugged in and showing a less than ideal trace, I powered up the Rigol. Same thing - so it must be the amp.
I power down the Tektronix for some reason - the problem disappears. That cannot be. I power it up again. 72 kHz showing on the Rigol.
Turns out, the LCD screen, or the Artesyn power supply that sits behind it (I can see the name through the ventilation slots) is pumping this dirt out. I wound a few turns of wire into a coil and connected it to the rigol. Its definitely coming from the Tektronix.
The low level trace (5mV FS) on the Rigol is clean, but not the Tek. I've been chasing my tail for hours.
Anyone have a similar experience and do I have grounds to tell Tek its not acceptable? Its a 4 channel 200 MHz BW 1GS scope.
Oh how I miss my Philips analog scope . . . .
Anyway, with the Tek plugged in and showing a less than ideal trace, I powered up the Rigol. Same thing - so it must be the amp.
I power down the Tektronix for some reason - the problem disappears. That cannot be. I power it up again. 72 kHz showing on the Rigol.
Turns out, the LCD screen, or the Artesyn power supply that sits behind it (I can see the name through the ventilation slots) is pumping this dirt out. I wound a few turns of wire into a coil and connected it to the rigol. Its definitely coming from the Tektronix.
The low level trace (5mV FS) on the Rigol is clean, but not the Tek. I've been chasing my tail for hours.
Anyone have a similar experience and do I have grounds to tell Tek its not acceptable? Its a 4 channel 200 MHz BW 1GS scope.
Oh how I miss my Philips analog scope . . . .
Perfect test to see if some ferrites on the input help with the 72 kHz hash?
Good, albeit frustrating, investigation. I can hook up a couple of our Tek's together and see if I see anything in lab today (haven't before, but not sure what kind of filtering our lab amps have).
Good, albeit frustrating, investigation. I can hook up a couple of our Tek's together and see if I see anything in lab today (haven't before, but not sure what kind of filtering our lab amps have).
Finally a justification for not replacing all my old Tek 7000 stuff. I have seen this on a number of occasions. I think that Tek was more sensitive to these issues in the Beaverton days. If most applications of scopes are high speed digital then this low level analog stuff matters much less.
If you are still able to return the scope maybe that's the best path. Its probably a design failing and the current generation of these products don't lend themselves to fixes. Can the Tek see its own radiation using the pickup coil? Is the radiation much higher than a typical LCD monitor? (Doesn't the Tek use LED backlights now?)
If you are still able to return the scope maybe that's the best path. Its probably a design failing and the current generation of these products don't lend themselves to fixes. Can the Tek see its own radiation using the pickup coil? Is the radiation much higher than a typical LCD monitor? (Doesn't the Tek use LED backlights now?)
My Rigol shows ~ 100 MHz triangle waves at 20mV amplitude, when I clip the alligator clip ground lead to the probe tip. But when I use bare 30AWG wirewrap wire to short the tip to the ground collar, the amplitude falls below 5 mV.
At UCLA many years ago I had struggled with very old test equipment with attendant bandwidth and sensitivity limitations. Abruptly there was money available from another department who hadn't quite spent all of their budget, which as we know is a recipe for having said budget cut the following year. So I was able to order some things: a Tek 475 200MHz scope, an FET active probe, and various other things. I also got the NiCad battery pack for the scope. I thought how wonderful it would be to have isolation from the mains.
Alas, the switching supply in the battery pack was hopelessly noisy, and aside from one visit to Mt. Wilson where I walked around outside with the battery-powered scope sniffing out RF to compare to the levels inside a solar facility (after a huge investment in the facility, the RF was down by about 3dB, an embarrassment), the battery pack was shelved and withered and died, a complete waste of money.
It's also instructive to take a scope probe and move it close to the CRT (for those retaining their analog scopes). Sometimes there is a electric shield there, sometimes not.
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