Test Equipment Anonymous (TEA) group therapy thread

[med6753]

How old is yours Med ?
For the last couple of years at least all Siglent gear has been shipped with traceable Cal sheets.

It's a year old and I have the cal sheet.

[mnementh]

I rest my case.

mnem
 

[med6753]

Tautech....here's the cal sheet.

[med6753]

I rest my case.

mnem
 

Don't rest too long, you may fall out of the chair. 

[mnementh]

I unrest my case. 

I for one would much sooner trust the cal of the people who made the Siglent meter over that of the people who made your standards, which may or may not have been cal'd against a properly cal'd meter to standards which are at best dubious in their own right.

mnem
Ain't I a stinker...?

[tautech]

I unrest my case. 

I for one would much sooner trust the cal of the people who made the Siglent meter over that of the people who made your standards, which may or may not have been cal'd against a properly cal'd meter to standards which are at best dubious in their own right.

mnem
Ain't I a stinker...?

Yep, and a stirrer !     

[med6753]

I unrest my case. 

I for one would much sooner trust the cal of the people who made the Siglent meter over that of the people who made your standards, which may or may not have been cal'd against a properly cal'd meter to standards which are at best dubious in their own right.

mnem
Ain't I a stinker...?

We're all stinkers. What time is it? Is it REALLY??

[Specmaster]

I refer you to my original point, in the grand scale of things, the differences are small bloody small that they make diddly squat difference in real life. 

[mnementh]

Thank you, fellow voltmutt.

mnem
 

[med6753]

I refer you to my original point, in the grand scale of things, the differences are small bloody small that they make diddly squat difference in real life. 

Point taken. I was very happy at 4.5 digits. Everyone played nice. Then I decided upon 5.5 digits and all hell broke loose. And people want me to upgrade to 6.5 digits? Pffffffffft. 

[Specmaster]

On a different topic I have just come across this item on eBay for sale and I just can't get my head around how in blue (not you med) blazes did they arrive at this valuation?

https://www.ebay.co.uk/itm/THURLBY-THANDAR-INSTRUMENTS-PL154-PL154-USED-TESTED-CLEANED/392307915465

[mnementh]

I refer you to my original point, in the grand scale of things, the differences are small bloody small that they make diddly squat difference in real life. 

Point taken. I was very happy at 4.5 digits. Everyone played nice. Then I decided upon 5.5 digits and all hell broke loose. And people want me to upgrade to 6.5 digits? Pffffffffft. 

In all honesty, If I had that meter the ONLY reason for fucking with it would be to send it out for NIST-certifed cal. Nothing less would be a good enough reason.

mnem
My reality check just bounced.

[mnementh]

On a different topic I have just come across this item on eBay for sale and I just can't get my head around how in blue (not you med) blazes did they arrive at this valuation?   https://www.ebay.co.uk/itm/THURLBY-THANDAR-INSTRUMENTS-PL154-PL154-USED-TESTED-CLEANED/392307915465

£860.43 = 20 baggies of coke = Office Party. 

mnem
 

[Specmaster]

I refer you to my original point, in the grand scale of things, the differences are small bloody small that they make diddly squat difference in real life. 

Point taken. I was very happy at 4.5 digits. Everyone played nice. Then I decided upon 5.5 digits and all hell broke loose. And people want me to upgrade to 6.5 digits? Pffffffffft. 

I know, I was happy with 3.5, upgraded to 4.5, upgraded again to 5.5 and upgraded again 6.5 and the upshot of it all is that they all within a very small value mV agree with each other and also when looking at service manuals for equipment, very rarely do you come across any voltage values to go beyond 1dp anyway.

In areas where you might well be dealing with mV or even uV, then the specified test instrument is going to be more than likely a dedicated meter specifically designed as a uV meter anyway. 

Edit.
the above is especially true on a lot of the gear that we work on is so old that you need a decent analogue meter anyway to check and adjust voltages because of the circuit loading effect on DUT.

[med6753]

I refer you to my original point, in the grand scale of things, the differences are small bloody small that they make diddly squat difference in real life. 

Point taken. I was very happy at 4.5 digits. Everyone played nice. Then I decided upon 5.5 digits and all hell broke loose. And people want me to upgrade to 6.5 digits? Pffffffffft. 

In all honesty, If I had that meter the ONLY reason for fucking with it would be to send it out for NIST-certifed cal. Nothing less would be a good enough reason.

mnem
My reality check just bounced.

As Specmaster stated...in the overall scheme of things it don't mean diddly squat. NIST traceability be damned if I can get the ability to tweak the Siglent I'm gonna do it. There, I said it.....call be fucking stubborn or stupid. You and your horse can take a ride into the sunset. 

[BU508A]

Point taken. I was very happy at 4.5 digits. Everyone played nice. Then I decided upon 5.5 digits and all hell broke loose. And people want me to upgrade to 6.5 digits? Pffffffffft. 

Tektronix 6.5 digits DMM:

https://www.tek.com/tektronix-and-keithley-digital-multimeter/dmm6500

Edit (better price):
https://www.ebay.com/itm/173890370739

[chris_leyson]

A Beehive Electonics 100C H-field probe, it will keep the 100A and 100B probes company. Now I can get a reasonable estimate of flux leakage from a misbehaving 1.5kW swithed mode supply. It generates short 10us busrts at 12MHz which are sometimes strong enough to kill cmos i/o pins.

[worsthorse]

Reminder: "TEA Time" live stream Saturday, 2020-01-11 @ 21:00 UTC on our Discord server.

No software installation required to join in on the mayhem.

If you don't want to talk on a mic, there is a text channel, #teatime, for posting questions, comments, suggestions, links, etc. during the live stream.

No scripts, no budgets, all TEA.

See you there!

Sorry I missed it. I will let you imagine the reaction I would have gotten had I skipped the birthday part of a dear friend with, sorry love, i know this party thing has been on the calendar but there's a bunch of people are getting together on discord to talk about test equipment and i just gotta be there.

    

Hope it was a blast!

[worsthorse]

TBH I’m spending most of the day upgrading a PC from windows 7 to 10 

Have fun. I have to do that too....in the work cue. But mine will be a complete wipe and fresh install.

I spent yesterday updating windows 7 on four machines. Not going to move to 10 for now, maybe not at all if I get a little more comfortable maintaining linux boxes and go through the pain of my prized collection of ancient windows apps over...

[worsthorse]

I totally get it that there is no bottom to the rabbit hole.

I did fail to mention the HP 8640B here, again in an unknown state of cal.  Perhaps for now I will compare that with the 2445 and if they reasonably agree put the "for indication only" sticker on 

I wouldn't even do that. If they are reasonably close run them as is. No sticker. But you'll have to decide the definition of "reasonably close". Do you think that every Tek scope I have here is fully calibrated to factory specs? Hell no. Are they "reasonably close"? Hell yes. The 3 important parameters to me are sweep speed accuracy, vertical accuracy, and compensation accuracy. All can be easily achieved "reasonably close" with standard equipment. I don't have the thousands of dollars of equipment to do a factory spec cal and I don't care.

The only time I do sticker something is equipment I KNOW is out of spec. For example: The DMM option on the 2465 DMS. I know the ACV is out of spec. I don't have the equipment required to calibrate it so it's stickered as "not calibrated".

I hear ya Med, but you see...I have the accuracy sickness....

There's a way in that isn't too expensive as long as you don't need six digits of accuracy at high voltage, current or frequency (you can define high).  You don't need to own a bunch of calibration equipment, you merely need access to someone who has calibrated equipment: a DMM, frequency counter, and scope will do. Use that stuff to "calibrate" a decent voltage source and a decent frequency source. Calibrate your scope, frequency counter and DMM against your two new "standards".

If you must have a calibration source, you can pick up a mV accurate calibration source like the DATEL DVC-8500A for about two hundred bucks.  Med built a perfectly adequate calibration voltage source for a lot less than that.  10MHz reference oscillators are pretty cheap, too, these days. 

But then, practically speaking, for the stuff I do I rarely need to make measurements that are dependable down to micro volts, hertz, or amps, so as long as my meters and scopes and such agree with each other and the measurement value makes sense, I am good to go.

[WastelandTek]

Tautech....here's the cal sheet.

your wang?

[mansaxel]

As a matter of fact, The Holy Grail of condenser microphony, the Neumann U47 (which was sold under the Telefunken brand in the USA) is mentioned in the song. The U47 is the reason all those China microphones look the same, they are trying to mimic the U47.  Of course, the U47 is a valve microphone, using an unobtanium VF14 pentode, so acts just like the Devices we're more commonly talking about in here. 

I do not own a U47 (which I'd like to have, really!). Those things are stupidly expensive. If you find a complete one in good condition, the price range goes easily something between US-$ 5k and 15k. For the Neumann U47 or the Telefunken version.

What I have is a RFT CM 7151. It sits since a while in my repair / restoration queue. One of the advantages of this CM 7151 is: the Neumann capsules for the U47 fits on this microphone as well. And I do have the legendary M7 capsule (kidney shaped characteristic).

What a wonderful microphone. Which valve does it use?

Previous employer owns perhaps 4 or so U47 microphones. Current employer, I think, "only" has a collection of U87 and similar newer large diaphragm mikes, like C414 et al. And, of course, boatloads of KM84 and similar modernities.  According to the Neumann coffee-table book, the KM8x series are the reason we have 48V phantom feeding our microphones today. They needed a simple way of powering microphones in the all-transistorized! radio studio complex they built for NRK in Norway in the early sixties, and since 48VDC was at hand, used that. (Similar Transitorize! frenzies by managers and incompetents have lead to U47 and M50 microphones having to be saved literally from the scrap heap. Happened in the 70s in Sweden. In the end no microphones were harmed, IIRC.)

[kj7e]

So, I couldn't resist.  Solid aluminum knobs and dials, brushed aluminum face, I had to polish it.  Good old Mothers Metal polish, Q-Tips and too much time later and now I have another shiny object to play with...

PS, got the O.S.I.D. tag off the front too.

[Cerebus]

So, I couldn't resist ... I had to polish it.

That usually belies a background in the British Army or the Marine Corps, or a parent who was in the same.  I you can't polish it, paint it; if you can't paint it, whitewash it.

[med6753]

Wow, that polish works well.  I'll have to keep that in mind.

Ebay ordered CA plug-in has made it cross country. Came from Seattle and apparently into Newark Airport rather than JFK. Currently at Jersey City USPS hub. There is an outside chance I could get it Monday but it's probably going to be Tuesday.