Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

I keep telling my wife that it's "audio gear" and she keeps telling me I have too much! Then I ask her if I can buy a few pieces of test gear to maintain my "audio gear" and I'm good for another year before she catches on!   

That wouldn't wash with my SWMBO who thinks that the sound quality coming her iPhone or iPad speaker is perfectly OK for listening to music 

[med6753]

Hahahaha. If you want to piss them off properly, stuff this on: S.A.M. - Bull Fuсking Shit.

Perfect! 

[Specmaster]

Agreed a better input box would be worth it but for a bit of a plaything I will start here. It would be easy to drop $100-200 pesos but this will do for now.

I see nothing wrong with the sound from that microphone with it being just plugged in the microphone socket of a desktop PC. Its only used for chatting via skype or discord. If you was broadcasting on radio or TV then maybe you would want extra bells and whistles but otherwise the sound is perfectly acceptable.

[mansaxel]

I see nothing wrong with the sound from that microphone with it being just plugged in the microphone socket of a desktop PC. Its only used for chatting via skype or discord. If you was broadcasting on radio or TV then maybe you would want extra bells and whistles but otherwise the sound is perfectly acceptable.

Then, most home electronics labs could make do with a USB scope, a Uni-T DMM, a copycat SMPS and a chinaclone function generator, all connected with the cheapest leads found on aliexpress, because that is the comparative level of that kit.

Me, I go full spectrum over the top. 

[Specmaster]

I see nothing wrong with the sound from that microphone with it being just plugged in the microphone socket of a desktop PC. Its only used for chatting via skype or discord. If you was broadcasting on radio or TV then maybe you would want extra bells and whistles but otherwise the sound is perfectly acceptable.

Then, most home electronics labs could make do with a USB scope, a Uni-T DMM, a copycat SMPS and a chinaclone function generator, all connected with the cheapest leads found on aliexpress, because that is the comparative level of that kit.

Me, I go full spectrum over the top. 

Yes, but, the important part is the bandwidth and latency etc of the internet connection between everyone, it is not of broadcast quality and suffers from drop out etc as can witnessed by the various reports on the thread. Its not about how you can hear the difference at your end, but at the receivers end thousands of miles. Hell, my sons uses the internet to make phones calls to me from 1.8 miles away and the sound quality is far worse than the phone line even.

[Ero-Shan]

would you giv fünfhundert Euro for a 5245L + 3 Plugins  BU?

too expensiv..

i got my  for 50€

And it looks like it's in excellent shape! Compared to other counter offerings, especially Nixie models, 100 bucks would still seem quite reasonable for a 5245L.

[mansaxel]

Yes, but, the important part is the bandwidth and latency etc of the internet connection between everyone, it is not of broadcast quality and suffers from drop out etc as can witnessed by the various reports on the thread. Its not about how you can hear the difference at your end, but at the receivers end thousands of miles. Hell, my sons uses the internet to make phones calls to me from 1.8 miles away and the sound quality is far worse than the phone line even.

All valid points, but, my day-job is making sure it is possible to hear the difference between various microphone preamps connected via such network connections, so of course I've gotten some permanent damage in the process  . War story: When we went from 128Kbit/s mono MPEG2 to 560Kbit/s stereo APT-X for sports commentary in a previous job we also had to replace the microphones, because they now were obviously lacking once we heard them better..

Discord uses afaict 40kbit/s Opus, which is a very good codec for network audio; it handles latency variation and dropped/late packets very well, so no, I do not think it is actually relevant to get a better microphone preamp here, but relevance has no place in TEA. 

[mnementh]

*BLEEEEEEEP! BLEEEEEEEEP! BLEEEEEEEEEEEEP! BLEEEEEEEEEP!*

ATTENTION!!!

THERE HAS BEEN NO ABNORMAL RELEASE OF RADIOACTIVITY FROM THE PICKERING NUCLEAR GENERATION FACILITY. THE PREVIOUS ALERT WAS SENT IN ERROR. PLEASE MONITOR LOCAL MEDIA FOR FURTHER DETAILS.

 

*turns off nuclear Armageddon and goes back to sleep*

mnem
I would be the dwagon who slept through the end of the world.

[Cerebus]

Ordered one of these too eBay auction: #324030959176 for the next streaming session that and a few of my Chinese suppliers in particular want to practice their English via Skype rather than use email Cheap and cheerful but eposvox on youtube made it sound good but his voice helps a lot. If nothing else stands and arms for other projects is a worst case for the few $

I'd get a real audio interface with a balanced microphone input capable of phantom supply to go with that, and ditch the USB dongle and the 3,5mm cable. Then you'll discover there's difference between the good and bad Chinese microphones. Some of them, like the Studio Projects B1, do an at-the-price-point impressive job capturing audio. 

And then you'll discover the truth about condenser microphones, well, it's like in the Zappa song[0], "Some of the really good ones come from over there"; their makers speak German...

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 think a U47 might just be overkill for conferencing, plus it might be a bit difficult to see around it to use your screen; or indeed get behind it with the counterbalanced boom stand you'd need to hold the mike in the right place. 

My conferencing setup hints at my pro audio past. I've got an Austrian AKG C451E + VR1 + CK1 microphone hanging over the top of my screen.

For the microphone non-aficionados amongst us, the C451 series is a professional condenser mic system which dates back to the 1960s. It was AKG's first FET (as opposed to valve) condenser microphone. The electronics part of the system has been updated several times, the mechanical part has remained largely the same and interchangeable between revisions. It had a separate phantom powered pre-amp/body onto which you could screw in different microphone capsules according to your requirements - omnidirectional, cardioid, hypercardioid, there were even two 'shotgun' capsules. There were also a couple of goose-neck extension tubes that you could screw in between the pre-amp/body and the capsule making for a mic that had a low visual profile. In the days before reliable radio mic packs and good quality lavalier mics the TV companies used them where they needed a mic in shot but wanted it to be relatively unintrusive. The BBC used them by the bucket load. Here's Michael Parkinson interviewing Lennon and Ono with three of the mics in shot (all essentially identical to mine):



I have mine set up in a desktop 'anglepoise' style stand clamped to my desk behind my monitor, with just the goose-neck and capsule poking over the top of the monitor. It's relatively unobtrusive and because it's got well controlled directional properties it picks up me but not the room or other background noises.

And for scale, here's the same John Lennon singing into the aforementioned Neumann U47, a tad clunky for domestic conferencing usage^*:

0: The reference is to Joe's Garage Act II, Scenes 9 & 10. Parental guidance is recommended when enjoying these lyrics.

And if you need parental permission to listen to that, don't even think about asking whether you can listen to "Bobby Brown". 

^* To which you have to add the floor-standing high voltage supply for the tubes, and the fat, heavy cable from this to the microphone.

[McBryce]

yep.  remember my first calculator better than my first girlfriend.  it was a ti sr10.  there is a rumor that my brother still has it in a pile o junk somewhere in his garage.  gotta' keep nagging him to dig it out.

"You silly twisted boy, you!" I definately remember my first girlfriend better than my first calculator. The girlfriend looked like what I imagine a young version of Jaime Murray looked like, the calculator was a Sinclair Scientific calculator that I built from a kit. I learned a lot from exploring both of them.

Which of these two would you opt to assign memory storage to?

Jaime Murray: Sinclair Scientific:

I hope you turned her on instead of taking her apart!! 

McBryce.

[kj7e]

Took the HP 8920A apart to clean out the dust bunnies hiding all over inside.





Also, a new book arrived YAY!



And Option 004 Signaling board, this allows Encoding and Decoding of CDCSS, PL, DTMF and a dozen other formats.





And found a like new front cover, complete with some still in plastic quick reference books.





Now to take its place on the vintage HP gear shelf.

[Cerebus]

@bitseeker et al - thanks for the discord - sound issues on my end (mainly microphone) - I think mainly because I started in the car hands-free using Android Auto and then hopped out, and tautech's comments on the blog were helpful - I think there is a bit of a delay in the Southern Hemisphere - not unexpectedly!
It's a good time of day for me.
Rob (Adelaide - South Australia)

Perhaps it might be a good idea to fix a time for a chat on the channel that's explicitly for people to mess around with their audio setups; with a few people 'on' it would be possible to get feedback from others about audibility, levels etc.

[kj7e]

The Power Designs PD 2020B came out well. Found the contacts for the 1v decade dirty and some of the resistors in the decade drifted some, the good thing is, they all seem to have drifted up, so a well placed parallel 2.2MOhm resistor here and there netted them back where they should be.  The setability is now within 0.05% (I think the spec is 0.1%).  I posted a bunch of photos on the PD thread, but here a few anyway.  Love the loomed Teflon wiring and solid machined aluminum knobs.  Something real about dials that click.  This also has to be one of the cleanest power supplies I have ever seen, no detectable hum or ripple with my gear at any voltage or current setting.  Im sure there is, but its in the nanovolts.

[mansaxel]

I think a U47 might just be overkill for conferencing, plus it might be a bit difficult to see around it to use your screen; or indeed get behind it with the counterbalanced boom stand you'd need to hold the mike in the right place. 

My conferencing setup hints at my pro audio past. I've got an Austrian AKG C451E + VR1 + CK1 microphone hanging over the top of my screen.

Oh, indeed! The U47 is a tad big, even without its 120V power supply, and the C451+CK1 setup is a lot more suitable.  I'm using one of my Neumann KM85i for similar duties, when called for, but mostly for visual effect in video conferencing I've rigged one of my Studio Projects B1 complete with suspension and all.

0: The reference is to Joe's Garage Act II, Scenes 9 & 10. Parental guidance is recommended when enjoying these lyrics.

And if you need parental permission to listen to that, don't even think about asking whether you can listen to "Bobby Brown". 

A gay friend of mine was, in the 90s,  constantly being harassed by the sports dudes in our hometown, but he got his revenge when said 'phobic dudes, oblivious to lyric content, danced to Bobby Brown. I find Joe's Garage a more complete critique of Moral Corporate America than Sheik Yerbouti, but it is still a good album.

[Cerebus]

... but mostly for visual effect in video conferencing I've rigged one of my Studio Projects B1 complete with suspension and all.

No doubt with the obligatory DT109 headphones with one earpiece on and one pushed back behind the ear.

A gay friend of mine was, in the 90s,  constantly being harassed by the sports dudes in our hometown, but he got his revenge when said 'phobic dudes, oblivious to lyric content, danced to Bobby Brown. I find Joe's Garage a more complete critique of Moral Corporate America than Sheik Yerbouti, but it is still a good album.

Heh, heh.  "Bobby Brown" is a bit of an ear-worm too; I can imagine if he'd played it to them often enough then they might have gone around singing it in the corridors - "I can take about an hour...".

[WastelandTek]

. Later this morning at around 10 AM or so I'm going to have a Rush dedication. Loud.

Did that here Friday night.

Fell off the wagon and watched live concert vids till the wee hours...

This one hurts.

[mnementh]

It pisses me off to no end that the Siglent SDM3055 reads 0.0003VDC lower than the two Fluke 8800A's. 

I been nagging them to release that manual Cal procedure ! 

I'm sure you have and I appreciate it. 

At this point, it would be less assache to make the 8800As match the SDM3055.

After all, that WAS kind of the point of getting that particular bit of new hawtness, anyways.

mnem
*passes out on the keyboard* whatthemrmphllmpppphhhhhhh...

Nope, then med would have to massage his reference too ! 
F**king rabbit holes ! ! ! 

References....plural. That's how I know the Siglent is off. 

But DO YOU... REALLY...? 

"Confidence is high" ≠ "know". Minimum standard to "know" is a calibrated measurement device that agrees with some appropriate calibrated standard, and even then ONLY in the ranges appropriate to that calibrated standard. By your own admission, you don't have a single piece of calibrated gear on your bench.

The odds of two identical meters which load a reference exactly the same being exactly the same amount right or wrong are actually a lot higher than you want to believe. The Siglent reading slightly different doesn't necessarily make it wrong; you need a lot more than two contrary samples² to make that assumption.

I'm just reminding you and those playing along at home of what you already know... I've seen you lurking in the voltnut threads; I'm more than happy to hang out here, in the voltmutt thread. 

mnem
FLUKE SEZ BAM!!! is good enough for me.

[BU508A]

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).

This is the case of the CM 7151:


This is the disassembled CM 7151:


This is the wooden case of the Neumann M7 capsule:


And this is the M7 capsule itself:


A word about the VF14: you can get those tubes. They aren't cheap, but one can get them. What is really hard to find is the VF14K, which has been used in the U47. The difference is: the VF14K is less prone to microphonics. If you will find this tube in a good condition, it'll cost easily something about 500 to 1000 USD (used condition). NOS tubes are way above over this. Once I saw one for about 1500.- (or more, cannot remember exactly) USD.

Example for an UF14 (steel case, 100mA indirect heating):
https://www.ebay.com/itm/291901673472


Example EF14 (steel case, 6.3V indirect heating)
https://www.ebay.com/itm/291070434400


This is a used VF14 (steel case, 50mA indirect heating, not the K version!) for 3000.- USD:
https://www.ebay.com/itm/253653136539


And this is an example for a refurbished Neumann U47, located in UK (for 11000.- Pound Sterling):
https://www.ebay.com/itm/233288541306


And, as promised, some pictures of the cakes I've made for today's birthday celebration of my father:

[mnementh]

@bitseeker et al - thanks for the discord - sound issues on my end (mainly microphone) - I think mainly because I started in the car hands-free using Android Auto and then hopped out, and tautech's comments on the blog were helpful - I think there is a bit of a delay in the Southern Hemisphere - not unexpectedly!
It's a good time of day for me.
Rob (Adelaide - South Australia)

Perhaps it might be a good idea to fix a time for a chat on the channel that's explicitly for people to mess around with their audio setups; with a few people 'on' it would be possible to get feedback from others about audibility, levels etc.

Isn't that kindof what this channel is for...? At pretty much any time we can find some of our friends online here and go meet there, as we've done several times already. 

Howsomever, I've already suggested making it an informal "...same Bat-Time, same Bat-Channel" thing every week; not necessarily recording a podcast every week, but more just using the already established place & time to know when you can drop in & shoot the shit with whomever made it this time. 

mnem
poit!!!

[Mortymore]

...
And, as promised, some pictures of the cakes I've made for today's birthday celebration of my father:

Happy birthday to your father. He should be proud of his son pastry abilities.

[med6753]

It pisses me off to no end that the Siglent SDM3055 reads 0.0003VDC lower than the two Fluke 8800A's. 

I been nagging them to release that manual Cal procedure ! 

I'm sure you have and I appreciate it. 

At this point, it would be less assache to make the 8800As match the SDM3055.

After all, that WAS kind of the point of getting that particular bit of new hawtness, anyways.

mnem
*passes out on the keyboard* whatthemrmphllmpppphhhhhhh...

Nope, then med would have to massage his reference too ! 
F**king rabbit holes ! ! ! 

References....plural. That's how I know the Siglent is off. 

But DO YOU... REALLY...? 

"Confidence is high" ≠ "know". Minimum standard to "know" is a calibrated measurement device that agrees with some appropriate calibrated standard, and even then ONLY in the ranges appropriate to that calibrated standard. By your own admission, you don't have a single piece of calibrated gear on your bench.

The odds of two identical meters which load a reference exactly the same being exactly the same amount right or wrong are actually a lot higher than you want to believe. The Siglent reading slightly different doesn't necessarily make it wrong; you need a lot more than two contrary samples² to make that assumption.

I'm just reminding you and those playing along at home of what you already know... I've seen you lurking in the voltnut threads; I'm more than happy to hang out here, in the voltmutt thread. 

mnem
FLUKE SEZ BAM!!! is good enough for me.

We could go round and round on this forever.

These are my 2 "transfer" standards. They are from 2 entirely different lots which gives some better level of credibility. I have no reason to doubt their accuracy.

The two 8800A's agree with both of them, 100%. The Siglent is consistently off by what I mentioned before. I think it's unlikely (but not impossible) that the Siglent is right and everyone else is wrong. Which way do YOU want to bet the farm? 

[mnementh]

My point is that all your meters could be right, and that the difference is entirely due to different loading presented by the meter itself. In my opinion, this is actually the MOST LIKELY scenario... and knowing this, I'd be much less inclined to fuck with the ONLY meter you own that you KNOW has recently passed all the MFR's QC and remains for sure "un-fucked-with".

The Siglent is the one you bought to be "the one meter to rule them all". If you go fucking with it, it becomes another "fucked-with" meter and loses the above-stated trust in the MFR's QC. It ceases to be any more than just another used meter of unknown accuracy. Period.

mnem
And this is why I am happily a voltmutt.

[tautech]

My point is that all your meters could be right, and that the difference is entirely due to different loading presented by the meter itself. In my opinion, this is actually the MOST LIKELY scenario... and knowing this, I'd be much less inclined to fuck with the ONLY meter you own that you KNOW has recently passed all the MFR's QC and remains for sure "un-fucked-with".

That is a possibility but you'd expect it read high if that was the case. 10 M vs 10G input impedance. 

[med6753]

My point is that all your meters could be right, and that the difference is entirely due to different loading presented by the meter itself. In my opinion, this is actually the MOST LIKELY scenario... and knowing this, I'd be much less inclined to fuck with the ONLY meter you own that you KNOW has recently passed all the MFR's QC and remains for sure "un-fucked-with".

The Siglent is the one you bought to be "the one meter to rule them all". If you go fucking with it, it becomes another "fucked-with" meter and loses the above-stated trust in the MFR's QC. It ceases to be any more than just another used meter of unknown accuracy. Period.

mnem
And this is why I am happily a voltmutt.

Loading has absolutely nothing to do with the readings. I've had as many as 3 DMM's connected to the same reference at the same time and the reading does not change. The Siglent and the Flukes still read same regardless of number of DMM's connected.

And as far as fucking with the Siglent. How do we KNOW that the calibration was done properly or the equipment used to calibrate it was indeed in spec? We don't.

The chicken and the egg syndrome.     

[tautech]

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