Test Equipment Anonymous (TEA) group therapy thread

[bd139]

There shall be no Bose crap in this house.

There is no definition in Bose sound. It is the perfect sound system for a hairdresser's; soapy, slimy, sweet muzak supplier for people who hate music and want acoustic wallpaper.  And don't get me started on their alleged subwoofers. They're mid-HONKers to me. So much low mid resonances that I can pin-point exactly where the  "you can place it anywhere; isn't that convenient?" shit box is.

True marketing slogans (not) from them:

"No highs, no lows,
Gotta be Bose!"

...and:

"Bose -- better sound through marketing!

The time for lots of actually decent 4" drivers trying to play loud and failing to do it coherently never was, never will be, and it was always a bad idea to start with.

Bose stuff does indeed sound absolutely bloody horrible. I couldn't identify why until you mentioned the lack of lows and highs. That's exactly it. And as for hairdressers, yes exactly that (stab at ex wife) 

I am however pleasantly surprised by what they have done with some of the more "engineered" audio systems out there. In fact a couple of have shocked me at how good the output is but they clearly weren't designed by Bose engineers.

if you want to challenge your stereo set play back the 1812 Overture.

Hmm. Some refinement is required to test a stereo. That is dynamic range. One of the reasonably good live recordings of The Lark Ascending by Ralph Vaughan Williams is a good one to throw at it as it has quiet bits too.

Edit: Nigel Kennedy didn't murder it:

[mapleLC]

Is there a reputable company that can pack some test gear for me and drop it off at UPS as a service?

The shipment is in CA, by the way.  The commie one.  Oh, that doesn't help.  The CA below the other CA.

[Vince]

I am just done sorting all these transistors in these 2 plastic boxes I showed. Old man's stock from ex-work.

A chore, looking at each and every of these tiny TO92  package one by one to see what they were.

Then pulled all the datasheets.

Created a folder named "Stock", created a spreadsheet in it, below, to list all the components, write down type, basic specs, comments, quantity.... and created subfolders to hold all these datasheet for future reference. I am getting organized....

Somehow I find it satisfying to look at this spreadsheet. I now know at a glance everything that was in these boxes, specs and quantities. Information is power.... 

I didn't find any BU508A nor a BD139, but I do have a BD136 so if you flip the last digit upside down, that gives me BD139 

Old stock so no MOSFET, but I otherwise have a bit of everything.

Small signal NPN and PNP, even weird stuff like UJT and JFET.
Beefier NPN and PNP, even a Darlington, because who doesn't like a Darling..ton.
Even have a VERY beefy TO3 NPN, that 2N3772 rated at 60V 20A !!    Have 4 of them, could make one hell of a power supply ! 
Datasheet says there is even a bigger version the 3771 rated at 30A !
I know, I know... a modern MOSFET can probably do the same for 20 cents and a package the size of an ant, but I am not talking MOSFET here of course.

Then the big surprise was this AD142 and AD149 (one of each) TO3 PNP !!
They are...  GERMANIUM !!!   Daddy retired 20 years ago, not 60 years ago !! I have no idea why the hell he had these two antiques in his drawers at work !
But well, maybe I can make use of them in my Vintage TE restorations, one day.. though I guess if I opened the cans I would be greeted with lots of tin whiskers 

Then a couple opto-couplers, TIL 111 and 113.

A couple op-amps, TL071 and LM358M


It was a pain to do, but now it's done, it's so cool to know what I have got.

Can't dedicate an entire drawer to each part number, would be wasteful especially since I guess most of this stuff is obsolete and will never get used....
So I am thinking, since most are small packages, maybe I could compromise and stick several types in a single drawer, each in their tiny zip bag.

For example I could make drawers for :

- Low power NPN
- Low power PNP
- Power NPN
- Power PNP
- MISC : Darlington, UJT & JFET, Germanium
- Optocouplers
- OP amp

Still have lots more stuff to sort, mostly IC's digital and linear, but at least these two plastic boxes of transistors, it's done, phew. Now motivated to carry on with all the IC's...

Will expand the spread sheet. Think I better split the file into several "tabs" to make my life easier, make it more manageable.. Could make various tabs for transistors, voltage regulators, linear IC's, digital ICs, diodes...

[Vince]

Oh no, just realized I made mistakes.... spending hours sorting stuff is not fun...

My inventory showed TIP 31B and 31C which I found strange... why have two versions of the 31 rather than have one version of the 31, and the matching version of the 32 its complementary.

So I just looked at my TIP31B and TIP31C drawers and... sure enough I they contain also TIP 32B and TIP32C  ! Makes more sense now !

so need to look at each of them again to see what's what and update the inventory...
But.. it's cool, means I have complementary pairs now, of both the B and versions as well, that's more useful 

[Neper]

There shall be no Bose crap in this house.

Most German spell checkers routinely correct it to Böse. 

There was for many years a wonderful article on the web taking the whole Bose concept very skillfully apart but it has sadly disappeared. At least, I'm no longer able to find ist.

[mnementh]

Actual text conversation this afternoon:

SWMBO: Hey... I just got a message from our middle school saying to be careful picking up the kids; a bear has been spotted on campus.

Awwww, that was just me, baby. I was grumpy when I dropped off the kids this morning.

SWMBO: Yeaaahh... okay. 

I was VERRRY grumpy.

mnem
"Fred, he's as sweet as a ol' basset hound... which is good, cuz he so uglee it looks like somebody done shaved a grizzly bear." grand-dad

[Saskia]

finally.
6 hours to rearrange the stereo system and put the new rack in ...
 
mah back hurtz ...

but you asked for it, so

did you find your precious photos ?
someone was there ...


here are some photos ... and yes, I am for the old heavy style, not that bose, sonos, beats rubbish ...

Also, the tuner in the last photo is a new arrival ... need to test it, but it won't fit in the rack.  Cannot obstruct the vents of the power amp on the bottom shelf ...

gross weight of that system ? You do not want to know.

[mnementh]

The name "Mole grip" is because that company was the main manufacturer of such devices in the UK, back in the day, so it has the same sort of origin as "hoovering" for using a vacuum cleaner...

I figured it was because you scone-eaters just really like to keep a good hold on your moles. I dunno... for Tax purposes? 

mnem
I wonder if those would hold a water-shrew... 

HEY! I heard that! You are just lucky that my uncle is a very busy man...   

           BWAHAHAHAHA!!!   

You made me a joke I could noh'h refuuuse...

mnem

[BU508A]

Try “All is full of Love” by Bjork.

For some fun play the "Forward March" by Pat Metheny with elevated sound pressure level.

In this respect, I'd suggest "In the lap of gods" from The Alan Parsons Project.
Starts silently and becomes over time louder and louder.
And it probably would fit Papa Smurfs musical taste. 

[mnementh]

Did I just imagine that or what, did anyone else see it a few minutes ago here, I was on line catching up with events when I noticed that my handle had changed from Specmaster to "Online Specmaster" 

I think it has to do with latency... if the images aren't served fast enough, you get some conglomeration of the text-only version and the full monty. Seems to happen most often when there's something broken in one of the akamai advert links making the page load funny.

mnem
 

[med6753]

I was already into the hobby but my first Heathkit was an AA-14 Amplifier. And it did work the first time I plugged it in. 

For how long? 

First kit I built (well first kit I could afford to buy to build) was a Maplin CMOS logic probe in 1992. Didn't work because I blew up the 4001BE in it.

It worked fine for many years until I gave it to my brother and he blew up the outputs. 

[mnementh]

...It's entirely possible Craftsman contracted with Vise-Grip to make them; they would get the Vise-Grip patented design along with. They did a lot of that back in the day, when the Crafstman name was more than just marketing wank.

I don’t think these were made by Vise Grip - the release lever is a different setup (which, truth be told, I like better) - the lever on VGs gets pinched against the movable arm on them; on the Craftsman pliers it extends beyond the end of the movable arm and gets pulled towards the adjusting screw/body of the plier.  If they’re not cranked down super tight, it’s easily released with a squeeze of the little finger; takes a bit more when tight but can still normally be done one handed.  With VGs, I often need to use two hands to release them.

And yeah, these are definitely from the good times of the Craftsman brand.   -Pat

Yeah... I hated the "EZ-Release" versions; they always get knocked loose when you don't want because of that little flip sticking out. Vise-Grip made them for a while too; I know some mechanics raised holy Hell aboot it with the tool trucks. I just stopped buying new ones for a while until the regular kind started being available again. 

mnem
The moose is loose... 

Uhhh... tighten 'im up a little, willya...?

[Vince]

Oops... I got carried away.... no I am not goign to move on to sorting the ICs. Just remembered I had a couple bins of more trannystors to sort first ! 

TO3 and TO220 packages. some salvaged and usable (long enough legs), but motly intact legs so must be old stock.

At least these packages are easier to grab and to read the part number from, than all these pesky TO92 I just sorted.

Downside is... this sea of TO220 is most likely to be just as many different part numbers, will take me 3 days to pull all their respective datasheets to figure out what each and everyone of them
is !!!! 

Good side is... well, more varied stuff in my stock to play with ! 

[tggzzz]

<snip>
I can literally throw this entire building into resonance with the heartbeat from Dark Side of the Moon. And I don't give a flying fuck. 
<snip>   

Don't ya just love it when the walls, floors, and windows vibrate and anything that is loose just rattles wildly with that rhythmic drum beat on that sound track 

Try “All is full of Love” by Bjork.

That one really fucks off the neighbours 

I'd use "The Faust Tapes", because they would wonder what the hell was happening on the other side of the wall.

Basically it is many very short pieces of experimental Krautrock that some seem to have regarded as prog rock - but that's probably because it doesn't fit into any category.

While at university revising for exams, I thought of it as the music to listen to when sick and tired of all other music.

[mnementh]

I was already into the hobby but my first Heathkit was an AA-14 Amplifier. And it did work the first time I plugged it in. 

For how long? 

First kit I built (well first kit I could afford to buy to build) was a Maplin CMOS logic probe in 1992. Didn't work because I blew up the 4001BE in it.

My first kit was a Pioneer SX-580 with the upgraded mahogany veneer (not vinyl) cover in a box that somebody else tried to fix. 

Yes, I fixed it, and it soon morphed into a SX-650, then a SX-780, then a SX-980, then several in the SX-3x00 family. Those were some of the most beautiful receivers ever made.

Y'all can lambaste me now... I have a pair of 301s that I quite like as rear surround speakers with my AR M6es.  I like the way the diametrically opposed tweets bounce off the back sidewalls of the room.

mnem

       What the actual fuck...?

[Specmaster]

<snip>
I can literally throw this entire building into resonance with the heartbeat from Dark Side of the Moon. And I don't give a flying fuck. 
<snip>   

Don't ya just love it when the walls, floors, and windows vibrate and anything that is loose just rattles wildly with that rhythmic drum beat on that sound track 

Try “All is full of Love” by Bjork.

That one really fucks off the neighbours 

It also has a fecking strange video 

[mansaxel]

There shall be no Bose crap in this house.

Most German spell checkers routinely correct it to Böse. 

There was for many years a wonderful article on the web taking the whole Bose concept very skillfully apart but it has sadly disappeared. At least, I'm no longer able to find ist.

Actually, Bose is like multimode fibre.  In a multimode fibre cable, one has, as the name indicates, several modes of light entering the conductor. The conductor core, being as large as 50 or 62,6 µm in diameter (depending on quality tier of cable), will conduct those modes along slightly different paths, sometimes reflecting the mode in the cladding. At the end of the conductor there is a detector circuit sampling the light pulses (for all digital uses of multimode, the signalling is basically very fast Morse code, none of that 64QAM fancyness) and trying to make essentially square wave of what is now very fuzzy sums of light modes.  This is why friends don't let friends run multimode, and why you're limited to silly distances like 550m or so for 1Gbit links on OM3, when even the €10 China optick transceivers for singlemode reach 20km without even breaking a sweat.

So. The entire problem is time domain smearing. In the Bose case, if you have several drivers spread around a cabinet, playing the same signal, that signal is going to sum badly at every possible point in the room. The idea that drove Bose was that if the distance between the drivers is much less than a wavelength, they will sum slightly less badly. Hence, their puny 4" drivers will play LF at a level that is impressive for the size, but pathetic compared to a real, say 15" or so, driver. But, as inter-driver distance starts to approach and surpass the wavelength of the signal, the result will be cancellation and summation in a chaotic manner. This means that typical music transients and other broad-spectrum sounds will have a strange time-domain-spectrum skew that is best described as muddy. This to some extent is countered by the lack of crossovers in the system (except down to the mid-HONKer, usually 1-2 octaves too high) which makes for a somewhat coherent midrange and a sometimes inviting experience with voices. And this is the Bose idea, as tersely described as possible.  A compromise that failed, after which marketing takes over.

If you want the fullrange driver done right, look at the real, old Tannoy drivers; with a concentric HF driver, they are a point source which goes a long way towards truth.

If you want to sum drivers right, you either need to focus them so they work in parallel with minimal interference, like old Turbosound (Flashlight era) or more recent Funktion One systems, or you need to go all the way in another direction, like L'Acoustic and build a line array that actually works, because the designer understands and works with the physics.

[vk6zgo]

In the garage while I'm working I have a 8-year-old Kindle Fire/Prime Music app & a 10-year-old iHome BT speaker... It just works. Put Kindle to sleep, speaker goes to sleep. Start playing music and the Kindle reconnects, speaker wakes up in less than a second. 

Too simple. I've got a central matrix with balanced outputs to all rooms, and a collection of sound sources, among those a bluetooth receiver.  The matrix, being old, is controlled via MIL-STD-1782, which is used by a Perl-CGI script (running on the media web server VM) that makes a routing panel webpage available. In each room, there are active loudspeakers or passive ones with a power amp. There also is a simple voltage divider potentiometer volume control.

Bet you wish you had one-a deez!

mnem
 

I did have one in my work tools----really good ifyou need to remove or reconnect a bnc cable amongst a forest of others.
One place had a "home made" version, which worked just as well as the "bought ones"!

[Specmaster]

I remember many years ago, when Laskys had a store in the Brent Cross shopping mall I had discovered that they had what I think was the last pair of Wharfedale Dovedale 3 speakers for sale, reduced as the new Dovedale SP's had just been released and everyone was stocking those.

I took along, with my Mum, my vinyl LP of Eddie Dunsters "The Bells of Christmas" to audition these older speakers and the salesmen brought out these speakers into their testing room and played this LP through them. Within a few minutes there was quite gathering of customers standing around enjoying the sweets sounds. Several of those listening asked the other sales people if they could have a pair of these speakers but they were disappointed as I had already made my mind up, they were mine.

My Mum also decided that she wanted a pair but she had to make do with their newer version which featured 2 smaller woofers with foam suspensions, mine had rubber. A few years later I had to replace all the woofers in Mums as the foam had fallen apart, and boy were they expensive. Mine on the other hand were still as new and I had those speakers for over 30 years until SWMBO complained about their size and the deep bass they gave out which drove her crazy, so when they went, the rest of my Hi-Fi gear went as well. 

[Neomys Sapiens]

In the garage while I'm working I have a 8-year-old Kindle Fire/Prime Music app & a 10-year-old iHome BT speaker... It just works. Put Kindle to sleep, speaker goes to sleep. Start playing music and the Kindle reconnects, speaker wakes up in less than a second. 

Too simple. I've got a central matrix with balanced outputs to all rooms, and a collection of sound sources, among those a bluetooth receiver.  The matrix, being old, is controlled via MIL-STD-1782, which is used by a Perl-CGI script (running on the media web server VM) that makes a routing panel webpage available. In each room, there are active loudspeakers or passive ones with a power amp. There also is a simple voltage divider potentiometer volume control.

Bet you wish you had one-a deez!

mnem
 

WTF is the second from top?

[mnementh]

That... is a vintage mnem original. My 2nd high-school machine-shop project; it does exactly as intended: it holds a drift punch securely so you can place it precisely (specifically in applications like driving a bearing race in a hub or axle tube) yet allows you to keep your hand clear of your heavy fucking hammer in case you strike a glancing blow.

It requires a light touch; you need to hold it just right so that if it does its job, the force imparted to the handle through the drift doesn't whang the hell out of your palm. But it still beats smacking the back of your hand directly with the hammer in the same scenario.

Those are all favorite tools that do exactly as intended... a joy in the hand for one reason or another.

mnem
*perfecting percussive maintenance (spiritual and otherwise) for almost half a century*

[Specmaster]

I thought it was a rudimentary homemade device for undoing badly corroded or well-rounded nuts / bolts that conventional spanners can't bite on.

[tautech]

That... is a vintage mnem original. My 2nd high-school machine-shop project; it does exactly as intended: it holds a drift punch securely so you can place it precisely (specifically in applications like driving a bearing race in a hub or axle tube) yet allows you to keep your hand clear of your heavy fucking hammer in case you strike a glancing blow.

It requires a light touch; you need to hold it just right so that if it does its job, the force imparted to the handle through the drift doesn't whang the hell out of your palm. But it still beats smacking the back of your hand in the same scenario.

And it needs a long overdue cleanup and lube......should you value your goodies.   

[mnementh]

Yeah... I'm in desperate need of a decent 3/4 horse bench grinder; something can handle a 8 or 10" wire wheel. I'll prolly have to build that myself too, unless I get really lucky on Craigslist. 

mnem
"damn... another hole in my hide..."

[mnementh]

The idea that drove Bose was that if the distance between the drivers is much less than a wavelength, they will sum slightly less badly. Hence, their puny 4" drivers will play LF at a level that is impressive for the size, but pathetic compared to a real, say 15" or so, driver...

Y'all do know that Bose made lots of other models than the 901, right? And that most were conventional designs?

mnem
CV makes the rockin' world go round...