EEVblog #856 - Mailbag - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: February 29, 2016, 10:04:14 pm
content: More Mailbag MondaySPOILERS:Qiktag Indiegogohttps://www.indiegogo.com/projects/qiktag-it#/Apple iMac Power SupplyVictorinox Minichamp Swiss Army KnifeCaran d'Ache penKübrich Ingenieure Hose Clamp aren't the Dodgy Brothershttp://www.kuebrich.com/HF Splitter Teardown from Bitshift Dynamicshttp://www.bitshift-dynamics.de/The finiest Audiophoolery from Nordost, the Odin reference speaker cable:http://nordost.com/odin-supreme-reference/odin/speaker-cable.phpAnd a package for Sagan

author: indole
author_rank: Unknown
timestamp: February 29, 2016, 10:40:32 pm
content: Looks like the SD audio board is similar tohttp://www.ebay.ca/itm/TF-card-U-disk-MP3-Format-decoder-board-module-amplifier-decoding-audio-Player-M-/291687925029Cheapo MP3 player, maybe hack one together into a personalized FAIL button?

author: muffenme
author_rank: Contributor
timestamp: February 29, 2016, 10:55:57 pm
content: The other one look likehttp://www.ebay.ca/itm/GPD2846A-TF-Card-MP3-Decoder-Board-2W-Amplifier-Module-for-Arduino-/381374686711?hash=item58cbb3e5f7:g:ttsAAOSwyQtVr3J3.It's a GPD2846A TF Card MP3 Decoder Board 2W Amplifier Module. Nothing to wright home about but for someone new to electronics then this could be cool. This unit is a $2 USD item.This bigger mp3 is ahttp://www.ebay.ca/itm/Audio-Player-Amplifier-MP3-Format-Decoder-module-3-7-5-5V-for-Arduino-/201467969361?hash=item2ee86d3f51:g:LMAAAOSwIwhWSYn9.It's a Audio Player Amplifier MP3 Format Decoder module 3.7-5.5V. This unit a $3 item.Great show.

author: tpw_rules
author_rank: Regular Contributor
timestamp: February 29, 2016, 11:31:51 pm
content: One interesting detail with the iMac power supply is actually how it fits in the computer's architecture. As opposed to a standard computer where the power supply takes mains in and outputs 5V, 3.3V, 12V, etc, that board only outputs 12V at 30 amps if I can read it right. There is another board with several DC-DC converters to generate all the system voltages, kind of like a laptop. This means a) if that board works, it's a fairly nasty 12V supply and b) you can run an iMac off a car battery. I had an older one with a failed mains board which ran fine like that. I'm not sure anything (except perhaps the hard drive) gets the input voltage so it was fine with any voltage from like 10 to 14 volts.

author: Andy Watson
author_rank: Super Contributor
timestamp: February 29, 2016, 11:59:00 pm
content: Potterverbwork, act in feeble, unsystematic way.In the Old Dart, sheds are good places to potter.

author: rrinker
author_rank: Super Contributor
timestamp: March 01, 2016, 12:03:54 am
content: So Down Under do you need to hook those fancy speaker cables up the opposite way so the nanobullshit particles don't all fall out?

author: Don Hills
author_rank: Regular Contributor
timestamp: March 01, 2016, 02:03:34 am
content: That "orange peeler" thingy on the Minichamp is also useful for opening welded clamshell plastic bubble packs.

author: SNGLinks
author_rank: Regular Contributor
timestamp: March 01, 2016, 02:19:28 am
content: Portion Down is a British government research establishment known for its controversial chemical and biological weapon research.https://en.m.wikipedia.org/wiki/Porton_Down

author: Towger
author_rank: Super Contributor
timestamp: March 01, 2016, 11:20:42 am
content: I though Daddy would have a laugh, even if most of it currently goes over Sagan's head. Many of the 'stories' are very British, even Yanks may not understand them.From the days when engineers wore suits:

author: LazyJack
author_rank: Frequent Contributor
timestamp: March 01, 2016, 12:05:35 pm
content: The pronunciation of Caran d'Ache is something like Caran-d-ash. It actually comes from the Russian word for pencil. See:https://en.wikipedia.org/wiki/Caran_d%27Ache_%28company%29

author: rrinker
author_rank: Super Contributor
timestamp: March 01, 2016, 01:14:44 pm
content: Those organized tins of hardware that Dave bought? That guy was clearly related to Roland.

author: Fungus
author_rank: Super Contributor
timestamp: March 01, 2016, 01:20:00 pm
content: Am I the only one who imagined a mini Jacob's Ladder when I saw this?All it needs is the right sort of transient...But come on: That thing has a backlight, a trimmer, a MOV, a proper shunt (trimmed with solder blobs) ... it's a luxury multimeter!

author: kunzem
author_rank: Contributor
timestamp: March 01, 2016, 02:14:34 pm
content: on the cabletv amplifier the things are transformers for impedance matching and allow to injection the supply voltage into the signals.

author: Groucho2005
author_rank: Regular Contributor
timestamp: March 01, 2016, 02:56:09 pm
content: Quote from: rrinker on March 01, 2016, 12:03:54 amThe cables do have to be hooked up the opposite way in Aussieland but the reason is another - The nanobullshit particles are constantly spinning within the wires but, just like water in a drain, they spin the other way in the southern hemisphere.Also, these cables need a very long burn-in time until the molecules (and the nanobullshit particles of course) have aligned themselves for maximum listening pleasure. Before serious listening, burn them in with the amplifier at maximum power 24/7 for about 8 months.

author: Zbig
author_rank: Frequent Contributor
timestamp: March 01, 2016, 03:33:08 pm
content: Quote from: Groucho2005 on March 01, 2016, 02:56:09 pmI know that just trying to apply any reason to the "directional speaker cable" BS is a mistake but is this bunch really so dense that none of them actually realizes that audio signal is f*%^!$g bipolar? Like, the current flowing in each direction more or less half the time?

author: Fungus
author_rank: Super Contributor
timestamp: March 01, 2016, 03:34:17 pm
content: Quote from: Zbig on March 01, 2016, 03:33:08 pmBut... one end of the cable is connected to ground, isn't it?

author: Groucho2005
author_rank: Regular Contributor
timestamp: March 01, 2016, 03:36:40 pm
content: Quote from: Fungus on March 01, 2016, 03:34:17 pmNot necessarily.

author: Brumby
author_rank: Unknown
timestamp: March 01, 2016, 03:37:47 pm
content: eg .... a bridged amplifier.

author: Groucho2005
author_rank: Regular Contributor
timestamp: March 01, 2016, 03:39:51 pm
content: Quote from: Brumby on March 01, 2016, 03:37:47 pmOr simply a symmetrical amp.

author: rrinker
author_rank: Super Contributor
timestamp: March 01, 2016, 03:42:46 pm
content: Quote from: Groucho2005 on March 01, 2016, 02:56:09 pmYes, I realized my mistake after posting. Clearly it is rotationally influenced, not up/down. Hmm, perhaps someone needs to sell a burn-in rig so people can optimize their cable performance. Think your $100K cable gives you the best listening experience? Think again. Your cable can be even better after it is properly burned in to align 100% of the nanobullshit particles. Make sure you optimize your ultimate cables with our new BullBurner cable optimizer.Of course then the company making the cables would simply change over their literature to indicate that the cables are 100% burned in at the factory and come ready to use.Was that here, or somewhere else, that I saw the multi-thousand dollar 1 meter long Ethernet cable which was also 'directional'? Designed to optimize your MP3 experience....

author: Zbig
author_rank: Frequent Contributor
timestamp: March 01, 2016, 03:43:03 pm
content: Even in the implementations it actually is, what's the difference anyway? Isn't these guys' point that the current flows "better" in the "right" direction of the cable? What does the presence or the lack of the ground reference on either of the amp posts change in that respect?EDIT:What I mean is: regardless of the implementation, your speaker's diaphragm doesn't sit half-extended during the silent periods of the audio signal, right?

author: Brumby
author_rank: Unknown
timestamp: March 01, 2016, 03:45:51 pm
content: Quote from: rrinker on March 01, 2016, 03:42:46 pmI think you might mean this. It was here....https://www.eevblog.com/forum/chat/eevblog-2015-top-5-bullshit-products-award/msg822776/#msg822776Quote from: Brumby on December 16, 2015, 10:47:14 am

author: Groucho2005
author_rank: Regular Contributor
timestamp: March 01, 2016, 03:50:10 pm
content: Quote from: Zbig on March 01, 2016, 03:43:03 pmNothing.

author: Groucho2005
author_rank: Regular Contributor
timestamp: March 01, 2016, 03:57:45 pm
content: Quote from: Groucho2005 on March 01, 2016, 02:56:09 pmI forgot to mention that the burn-in procedure cannot be done with just any signal or music material. For people who prefer a more relaxed and valve-like sound, use a mixture of Kenny G, Bananarama and Cole Porter. Make sure that the room temperature is between 22 and 24 degrees Celsius at all times.For people who like a more analytical sounding system, use Sex Pistols, Kraftwerk and 50 Cent. Room temperature in this scenario should be between 18 and 20 degrees Celsius.

author: FrankBuss
author_rank: Unknown
timestamp: March 01, 2016, 04:16:13 pm
content: What's wrong with these cheap Chinese multimeters? Of course, you shouldn't use it for measuring mains, the inside doesn't look very CAT II safe as printed on the top, and the cables don't have enough copper for 10 A, but otherwise it might be useful for reasonable accurate low voltage and resistor testing. Might even have a faster continuity tester than more expensive multimeters.

author: Zbig
author_rank: Frequent Contributor
timestamp: March 01, 2016, 04:38:13 pm
content: Quote from: FrankBuss on March 01, 2016, 04:16:13 pmIt just seems fashionable here, somehow

author: rrinker
author_rank: Super Contributor
timestamp: March 01, 2016, 04:59:38 pm
content: Quote from: FrankBuss on March 01, 2016, 04:16:13 pmI use them on my model railroad, it's all low voltage and some basic continuity checking for the most part. They're fine for that sort of thing, and when it gets dropped, or stepped on, or covered in plaster and glue, I just toss it and pick up another, often free. I would not want to subject my Fluke 8060, or a nice new 87V, to such abuse.When I need to make 'real' measurements, I use a 'real' meter.

author: Macbeth
author_rank: Super Contributor
timestamp: March 01, 2016, 08:16:17 pm
content: Quote from: Towger on March 01, 2016, 11:20:42 amI laughed my arse off when Dave mentioned "Porton Down" as a shed. Clearly this is a troll book, indeed part of a comedy series for adults who were brought up on Ladybird books as children.e.g. My favourite Ladybird book as a childMaking a Transistor Radio. I wouldn't recommend an old TRF PNP design in nowadays it has to be said!I think the subtleties of humour in the Old Dart go over Aussies heads maybe as much as it does the Americans?The great thing with this book is it will still appeal to children despite the obvious to adults utter non Political Correctness.

author: Fungus
author_rank: Super Contributor
timestamp: March 02, 2016, 12:03:58 am
content: For non-UK readers:"Pottering" is what men do in sheds. It's nothing in particular, just pottering, doing your thing."Porton Down is where government workers will potter in the in the event of a Nuclear Attack."

author: Macbeth
author_rank: Super Contributor
timestamp: March 02, 2016, 12:24:20 am
content: Providing they aren't too busy experimenting with nerve gas on the enlisted rankshttps://www.theguardian.com/science/2004/may/06/science.research

author: thoper
author_rank: Newbie
timestamp: March 02, 2016, 01:32:42 am
content: tell me the truth Dave, did you put your finger in that hose clamp and applied pressure?

author: all_repair
author_rank: Frequent Contributor
timestamp: March 02, 2016, 01:44:37 am
content: Quote from: rrinker on March 01, 2016, 04:59:38 pmSo it is not just meI get more value from cheap handtool than my expensive ones. I am not afraid to abuse and to wear them out, and have kept sharpening them. But the expensive ones like the Royal family, they are sitting there and be pretty. I do bring them out to use in front of customers and visitors. Only we know what are the good cheap tools, and what they are good for. But in front of customer, I don't fight them, show them Fluke and they let me get on with my job.

author: Cerebus
author_rank: Super Contributor
timestamp: March 02, 2016, 02:05:32 am
content: Quote from: Brumby on March 01, 2016, 03:45:51 pm... your wallet to our bank account.

author: Cerebus
author_rank: Super Contributor
timestamp: March 02, 2016, 02:13:48 am
content: Quote from: Macbeth on March 01, 2016, 08:16:17 pmI haven't seen the 'Ladybird' book that Sagan and Dave got sent, but I presume it mentions the necessity of the shed to the British gentleman for having a crafty fag and a few pints of homebrew with his mates?From the original Ladybird books I cannot recommend highly enough the "Ladybird Book of the Internal Combustion Engine".

author: nowlan
author_rank: Frequent Contributor
timestamp: March 02, 2016, 02:38:39 am
content: I thought the letter said something about pb swiss. Was looking forward to that, instead we got a pen?

author: wblock
author_rank: Regular Contributor
timestamp: March 02, 2016, 03:11:19 am
content: Quote from: FrankBuss on March 01, 2016, 04:16:13 pmWatching the readings fluctuate on cheap meters is really annoying, but rather than throw it away, it would be good to stick in the glove box. Too crappy for regular use, but better than nothing in an emergency. (Are they called a "glove box" in Australia? Or something colloquial like "wombat pouch"?) There were some things on that meter that could have stood a little investigation, too. Was the footprint around the COB for a QFP IC, or was it for a testing jig? The layout of the backlight and display kind of looked like a standard 16x2 character LCD. I also wondered if the solder on the current shunt might actually be filling a cut space to act as a fuse.

author: Brumby
author_rank: Unknown
timestamp: March 02, 2016, 05:59:09 am
content: Glove box is the term.'Wombat' either means the animal or a person doing something silly or stupid.There's also a thing called a 'wombat crossing' - which is just like an ordinary pedestrian crossing across the road, except that it is raised - making a long flat speed bump for traffic.But back top the subject ... it's a glove box.

author: sony mavica
author_rank: Frequent Contributor
timestamp: March 02, 2016, 06:52:24 am
content: i love Swiss Army Knives its sad that i lost minethey are amazing

author: G7PSK
author_rank: Super Contributor
timestamp: March 02, 2016, 08:01:46 am
content: I think the picture of Roland sorting screws in his shed was of a typesetter.

author: Cerebus
author_rank: Super Contributor
timestamp: March 02, 2016, 01:34:47 pm
content: Quote from: Brumby on March 02, 2016, 05:59:09 amThe word "wombat" is almost always preceded by the word "You". The equivalent English, especially London and the South east, usage is "You muppet!".

author: Cerebus
author_rank: Super Contributor
timestamp: March 02, 2016, 01:38:56 pm
content: Quote from: G7PSK on March 02, 2016, 08:01:46 amThe illustrations have clearly been re-purposed from the huge stock of artwork from the original children's Ladybird books - they must be a goldmine of humour if looked at with the right eye.

author: rrinker
author_rank: Super Contributor
timestamp: March 02, 2016, 02:12:48 pm
content: Just Google image search for Ladybird Books. It is indeed a gold mine of humor.

author: Fred27
author_rank: Unknown
timestamp: March 02, 2016, 02:17:36 pm
content: I got a few of those Ladybird books for Christmas. They're excellent. Yes - I think it says that the pictures were taken from genuine books and just the text redone.

author: Macman
author_rank: Regular Contributor
timestamp: March 02, 2016, 02:27:40 pm
content: Quote from: Macbeth on March 01, 2016, 08:16:17 pmMention of that book bring back childhood memories for me. When I was at primary school (about 11 years old) I made the regenerative radio from that book and took it into school and proudly showed it working to the other children in the class. We were not allowed to bring radios in to school so the teacher confiscated it. The teacher didn't believe I made it because I was considered the dunce of the class.Later I got called into the head masters office where I was asked about the radio and given it back.

author: f4eru
author_rank: Super Contributor
timestamp: March 02, 2016, 09:19:55 pm
content: The RF cable modem thingy is supposed to be a bidirectional amplifier.In cable applications with broadcast and internet, there are often bidirectional amps in the network (sturdier ones).This is done to compensate long lengths of cable.Stably amplifying in both directions is not easy, it can quickly turn into an oscillator. This is why they took many precautions.... But there seems to be only one path, strange. Something on the other side of the PCB ?

author: SL4P
author_rank: Super Contributor
timestamp: March 03, 2016, 03:01:52 am
content: Everyone knows that signals are 'sourced' or 'sunk' at the appropriate intervals to create pulses of energy that often become 'sound' when modulated at audio frequencies.To a novice, the technical concepts ofsinkingandsourcingcan be literally replaced withsucking and blowing. These are also terms familiar to the audiophool.

author: SeanB
author_rank: Super Contributor
timestamp: March 03, 2016, 05:00:31 am
content: Quote from: wblock on March 02, 2016, 03:11:19 amYou all missed the view of the cut leads, showing the unmistakable sight of the white shiny inner of the wire, not copper but copper coated aluminium. this is showing up in all Chinese products built down to a price, as they seem to have gotten the ability to draw it reasonably reliably, and of course it is much cheaper than copper in material cost. Simplest test is the lighter method, where copper simply glows red but this droops, and steel is magnetic.

author: ejeffrey
author_rank: Super Contributor
timestamp: March 03, 2016, 06:59:37 am
content: In China it is normal to put the family name first, so Jianwei and Haibin are their given "first" names, and Song is their shared family/surname.The way I have heard Jianwei pronounced is with the 'Jian' as in "Jean-Luc Picard". Not sure how close that is to the way a native would pronounce it.

author: kalleboo
author_rank: Regular Contributor
timestamp: March 03, 2016, 11:43:25 am
content: It's probably for the best the watch didn't turn on:A cheap smart watch often peddled on eBay uses a pairing app for Android or iOS that contains a backdoor that quietly connects to an unknown Chinese IP address

author: station240
author_rank: Unknown
timestamp: March 03, 2016, 04:16:21 pm
content: That crappy multimeter had other issues Dave didn't mention. Most of the pins for the transistor tester socket weren't soldered, also a blob of solder on the plastic case under one end of the PCB.I have a rather sturdy hammer to use on such products, so they don't fall into the wrong hands.

author: SeanB
author_rank: Super Contributor
timestamp: March 03, 2016, 04:38:02 pm
content: Quote from: station240 on March 03, 2016, 04:16:21 pmJust busy putting a new handle on the one I have, the old one broke........... Good thing is the hardware shop 50m away has a few spare ones in stock, for the price of $2. Now just have to do a little work on the fit and put a coat of paint on the handle and some furniture oil on the new Meranti handle.

author: Cerebus
author_rank: Super Contributor
timestamp: March 04, 2016, 12:04:58 am
content: Quote from: ejeffrey on March 03, 2016, 06:59:37 amThe J at the beginning is a mix between an English 'ch' sound and 'j' sound. That's a bit of guess though because there have been about 10 formal systems of romanization of Chinese and dozens of informal ones. Without knowing which is being used it's a bit of a crap shoot; but the suggested pronunciation fits a very common name and I happen to know someone with the same name.

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 04, 2016, 06:34:36 am
content: Directional cables actually do exist. The truly directional ones have multiple layers of shielding and the outer layer only connects at one end. The idea being that end should connect to the part with a more direct ground connection.

author: Dawanpi
author_rank: Newbie
timestamp: March 04, 2016, 08:18:40 am
content: Quote from: Cerebus on March 04, 2016, 12:04:58 amThe family name is Songhttps://en.wikipedia.org/wiki/Song_(Chinese_surname)"Jianwei" and "Haibin" are given names. Both are very common in China.

author: Neilm
author_rank: Super Contributor
timestamp: March 06, 2016, 05:20:38 pm
content: Dave should have kept that meter. It was marked 600V CATII which I think is a 4kV transient superimposed on the 600V. Could have used the high speed camera to film the explosion.

author: apis
author_rank: Super Contributor
timestamp: March 06, 2016, 10:39:07 pm
content: Quote from: Dawanpi on March 04, 2016, 08:18:40 amI've heard it's common to have the same family name in China but thesurnamesgiven name is often more unique?

author: apis
author_rank: Super Contributor
timestamp: March 06, 2016, 10:46:02 pm
content: I recently got several new Victorinox knifes, they really are great quality. When I was very young and very stupid we tried to deliberately break the blade on one but failed, it probably can be done but it survived a lot of abuse. I conjecture the most common failure mode is having it stolen or forgetting it somewhere (or confiscated by airport security).

author: Macbeth
author_rank: Super Contributor
timestamp: March 07, 2016, 12:09:35 am
content: Quote from: apis on March 06, 2016, 10:46:02 pmI agree with this. My most prized possession at one point as a child was a Victorinox pen-knife that had EVERYTHING, eyeglass, rule, drivers, scissors, can opener, the lot. The electrician had left it behind and I figured "Finders Keepers" as he left it so long... and nobody noticed...Unfortunately my mum found me showing it off to all the kids and strangely enough the electrician turned up soon after claiming he left a tool behind, and I had to sheepishly give it upOh actually I remember another one around the same time - A continental lorry driver overturned his truck and all the police were out in force at the accident scene. I spotted amongst the truckers debris a very nice locking switchblade, which happens to carry an absurd mandatory sentence for carrying in the UK (I didn't know that when I was 10). I purloined it and sadly a copper spotted me and got it back. While the trucker probably got prosecuted for falling asleep at the wheel, he probably ended up in prison for 5 years for having the perfectly reasonable safety locking blade in his kit of tools at the time and it having no bearing on the accident whatsoever.Sadly all the really good multi-tools will have locking blades, but a perverse lacuna in the UK knife law is that makes them illegal.

author: apis
author_rank: Super Contributor
timestamp: March 07, 2016, 01:14:16 am
content: Quote from: Macbeth on March 07, 2016, 12:09:35 amYeah, some knife laws are dumb. They had some trouble in Denmark recently, politicians had made further restrictions to their knife laws and suddenly people were sentenced to jail for having multi-tools in their car... And recently in Sweden prosecutors took a knife case all the way to the supreme court (woman had a folding kitchen knife in her bag when walking home from a friend, she had helped with preparing food for a party). Luckily they responded with a very reasonable list of when it is legal to carry knifes. Knives are tools, well pocket knifes anyway, and should be legal. A crochet needle is probably just as dangerous if someone is intent on causing harm, not to mention fists and legs, and people in general.

author: Macbeth
author_rank: Super Contributor
timestamp: March 07, 2016, 01:57:46 am
content: I have an inkling that those knife laws don't apply to "our new friends" - Saudi curved blade head-lopping scimitars and janburi daggers for example will be dealt with "diversity" and "cultural needs" taken in to account.

author: Fungus
author_rank: Super Contributor
timestamp: March 07, 2016, 09:57:44 am
content: Quote from: kalleboo on March 03, 2016, 11:43:25 amLucky for us the $1000 USA built ones don't connect to random USA IP addresses, eh?

author: Fungus
author_rank: Super Contributor
timestamp: March 07, 2016, 10:09:11 am
content: Quote from: apis on March 06, 2016, 10:46:02 pmI was in the UK last week and I had my minichamp with me. I stupidly forgot to put it in my checked bag on the way back so I was worried they would confiscate it. I had it in my pocket and I put it in the tray with my keys and loose change. It got through two security checks just fine (technically it's not illegal to carry it, but...)On the other hand: Both metal detectors I went through made a beep but on the other side theydidn'tcheck me for metal or make me go back through the arch. Both times they just swabbed the palms of my hands for chemicals. What's that all about? Do I look like a bomb-maker or drug smuggler?The beep at the arch was obviously somebody pressing a button, not metal detection.

author: apis
author_rank: Super Contributor
timestamp: March 07, 2016, 01:34:36 pm
content: Quote from: blueskull on March 07, 2016, 02:30:37 amAh, I meant given name. Here it's common to have the same given name but not so common to have the same surname/last name. Someone told me it's the other way around in China, not sure if it's true?

author: apis
author_rank: Super Contributor
timestamp: March 07, 2016, 01:43:20 pm
content: Quote from: Fungus on March 07, 2016, 10:09:11 amI've heard they can be set to beep at random when people pass through. It might have been to get a truly random sample of people to swab?

author: Fungus
author_rank: Super Contributor
timestamp: March 08, 2016, 11:17:08 am
content: Quote from: apis on March 07, 2016, 01:43:20 pmIt certainly wasn't because I had any metal on me.Quote from: apis on March 07, 2016, 01:43:20 pmTwice in one day?Couldbe random.... but I'm wondering if it was because I was wearing baggy army trousers with lots of pockets.OTOH they're not supposed to profile based on appearance, right? That would be security failure 101.