Test Equipment Anonymous (TEA) group therapy thread

[tautech]

Thanks for the overview on the 3325B  Looking at the spec sheet and what it will do or not do (discounting stability, accuracy and presence ) I would only be gaining a higher frequency Sine wave with limited adjustment over my Feelcrud for the $ spent.

It would be interesting to compare one of these anchors with a GPSDO fed into my box of crud on the stability and accuracy front too. Maybe time has moved on for old sub 100mHz Sig Gens (heresy I know)

The Tautech mob might get me yet 

In a few weeks when it arrives I’ll tease you more with some info and tests with a 2.1 GHz RF sig gen..... might even hack it to the 3.2 GHz model. 

[med6753]

It seems to me that since part of the "process" of calibrating via a "Transfer Standard" (what I believe med is attempting to build here) is confirming that the reference voltage hasn't drifted by remeasuring with the "reference meter" after adjusting the target meter, that your "uncertainty" should be minimized.

mnem

Exactly what I'm trying to do. But there is always a degree of uncertainty and I realize that. And the more DMM's you have the more uncertainty goes with it.

I do have starting points. In October 2017 all the DMM's I had at time were checked against the references I had at that time and it's all documented. The one reference with the greatest uncertainty was the 190V reference. So with this new reference I'm confident this time they will better calibrated. 

[0culus]

0culus, here's what's in the March 1990 manual for the 3325B.

[Rear Only] key: In standard instruments, this key switches the signal output from front-panel to rear-panel. The rear-panel output is active when the adjacent indicator illuminates. In instruments with the high voltage option (002), this key switches from normal to high voltage output. The adjacent indicator illuminates when the high voltage output is enabled. The key is labeled "40V_pp, 40 mA, 0-1 MHz" for option 002. In option 002 instruments, no rear-panel signal output is provided.

It's interesting that yours doesn't have the labeling mentioned for option 002. I guess it was added to your unit sometime after the original purchase.

Yep, it was retrofitted. I wonder if HP provided a kit for it? Sometimes they did provide options as aftermarket kits. AFAIK the guy I bought this from did the retrofit himself.

[0culus]

Thanks for the overview on the 3325B  Looking at the spec sheet and what it will do or not do (discounting stability, accuracy and presence ) I would only be gaining a higher frequency Sine wave with limited adjustment over my Feelcrud for the $ spent.

It would be interesting to compare one of these anchors with a GPSDO fed into my box of crud on the stability and accuracy front too. Maybe time has moved on for old sub 100mHz Sig Gens (heresy I know)

The Tautech mob might get me yet 

Honestly I bought this one for use with future audio projects, so the bandwidth limitations are not a problem for that use case. At any rate it's way more accurate than the DDS it replaced and has much better spectral purity.  YMMV, however!

[beanflying]

Honestly I bought this one for use with future audio projects, so the bandwidth limitations are not a problem for that use case. At any rate it's way more accurate than the DDS it replaced and has much better spectral purity.  YMMV, however!

I don't have much interest in Audio other than I like my 30 year old Kenwood components and how it sounds to my ears. Something that looks like sort of a Sine wave does me but a nice crisp rising edge on a square wave and knowing when it happens is far more important. Some of the older HP Oscillators have appeal should one come my way affordably (can always hope).

In a few weeks when it arrives I’ll tease you more with some info and tests with a 2.1 GHz RF sig gen..... might even hack it to the 3.2 GHz model. 

Apart from owning an 18GHz counter I have no real visions of getting into RF apart from using parts of it to drop data on. Sorry NO SALE 

[bitseeker]

So, bean, is an arb what you're needing? It sounds like an analog function or signal generator and a pulse gen (for fast rising/falling edges) would suffice.

[beanflying]

So, bean, is an arb what you're needing? It sounds like an analog function or signal generator and a pulse gen (for fast rising/falling edges) would suffice.

I really haven't reached the ends of what the Feeltech can do but as it effectively isn't supported has no way of repairing or upgrading firmware with next to zero factory support if it gets a brain glitch it is a bit of dead end longer term. Some of what I would like it to do is limited by the 30MHz.

When I say crisp I meant crisper than Sine with spectral purity What I am looking at is toward one bit of gear to cover all things as well as it can that meets current needs and any likely future directions I might head in so a tweaked SDG2042X is overkill (no such thing ) but is within a 'reasonable' budget.

[bitseeker]

I see. So, an all-around kind of machine like the FeelTech, but with cleaner output and higher frequency without killing the wallet. Was it the SDG1032X that could be "enhanced" with higher frequency or just the 2000-series generators?

[tautech]

I see. So, an all-around kind of machine like the FeelTech, but with cleaner output and higher frequency without killing the wallet. Was it the SDG1032X that could be "enhanced" with higher frequency or just the 2000-series generators?

Both. 

[beanflying]

Getting down to looking at pricing from the usual suspects on the 2000X series shows no decent source on Aliexpress and best pricing on evilbay into Oz is actually on a 2082X not a 40MHz one ex Hong Kong. Over $700USD landed.

It works out cheaper for me to buy one retail from Saelig including post than anyone else with online pricing available (without the forum discount). Under $650 landed.

I will give Trio/IPD a call Monday to see how much more it will cost to shop locally  As the differential between the 40 and 80 is very little it actually makes some sense to consider paying for the sticker in case of resale.

** Landed means including GST 

[mnementh]

In Other News...



I just picked up a pair of these for $7 at the local thrift in like-new condition. I recognized the name being bandied about as high definition gaming gear, so figured what the hey. 

Installation was painless; plugged them in and Windoze installed drivers and the sound is awesome. Unplug and Windoze instantly defaults back to whatever I had sound coming out of before; it even remembers the respective volume settings.  Well done.

Then I made the mistake of looking them up on the MFR's site and discovered there is a software suite for these damned things that lets you control everything... and they support Dolby 7.1 surround sound. AND the software knows which of their dozen or so models I have plugged in, and it brings up a picture so I know it knows, and all the right settings panes for that particular headphone.   

Fuck... even my gawddamned headphones are smarter than I am now. 

mnem
And... they have a whole integrated family of keyboards, mice, even illuminated mousepads that go with it.

[med6753]

Here's the 190VDC reference completed and ready for work.


And this is the most important part. Consensus between 2 DMM's that I have a high level of confidence are accurate and within cal on their 200VDC range.

[tggzzz]

Fuck... even my gawddamned headphones are smarter than I am now. 

Just be grateful they aren't smarter than your ears.

[Brumby]

Tonight I showed SWMBO what I got with the gift card she gave me.  The conversation was slightly clumsy - but that was probably from me tripping over my tongue.

Showed her the display with signals on both channels on one of my 27" screens and she didn't really "get it" - but then I show her all sorts of fun stuff that goes over her head.   Showing the price of new units on eBay seemed to help and things seemed to pan out OK.

I think she's happy that I'm happy.  If not, I'll find out sometime.

[URI]

Here's the 190VDC reference completed and ready for work.


And this is the most important part. Consensus between 2 DMM's that I have a high level of confidence are accurate and within cal on their 200VDC range.

Congrats, med!   
You've built a very handy and appropriate (..for the class of multimeters) reference!   

[med6753]

Tonight I showed SWMBO what I got with the gift card she gave me.  The conversation was slightly clumsy - but that was probably from me tripping over my tongue.

Showed her the display with signals on both channels on one of my 27" screens and she didn't really "get it" - but then I show her all sorts of fun stuff that goes over her head.   Showing the price of new units on eBay seemed to help and things seemed to pan out OK.

I think she's happy that I'm happy.  If not, I'll find out sometime.

Trust me, if she's not happy it won't take long to find out.   

I've tried to explain to my woman what all my stuff is she readily admits she understands none of it. And one thing she struggled with was trying to explain to her friends/coworkers what it is that I do. I finally had a break through when I described it as follows:

"As my hobby I collect and repair the electronic equipment that is used to repair TV's, Stereo's, Computers, etc". That she understood....sort of. 

[bd139]

One never knows what SWMBO understands and doesn’t. Beware.

@med6753 - good result with those MF resistors. Wasn’t expecting that good a result TBH!

In the middle of ripping all the Crimbo crap down. Thank fuck it’s over now. Can concentrate on making stuff again now. First project of the year is going to be a step attenuator I think.

[med6753]

One never knows what SWMBO understands and doesn’t. Beware.

@med6753 - good result with those MF resistors. Wasn’t expecting that good a result TBH!

In the middle of ripping all the Crimbo crap down. Thank fuck it’s over now. Can concentrate on making stuff again now. First project of the year is going to be a step attenuator I think.

I was surprised at the result too. And I have you to thank for the suggestion. 

Yep, the holidays are over...good!  Making stuff: I have to keep pinching myself that I now have all the time in the world to do what I want, when I want, and now have to worry about going to work. And if I decide not to do it today...fuck it...can do it tomorrow!  What a strange feeling that is. 

[bd139]

From experience with the several month long contract breaks I have taken I would suggest not putting stuff off. I’ve spent the last two weeks undoing stuff I put off 

[mnementh]

Here's the 190VDC reference completed and ready for work.
      
And this is the most important part. Consensus between 2 DMM's that I have a high level of confidence are accurate and within cal on their 200VDC range.

Congrats, med!   
You've built a very handy and appropriate (..for the class of multimeters) reference!   

I remember you saying you weren't going to heat-sink the regulator; but what if you potted those resistors to it with thermal paste? Do you think it would act as an oven/thermal loop and eventually achieve stoisis? 

mnem

[Wolfgang]

One never knows what SWMBO understands and doesn’t. Beware.

@med6753 - good result with those MF resistors. Wasn’t expecting that good a result TBH!

In the middle of ripping all the Crimbo crap down. Thank fuck it’s over now. Can concentrate on making stuff again now. First project of the year is going to be a step attenuator I think.

I was surprised at the result too. And I have you to thank for the suggestion. 

Yep, the holidays are over...good!  Making stuff: I have to keep pinching myself that I now have all the time in the world to do what I want, when I want, and now have to worry about going to work. And if I decide not to do it today...fuck it...can do it tomorrow!  What a strange feeling that is. 

Enjoy life, but dont forget to put the schematics 

[Specmaster]

Yep, holidays are well and truly over now, all of my crimbo stuff came down Tuesday and put back in the loft of the garage and now today I've started back on the bench with my Aiwa hifi unit again trying to sort out the damage done to it by the courier. A plastic bracket was well and truly smashed beyond any repair but thankfully there is sufficient other support for the panel that should be supported by it. What it does mean though is that it is unlikely that I can flip it now because the fixing screw, or lack of it, is visible from outside  , so I'll probably have to keep it or give it away.

The main problem with it I think is that one of these horrible flat ribbon cables got mangled and I have had to cut off part of the contacts and currently gluing another piece of thin plastic onto the reverse of the remaining contacts to give them support and thickness at the same time to make proper contact with the socket again, truth time is approaching soon.

Next on the bench will be an electric piano I got just before Christmas, it works but I just want to give it the once over internally and clean the contacts and need to resolve a small problem either with the socket where the foot pedal plugs in or the pedal itself before flipping it.

Anyone got one of these Amazon Alexa Echo smart speakers? My oldest son got me one as a combined Birthday and Christmas present and I'm genuinely quite amazed by it, its playing right now on my bench with decent bass quality from its 2.5" woofer and I love its ability to do shopping lists etc, using it to do both household shopping list on but also one for electronic parts I need to order so as I discover a faulty item, instead of writing it down, I just ask "Alexa" to enter it on the list. How do you use yours?

I'm looking for a second unit at a decent price to add downstairs so SWMBO can update the shopping list as she runs out of an item, I'm getting fed up with constantly having to drop stuff and go shopping because  she can't jot it down on a pad for me  . So far I have uncovered 3 bogus eBay accounts selling these smart speakers (bastards scammers), got a Echo Dot 3rd gen on order with Amazon now for £29 but delivery is March 8th 

[bd139]

I hide in the corner where my telescreen can’t hear me and write my thoughts with paper and pen.

[Specmaster]

Worried about big brother knowing your thoughts eh? Is your telescreen voice controlled then? 

[URI]

Last night has become expensive for me.   
[D I S C L A I M E R :  And this posting can lead to similar situations for the reader, so beware..]

The first part of the story of last night starts with our change from ISDN/ADSL based telephone line/internet access to the modern standard all-VoIP.   
I kept the ISDN telephone line as long as I could but with end of 2018 it was terminated by the carrier so we had no choice.

The switching from old to new technology was done smoothly and surprisingly flawless:
I bought a FritzBox 7590, AVMs top of the line model for DSL-connections, because it has an ISDN S0-Bus-Connector and can act like the former ISDN network to my existing ISDN telephone system: I configured our telephone numbers in the FritzBox, moved the ISDN-link from the carriers network termination to the ISDN S0-connector of the FritzBox and it worked all perfectly.      

BUT...

...on the day of the conversion the line broke down several times only a few ours afterwards.. annoying.   
I checked the cabling, the FritzBox configuration, altered single conditions/configuration details and waited day after day for the line to stabilize.

It didn't.

Last night I changed the whole flying DSL-cabling in our apartment and changed it from two plugged chained cables to one star quad J-YY telephone cable by connecting it to the LSA-block of the telephone terminal (avoiding a plugged connection) on the one end and mounting a RJ45-plug on the other end for plugging it into the FritzBox.
The FritzBox detected the length of the to its DSL-counterpart 12m shorter after that -with the same physical length of the cabling in our apartment.   

Around midnight I had it all done.
But I wanted to observe line stability so I watched several siggen and SA related episodes of Shahriars "The Signal Path"-videos under realistic conditions (<>idle state).
Ouch.
Highly infective.
I'm now thinking even more of getting a decent signal generator and spectrum analyser.      

Because I couldn't watch youtube videos all the time (my desk chair isn't as comfortable as an armchair) I also started to randomly check OCXOs I have laying around.
My GPSDO is always on (so it's always stabilized well) and I used it as the reference ending up testing the specified accuracy limitations of my Fluke/Philips counters PM6685/PM6681.   
I think I'll repeat that when the HP 53132A counter arrives..       

Well, in that run I came across the eevblog thread of BG7TBL GPSDOs and found that it might be better than my Trimble 57963-D based GPSDO..
I couldn't withstand and ordered one (the last model).   

All this time nuttery lead me to order even more OCXOs:
- Trimble 34310-T 10MHz 12V 50*50*38mm sine wave OCXO (double oven, I think)
- Trimble 65256 10MHz 12V 51*51*15mm sine wave OCXO (as a possible GPSDO spare part, see above..    )
- Oscilloquartz 8663-XS 10Mhz 12V sine wave OCXO
- Morion MV89A double oven 10MHz 12V sine wave OCXO
..all together 10 extra OCXOs*...   

...and a 10MHz rubidium reference, a Spectratime LPFRS-01 (like in this repair thread).
This unit is still well documented by its manufacturer, that's a big plus for me.   

To close the circle (direct translation from German, I hope it's understandable; is there a better native english expression?):
The DSL-line was stable after my work on it but broke down shortly after 03:20 in the morning anyway so I had to further observe it.   
I bought the rubidium standard after watching one of Shahriars videos at around 06:00 in the morning and then went to bed afterwards when I had the strong feeling my bank account would severely suffer further if I didn't stop watching Shahriars videos.   

URI
PS:
*- Please don't ask what I need these for neither what I need a second (in fact third) GPSDO or a rubidium standard for. It's just addictive behaviour. You could help through expressing your understanding..