EEVblog

[@walts555]

In RF land we call that a transmission line transformer. At low frequencies, the ferrite coupling does the heavy lifting, and at high frequencies, the transmission line coupling does the heavy lifting. Simple in principle, but getting the crossover really flat in amplitude and phase takes a good bit of experimentation.

[@redoverdrivetheunstoppable4637]

this starts to make sense now

[@steverobbins4872]

On the transformer, twisting the primary and secondary wires together before wrapping them on the core is a common technique called bifilar winding. On the main unit, of course there are no directional couplers because this thing operates at way too low a freq range for that. What they must be doing is digitizing both the voltage and current, then computing the s-parameters from the impedances. And the board material does look weird, but I[m sure it's not Rogers material. You'd only use that for stuff in the GHz range at least. But I liked the video. Thumbs up.

[@50Hz]

We use a lot of omicron stuff, they make some top quality stuff. The software that runs the stuff is what makes it special

[@xXTepicwinTXx]

$500 transformer > ziptied wires to the plugs

[@StreuB1]

Piece of chalk - 25 cents Knowing where to draw the X to mark the problem - $10,000

[@GRBtutorials]

$10000.25! That's really expensive just for marking the problem... My tariffs are better, just $1000 for solving the problem: Hammer - $10 Transportation - $40 Knowing where to hit with hammer to solve the problem - $950

[@OblivionLPS.]

@@GRBtutorials Hahahahahahaha :-) You made my day :-) But that's true.

[@CornishMiner]

Lots of people claiming they could make a wideband injection transformer for a few bucks. Time for a competition perhaps Dave?

[@youdonotknowmyname9663]

It is one thing to make 1 of those. Producing lots of them is a completley different thing!

[@gavincurtis]

For $500 dollars, I would at least expect the label to be applied straight on my project box. Beautiful transformer though, wouldn't surprise me if those windings were spaced apart by hand during calibration to optimize. Specialized kit and the knowledge to get it where it is costs special money.

[@BarriosGroupie]

Yeah, and Dave was moving them with his fingers lol

[@samfedorka5629]

looking at the graph at 1:28 the frequency response falls off quite a bit at low freq. -15db at 1hz. it doesn't go back up to 0db until 100Hz which is much more doable I think.

[@ekus6196]

I agree with your point about the 10V at low frequency and core saturatrion . It does not make sense . Usually for loop response one would use less than a millivolt to avoid saturation of the error amp .

[@Mihail_K.]

A russian guy once repaired a cheap lab power supply and the fault was in the mains fuse holder, it was just broken. He didn't have any holders so he just soldered the fuse. "The fuse holder can't brake if there isn't one".

[@marcoaurelio4903]

Are you from the most bizarre semiconductor land?

[@redsquirrelftw]

Russians know how to fix stuff. If you take away the part that breaks and the product still works, well you fixed it and increased reliability! Heck, you don't even need fuses, that's what the rest of the components are for! :P There's a funny saying that expensive transistors are designed to protect fuses.

[@Electroblud]

I actually did a "mini-internship" at Omicron in Austria a few years back. No nude virgins assembling the devices though :/

[@valerionappi7839]

ElectroBlud give us the insights

[@wanderinguser7665]

Clothed virgins, males.

[@AndreAndFriends]

valerio ew they have only one Virgin for the whole company. She is 72 years old. ...... run away, while u still can. From 72 years old virgin.

[@skuzlebut82]

Xy Zi Your comment wins

[@itechflagstaff]

tell the truth.. Were you one of the 'nude virgins' 😁

[@scuba31]

I'm surprised by all of the negative comments. This equipment is more common than many engineers must think. Every gadget which has a power converter, switcher or linear, should be using one of these to check stability of the control loop under numerous conditions prior to going into production. Cellphones, tablets, computers, other test equipment, etc, everything that uses volts and amps needs something like this to confirm the stability of their power supplies. This equipment can be used for many other measurements as well. Other competitors to this bode box are priced in a similar range for their equipment. Large companies have dozens of these. Our large company has at least 15, most of which are in use almost constantly.

[@skuzlebut82]

$15 worth of parts. $485 worth of magnetic voodoo.

[@Zadster]

Top tip for anyone wanting to make a transformer with better performance than this: Use binocular ferrites. Hard to get, but if you are serious about being a manufacturer of quality test gear, it is viable when you are charging hundreds of bucks for a wideband flat transformer. If you are being *really* snazzy, use a pair of binocular ferrites.

[@rfengr00]

The transformer is bifilar wound. The capacitive coupling aids the high end of the BW.

[@oswaldjh]

The wire is specially manufactured. The wire drawing machine uses normal copper but the machine has to be oriented in such a way so the wire is drawn from north to south in the Northern Hemisphere. The machines in the Southern Hemisphere needs to draw the wire from south to north. This will align the copper crystals for proper conduction in one direction. Look for arrows on the wire jacket to see which direction the toroidal core needs to be wound. :)

[@EEVblog]

Sounds legit.

[@mistwolf]

You work for Monster, right?

[@oswaldjh]

Jamie Norwood : Actually, the Monstrous amount of B.S. that I spewed in my original comment wasn't much work to concoct.

[@mistwolf]

Jerry Oswald it was truly impressive. I could easily see it being the pitch of 19k/meter speaker cabling.

[@userPrehistoricman]

Oxygen free injection transformer.

[@kensmith5694]

The term you were looking for on the transformer was "bifilar windings" it is a common trick for making a broad band transformer. As an injection transformer, it is usually better to have a 10:1 step down so that the 50 Ohm output impedance of your generator looks like 0.5 Ohms on the system under test. I was slightly surprised by the small cross section of the core. Generally, the more massive the core the more energy it can store. On the high current side of the transformer, you can have significant DC current leading to significant stored energy in the transformer's core.

[@xxJohnxx77]

We used the Bode 100 some years ago in school. Cool to see what’s going on inside.

[@jfrede1976]

T think the transformer is just a Amidon T240-2 iron powder core with a bifilar winding. The wire is most likely PTFE insulated to get around 100 Ohms of impedance. That is a very common construction that is used in hamradio all the time.

[@jfrede1976]

Yes the Hamradio Transformers normally work from very low to ~30MHz that is at least the specification of the Core.

[@Mikkel324]

The T225-2 (the closest size available in -2 material from Micrometals/Amidon) has an Al value of 12 nH/N^2. With 40 turns (as seen in the video), this gives a magnetizing inductance of 19.2 µH. With a 50 ohm source impedance, this gives a lower 3 dB cutoff frequency of 420 kHz. This injection transformer has a lower 3 dB cutoff frequency of 7 Hz, so the core must be something with much higher permeability, most likely nanocrystalline.

[@Graham_Langley]

I thought PTFE when I saw the stripped ends.

[@OneBiOzZ]

i also should say i like how both input front ends are mirrored not just copied ... someone manually did that

[@michaelnobibux2886]

Btw you can make directional couplers, hybrids ,circulators etc with good opamps at arbitrary impedances. At 10 Mhz this is no big deal!

[@rfengr00]

That plot shows shows the transformer is -15 dB at 1Hz. I’d say the BW starts at 10 Hz.

[@adilmalik7066]

Are you sure this is a superhet? Looks like a classic direct conversion receiver(near zero IF) for these low frequencies VNAs. The 2 DDS are usually just offset by the bandwidth of the ADC...

[@nezbrun872]

Adil Malik my thoughts also, low IF (each DDS a few tens of kHz apart) plus a pair of Tayloe quadrature mixers on the RX sides, explaining some of the analogue switches. Low IF so a low speed ADC. Low IF avoids mixer DC offset and phase noise of downconversion LO. So it is “superhet” as there is frequency downconversion rather than direct conversion.

[@EEVblog]

That's what they claim on the product page, superhet.

[@sauerdrops484]

At 13:53 you can see the mixer at the down left, AD834 four quadrant multiplier.

[@EEVblog]

LA2STA Laboratory -Damn, did I miss the most important chip in the whole thing? Doh!

[@nezbrun872]

Good spot!

[@electronicsNmore]

Great teardown Dave!

[@TheDefpom]

Dave, can you measure the dimensions of that toroidal ring? I might try making one.

[@simontay4851]

Should be quite easy to make using solid copper wire from Ethernet cable.

[@pigrew]

The composition of the ferrite ring is a very important parameter, but not easily measurable. I don't think the dimensions matter that much.

[@pa4tim]

the magic is in the core material, without knowing that you can not replicate it.

[@gerrykavanagh]

Looks like 2 inch mix 43. Building it would be trivial, but you need some very pricey gear to characterize it afterwards.

[@esdblog6100]

Could post frequency response of your DIY injection transformer? There more into it than just number of windings and core. Yes, part of the magic is in the core, but even lid taken off changes frequency response.

[@NeilRieck]

Back in the 1970s I had a part time job at a music retailer doing bench repairs. That was the first time I saw the insides of a guitar amplifier made by a British company called Orange. All the transformers (input, output, and power) were wound on circular cores. Also, all the signal resistors were oversized to minimize thermal noise.

[@Spookieham]

$15 for the parts, $485 for the virgins.. Its a specific piece of test equipment. If you need one you don't particularly worry about the cost; it's a drop in the bucket compared to all your other test gear

[@SamZeloof]

I believe that is bifilar winding

[@WacKEDmaN]

defiantly not worth the price....but still a nice bit of kit

[@bobcunningham6953]

I'd really like to see the ToE in DaveCAD for this one! Also probe various points during acquisition, starting with the connectors and working inwards, all the way to the USB data stream. Edit: What I'm looking for is ways to make better use of simpler and cheaper tools, such as the Red Pitaya, by adding some external components and software.

[@youdonotknowmyname9663]

3:08 There is just a fuse under that black heatshrink to protect the transformer from (most) "user errors" ... Oh, never mind, he gets it open later ... And no, an "inline fuse holder" would be a bad idea, because every "connector" adds more "things that can go wrong" and possible "crappy connections". That's why the fuse is soldered. 9:15 Oh, that annoying FTDI chip ... I hate those things ... 11:59 Fun fact about those through hole resistors: The length of the leads between the board and the actual resistor body makes a big difference for things like reflections! 13:49 Yes, there are is tons of switching going on! Coupling, filters, range switching, termination switching, lots of things that can be configured by the user via the UI. No, the relays don't really need to be shielded, because you aren't really dealing with "ultra small signals" ... 17:12 " ... rather simplistic ..." Well, a simple solution is an elegant solution ;-)

[@TwistTapeTechnology]

Just imagine someone walking past outside the lab, and hearing: "its a bit naked, all the magics happening in the cans"

[@marcus_w0]

3:52 - Yet :) This thing seems doable to me. With a lot measuring and twiggeling, but in the end this thing could be pretty much done cheaper. It's no nude virgin moon juice instrument anymore - but who cares, if it's $50 instead?

[@galileo_rs]

You are paying for software. The hardware is basically a first gen SDR from the early 2000s. And yes the cost of it is obscene. For anyone that wants to complain and BS about low volume and research: lookup HAM radio SDR transceivers, 10x the complexity, 5x more expensive hardware and at least 20x more complex software.

[@herbertsusmann986]

Everyone knows Austria is the same country as Australia. Just missing a few non-essential letters...

[@bfrost999]

The twisted pair is a type of bifilar winding. It insures the two transformer coils occupy on average exactly the same magnetic space as each other allowing for an almost perfect one-to-one ratio. A typical accuracy of such a winding can be better than 1 PPM.

[@OrbiterElectronics]

That transformer in a box after testing is worth $50 at best. How they came up with $499 unbelievable. Their course lessons in extortion have obviously been adhered to.

[@kensmith5694]

It is a low quantity product. Thus more like $100 would be expected.

[@JasperJanssen]

Is that why nobody else is selling one even as cheap as $500, let alone $50?

[@chrisbalfour466]

It's so similar to the hardware for software defined radio.

[@michaelnobibux2886]

It's called a bifilar winding! The toroids look like Amidon powdered iron cores ur = 10. I don't think that any windings are squeezed or stretched to optimize frequency response, it seems that they just have been evenly spaced! Pretty underwhelming !! A better core geometry would be a binocular core and i think that a balun on the floating side might give some more improvement !!

[@v8snail]

So those relays would be multi-meders?

[@MAX_Brother]

Hi Dave! About resistors in B-SMC. As I see, all resistors there is 4R7 1%, except one between Source BNC and CH1 BNC. What are the colors of this resistor? I can't determine. Regarding the disputes about the core material of B-WIT 100, I can say with sure that it's an VITROPERM 250F.

[@CoolDudeClem]

I didn't even think such a transformer could even be possible.

[@Factory400]

I know very little about winding transformers.....I am guessing this was hard to figure out.

[@xDR1TeK]

For those price tags people would always prefer the hand job and avoid that hole in their pockets. Of course people would choose cheap thrills. They last longer for that amount of cash.

[@yaghiyahbrenner8902]

Hi! finally some decent gear its been bloody ages!

[@redsquirrelftw]

I imagine they can also get away with this price tag because it's a rather niche product, but also because of the (I presume) various levels of certifications it went through, whether it's self or 3rd party, they probably run various standard tests on these to produce some graphcs and other stats and then each one has to match etc. Probably a lot that goes into that. And of course the software too. But yeah I'm sure someone that wanted to could probably produce this for a much lower price tag.

[@diabolicalartificer]

Price seems more than fair for what it can do. Vintage Tek and HP test gear cost the equivalent of a house back in the day; the magic has shifted from complex circuitry to the software. Hi end test gear has always cost big money. Whatever, with both your paying for precision and dependability and these cost money, it's not an Iplonk or Wankows OS that will need numerous updates, fuck up every 2 weeks and leave you weeping and reaching for a hammer.

[@bart416]

If you don't care about the sub-kilohertz range you can pretty much get away with a

[@filipclaessens1506]

This box is going viral these days

[@Skyliner_369]

The price of the surface mount tester probably comes from the gold. I wouldn't put it past them to use solid gold, or very thick plating instead of thin gold plating. Make it so if ever needed, a clean surface is easily revealed.

[@qhack]

They put the components in upside down in the Australian model so that the electrons don't fall out when you are down under.

[@aivansama6265]

Dave, I have a little project idea for you. Since all these ppl think that the transformer is $5 piece and can be easily made, make one. Generic core and replicate the winding. Then characterize it :D

[@EEVblog]

Yeah, that would be interesting.

[@KrisX7331]

But how does the frequency transformer work? Its just core with windings ratio 1:1. I thought you need fancy electronics.

[@danielaustin7643]

why the bannana plug output on that transformer? surely they will be poor at 50MHz.

[@soothcoder]

Could they be doing something like equivalent time sampling to make the slow (but precise) ADC work? That is rather than mixing.

[@DataStorm1]

@9:51 We got yet another AD09851 upside down, so all the electrons gonna fall out... LMAO

[@MrTada98]

Can you please explain the purpose of these devices? I have a bachelor's degree in electrical engineering, but i still have no clue what these things do.

[@krawutzimon]

Not to be mean, but you should maybe return your degree...

[@MrTada98]

Actually, I have a degree in robotics, but there was still a lot of electronic involved. What I meaned by this comment was, that it might not be obvious even for people who know something about electronics. I can recognise a toroidal 1:1 transformer. But what is it good for? You won't be using 500$ transformer for galvanic isolation.

[@kensmith5694]

MrTad98: You are going to use a transformer like this for isolation but not for power transfer. Imagine you have some system that you want to measure the performance of with regard to RF coming in on some connection. You want to send RF in there but not let it go through some other path in the total system. You use the output side of the transformer to apply the signal.

[@johncundiss9098]

Not sure about the nude virgins. Looks Like a simple #2 iron core with bifilar turns on it. Good "Q" to 30 MHz. I suspect that core wound was put together by a ham. Made many myself. Material 43 might have been batter choice though. The AD9851 is the jellybean DDS chips for making VNA's for the HF bands. Working with them myself. Although the prices at DigiKey do not reflect the jelly-beany-goodness.

[@EEVblog]

I said it in the video and I'll say it again. If you can make and sell a good low cost wideband injection transformer cheaper than you'll sell 10's of thousands of them.

[@7head7metal7]

BurrBrown marking on the OPA2277, still nice to see their heritage

[@domedom2227]

Often to make it simpel is the hardest thing to do !

[@AlanLiefting]

Dave, did I see you using a Philips screwdriver on Pozidrive screws?

[@varnimgoyal5295]

Can I use this I'm series with my DC supply to get dc signal with AC added on it? For charging with 2.5 A?

[@ShinyMajor]

For what it's worth, 2PPM isn't that great these days. Maybe for a tiny crystal, but as a reference oscillator it's pretty bad

[@shana_dmr]

And if you can design injection transformer like like that and wire it by hand while getting less than $600 (for whole project) you should really reconsider your current workplace.

[@AndreAndFriends]

Karol Piotrowski Polish Virgins would do it for less. I'm sure🇮🇩🇵🇱🍺🥂👍😎

[@KX36]

Go ask the nude polish virgins at toroidy.pl.

[@shana_dmr]

Last time I've checked they were clothed and didn't deal with anything over audio frequency ;)

[@p_mouse8676]

For that price, what a joke. It's absolutely not bad, but worth the cost? Nope. Am I the only one who is underwhelmed by it all?

[@vinceh121]

Piet Muijs a lot of the price is for the software it comes with.

[@p_mouse8676]

vinceh121 . Which is the price similar to an high professional editing suite with a lot more capabilities.

[@simontay4851]

No you're not the only one. Those plugin boxes are a total utter rip off just on their own. The second one. $600 for _that_! Its just a box with resistors (probably 0.1% resistors) that cost a few $ at most. The box probably costs more to manufacture than the components inside it and it is just an off the shelf aluminium box. I could build that in a couple of hours for less $50 including labour.

[@restcure]

1% resistors (brown tolerance band) I'm sure the component holders are ptfe & gold (maybe)

[@EEVblog]

What do you think it's worth? Why don't you go and produce a competing product at a much lower price and OWN the market?

[@MarkTillotson]

Dave I think "I won't go into detail" is your middle name!!

[@DLSDKING]

Hey Dave, How about you make a video about that dickey microphone cable analysis video using the vector network analyzer. That way we can learn more about the importance of vector network analyzer in component selection and system design. Thank you

[@EEVblog]

It's just a dicky contact, I'm sure

[@sefarkas0]

That toroid is wound with a bifilar winding.

[@EEVblog]

Actually I don't think it is, because bifilar implies the same return wire in the pair (as a coil usually). This is a transformer with separate pairs twisted.

[@EEVblog]

I actually said bifilar as my first reaction when shooting the video, but I edited that bit out.

[@kwazar6725]

Can you explain the superhet sampling trick?

[@khronscave]

Would be nice to see the bottom of that toroid. The colour kinda reminds me of Micrometals' "-2" iron powder material (red body and one clear face). T130 (1.3in OD) size, perhaps?

[@sureshotstudio]

Twisted pair helical toroidal? it's called bifilar winding

[@davidf2281]

When I was fifteen years old, I thought it would be cool to turn my project boxes upside down so you couldn't see the screws. WHEN I WAS FIFTEEN YEARS OLD.

[@bfx8185]

This is for sure to much apart from SW which is really great.

[@GRBtutorials]

Sure, I'd spend a month of Sundays, but I'm not a company and I have more time than money right now.

[@mduvigneaud]

I want to try to make a current sensor with... 10 wraps? (maybe 20? I dunno yet!)

[@helmut666kohl]

The things you can do with OpAmps… If you can!

[@OneBiOzZ]

im shocked the 9851 is doing the DDS, i have so many of those chips laying around and i never thought of them as stable for instrumentation of this class

[@Zadster]

Stable? It is a mature known product and is 99% digital. I guess 10-bit 180MSPS is all you need, but for a $5K class machine, that's really kinda cheap. I suspect the design has been around for some time and they just haven't needed to update it.

[@OneBiOzZ]

well simply the AD9851 DDS is not a precision part ... its jitter is quite high, its nonlinearity is not great for this application and its voltage accuracy is variable with temperature

[@Zadster]

Got any citations for that? Jitter is listed as 80ps, way outside the 50MHz LPF of this application, and DDS code jitter isn't rocket science to work around in software, especially at this sort of accuracy. Absolute voltage accuracy isn't particularly a problem either, as you are measuring ratios, measuring both your own incident and then transmitted / reflected wave, it effectively calibrates itself out to a large extent.

[@MarkTillotson]

Would expect gold plated BNCs at that price point really...

[@GeneralPurposeVehicl]

Fully characterize your head ear to ear. We must know the capacitance of the average EE's brain.

[@izimsi]

If that transformer's core isn't some kind of magic Martian material, that should be doable for 50 bucks or maybe even 5.

[@DarkFire515]

Those input & output cables...

[@1toneboy]

'I'm payin' money' as Rex hunt would say.

[@mirabilis]

that donut looks delicious

[@yaghiyahbrenner8902]

that transformer looks like a micrometals arnold part.

[@kraftrad7840]

Compare it with the AP310 from Ridley, that costs 15000 bugs.

[@akkudakkupl]

Okay, wait a month or two I'm comissioning wide bandwidth transformer production in China. 100$ seems a fair price, right? ;-)

[@ourplesoop]

I feel like I could make that transformer unit for like $20....

[@nerotek7347]

when you factor in production hours with calibration, qualificiation etc; you'd probably get close to 100-250 dollars worth of hours, and there has to be a fair margin of profit regardless, so I don't think its too unreasonable of a price

[@TheDefpom]

17:50 could 3D print something to do that...

[@andreylev5092]

Hello, please make a review BM75- EU Brimen

[@skoronesa1]

Looks like teflon coated wire.

[@whatthefunction9140]

seems like a virgin would most likely be fully clothed, but ive never been to Austria

[@MatthewSuffidy]

Couldn't stay away from the old woow woow.

[@simontay4851]

That transformer is nicely wound but its definitely not worth the price. That is price gouging is ridiculous! I would've expected a panel mounted fuse holder in the side of the box for that price. If someone had a torroid the same size and some solid core copper wire (ethernet cable is a cheap source of solid copper wire) in their scrap parts box (which is likely) and counted the number of turns of this transformer in the video, they could easily make an identical transformer like that and put it in an off the shelf aluminium project box for a lot less money. Less than $100 including labour.

[@EEVblog]

If you can make and sell the same performance one for $100 then you'll sell 10's of thousands of them. I'm serious.

[@JamesP6084]

Boy o Boy you can't tell me there is value in that R I P O F F

[@darthvader8433]

No idea how you'd use these things. Worth a video?

[@DAVIDGREGORYKERR]

A BALUN would be wideband.

[@sokolum]

500 USD for a bunch of wires.... They must love their salesman....

[@Robbie1949]

Well I am sorry Dave but at least with HP when you opened it up you saw the quality, you don't see it here and they even leave solder flux behind to contaminate, regardless of how good the software is this is not $5000 and with all the expensive optional extras to make it all happen. No high quality gold plated PCB's here, just assembly machine built PCB for what is not a small sum. It doesn't look any better than assembly machine built electronics coming out of China. I supervised techs working with Military avionics installed on the FA/18 hornet, the quality there was apparent but hey this was 1990's and each PCB in a piece of equipment cost over $10,000 with no sales tax , but guess what ,the solder flux was cleaned off with 100% pure isopropyl alcohol. After mirco miniature repair to these boards by specialists all soldering flux was cleaned off as well before the boards were deemed serviceable.

[@KX36]

I'm sure the high price is because of the high initial fixed costs for R&D etc, software development costs and continuous cost of staff all combined with the low volume of sales that come from making a very niche product. You're not paying the money so much because it's expensive to manufacture each unit, you're paying because it's low volume manufacture. They could still have gold plated the PCB and cleaned the flux and given you more of a feeling of getting quality for your money. Cost would have been negligible. Also as you can probably tell this design's been in production for a good while already.

[@Robbie1949]

Well I can see where you are coming from Dave but even on the video I could see you were expecting something better, am I right ? I own quite a lot of test equipment, I just love collecting old good quality equipment. When I open up this equipment I am not ever disappointed, and hey mate the price can be right, very right. I absolutely love electronics and have since the tender age of 12. It has been my whole life except for learning to play the organ at 18. I repair and calibrate high quality , Revox B77, Teac A-6300 reel to reel tape decks, even the old Sony TC-377 and hope to sell a few eventually. My love for organs has lead me into repairing and refurbishing them, mainly High end Conn organ models of the professional console variety. I used to get as excited as you over equipment but age has dulled my enthusiasm, 69 last month. My workshop is up the back yard here in the small town of Sale, Victoria with many a fluro and LED arrays on separate circuits. Very disappointed in high power LED lighting the MTBF is abysmal . We are totally off the grid by choice with solar PV array of 6 Kva, a 48V (nominal) charger into AGM battery bank 48V at 1000AH. The inverter is a 6Kva 48V to 240V single phase which gives me lock solid 50 Hz at 240-50 volts. No chance of a blackout of brownout. As I started life as an electrician I have wired it all myself including the house. As you may gather we pay no power bills and in Spring, Sumner and Autumn there is an abundance of power available. Regards Robert

[@EEVblog]

You do know that gold plating costs pittance, and you can get that on $10 prototype boards, right?

[@EEVblog]

Robert Scott - "I could see you were expecting something better, am I right ?" No, you are not right. I was expecting something "more complex". They got away with a much simpler design that I was expecting. That doesn't mean what they have designed and built isn't good quality, it is.

[@Robbie1949]

Gold plating in this case was part of the manufacturing process of the boards so it had to be more than just a minute gold flash to stand up to the etching process involved in making the boards, in fact it's quite thick about .005 " I believe. It was an old PCB manufacturing technique but hey these were the days before digital and a lot of test equipment was just analogue as the HP 334A Distortion Analyzer and dare I say it built to last back in 1971. I have three of them, would you like one posted to you to take apart , I have seen you dismantle other older test equipment for an interesting video ? I don't know how old you may be and what your experience levels are but I go back to these times and there is something to be said for venerable old test equipment including analogue multimeters.

[@embeddedusystems]

for the money they could have stuck the label on straight!

[@srscricket]

Anybody see which mixer they used?

[@EEVblog]

I didn't see a mixer.

[@robbyxp1]

Think Dave needs to go on one of my many Corporate training courses telling you how to be politically correct...

[@brandi1233]

They can't be bothered to put the label on straight. Quality should be better.