Inside an audio isolator transformer module.

[@dtvking]

Hi Clive, the idea of the tin foil is to join the two transformer shields as one Faraday Shield. It may be that the same components/circuit are used with a plastic cover. This is normal for use in vehicles, due to air-born interference, like you said from the ignition high voltage spikes but the main use of this type of audio signal isolator in vehicles is to suppress the alternator electrical noise. It used to be worse in the bigger type cars due to the high output alternators used having to cope with the amount of electrical items such as Electric windows/Sunroofs, Air-con, Rear heated screens etc, all quite modern in the day. I used many of these in my days as an Auto-Electrician in the 80's on big audio amplifier systems. Great videos, keep it up. Many thanks

[@alexatkin]

+Mark Andrews But then why only on the top, it would need to wrap around the whole thing wouldn't it?

[@dtvking]

The outer covers the complete unit. The tin foil is only to join the two half's of the outers as they are only joined with tape on the outside.

[@alexatkin]

Mark Andrews Good point.

[@JoeCdaYT]

+Mark Andrews I have worked on the car audio amps myself and seen what you say but have also seen what is called a ground loop effect as what Clive was talking about. The ground reference for some of the kids of my generation like doing is applying the ground connection to their amp in the back of the car to the body and usually in a most horrible way(wire stuffed under a screw that is nothing more than a 16 AWG) and the grounding point of the car stereo connection point somewhere under the dash or to the engine. These get really bad on the thin metal car bodies of the current manufacturing process. See these items install most of the time. Best fix I have done of my cars is to install a decent wire from the ground of the amp to stereo and also run a ground wire of suitable size back to the battery or alternator case for the amp and install a half to one farad cap with the amp.

[@dtvking]

+Joe Esteph that is correct

[@marcchabotyt]

i bought one identical to that one from ebay. i just got it today, and it works perfect. the background noise disappeared. fantastic!

[@Metranomik]

So, I’m at Uni studying music production and have had whole 2-hour lectures on something you essentially explained in a 9 minute video... -_-

[@seannot-telling9806]

The professors have to justify there pay somehow.

[@johncsuti6118]

I laugh way to hard at this 😂

[@rm9308]

This is the problem...

[@domino52o26]

@@rm9308 you're exactly right

[@brabhamfreaman166]

Because it takes WAAAaaaaay longer to explain HOW something works than to SHOW how it works. As Clive has previously lamented, you really should be *doing* and not talking and writing about doing. Without some experience in this field, what are you going to do for work if you graduate?

[@punman5392]

The foil was likely being used as a shield to block out hum/noise. It's a technique often used in guitar electronics where the cavities that house all the wiring/controls are lined with a conductive foil (usually copper) and then the foil is connected to ground. This makes it so that any electrical interference is picked up by the foil and sent straight to ground

[@rmblwgn]

For those wondering. Car alternators can leak out small amount of AC voltage which can be picked up by RCA cables going to your amplifiers.

[@DordiHOTS]

I have installed one of these in my car and it works fantastically. Around the time of the install, I also made sure that I had all power and signal wires isolated and insulated. The combination of doing these two things completely rids the car of a static hum.

[@therealjammit]

The metal case is a special metal called a mu-metal. It really likes magnetic fields. It likes them so much it acts like a magnetic short circuit (low magnetic resistor). The aluminum foil on top of the transformers is used differently. Aluminum doesn't like magnetic fields, so fields are reflected away (high magnetic resistor). I don't know why they didn't mount the transformers 90 degrees from each other to prevent channel crosstalk.

[@kl1nk0r]

+Jammit Timmaj: Because it would not work. If you rotate one of them by 90° on the circuit board, the magnetic field vectors are still parallel to each other, because they are oriented perpendicular to the PCBs surface. Btw, I have heard that mu metal is rather expensive so I would think they were not using it here, but I could be wrong. However the thickness seems to be really thin, so I doubt they are actually effective at audio frequency levels.

[@therealjammit]

+Simon K. I meant to rotate the transformers so their magnetic fields are rotated 90 degrees. Sorry for any confusion. It'd probably make the PC board manufacture a nightmare... unless they decided to use non-traditional transformer type, like flying leads come out from the "wrong" side, both transformers are wound differently, that kind of thing. Mu metal (sounds like a punk rock speed metal music genre) is expensive if you get the really good stuff, and the cheap stuff is ok enough. The metal isn't designed to block out by screening, but by being a shortcut for magnetic fields. The magnetic fields flow so easily through the metal it doesn't "poke" out the other side very easily.

[@Slikx666]

I think that they put the transformers in that way so that they would fit in the tube.

[@irnavas]

+Jammit Timmaj 1- More the metal "likes" magnetic field it will shield it better. 2- The noise from ignition and mains are usually electro-magnetic interference, not magnetic. It can be blocked by a tick conductive shield, and the foil will not have that much effect. 3- This device only blocks electric coupling and attenuates non-audible frequencies. More filtration and shielding is needed to get rid of all interferences. 4- Rotating the transformers is neither practical nor practiced.

[@therealjammit]

Has Nas 1) Better explanation than I was able to do. 2) The isolator in the video is used to isolate a common ground in an effort to remove common ground noise. You can get conducted noise from nearby wires (think high power switching an inductive load). The radiating noise can be coupled into nearby wires and especially transformers that were designed to couple electromagnetic energy. Electromagnetic energy is still magnetic energy. I think you might have used the wrong word and meant something else. 3) The device in the video is only used to isolate grounds. There is some frequency modification, but that isn't intentional and is instead designed to prevent this. I'm certain 10khz will pass fine with little attenuation and 100Mhz will be attenuated, but that's just a happy accident and not intended. An audio ground isolator tries its best to not change the frequency response. 4) Rotating the transformers 90 degrees to each other will help attenuate cross channel interference, but is not done because the cost of changing the circuit board is too expensive and probably has minimal effect on the relatively high signals passing through (1V RMS will bury 1mv RMS of crosstalk).

[@kenwolfe6093]

The foil is so the aliens can't listen to your music. ;)

[@VREDFOX]

+Ken Wolfe But the Illuminati still can

[@RnO7579n7578]

+VREDFOX lol

[@kenwolfe6093]

Robert Gaines lol!

[@paulstubbs7678]

Have a look at those medical shows where the run a 'probe' up a vein all the way to the hart, or brain - Gesss where the entry point is. The groin, vagina etc, big blood vessels, easy access. Obviously those aliens are showing the way to the medical elite.

[@samj1012]

china made car audio often pick alternator whine. .so annoying. .what if ur not using extra amplifier just a Normal stereo where to place this filter ? is it between the radio output and the speakers?

[@BMRStudio]

The foil looks to me, bodge job :) Usualy, we always place pair of stereo trasformers 90 degree (eliminate magnetic crosstalk), then we connect the transformer shielding together (eliminate EMF noises) the outside shell is a simple raw steel, to block low frequency magnetic waves from the transformers core, because this transformers has a bit air gap. on consumer level, working perfectly. The best ones uses precision winding, hexacore coils, gold or silver plated shield, and some kind of special core. I even seen mixed E and toroid transformers. What I dont like about this transformers, is the way, how they destroy the high frequencies and the saturation. Use short strong rca cables, and for big distances, no other way, just balanced signals. And yepp, same source low resistance earthing. Or digital interconnect. Thank You for sharing :)

[@reddragon27284]

These are great. I've used them in several projects. Most notably was my 80s Bluetooth boom box where I used it to eliminate the horrible noise the Bluetooth adapted was creating. None of the ones I took apart had that foil on top though but we're surrounded by a razor sharp piece of tin inside the outer cylinder.

[@100SteveB]

I used one of these to solve a very bad hum with a sub woofer, was doubtful it would work, but was pleasantly surprised to find it done the job perfectly.

[@klayshen]

i would say the foil is for magnetic shielding they probably make that internal piece and sell it to people who install it in cases that probably offers a slight bit of magnetic shielding when that same component is in a plastic case

[@PileOfEmptyTapes]

Unbalanced audio connections can pretty much be considered broken these days. With computers, shielded network cables and all that good stuff in modern setups, there's earth connections coming in all over the place. You'll be catching a ground loop faster than you can say "ground loop". Ground loop isolators are handy when having to interface unbalanced to balanced. One system relies on floating ground, the other is earthed everywhere. The important thing about balanced connections is the balanced impedance part, actually (if in doubt, consider the case of no signal). The whole thing can be treated as a Wheatstone bridge. If shield currents cause audible noise, usually one component suffers from a faulty shield connection hookup known as a "Pin 1 Problem". AES48-2005 clearly states that the shield (XLR pin 1) *must* go to chassis directly and immediately, and must not connect to local audio ground first (the connection between both is made elsewhere). Now components that disagree should mostly have gone away by now, but it looks like even recent KRK Rokit speakers (5", 6" models at least) are still affected.

[@RonnieMacJr69]

I was playing live one time and none of the equipment was mine I got up to do the first song and holy crap that mic shocked tf out of me the entire song

[@TornTech1]

i was always taught(and please correct me if im wrong) but "balanced" audio was the act of running the same audio signal through two separate wires with one being "normal" and the other being polarity inverted, once combine they cancel out any noise... ---------------------------- In fact, a little bit of googling brought up this: www.ians-net.co.uk/articles/balanced_lines.php To remove noise from a signal we need some way of working out what is our wanted signal and what can be thrown away. Balanced lines achieve this by transmitting two versions of the signal down their length. The source equipment sends the normal signal down one conductor and a polarity-inverted signal down the other. This is usually done using either transformer-based or electronic output stages. The cable itself is designed with the conductors having very similar impedances and twisted along their length so that any noise is picked up equally by both conductors, no matter where in the cable it occurs. The receiving equipment has a transformer or electronic differential amplifier, and takes the inverted signal and returns it to it's correct polarity. At this point, the wanted signals on each conductor are both the same polarity, whereas any noise is of opposite polarity. Summing the signals from the two conductors together reinforces the wanted signal and cancels anything unwanted, leaving a recovered signal which is very close to the original. (this is known as Common Mode Rejection - i.e. any signal which is the same on both conductors is removed.) Even balanced lines aren't perfect, though - slight differences in impedance, twisting or input gain will allow some noise to slip through. This isn't generally a problem unless you're using very long runs or working in areas of high interference. It looks like the same as what twisted pair does with networking/telecoms...

[@bain5872]

+TornTech Almost.....Balanced lines are indeed, differential pairs. Each line of the pair, contains the 180degree inversion of the others signal. The amplifier will only amplify the sum difference between the two lines. Any noise, picked up on the lines will be of the same phase and amplitude, on both lines, hence, no sum difference in noise to be amplified. Clive's explanation was correct however, it did lack a bit of detail.

[@eurobum2012]

+bain5872 Almost. DIFFERENtial pairs do not require the two signals to be inversions. In fact you could have all the signal on one conductor, and 0V on the other. The "difference" between the two is still the audio signal you want, and the common mode interference is still rejected. In order for differential signaling to work, the IMPEDANCE must be the same on both lines. That way, common mode interference affects both lines EQUALLY, and is thus subtracted properly on the output. The reason inverted signals are used, is because it increases the dynamic signal range, and drops the noise floor.

[@eurobum2012]

+bain5872 The term "balanced" means the impedances are balanced on each half of the pair. It does not refer to inverted signals.

[@bain5872]

I am aware of this however, without a differential signal (inversion of one line as opposed to the other), there is no amplification nor noise cancellation. It stands to reason that if there is a mismatch in either lines impedance, there would indeed, be a differential signal on that line. This is the point that you seemed to not understand. If I misunderstood this, please accept my apology.

[@bain5872]

Euro Bum You are clearly speaking on a subject for which you have a very limited knowledge. I suggest instead of finding factoids, to bolster your sense of worth, you do real research on the subject and please, stop using Wiki as your source material. Good day Sir.

[@RiaRadioFMHD773]

As an audio engineer I can tell you there will definitely be some frequency loss. The reason is the transformers are in effect "seen" by the source and amplifier as transducers, even if the impedance is very high. Like any single speaker, it can not reproduce (pass) the entire range of human hearing effectively. I tend to think it would loose a significant portion of high frequency because inductors in AC resist (impede) changes depending on the "Henry" rating of the coil and frequency of the varying AC waveform.

[@pickholder6189]

Hello Ria - I do agree with you 100% but most users of these are using laptops or PCs playing some kind of heavily compressed audio so in the real world those comments in my humble opinion do not apply. Obviously you would use a CD or high quality audio player from a digital output to get the best quality for broadcast. I have worked in some radio stations that actually (shockingly) use youtube grabbed audio or MP3s. These sound awful on FM broadcast. In quality stations everything runs balanced line or digital. For most typical users of audio if any high end was lost they would turn up the treble bands on a software based graphic equalizer. Anyhow - well educated post.

[@RiaRadioFMHD773]

FLAC Rulez lol

[@pickholder6189]

RiaRadioFMHD773 yeah. It's good but I just use wav or aiff for the reason of hard drive space being so cheap now. Just don't like MP3 as a rule. It's okay to email ideas with but that's it.

[@FubarGRblog]

These are ferrite core transformers, like those used on SMPS and can operate up to hundreds of KHz to several MHz. Actually I would be more concerned about low frequency response. If the core isn't sized correctly it could easily saturate at low frequencies. But I guess this shouldn't be a problem at line level signals. Just don't try to pass amplified signals through that.

[@Daytona574]

I recently pulled this ethernet transformer off a computer motherboard. wl500g.info/attachment.php?attachmentid=1690&stc=1&d=1186217169 (Delta LF8505 for those that would rather search themselves) Just for grins I'm going to hook up some RCA jacks to it and see what kind of funkiness it does to an audio signal :D

[@Scooty9794]

Using one of these in my car helped on eliminating very annoying interference noises from the alternator and the servo steering in my subwoofer amp. Awesome to have an explanation on how it works :3

[@TafJaf]

I bought two audio isolators ( rca + 3.5mm) after watching this video. This stuff works since for some reason my pc causes a hum and buzz whenever I run any games that utilizes my graphics card heavily. Thanks bigclive

[@MikkoRantalainen]

The hum and/or buzz from PC is caused by poor quality power supply and/or poorly implemented voltage regulators on your motherboard. And audio isolator will fix the problem despite the source of ground loop.

[@FischOderAal]

I had a similar issue with my external USB-AMP (no ground Audinst HUD MX1) connected to my PC. I was soooo glad when I got one of these and it solved my issues. The AMP is also creating a very loud humming when the USB is not connected to the the PC but its power supply is connected to the mains. Thanks for showing us what is inside!

[@JanBabiuchHall]

This also frequently happens in car audio setups where you'll get a high pitched hum at the same frequently as the alternator is rotating. It can end up being a completely overwhelming whine. And this little device fixes that perfectly as well.

[@ellenmadden8343]

A couple of years ago I was going to modify an old tube radio with an aux-in jack for my grandfather, but I eventually gave up on it because I learned that they operate on half-wave rectified mains voltage, and the plug was non-polar. So just by plugging it in the wrong way around, you could end up with live mains on the aux jack. This is exactly what I needed, and I think I might re-investigate doing that now.

[@nivlick]

They are magic in older car audio systems. I’m glad I found your video to explain how it works. It fixed the hat was going to cost me hundreds to fix and only cost $12 aud.

[@FeCr3]

These one are VERY helpful and was THE solution for a little project some months ago.... I had needed such one too to connect my Samsung galaxy S3 with an pam8403 DIGI amplifier board AND a power bank cell charger for cell phones at same time. (Power bank charger as power supply(5V) for the amp and for charging the Samsung S3 at same time.) WITHOUT the audio isolator transformer,i had cannot charge the S3 and powering the pam8403 amp at same time because of ground problems(weird noises and probably BAD for the digi amplifier).

[@ccleake1]

I'm a sound designer, and I've decided I need about 500 of these

[@RnO7579n7578]

you need to get it from a audio isolator factory and duct tape factory.

[@rich1051414]

I have a lot of electronics and wires dangling and often pick up noise, I have 3 of these now. The same brand as what big clive has, great, as long as it's on the high impedance side. You can also use these to downmix balanced audio to single ended, but you will need to make your own RCA cable for the balanced end. The grounds of each input are kept isolated throughout, VERY helpful!

[@fenleyjones]

Thank you so much for making this video, I bought 2 of these a couple weeks ago and I was wondering what was inside of them but I didn't want to take them apart and damage them.

[@KK4CNM]

These are good for eliminating group loops when you are powering the source and amp off the same DC supply or battery. Very handy indeed.

[@BrekMartin]

I did a quick test with audio signal generator on one side and a scope on the other, and it looked fairly flat from the high range all the way down to 100Hz, where it started dropping off rapidly. Better than I expected for such small formers, but Altronics have a similar one that makes even better claims about the low end. At those frequencies, I doubt the audio would suffer much by just boosting the low end with the sub amp or EQ though.

[@DaveK183]

Thanks for your info. They were recommending me these for my hifi, but I doubted the audio would be without a flaw.. you fullfilled my expectations.

[@PIXscotland]

I usually end up buying stuff you show, but in this case I've already got a stack of these in use today to break open the earth loops between my 3 PC's, mixer and amp. They're very cheap and work well. Decent bandwidth if I remember right. They've been around for many years. I remember selling them in the electronics shop in Newington 15 years ago! ___________________________________ Maybe the foil was used to join the two transformer frames together to help with channel isolation?

[@alec4672]

Quite an old video this but the most common ground loop in a car that I've fixed more then once for friends with this very thing is alternator hum from an external audio source feeding the stereo. Like a phone being charged while plugged in through the auxiliary cord. This thing works every time.

[@ewozniak5228]

Car Audio systems are notorious for an alternator whine that changes frequency with engine rpm. This IS and probably ALWAYS WILL BE the fix for poorly isolated high-power car audio components. Isolators work every time. 😉

[@aslmx8320]

Would you need one on each channel?

[@ewozniak5228]

Aslmx , each isolator takes care of 1 pair (1left, 1right). . If you have front, rear, and sub outputs from your head unit, and you wish to connect an amplifier for each, then yes, you need 3 isolators. Hope this helps you. :)

[@rich1051414]

I have never had a situation where an Isolator didn't fix a noise issue, as long as you use it on the offending end. Once that noise is processed as signal, you can't get it back out again.

[@TheOneWhoMightBe]

This video and these comments are great for me and my Brother-in-law, who are both trying to figure out why our cars have very annoying feedback in the audio systems (his is worse than mine). Looking at the wiring diagrams there must be dozens of chassis grounds, which can't help.

[@iamdarkyoshi]

I know your comment is 4 years old at this point, but I solved my alternator whine by slapping a big ass inductor on the +12v side before the big ass capacitor right before the amplifier. Somehow whine was making it through a 0.5F capacitor...

[@twocvbloke]

Only mains hum (and AM radio broadcasts!!) I've picked up on audio gear is when I built a cheapo stereo amplifier kit, earthing did sort-of quieten it down, but, not enough to make it any good for anything other than the bin, everything else I've wired up properly and no mains hum... :P

[@RambozoClown]

A must have for car audio, too. Great for alternator whine and other issues. Quite often it's not practical to have all the equipment grounded to the same point (star ground) so there will be slight voltage differences in different chassis grounds. Also the signal wires will be a bit long from the dash to trunk mounted amplifiers, and often will have to run near other wiring and pickup noise. As you said, a great get out of jail free card to have in your box. There is super posh version of this where the audio signal is changed to light and run over fibre then converted back at the other end. Great when the cable has to run past very noisy equipment.

[@ChipGuy]

The problem in cars is that once you got audio signals from your radio to an external amp the return currents won't just flow through the chassis or the wire but also through the audio ground. The generator puts out a lot of ripple so you end up hearing your engine RPM times 3, 6 or even 12(depending on the generator) in the speakers. This is where the isolator comes in. It stops the ground current and ripple, so you won't hear the whistles in your speakers.

[@ronniepirtlejr2606]

I have an older Toshiba flat screen television that I'm using one of these devices on. Mine has some variable resistors built-in to adjust the volume. I had tapped in to the speaker outlet & send the signal to a stereo system built for computers. It is a nice unit made by Creative. it has a subwoofer box & two nice stereo speakers. I knew when I tapped into it, this was the only way it would work.

[@TheChipmunk2008]

Different substations can be a massive issue even for mains electrical work (as you no doubt know!) let alone audio. I remember measuring 50ish amps flowing down the armour of an SWA. The voltage was tiny...

[@TheTruthIsHere12345]

Thanks again for the vids Clive kept me entertained for a while today. I'm already looking forward to the next one.

[@MDSilverstar]

The alternator in a car, can make a lot of noise in the audio system :)

[@dualmode1]

so its just an 1:1 transformer, aka isolation transformer. and yes in car aftermarket audio systems you can have problems, sometimes the car alternator can leak some humm on wine to your audio signal. i love your channel😁

[@danieldumont9334]

Humbuckers or DI boxes are the two mainly used in the AV industry. Di boxes have switches on them so you can choose left right or stereo and earth lift. A bit more expensive than a humbucker, but more versatile.

[@standishgeezer]

These really are, as you say, a toolbox essential. I made my own, on the cheap and in a hurry, with two 1:1 (600 Ohm) fax modem transformers that I had lying around from old defunct kit. OK, I know it's the audiophiles will tell me how poor a solution this may be but in practice, to run sound files for a show, the little box worked a treat. I do however have two of the very same product featured in your tear down.

[@Elfnetdesigns]

The situation where you have line noise on the audio line is called a ground loop. I use a direct box to connect my laptop to my main mix and amp to eliminate this situation but one of these little things will work also but it's intended use is in car audio environments.. Sure you can use them in home systems as a temporary fix but its best to get equipment all on the same circuit and have proper balancing when installing a home system. Commercial system are more versatile and are made to be moved about a lot so the "on stage" direct box is the answer to those problems. In car audio you get noise from the alternator, fuel pump and, onboard computers. The noise is more prominent through HF Ham radios and CB radios but those require a DC capacitive filters and not an audio transformer, Car audio amplifiers of the cheap breeds will need these transformer baluns in the input lines though. The foil on top looks like it may help with phase matching or the electromagnetic flux matching but it does not seem very effective since it only foil and not a metal shim.. It could be something like you said also to help keep interference out, there is just no real good way to tell. I mean it could be there because the foil tape matched the transformer casing. who knows..

[@LasseHuhtala]

I used to rehearse in a shared practice room in the 80's, and somebody had put electrical tape around the ground pin on my bass amplifier mains plug. So we were playing along, I put my shoeless foot up on a radiator, and got a spectacular electrical shock. That's when I learned about the bad way of ground lifting. I also must have left the ground for a moment there too. Scary stuff.

[@MrFlint51]

I was PAT testing in a local church recently and found that ALL the amplifiers (main, monitor and induction loop) had their earth leads cut off inside the mains plugs

[@bigclivedotcom]

That's unfortunately really common in the audio industry due to misinformation passed by word of mouth. Even worse now that many of the people doing it have effectively become electrically qualified with a one or two day slideshow and are moving into other electrical areas with the same mentality.

[@CristianGabrielStan]

My thoughts on this: the metal casing's essential role is to provide a Faraday cage, meant to ensure that no RF interference can be caught up, then amplified. Given the car audio focus, you are right, the ignition would be the main culprit however other RF sources should not be ignored. After all, you cannot create a winding with the unscreened audio signal cable and hope for the best - that's how you end up with an antenna. The bit of foil between the transformers should serve to discharge any potential that could build up in-between.

[@locouk]

I used to work for a company, Road Radio way back in the 90's. I can't say I've ever come across one. We used to fit anything from Philips to Nakamichi audio systems, getting rid of audio noise used to involve cleaning all earthing points and soldering the wiring on the more elitist jobs. Sneaking one of those in to a system would have probably saved a lot of work lol. Thanks for the post.

[@Dullthud007]

Sorry if this has already been mentioned but balanced line signals are designed for longer distances. Yards and yards, sometimes hundreds of yards, with very puny signals, such as that which comes from a microphone. If you 'lift' the ground you have no signal ground reference but sometimes, as you mention, this can be preferable and the receiving device uses its own ground. The real magic is that the two signal wires carry the same signal but one is inverted. At the other end both signals are recombined and any external distortion, which could be rather inposing to such a little signal over a great distance, is conjured away by the inverted distortion cancelling out the distortion on the other one.... I think....

[@ethanpoole3443]

Dullthud007 The ground that is lifted is the shield ground at one end, not the signal ground/return lead. That is to prevent ground loop currents from inducing a common mode current (and thus voltage) onto the signal leads that can cause signal integrity issues where significant ground loops exist -- in the worst cases it can also prevent currents of sufficient amperage to actually melt or burn up the shield conductor where very large ground loop currents exist (although such ground loops can also be a major safety issue in addition to being a nuisance).

[@stargazer7644]

Differential signals don't have a ground reference.

[@UncleWalter1]

As a soundie myself, I am astounded at how many others I have seen who have pulled the cutting the mains pin trick to clean up ground loops. When I was an in-house guy in one venue, cables like that brought into the venue (usually by outside techs) would end up in the trash.

[@transmitterguy478]

I'm glad I'm not a car audio builder today. With all the external signals like can buses, wifi, Bluetooth, and radar equipment in vehicles today, it might be tough to get a clean audio signal. I recently turned up the volume on my wife's Honda CRV with all that equipment in it and on USB audio with no USB device installed, I heard all kinds of squeaks and buzzing, in the background. It also sounds like they have the high-end cut at a steep slope to filter noise also.😮

[@frankstone919]

Thank you for the tear down. The transformers in the Pyramid NS-20 are about a quarter of the size in the unit you have there. The NS-20 has a plastic clam shell design and has just a small piece of foil for shielding. Also , the transformers are wrapped with tape before the foil. So , the foil is just shielding in the NS-20.

[@LMacNeill]

In a car, because you're generally using the body of the car for your "earth", there's a very large possibility that the earth reference-voltage will be different for every component in your audio system. Because it's such a large surface area, it's very prone to picking up e.m. interference. Whether that interference is from your alternator, your ignition system, or even your mobile phone, it can easily produce a voltage difference between the various earth-connections of the various components in your car's audio system. One of these audio isolators can really fix that problem quite well. And because an automobile is generally such a poor place for audio, you won't really notice the very slight drop in quality of the signal.

[@abc-coleaks-info]

My vehicle stereo works very well except when I plug in my phone to listen to mp3 ' s. At that point, I get to listen to the engine as it accelerates or slows down. I sure don't have any miss - firing spark plugs! Lol I'm not sure how I could hook one of these up since the mp3 jack does not use R CA plugs, but I'm sure there is one out there for my needs. I just haven't looked real hard yet.

[@abc-coleaks-info]

My vehicle stereo works very well except when I plug in my phone to listen to mp3 ' s. At that point, I get to listen to the engine as it accelerates or slows down. I sure don't have any miss - firing spark plugs! Lol I'm not sure how I could hook one of these up since the mp3 jack does not use R CA plugs, but I'm sure there is one out there for my needs. I just haven't looked real hard yet.

[@Matthew002262]

+Merle Mitchell it's the same on my at when I'm listening to radio I can hear the stator mess with the radio

[@youtubered7856]

Merle Mitchell my stereo system does the same thing when hooking up my cellphone to the aux in.ive noticed that if I'm not charging my phone there's no noise(unwanted noise)!But as soon as I hook up the micro usb cable which is changing from the usb adapter plug in my cigarette lighter socket.if I use a powerpack to charge my phone there's no noise. Any idea's on a solution for this issue?

[@newguy69]

"I'm not a car audio expert" - is literally an electrical engineer 🤣 If that doesn't qualify to do any car audio job, I don't know what else does.

[@ikonix360]

My guess is perhaps the foil was used to ground the outer case to the transformers provided the transformer shells are grounded to one of the audio cables.

[@donkmeister]

I remember as a student having the revelationary information bestowed upon me of "not all earths are the same". This was 3 months in to a Physics degree, so the concept of "moving clocks run slow" (i.e. Special Relativity) was already taken as read, but the concept of the earth pin on one socket having a p.d. to the earth pin on a neighbouring socket seemed alien. As my uni had a strong musical tradition, the weird thing was that many/most of us had already experienced this when playing at the open mics and music societies, but like so many things in life few people (myself included) actually understood and hence tried to combat the noise, instead accepting it was just an artefact of the equipment.

[@alandeejay3753]

Great video. As a DJ of several years when I switched from using cd decks to a laptop I found I was getting a lot of background noise over my system from the laptop. Bought one of these from a nearby electrical retailer for £7 and voila! Problem solved.

[@lars3213]

another way of getting rid of noise like that is using Differential signaling, commonly used in XLR plugs, where the regular signal is in one conductor and the 180 degree phase-shifted signal is sent over another, and in the other end the two signals are added and the noise is added too, and so it cancels out. ;) en.wikipedia.org/wiki/Balanced_audio look under 2.Interference Reduction and 3.Differential signaling this is however not common in most home or car audio equipment sadly

[@Pelonius]

I have been in the Pro AV industry for 20 years, what I was trained about lifting the ground is slightly different. The ground wire on a balanced line needs to be earth ground, some older equipment the shield pin was tied to D.C. Ground which was the path that the noise on the shield wire was introduced. If I ever had a humbug was always that the previous installer lifted the shield and didn't maintain the cable twist. I would also double check the equipment by metering the shield pin to the chassis, if they were not connected I would ground the shield to the chassis not the pin and there wouldn't be a hum. I was taught that as long as that shield goes to earth ground a slight current on it isn't that big of an issue. I know LOTs of older AV guys who disagree with me. If your Amp shield is tied to D.C. Ground you are basically creating a huge antenna for it.

[@DasGrinch]

The last time I used one of these was 15 years ago, and it was purchased from RadioShack. it was in my car, and it was sold as a 'ground loop isolator'. Interesting to see what is actually inside one of them.

[@milindmahajan7901]

Two coils produces another magnetic field. And to stop inducing that back emf and eddy current aluminium foil is used as a shield. This is my opinion

[@PsychoticBovine]

we had to use these a lot during the 80's for car stereos. We would get a whine that changed with engine speed from the alternator.

[@Roy_Tellason]

The foil is for electrostatic shielding. Some transformer, power transformers in older tube gear even, come with a shield between the primary and other windings. Normally you'd just ground it.

[@gantmj]

I had to use exactly this to fix the hum in my car. This was back before portable digital music players were big, and I just wanted to use my laptop with an aftermarket head unit. The hum (in my case) was from the laptop, and not from the operation of the car.

[@Blutzen]

>This was back before portable digital music players were big... So pre-iPod days, which means 2000 or earlier... You were driving around with your $2000 Sony VAIO acting as an audio player?

[@Czanovid]

For a hi fi quality isolator for home / stage use I would recommend Omnitronic Lh-081. Should work ok in cars as well I guess but it may not as good as this one. The LH-081 frequencies range is 15Hz - 30KHz, input & output impendancies are 600Ohm.

[@thomascoughran1374]

It was common practice to put a filter (choke) in the alternator lead to reduce the whine in CB and HAM radio mobile installations.

[@howlingwolven]

Is.

[@bryede]

I've seen some comparisons/measurements of these devices and there's definitely different levels of quality out there. To get good transformers with extended bass response you've typically got to get something beyond the common $10-$15 devices.

[@paulhicks9399]

Yep it's normally caused by crappy laptop power supplies. Had the same problem till I replaced the psu with a Sony one.

[@PatrickOuthier]

Yeah I have one of these in my car for my CB Radio. Fixed my SWR problem.

[@davelowets]

I remember helping people fix "Noise issues" with their car audio systems back in the day. They always showed up with one of these devices, I never needed them, and the real issue was always one of 3 other issues... #1. Crappy ground connections, or grounding points at different points on the car that had high impedance between them. #2. Inferior or unshielded long RCA cable runs, that were ran next to a large, high current, power cable. #3. A shitty head unit, OR blown ground traces on the RCA output of the head unit or EQ, because someone carelessly let the end of their RCA come into contact with the B+ on their amplifier or somewhere else in the car. I'm in NO way saying that those noise isolaters are useless, they are very useful for mains powered equipment with ground loop issues, but they were very rarely needed in car stereo installations to cure noise issues.

[@kolby4078]

I made my own out of a super heavy mains filter, just removed the caps and fusing/filtering

[@reedytrippleseven4786]

The foil links both grounds and therefore will provide a uniform ground voltage for reference for both left and right audio signal,

[@claes5336]

Thanx for the tip for the Quicktester!

[@crocellian2972]

The quality of the protective earth is not just a safety issue it greatly impacts ground loop formation which sends op amps wild.

[@g0fvt]

The big power amps used in car audio suffer worse than you might expect, generally they contain big dc-dc converters, if you have a few of them you can often hear the beat frequency of the different oscillators as well as the other crap. I have previously used audio transformers from scrapped radio base stations to get round these earth loop problems. The transformers are used to interface the transmitters and receivers to leased land lines, nominally 600 ohm.

[@wedgoku]

I'm guessing but the foil must help to eliminate "EMI" as a form of shielding.

[@jasonfontanoz]

in the pro audio live sound scene we use "DI" direct boxes where an instrument has an unbalanced out going to our balanced mixer board in. all they are are balancing transformers but they are electrically isolated. in the car audio world you can get alternator whine and noises of the like. its sometimes funny when using am radio and you have all this interference, usually in the cheaper made products.

[@LetsGetStarted]

Oh man, The talk about grounding reminds me of a small home church I went to in Indonesia. Their microphone was all taped up and I thought their mic was just broken. I asked by cousin and apparently the mic was giving people electric shocks. Now we know why...

[@michaelhelgeland4588]

The amp was either plugged in backwards or the wall socket had neutral and live reversed. It probably wouldn’t have worked if that were caused by a fault.

[@LetsGetStarted]

@@michaelhelgeland4588 Yeah. I have no clue about how it was plugged in.

[@realflow100]

I need one of those... except with 3.5mm connections.

[@ergbudster3333]

The "screen" on his side is the "shield" of the cable on this side. Of the pond. Meaning the ocean. The Atlantic ocean. That big gob of moisture between here and there.

[@TomCee53]

I apologize if somebody beat me to it, but in cars, the chassis is used as dc common, so the high frequency nose from so spark plugs can actually generate signals in the chassis ground loop between source and amp can transfer the audio noise through the chassis.

[@Krankie_V]

would this remove interference noise in my car stereo? I've got a whine from the alternator coming through my speakers, probably because the power wire runs close to the signal wires

[@_Kirby207]

Krankie V yes, this or a device like it will solve the problem, punch "alternator hum eliminator" or something similar into Google, there's ready made products made for cars

[@Krankie_V]

Eli Witt thanks for the response

[@Mr.Engine993]

Very well explained. I was really wondering what this thing does and whether it could solve my issue. Turns out it can, it's just a bit chonky. My guess is that the foil is for shielding. Like the equivalent of shielded cables but on the transformers. It should ensure that no noise can be picked up by the components. It might be an overkill since it is in a metal case already but you can never be too protected from RF interference

[@isettech]

The biggest offenders on cutting the power ground pin are those who are not using balanced audio and not using transformers. On a side note, on a more difficult radio station noise issue I had was on a DJ console for an AM radio station. The older console was using many single ended (unbalanced) input channels and was converted to balanced using small audio transformers inside the console. The wires went inside the console and the screens bonded to the chassis inside. Unfortunately a run between studios had the classic ground currents on the screen, but since the screen entered the console, the current on the screen traveled in the vicinity of the bank of audio transformers coupling the noise into them. The solution was to peel back the screens and bond them to the chassis right where they entered the chassis. To find the problem, an old piece of gear made to pickup audio from an analog telephone from the electromagnet in the handset (before it was legal to connect any consumer owned device to a phone line) called a telephone pick up coil was used to trace the current path of the noise. Google telephone pick up coil to see this blast from the past. The pick up coils were originally sold to plug into portable tape recorders to record phone conversations. Yes they looked tacky, and yes the suction cup would fall off. A tool to pick up magnetic fields on audio wires is an essential part of troubleshooting recording studio audio problems. An AC amp clamp with leads instead of built in meter is very useful in tracing currents in cables. Higher quality isolation transformers for pro audio use are fully enclosed inside a metal can with a screen in the transformer between the primary and secondary to stop capacitive coupling.

[@TheClioryder]

as for putting one of these in a car, you get very bad audio wine from the alternator when the phono cables are routed alongside the amp power supply cable, very good bit of kit

[@Storebrand_]

I bought a mic off Amazon for 10$ but was disappointed when I found the mic picked up AC interference and produced a 60hz hum. I was also told the mic made a high pitch buzzing noise. Could this solve my issues?

[@bigclivedotcom]

It's usually the cabling that is the issue. Poor screening.

[@jamessimmons7149]

I used one of these to get rid of my alternator whine when charging my phone AND listening to music from my phone through my car stereo. Worked like a charm.

[@eurobum2012]

I'm pretty sure that outer metal can provides zero shielding, since it's not grounded. If it is connected to one of the conductors in the cable, then it will act as an antenna, injecting all interference directly into your audio signal.

[@hadireg]

Nice topic, always faced the noisy connection from headphone output to input audio connections, until I've seen a japanese guy repairing old boomboxes and sometimes adding bluetooth function to them and using the ground loops devices. very interesting indeed! if soneone is interested hashy teddy is the name. nice old bomboxes being repaired in a professional manner.

[@kolby4078]

They are often sold labeled ground loop isolators as well

[@kylebarg880]

Thanks Clive. I think you just showed me my first project to try and make. My friend just purchased a new Lenovo laptop but when it goes to sleep the set of computer speakers it's hooked up to (or even the TV, if it's still on) start buzzing away.

[@bigclivedotcom]

+Kyle Barg That's a common issue. The computer stops holding the lines in a silent state and they pick up noise like an antenna.

[@ypoora1]

+bigclivedotcom My monitor causes this,as if it's leaking to ground. If i disconnect it's DVI cable, the speakers go silent. You're right about the computer pulling the line silent though, because once the audio driver loads up the bussing stops with a violent pop.

[@mr.hankhill5161]

Just wanted to say thanks for helping me realize why when I full-screened games I heard my speakers make noise!

[@automachinehead]

@@mr.hankhill5161 this is why people who claim they are into audio but use their pc as source are an even bigger fools than those boomers who spend a lot of money into audio stuff believing expensive stuff are perfect.

[@kwok3d]

How would this compare to a simple/affordable RF Choke in terms of getting rid of Radio noise/hum?

[@brianpiddock6074]

I have 2 of these in the bits box I do a lot of outdoor events some involve pluging in other peoples kit like cheap crappy radio mic receiver's mp3 players they work a treat.

[@climbnonstop]

What caught my attention are the poor quality of the RCA cables.They look thin and certainly unbraided.

[@olivermgrech]

Was thinking the same thing. I have two of these ordered and for sure I'm going to change/shield the cables.

[@nasticanasta]

when I was young. got my first car...I'm talking mid-late 70's, if a car stereo caused noises such as hum or buzzing we would just take a transformer from an old radio or something and the run the power wire through the transformer to the fuse block...instant noise elimination

[@TheZooman22]

A common issue in cars is with devices like a cellphone going into an AUX in, for example. The noise isn't a real problem until you plug the phone into a charger. An audio signal isolator will eliminate that noise.

[@zx8401ztv]

Clive, my mate had the same problem when he used his laptop+psu to drive a mixer for disco use, it hissed like mad and he came to me to fix it. I found a couple of line level transformers and plopped them into an old plastic film container, same wiring as your diagram, that was two years ago and all is still well :-D The magic of magnetic flux coupling :-)

[@braindeadtoo]

I've had one of these for a few years and it has never solved a noise/hum issue for me yet; nice to see inside though.

[@franchisefred4066]

That foil is what shields the static electric noise through the two coils

[@ethanpoole3443]

I suspect the foil is to ensure a conductive path between the two metal can halves as it would be pressed against the interior of both cans when assembled. If they had soldered the two halves together then I doubt it would have been used. In car audio you are most likely to require filtering on the power input, especially to a radio, as there can be a lot of conducted common mode noise on a vehicle's power rail that can then get into the tuner (most decent amplifiers will/should have adequate input filtering of their own since they do not have the added task of functioning as a proper radio receiver where the vehicle chassis (ground plane) is also a part of the antenna path. Usually these filters are a simple inductor and one, or more, capacitors to help filter ignition and commutation noise from the power input.

[@gemmapowlespowles8739]

thx so much i have been looking for ever to fix it with out a RCA isolator thx so much

[@MrLordBaer]

one thing you have to watch out for,in vehicles is the 'whine 'can either be the alternator OR the fuel pump. you also have to realize,all the wiring in the vehicle is acting like antenna so its not realy a simple thing to fix in a vehical

[@rowalong]

Great video! Thanks for explaining it so simply.

[@djs5089]

I use a Toslink optical cable to connect most of my equipment to my old Yamaha V800 6.1 receiver. As it needs optical light input to send audio, noice is not a problem. Most devices I want to connect have toslink-support but off course not every device supports toslink. In these cases, such a device is quite useful.

[@transmitterguy478]

As a 62-year-old electronic tech, I can't believe fiber optic didn't conquer the audio-video patch cable market. It would have been a much better quality sound plus they could have passed the remote control signals and video between devices too.🤔