Speaker Protect Circuits - In Practice 

Ignore the Trolls. You have a great channel and I'm sure I speak for the majority of your viewers when I say, "Thank you for all you do". If someone gives you a bunch of grief just to be mean, introduce them to the GFY acronym. 😉✌️

Peeps if you don't like long videos don't watch. Real information presented properly takes time, especially if you address all the points that might come up. Keep it up Tony, hater are just that. Know it all with no skills.

Thanks for sharing all your videos. I am disabled - bedbound and can no longer do the things you show. So, watching you doing them is pleasurable for me. If I find anything repetitive etc, I skip over it. My favourite parts are the diagnostics, which vary every time because of the varied nature of faults. Other stuff, like aligning radios or biasing power amps tends to be all the same, so less interesting over time - but all part of the job. So, please keep on sharing your videos. They are yours, and for your enjoyment. Many of us take vicarious pleasure from watching.

Tony, I've been an EE for more than 50 years, so I've seen a thing or two. I like your videos and don't have any issue with your presentation or content. Remember that McIntosh amp you restored by designing new PC boards? I got so many good tips on transistor substitutions for obsolete parts that I didn't need to hunt through tons of data sheets to modernize a power amp I built in the 70s. I'm retired now, but still enjoy, as you do, tinkering at the workbench. When I meet someone who wants to learn about electronics, yours is one of the channels I suggest. Keep doing these videos the way you like and ignore the keyboard warriors that have nothing better to do than criticize.

You nailed it! It's your plate! I've been watching you for years and have enjoyed every single episode! Not only are you extremely talented and intelligent, you have an amazing personality! Keep up the great work sir!

0:15 Intro 5:20 Looking at Schematic of the Speaker Protect Module 17:39 Building the Module (Solder & Chat) 38:19 Preparing the Chassis for install 42:09 Adding a buck regulator module to power the circuit 44:43 Testing the module with the original input capacitors 46:15 Replacing the input caps with non-polarized type 47:02 Testing the finished protect circuit

I love your chats, trolls are there to get a rise from you. My joy back in the day was going to like minded friends and learning and taking away what I learned from them. I think the most of the people that watch your channel are like minded people that enjoy what you give to us. Just do what you do Tony. You bring joy to the hobby.

You've done a great job over the years Tony, without asking anything in return. Sadly there will always be people who have nothing better to do than be negative

Tony, I absolutely enjoy your videos and have the same hobby when I have time. I also learned EE going to college for 5+ years before the internet era. I don't understand those folks who destructively criticize your videos, but still continue watching them. They should be 100% ignored. Dave Jones from Australia has spoken about similar situations recently. BTW, I was amazed by the restoration work you did in a Pioneer SX-1980 years ago. Absolutely great work, I have learned a lot from you to do my [much smaller/humble] restorations.

Thank You for reverse engineering and explaining the circuit, looking forward to part two.

I enjoy the fact that you are smalltalking. Small interesting stories. And often i get reminded of things that you have mentioned before but i have forgotten. Don't change (i know you won't) This is definitely one of my absolute favorite channels. Also because if the smalltalking. If people don't like it. Watch something else and don't complain.

Some people are such Miserable bastards and just natural arseholes and don't let them bother you, don't change a bit your great as you are and I for one am grateful for every tutorial you post and your style is 'you' and yep if you don't like it what hell are you doing here ? go somewhere else or make a beter channel yourself. I click the like button on every video before I watch it, call me weird but I'm grateful for the persons time and I may not subscribe or ever go back again but thats just me. Regarding the foreign clones they often have the circuit board correct and the thing works but they use rubbish components like rejects or seconds ...cheers.

Tip = I wear transition lenses. At my last doctor's visit, I asked them to give me a separate script for soldering glasses. They are a single magnification, so I don't have any aggravation with trying to find the proper focus zone. The script also has a little extra magnification, but they also considered the focal length, to give me enough room (under my nose, so to speak) to account for the length of the soldering iron. I highly recommend them. If you don't need any correction, other than magnification, maybe you could get away with a pair from the dollar store. I have heard of plumbers that had their prescriptions flipped, vertically, for hanging pipe, overhead, all day. I even added a magnification lens inside my welding helmet, long ago, so I didn't have to wear glasses, under the helmet. That was before needing to prescriptions. lol

I for one really enjoy your talky bits. You're an interesting guy and you have taught me, and I'm sure many others, a lot about Audio electronics. If some viewers are irritated by some repeated information you kindly provide, RU-vid provides a handy scroll bar to skip that section. Ain't technology great.

Wow, I love your channel. I’m in early 60’s and just getting started and I truly appreciate the time you take for these videos and NEED the explanations, longer the better. Learning a ton watching you. Thank you Tony 🙏

I very much appreciate all your videos and you taking the time to do this. I’ve learned so much from you for this new hobby of mine. I look forward to and enjoy all of them.

Keep doing exactly what you're doing Tony, long videos and lots of talking with details. I agree if anyone doesn't like it then exactly as you said why are they here? The world is now filled with people who are no longer capable of reading, listening to, or understanding more than 10 words at a time. They will try anything to bully others into their shallow stunted mode of thinking and doing things. I feel sorry for them because they will never have a deep understanding of anything.

first time commenting ,Im a beginner at this hobby,ive been an audiophile for many years. ive been watching your videos for couple of years.wanted to let you know how much you have inspired me .your passion for hi-fi ,and your knowledge is astounding. i love the way you talk about your day to day problem's. And i wanted to say dont let the haters stop you from what you do ,your a fantastic teacher. and your videos got me interested in learning more about electronics, keep it up tony!

For those DIYe'rs who are thinking about doing this . Beware that most of these kits are designed to work only on class a/b amps where the speaker outputs are tied to a common ground. These kits can easily damage a class-d amp that uses floating outputs or an amp wired in bridge mode. That's why a schematic should be included.

Thank you for your time and energy to do this demonstration/performance video! Nice little kit for cheap.

We appreciate your videos and what we learn from them!

Great Video, Great Talk Tony, you keep on doing things your own way and continue being true to yourself... I enjoyed every minute !!!

Tony , I never get tierd to watch all your video , longer video better , even if it is not about electronic video , Greeting from Sweden.

Another great video ! Your time and effort to produce each is certainly a gift . As far as vision, I never got used to bifocals (and I tried many versions) when first prescribed later in life, a large PITA! Have worn glasses for a good part of my life and still get them made for single vision lenses. I take them off when reading or bench work. I find that my eyes adjust better than using magnifying reading glasses. As for tiny print on some components, the camera on smart phone with magnifier works great and the phone flashlight is great for those hard to read stamping in plastic components. I consider wearing clear safety glasses when working around live high voltages and other hazards. Thanks !

Tony I want to thank you very much for your effort in making these videos and sharing your information with us I can really appreciate somebody doing this very much and thank you very much for your knowledge and hard work.😁👌

Thanks for taking the time to reverse engineering the circuit.

Your videos are above and beyond. Repaired consumer items for years. Nice how you go in depth on what you're working on.

I'm so enjoying the speaker protect series!

I am a "wood turner" making a particular style placer tool, though I do all the vendor kits also. We have been in business 5 years now and my wife and I do this full time. We are fairly successful...enough that it is worth doing anyway. I have often thought of making RU-vid videos, I think I have something to offer the community. I am not looking for money or fame, like you I just want to share what I do. But the stuff that you talk about here is exactly what is preventing me from doing this. I just don't need the negativity in my life. The know-it-alls who do it better than I do, the constant corrections and telling me what I am doing wrong, the stupid comments on irrelevant stuff...I applaud you for doing this and I am thankful, even grateful, that you take the time to share what you know. I have learned so much from you. I know it takes a lot of thought and effort to video this stuff, it takes you 5 times longer to do anything than it would without the RU-vid consideration. You have the right attitude about it. Again, thank you.

I'm grateful for your videos and everything you bring to us .

Great video Tony thanks again for your hard work. Always look forward to new content.

I was in the same boat Tony! learning on your own with a occasional mentor, a ton of reading, taking course's, putting thousands of hours on the bench. I was proficient in consumer, commercial repairs, and special design needs.

For me, the dislike button is only getting used when someone is claiming to show something in the video that is obviously fake or clickbait. On rare occasions, I've hit it because people were showing showing a "tutorial" and doing unsafe stuff and if people would repeat it it can cause damage. Even then, I usually just write a friendly comment, if the intent seems good. In fact, I can't remember the last time I hit it, so either YT has done a good job of filtering out that stuff, the content has gotten better or tolerance has built up. Thank you again for your videos, there is something to learn in each one.

I bought one the chineiseium protection boards. Mounted in a separate box with it's own power supply. It has speaker wire leads for inputs, and speaker type terminals for the outputs. Plugs into the switched auxiliary 120 outlet. This way I can use it for all of my amps or receivers, and nothing had to modded internally.

Protection relay boards are available that run directly off of 120 VAC. This will be easier to interface into many amplifiers then trying to find a suitable low voltage AC supply from the mains transformer in the unit.

It's worth noting that those protection boards typically are not compatible with differential output amplifiers, which is what most modern amplifiers are.

Thank you for another great video, Tony. I really enjoyed it and appreciate your time. Peace, joy, happiness to you too! Cheers Mark

Tony, just do what you want to do. That's why we're here.

I really don’t get the comments from people complaining about long videos. I love long videos from you, Mr. Carlson’s Lab, etc. it means more content to watch. Is it really that hard to watch part of a video, pause it, then come back to it later? I mean seriously, watch it in 4-5 segments if you have to.

Always a joy to watch one of your videos, great tips, Tony. About the transformer, I put some extra windings on a big toroidal transformer for an extra 12V winding.

Tony thanks for reverse engineering and explaining the theory of operation. This video is extremely helpful to me. I have an older quasi complementary BJT amp that has over-current protection, but no DC offset protection. I think a similar / same circuit you used in this vid would work on my amp. The only thing I'd need to determine is power handling. The amp is 200W per channel.

At about 9:00, It is worth pointing out that you don't necessarily have to have a shorted output transistor or driver transistor in order to have significant DC offset going to the speaker; a fault in the differential amplifier at the input of the power amp could result in several volts or more of DC offset voltage being fed to the speaker. (PS, it is a good idea to always change out the feedback capacitor in the differential amplifier to a bipolar type ---- many amplifiers used a polarized electrolytic capacitor here, and and they are known to fail).

Thanks for this video 🙏 i have a Phase Linear 400 and want to install this speaker protection 👋

And, for most, not all people seen your video's before this one. So it's good you mention those things. I have no idea how to run such a channel. But for me, you're doing a great job. You put some slow comments, and look like you have to need a lot of patience in this work, which is ultimately. And you answered already some questions in the preview videos to some practical questions. So mission accomplished. And another thing, we are here for the same, learn and having fun with electronics. < Oops talking too much myself 😇😊

Really loved your work, I really like your content and stuff you shows on the channel, I did try to reverse engineered this speaker protection board and I did it but I didn't understand the functions properly, like the actual theory of the circuit

One word Tony... brilliant ! I need to do this to my Adcom amp. I'll have to find a higher power unit though with a more robust relay I think. I saw some with built in ac power may try one.

the long video complainers probably says more about there lack of attention span, than your content. keeps as you are, one of the best electronics channels there is, along with mr carlson' lab . sometimes the theory goes over my head, but thats good, makes me want to learn more.

Just a thumbs up. Keep up the good work.

If you have access to a 3d printer it can be a great tool for small custom mounts, or enclosures to isolate physically anything you want double insulated or whatnot.

Interesting video for those who have to add some protection circuitry in a vintage amp. But as these only protect from DC or hard clipping, you should also specify they won't protect from any loud "Off" noise, nor be adapted for specific amp technology that can suffer from a missing output load. As for most high end or more recent amps generally already have some kind of protection circuitry, discrete or with one of these once popular ICs, you must always understand how your amp work or get some schematics first before investing in this circuit. Anyway, I also know people also having problems with "modern" digital amps (class D or whatever), literally frying their speakers! Apparently, the problem is these ICs don't necessary sufficiently protect their outputs when failing. So these tiny protection circuits are always an interesting feature to add! (I've seen someone complaining how some well sold Chinese Hybrid amp destroyed his loved and costly Klipsch speakers!). What is also interesting to know is about the supply decoupling solution... And the way you solved this problem, wich is probably most cost effective than the tiny encapsulated transformer you could use for that when not finding another proper solution (I'm also from the old school). It's also an effective idea when you don't find replacement bulbs with bizarre supply voltages with more effective LEDs, OLEDS or strips depending on what purpose.

D lab Electronics your utube videos are awesome

Thank you for another great video! My career is in computer aided drafting. I also like to do non-work related, drawings and design, projects at home. If you ever need a hand drawn schematic made into a computer drawing or pdf let me know. Glad to help!

Many thanks for this video 🙏

D lab Electronics you are good at electronics and restoreing shortwave receiver and fixing streo receivers

great vid. Thanks

Great video as always.Thank you for your time.One question , did you replace capacitors with same value just bipolar?Thank you so much.

Anybody? What the Maximum Dc this board can handle? So both of my Amps I have are +- 100vdc and 80Vdc rails. Do I Need a Bigger voltage for 100uf BP capacitors which I need to order?

This circuit is the same one that I tried helping others with (the UPC1237), just by looking at the chip datasheet and the board photos from AliExpress. Unfortunately, they never could get them to work correctly, but I chalk that up to neophytes that had issues understanding exactly what was being said (never did get any useful photos of their work).

Thank you sir, I like it

Clipping the leads before soldering is usually much better because clipping is very violent action and potentially weakens the solder joint if you clip after soldering (which I always do cuz I am lazy). Also, I am issuing a formal complaint: these videos are too short 😁

Hi Tony, Great video as as always. I've just built this kit and it seems to work well. I'm struggling to see which two caps need to replaced with bipolar caps on the board.

@20:08 "If you don't like it, why do you watch it?" 🙄 There is a big difference between questioning, and complaining. I can't remember ever "disliking" a video. I just "walk away".

I don't like noisy switching supplies; but I dislike AM radio even more 😁! If a buck or boost supply interfered with AM radio, I personally wouldn't care (AM is a vast, noisy wasteland already), but it might also interfere with a phono-preamp section. If you choose to use a relay module that is designed to be powered from 12VAC or similar (some Yamaha's use 24 VAC), you might be best off to convert the lighting circuits to LED's and free up some current for the relays. Most 1970s-80s receivers and amplifiers will have time-delayed and DC sensing relays built in, but big power amps sometimes do not, and even those that do will sometimes be prone to sending a big pop through the speakers if the power blinks off and back on quickly. An add-on relay circuit can be helpful in such cases. Another use for such devices, If the current carrying capability of the relay is up to it, is as a mains-power turn-on current limiter. Some amplifiers will have a big resistor or a bank of them in series with the power cord feeding the power transformer primary, to limit the current surge as the filter caps charge up, and a couple seconds after you turn the amplifier on a relay will kick in and shunt the mains AC around the resistors so it goes directly to the power transformer. I'm currently recapping a pair of Heathkit W5M mono block tube amps and those have surgistors in line with the power cord feeding the power transformer. Does anyone here remember surgistors? It's a wire wound resistor with a bimetallic switch next to it, and the resistor is wired in series with the power transformer, until the resistor heats up, and then the bimetallic switch bends, closes a contact, and shunts the resistor out of the circuit so that the power transformer gets full AC wall voltage. The purpose of this was to prevent the power transformer from being stressed or damaged due to the large amount of heater current drawn by the COLD KT66 output tubes (which have a very low filament resistance, almost akin to a short circuit, until they heat up) as well as the current surge caused by the filter caps charging almost immediately because the stock 5R4 filament-type rectifier does not delay the B+ voltage by more than a fraction of a second. For improved protection of the transformers, I might even add a thermistor or two into these amps as well.

You could never satisfied everybody they’ll always be trolls just have to learn to let it go through one year and come out through the other because it’s not worth frustrating yourself over trolls

Me personally, I like to wire the electrolytic caps with the (-) terminals facing outwards, and the (+) terminals wired together. Maybe this is just because I think in terms of electron current rather than conventional current, but - IIRC - polarized electrolytic caps are manufactured with the electrolyte on the (-) foil; so a non-polarized electrolytic would be a sandwich of electrolyte-dielectric-electrolyte, and two (standard) electrolytics wired + to +, would - essentially - be a sandwich of electrolyte-dielectric-foil-dielectric-electrolyte, very similar to an actual NPO electrolytic, like you might find in a speaker crossover circuit. I wonder if there’s any difference in performance between (+)-together and (-)-together?

That track that you played at the end of the video, does it have lyrics to it? I have a track that sounds exactly like it and it also has lyrics that are what sounds to me like Arabic but I'm not sure.... But it's a great sounding track nevertheless... This is another great video! I thoroughly enjoyed it! This is a great addition to any amplifier that doesn't have a protection circuit... Another great circuit which is also relatively cheap is a soft start circuit! Which means more relays but I kinda like hearing that mechanical click on startup! It's kinda like the mark of quality of a piece of equipment like the way the cassette deck door opens slowly vs a tape chucker LoL... Reminds me of that line in the movie The Fast And The Furious "Ejecto Seato Cus" where the bad guy is launched out of the car.... Maybe we might see you add a soft start circuit to an amplifier in the near future.... Only time will tell!

D lab Electronics you are good at fixing ham Transceiver

12:00 I dont fully agree on this as a non-polarised cap. The AC signal will be devided equally over both capacitors, so one of them will always have the signal in the right polarity, and the other will always have it in the wrong polarity. You could fix this by adding a diode in parallell over each capacitor. With the cathode to the positive side of the capacitor, that will short circuit the signal if it gets more positive on the capacitors negative terminal.

Hehe folks! Always some complains 🙈 I love your videos Tony and i hope You dont gett to mutch trolling 😁💪👍 Verry mutch teatching for me 😁👍💪

How do you manage to clear the burrs during and after drilling to avoid short circuiting the amp board?

48:07 in the video I have some 33uf 50V MUSE BP Nichicon capacitor and some 220uf 35v BP Panasonic capacitors both about 150pcs Please tell me which capacitor is good. To use in speaker protection, I plan to build a 60w to 100w amplifier, so I needed for it. At which ac output voltage point 33uf 50V MUSE BP will work properly or 220uf 35V BP Panasonic . You did something similar in older video, where you set the ac voltage output signal where such values BP capacitor. Something like limiting the ac output signal at some point.

D lab Electronics this is interesting on speaker protect circuits in practice this cool

place the led in the frontpanel

I want to watch your first part video on theory and can't find it. Could you put the link in your description? Thanks

hello tony where did you get the supply voltage of the buck converter ....somehow the minus directly from the power transformer and the plus from the rectified branch of the amplifier circuit? I ask this because it is recommended that the protection circuit be powered from a totally separate source to avoid interference......thank you!

Thanks for this. I've a Peavey Amp that has it's soft start on a daughter board that is of hideous design (using about 20 SM LED's to pull down voltage for the transistor contr4olling the relay! 1 component dies... board is done and amp will not work. Terrible design :P. I ditched the busted board and currently use a 12V trigger to switch a relay that switches the main power relay on the amp. Works great and my pro amp is now remote triggered. No soft start though! I'm investigating options to reintroduce it while keeping the 12v trigger and also add in a physical switch. I'd be very interested in knowing where you found the kits that offer more of a quality design :). Have you any suggestions?

Tony, I'm having trouble understanding why hard clipping triggers the same response as DC on the speaker lines. Can you explain this for me? Thanks!

do they make a speaker protect circuit for realistic sta-2080

I saw that the test is done with a 1.5v battery but I had 48vdc on my Technics with the shorted terminals. Does this board support these voltages? Thank you

Hello my friend, I have been following you for months and the first video I watched of you was for the Kenwood kr 710. 4 months ago I bought a broken one and it only had one channel working and in this channel only a speaker was working so I bought replacement transistors and replaced them and also replaced the small transistors that belong to them with the resistors. Which is 330 ohms, and the problem is that when you turn on the device, the resistors burn out every time. I tried about 10 times and checked some of the components in the circuit. Unfortunately, the problem still exists to the point that I bought another device exactly like it. The same problem was that the right side was broken, so I tried to replace the parts on the right side, and when it turned on I am surprised that the fuse is burning. I am completely unable to use this device. Do you have any ideas? Sorry for the long delay.

Please keep your subtitels a little longer on screen so non-native speakers (should I say "readers"?) can better follow. I can quite well and easily follow your speech, but the subtitels I can't often read that fast, especialy when they are longer. Otherwise thanks a lot, I keep learning and understandig amplifoer circuits and all around it, more and more. 😊

Hi XRay, Good Videos. Social Media in general is full of the stuff you are talking about. Young girls especially can be devasted with comments done that are truly not required or needed. Simpler when this media was not available. Forget them - "water off a ducks back" is an old saying... Anyway- to my point. Would a circuit like this delay output to speakers for a lot of vintage amp "Speaker Thump" which normally cant be overcome with existing units schematic.?

Hi!! If I use 12v power supply,what is the amper I need?

I have a question, what if your speaker protection board only has two channels and your stereo has four channels, how do you hook up a four channel to a relay board that only has two outputs?

I can't understand why you didn't just take your +32V rail and use it to drive the L7812 directly. They are rated for 35V and without a heatsink will dissipate 2W before shutdown. Those generic relays won't draw even 40mA and 80mA x 20V = 1.6W. Probably a lot less - or you could put a 120R 1W resistor in the line feeding the L7812. Surely that bit of dissipation is going to be less of a problem than the noise you'll get from a switching regulator?

Do not get Lasik at an advanced age! If you were in your 20s I'd say go ahead. Your eyes are always changing through the decades. I had to have cataract surgery in my late 50s (first 1 eye, then the other, 2 years later). I should have had my vision "corrected" at the time. I still wear glasses.

We don't all know this stuff.

Squint - you're going to need a bigger board 1100 transistors went in, 316 came out. The magic smoke took the rest.

Interesting video but made more so by the asides about negative comments - well worth repeating. Better to say nothing at all if you can't say anything positive.

16:39 Is it not possible to use a Capacitor dropper circuit, because at the end, it's only purpose is to feed 2 relays? If you use low current relays like the Finder 30 subminature series, those consume arround 12mA at 12V. With a Capacitor dropper circuit, you also don't inject high frequency noise like the buck converter does. Regarding the whiners, 1 word to remember -> WOTAE (Waste Of Time And Energy). It's your channel, and you do or don't do what you want, you say or don't say what you want. The most majority of us viewers love and enjoy your video's, no mather how long or short they are. And for the people that don't like your way of doing, they developed a exit door at the top right corner in form of a X to click on. The fact is they don't find the X and stick arround to place whining comments, that's there problem not yours. Keep doing what you do. Grtz

put up an online poll for your viewers to see how many would pay say 1usd a month and consider it to get rid of the crap you get

"If you read the instructions, and they're in Chinese..." My thought at that moment: "Tony, you da man!"

p͓̽r͓̽o͓̽m͓̽o͓̽s͓̽m͓̽ ❗

You don't talk to much.

you mean boost converter regulator, not buck regulator that reduces voltage you're a bunch of oxymorons if you don't like it but you want to be compelled to watch it 😂😂 well said