Amplifier repair - How do car amps work?? Part 1

[@jcorpus209]

Someway I eventually found your channel getting into car audio. Im 40 years of age. So, I appreciate this type of content.

[@maxedoutcreditcard6157]

Holy cow, I learned more on how amps work from this video than the last 10 years of my research. This is very incredibly well explained and documented, the drawings helped wonderfully also. Never before was i able to find something so detailed.

[@awesometylerable]

Dude...you could be sitting right here next to me while I'm going through my first teardown/troubleshoot on a similar amp and I couldn't possibly learn anymore than I did in this video. Perfect arrangement of information and perfectly conveyed. Thanks so much.

[@burhanuddin127]

great vid! and I wonder how you give this much info openly cause when technicians repair them, they don't even let you see, cause no one would give their knowledge for free, so hats off to you man...👍

[@bobbycowper2915]

true , most car audio guru's are complete douche bags. so yes HATS OFF.

[@benjaminlangston4153]

Thanks a lot! Been a decade since I worked on amps- found some Old RF in the shed and started remembering- then I came across this- Wow- you're such an excellent and humble teacher! Subscribed!

[@ludicrousspeed9711]

Not only do I appreciate videos like this for the information , the altruism and zero ego approach of delivery makes my day!! Thank you kind sir!!!

[@RoverWaters]

you not having electronics degree makes you explain things really understandable for the uninitiated

[@davidmoore7257]

Something ive had a hard time finding on youtube for quite a while, love this channel

[@ThatLoudF-150]

Ive completed simple repairs on home audio amplifiers in the past and recently had a buddy blow a relatively collectable car amp. Youve done an amazing job at explaining car amplifiers, thanks! now I can go into this inspection/repair much more confidently especially after learning there isn't much difference between car and home audio amplifiers.

[@MattsShop]

This video is the best amp repair vid on KZbin! I had to do the exact same thing to my Hifonics amp when it blew. All Mosfets, resistors, driver IC, driver transistors, bulged caps. I had to figure it all out on my own with a little help from forums here and there. This vid WILL help ALOT of people!

[@prodigalus]

hello. i have a couple Samsung subwoofers that interface via wifi to a soundbar.. but i don't have the soundbar. is there any way to hack these active subwoofers? they have no aux input, but there has to be a way to bypass the need for the soundbar? any thoughts?

[@prodigalus]

yes, please!! and there has to be a way to use the crossover, right? i have 2 Samsung subwoofers, which were $1 apiece, so i'd love to use them lol. i know that they were sold at that price because no one knew if they worked, or how to use them.. and it _has_ to be possible. and btw, please link me when you do this video. any idea when you might do it?

[@lowerthetone]

Extremely helpful! You've made something I've been struggling to grasp for years make sense to me in less than an hour! Can't wait for part 2

[@bigcountry55]

I tried repairing on my own for awhile but never got it because I didn't understand the function of the amp and how it works. This vid fixed all that!! I feel more confident than I ever have and am ready to get back in the saddle! I've got a crossfire vr2000d I'm gonna take a swing at. My wife was actually excited that I had failed at it because my desk was always messy with amp parts laying all over, now she's gonna be really pissed!! Thanks for the vid and keep all the pointers coming in because they help also!!

[@MrJeffroK]

Big Country. Ill trade you a working crossfire vr 1000 for your blown 2000 ?Let me know

[@scotto1568]

I have a bunch of blown amps so im trying to teach myself how to fix them . Thanks for all of your videos. I've learned alot from you. Next on my list of things to buy is an oscilloscope. Thanks again for all the excellent input.

[@maxtek73]

i have built my own amplifiers. one amp i threw together was a 400 watt output stage but driven by a 20 watt realistic home amplifier and it worked very well. that said i really like this technician in this video. he should teach because he explains everything so thoroughly and so clear, the video is actually entertaining. this guy could so easily be a damn good teacher..

[@joshhanson6777]

Sam! Congratulations! We're coming up on your 2 year anniversary for amplifier repair videos. Just imagine how many people you have helped and how many now can repair a amplifier. I know these videos helped me.

[@martintendayichirombe4016]

Simply one of the best repair videos I have watched on KZbin.

[@wdbaudio]

Fantastic video. Really well documented and explained! I think I will have a go repairing my Velodyne subwoofer amp

[@BlindFoldYT]

yo i love your video's! could i please get a shoutout??

[@ntmills1979]

WorldsDeepestBass which sub? I've a couple dd15's that need boards serviced. Sux that Velodyne quit servicing my model :(

[@wdbaudio]

Nathan Mills I'll be servicing my SPL-800i

[@HansPacker]

I completely agree with this comment. A super clear explanation.

[@ryry7886]

I am totally knew go learning the inner workings of electronics and am 11 minutes in and got to say, I love this video already. I do have a question though. When the signal coming out of the mosfet is 12 on 12 off, does that actually make alternating current as stated, or does that just make it a switched DC current? I've done car audio for 20 years but never actually opened an amp and replaced it, just changed defective ones. I am truly interested in and always have been interested but never really thought about finding a KZbin channel and not too big on library books so I'm actually super excited to find this channel and some similar ones. Thanks.

[@RaulRodriguez-cw6mx]

Excellent technician , I also used to repair car audio and high power amplifiers like Crown. I also used to use a audio tracer I made myself. I got identified with him. Good time . Right now is not cost effective as a business because people doesn't want to pay the repair sometime and your get a junk of equipment with the time. Great video.

[@leighthetwinotterflyerjone9460]

This guy is for car amps what Blueglow is for HIFI. Absolutely love the vids. Thank you

[@bungobill3637]

So glad I found the video learnt so much. You get to see inside these electronic items but wonder why so much electronics are needed. I can understand now why all these components are needed and the chap explains it words that folk can understand.Great useful video well done.

[@Jeremydmeyer76]

This is the best explanation of how an amplifier works I've ever heard. Great video! Looking forward to Part 2! I'd give it more than one thumb up if I could.

[@cat-lw6kq]

Thx for the video, I used to work in a repair shop but I often didn't understand how the units worked. Now I have a much better understanding how amps work and how to fix them.

[@indopleaser]

hope this video causes gain in business. very professional and honest. sd vs dd part three was long awaited and up to bare vids standards. the champ is confirmed!

[@owen-trombone]

Oh man thank you so much for this video! You get straight to the point and make it all clear. Well done. Your work in making this is very much appreciated.

[@thevintagehifiambassador8524]

I needed 5 minutes to be completely fascinated from your tutorial, sorry for having doubts the first minutes :-). now part 2

[@The_Active_Region]

Get yourself a Hakko 808 or equivalent desoldering gun. It makes short work of pulling those Mosfets. Saves tons of times on large amps like this.

[@Paul-IE-Repairs]

and clean the tip, that is definitely neglected

[@mikedee4399]

Thank you for this very good video!! You seem so calm and patient when teaching and explaining things, you were very informative when explaining everything and you do it so well! I have been working and doing circuit bored and cable assembly including troubleshooting and repairs for over 20 years now, I wish I had somebody like you there ti train me and explain stuff to me like you did in this video!

[@nortoncarty3585]

Hey keep up the good work am from Jamaica living in florida now am also a repair guy have bin doing it for about eighteen years now.

[@ephremedralin2545]

We just got a free lecture for electronics. Thanks man. You must be an electrical engineer?

[@Impedancenetwork]

He couldn't possibly be an electrical engineer. He doesn't even know the difference between AC and DC. Did you hear him at 11:02 say that it's AC because it alternates between 0 and 12 Volts. No electrical engineer would say that. We know the difference. It's technicians that don't know the difference between AC and DC. He is a technician that learned how to change mosfets and other obviously burned out devices.

[@RoadRunnerMeep]

Spending more time watching channels like these. Trying to design an amp for a project, the amount of information to work out can be complex, nothing like a little challenge :)

[@konakoffee5262]

Excellent video! I currently have a Rockford Fosgate P1000X2, that's on my bench. It's staying in "protected" mode, even directly connected to my battery, with no other wires involved.

[@barevids]

Output section ☺

[@Josh-hr5mc]

Absolutely great video. Not many videos like this past somebody throwing one on a Dyno. Thank you for this, keep up the work

[@yaghiyahbrenner8902]

I see your knowledge has grown, I like your enthusiasm on the subject.

[@barevids]

Thanks buddy! I know that's an inductor - I wasn't suggesting it was a transformer, I was going to say "transformers and inductors" but the snapped lead took me by surprise and I never finished my sentence haha!

[@yaghiyahbrenner8902]

sorry, I watched your video till the end, you probably made a mistake talking about it. Iv'e been doing so much research on this subject and came to the conclusion they (the manufacturer) blow the whole stage deliberately. if they wanted to, they could to trip the circuit when one fault is found. i.e when one mosfet is problematic, so one effects the others (i.e they draw more current then they should and blow)

[@barevids]

Yes youre probably right, it doesnt help that these board designs are absolutely ancient technology and the protection circuits awfully slow. On the contrary, the more recently designed Brazilian full bridge amplifiers are awesome for that, if they blow you only ever lose one pair of outputs and maybe the driver, the protection circuit saves the rest - and ive yet to see a power supply section go down either on the Banda amplifiers, the protection is so quick! Its definitely the way forward.

[@yaghiyahbrenner8902]

Interesting research. From what iv'e been seeing through the years is that the manufacturing culture in China is, copy and paste innovation, they trade IP for IP, not like the western world that protects IP with patents example: RockFord Fostgate, JL Audio Ect.. In china schematics are in circulation for trade, so the same problematic circuit is found every time as a result of the IP trade and brute force component cost reduction to a point where its a fire hazard product.

[@ballistic_mod]

These videos are very helpful, & I have just bought an HP 554602B 150MHz O-Scope like yours, & a variable power supply & hot air station and a bunch of other things & I'm really tiring to learn car audio amplifier repair.

[@AlvaroGomes]

Excellent video and explanation of how an amplifier works.

[@Sprank900]

wow, best electronics class I've ever attended! that amp is pretty much landfill with all of it's problems. lol

[@martinest9458]

One of the best videos i've seen on repairing amplifiers. Really nice to watch ! Great work !

[@harveybrown1939]

Why hhyg669757557

[@DragonsTaco]

Excellent basic explanation of your diagnosis process. Thanks for the video!

[@JaMarvelousjmar]

Love your videos so I say this in no disrespect; you said 12v is good for car speakers and later said that it is no good. I love the video concepts, I've learned a lot. Good teachers start with a lesson plan and go from there to keep confusion down. Keep em coming

[@barevids]

Did I? Where abouts lol? 12v is definitely no good for any speaker as it will just pop the cone up and stay there haha! I talk quite fast so may have misheard.

[@tody78able]

your lectures are therapeutic and calming... :) thank you...

[@spacemanrick2014]

Great video. Thank you. You are the YT amp repair guy I have been looking for. Be great if you explained a little about the ripple filtering caps on the power supply stage after the rectifier stage. I'll be watching you.

[@Puppy__Nietzsche]

Wow. Excellent explanation! I learned so much in this video. Thanks!

[@spunkyprep]

Dude, are you an electrical engineer? Nice break down. So much information and clarification on how to repair and what to look for. Nice.

[@kimt6333]

He's no way near an electrical engineer, just his explanation of transformers should be proof enough.

[@yafetgezahagn9570]

what an excellent job i wonder how many years to take me to be a master on electrician like you!!!!!!!!!

[@premiere3610]

Wow i really learn a lot from this one video compared to many videos i watched before this. Thanks for the theories because it helped to understand what really happening. This is a very good video. Thank you very much.

[@Phoen1x883]

Dude, I loved you in Far Cry 3 (but no seriously, this is a pretty good overview. Thanks for posting)

[@overtron9969]

Amazing knowledge you shared there. Very good video!!

[@joshhanson6777]

Please do a part two! Awesome vid! 2 thumbs up!

[@rbmwiv]

Thanks for the great video. It really helped me fix my amp. And it was great that you mentioned about not using a power supply with a ground pin. A multi meter is fine but you can really damage a scope doing that with a ground.

[@kerryemmerson8954]

Q&A forum time? if anyone is available to answer this. Bit of a greenhorn at electronics. I messed up my sub amp by reversing the pos / neg speaker wires . I didn't think it would have that bad an effect but anyway, aah. Opened the amp and everything looks good visually except for one potentiometer which was ruptured as they are designed to do. I tugged on it gently and it came out leaving two pins soldered to the spot as original. I was gonna somehow solder a new one to the pins. Will this work out? I know, you need to know the make, model and can't be sure unless the system is checked etc. Im just concerned about the pot itself. If I can do it to the best of my ability and if don't work, then I still have a fucked amp. No worries. Last but not least. Great video mate. I was riveted. Very well done. (for a pom).

[@PowerToneAudio]

a very informative video bro, it will help a lot in troubleshooting, keep up the good work..more videos please..thanks a lot.

[@c4love]

Awesome video very educational. Thank you for taking the time!!

[@pimphandgamester]

I want to see a video done on a mini amp. I'm fascinated how they are able to make them so small yet output so much power.

[@lunam7249]

to be simple, the size limitations are the amount of heat dissapation is needed...the size , a cell phone has 100 million transistors , but the heat is low...

[@mikz86ta1]

Great video! I got an old 1996 Orion XTR amp I need to repair. Been fixed once. Pops fuse in the side as soon as power is applied to the remote turn on. Before they replaced a Mosfet or Transistor....i forgot, been 10 years ago last time I looked at it

[@ruikazane5123]

I cannot really say anything. This video deserves more mate, really detailed. Still makes me feel like a student hahahaha

[@TradieTrev]

Really love love your teaching methods mate!

[@rudolphharry4358]

Nice work sam

[@danielramirez837]

Amazing! Video..u my friend have alot of knowledge. Hat off to u . So , I have a hertz 4channel class d amplifier. I got this from a friend who was going to throw it away . Is it worth fixing ?

[@scotshabalam2432]

when removing those transistors you can also use a side clipper to clip them at the base if you have enough leg-room and then remove pins individually. It makes the removal safer for the board.

[@ThomasXp]

Wow thats a lot of work! Cool video!

[@Clumpy710]

So this amp still has power in it? If so what parts should you not touch? Do you drain it? Thanks for all your help and videos. I appreciate your Q and A on your livestreams.

[@wadebradley7388]

Great video,I enjoyed it so much,I subscribed,I am a fairly keen electronics guy, But after watching this,I would easily try and do a repair myself, Thx brother!

[@Hertzsogood219]

Brilliant! Thank you so much for the video. Loads of information. Very informative and thoroughly explained. If you can keep up with him. I've watched it many times . Nice work!

[@LiLthirtSty]

So helpful great explanations looking forward to part two

[@MisledDan]

I'm hoping to find out from you whether or not my amp is repairable. I have a Kenwood Excelon X801.5 that I bought refurbished. Not until hooking everything up did I realize that the LR channel wasn't working, which turned out to be a dead ground. The way I figured it out was that bridging for the rear works perfectly fine being that it involves the LR positive and RR ground.

[@zquall]

A lot of good tips man, Thank you!

[@jedtalks8038]

Great video, Sam. Thanks mate.

[@thomasstetina6410]

Thank you so much! U taught me a years worth of elec. schooling in a half an hour!!!

[@Krotos1970]

this is way too tidius for me to do, I build my own computers that's as far as I go, if a component breaks I just replace it but on a amp where tiny parts are involved and soldering I bow to you!

[@kooltechno5108]

thanks for the beginner class I learn alot

[@drummonkeystuffuk1875]

I have an old school autotek 4000.1D amp had the mosfets replaced as they blew at the lower output at 4hom, then a few months later the fets went again! id love to have it working again as its a monster at 2ohm..benched it at 4188 watts rms!

[@CrazedPsychic]

Pretty well explained. I would honestly use solder braid though. Less likely to lift a trace or pad. But over all great work.

[@tomjulien3153]

such a good video! trying to repair my soundstream ref604, this helps me to diagnose it.

[@imawizard547]

Thanks for creating one of the better amp repair vids on youtube, it is a huge aid to have this quick and fairly detailed rundown as a beginner. Do you think that amp repair is in enough demand to make a living or at least supplement an income?

[@barevids]

Supplementary to start with. Only when you can bang out an amp every couple hours or less, and start taking contracts with amp manufacturers or shops/hire companies, does it have potential to be enough to comfortably live on.

[@ratgreen]

Also you should make an amp repair series. Record you fixing amps, and how you fault find and repair etc. Would be awesome.

[@barevids]

Haha i was thinking about doing live streams like Louis Rossmann. Would need to re-jig the workshop and buy some streaming gear and close up cameras though.

[@ilovetoyotatrucks]

Thankyou! I stumbled upon your channel - I gotta massive audio 4ch from early 2004ish a 25.4 with a loose pair of RCA jacks...

[@sandwich.entity3810]

Great video, thank you for giving your knowledge

[@19mati67]

Excellent video!!! Now I have to pull out an old Infinity amp. Most likely, I have issues with the oscillating part.

[@thecas360]

I would love to see a video of how to repair the driver card i have a atomic 5000.1 and the driver card is bowen !!! awesome info!!

[@GooPH00]

Thanks for this video! I will be replacing the supply mosfets on my jl 500/1 and I will definitely use some of your teachings!

[@Anontesla]

Thank you bro I love this stuff and you explain it very good!!!

[@cutweldngrind]

I have fixed several older Zed audio amplifiers in the past. Its been maybe 8 or 10 years since I tried repairing one.

[@omanprobashimahossain.2597]

Your explained is so good...👍👍👍

[@peten4251]

Absolutely wonderful video. Thank you so much for documenting this. Great learning tool!

[@American_Made]

Another great video. What are some of the best designed and built amps you have worked on?

[@axel31video]

32:23 Try a differential probe for oscilloscope. There is no ground reference for the negative. You can put the test leads anywere, no short circuit, no derivation.

[@LuxorVan]

Some people modify tools like screw drivers for pulling the retention tabs, but this would take a torch, grinder and knowledge for hardening the tip, just find an old wood handled flat head for modification!

[@dreamnight-mq1zg]

Love your videos BareVids. Keep them coming . I have a weird issue with my amplifier and am stumped On what the issue could be. Perhaps you could give me some insight on this weird issue. Thanks. So here’s my problem. When powering my amplifier up from a cold state, it runs fine at low amp gain settings for about 20minutes or so then begins to cut out intermittently on and off. However, the amplifier runs fine only if the amplifier gain is set to max setting. During this time period if I turn the amp gain back down just a bit, then it immediately cuts out intermittently again. So once the amp warms up, It will only run fine if amp gain is set to max. I’m stumped, never seen this issue before. Checked all wiring, ground and dc power voltage and everything is fine. Only thing that drops out intermittently is the voltage on the output channels, but dc voltage remains constant at around 13 - 14 volts or so. I’m assuming there may be a bad cold solder somewhere internally in the amplifier circuit board that could be causing a bad voltage connection once the amp warms up around 20minutes but I’m not sure as well. Could an incorrect amplifier bias setting also cause this issue as well? Or perhaps bad resistors or capacitors? I’m Quite stumped on this problem, any help would be greatly appreciated. Thanks BareVids. Keep up the great work, love your videos.

[@barevids]

When it cuts out does it go to protect? Does the power light remain on?

[@dreamnight-mq1zg]

barevids : The amplifier doesn’t go into protect mode at all. The power light stays on and dc voltage is constant and stable at around 13volts dc. I made sure to check that dc power voltage wasn’t dropping out and in intermittently when this occurred and dc voltage doesn’t seem affected at all. Amplifier doesn’t go into protect mode either and the dc power voltage remains on and constant . Only the output channels are affected and show a continuous intermittent cut off of AC output voltage every 3 to 4 secs. The AC output voltage cuts out and in (for 3 to 4 seconds in between each cutoff) simultaneously on all output channels when the amplifier warms up around 20minutes or so. The DC power voltage remains on and stable during this weird occurrence. All output Fets and Power Fets as well as rectifiers, seem to test fine and normal with a “diode” beep test. No shorted fets . I don’t have an Oscilloscope, so I can’t test to view square or sine waves on the power supply and output section of the board. But since all Fets, and rectifiers seemed to test fine with the diode beep test, I’m thinking there might be a cold solder joint somewhere on the board. This is an old school car amplifier, an MTX thunder 4160 to be exact. It has a large and small transformer on the power supply section of the board and I tried to wiggle the transformers to see if they may be loose but they both don’t seem loose as well. I tried moving the transformers to see if perhaps there may have been a loose solder joint in one of the transformer solder joints, but everything checks out good. Since the amplifier Is a four channel amp and all of the channels are being affected with this issue simultaneously at the same time, then I am thinking that perhaps the issue is occurring somewhere in between the power supply and the output section. The only thing I could think of is perhaps the rectifiers may actually be bad? Could the rectifiers cause this type of intermittent voltage cutoff if they are overheating? If they can, then It would make sense because the rectifiers are a chain link between the power supply and the output section. So if the rectifiers are indeed bad, perhaps they may be causing this issue which would affect all of the output channels simultaneously? What ever the issue is, I am thinking that it has to be something that is able to affect the converted AC voltage current that is being sent to all of the output channels in the output section. What do you think? I could be wrong, but I am stumped. Never seen this issue before. Thanks for your reply and help BareVids, I truly appreciate it. Keep up the great work brother!!!

[@Foof50]

The mosfet is also going to give you boosts in voltage and not just the transformers. The transformers are there to convert AC to DC and give a boost as a step up transformer. Look up 4way bridge rectifier for explanation on how the signal is rectified and flattened. Works very similar to power supply for a laptop, but in reverse.

[@encho9631]

Awesome explanation bro! Keep up with the great videos :)

[@AldenPez]

This is really good information man!

[@THEtechknight]

When I was in the repair industry, Rule of thumb: Any time you have a bank of output transistors or power supply transistors that have failed spectacularly, (like in the video), Please change the drivers! Shotgun them, 80% of the time they cant be trusted as they develop a C to E leak, or B to E leak from the failure. For this particular design, I use MJE171 and MJE181 as replacements. They are a tad overkill, but I have yet to see one fail afterwords and I have done more amp repairs than I can fill a garage with. This is the power supply section. Output section is a bit different.

[@drewcifer9755]

Teach us how to repair no output slash amps :)

[@THEtechknight]

As in JL 500/1? I already have a JL1000/1 on my channel. I used to repair a dozen or so JL 500/1 Amps. I would modify the power supply circuitry for IRF3205Z transistors, and then IRF4229 for the finals. The other thing they are known for is circuit trace and transistors failures in the remote circuit which is on the riser board.

[@drewcifer9755]

THEtechknight i seen your video. You were about to mention a problem is the pre amp section and continued with the outputs. I have a 1000 that turns on with very very output then goes silent.

[@THEtechknight]

That's still an output stage fault as I can remember it. (last time I was in the amp service business was 2015 on back). However, I do remember running into a few 500/1s with dirty switches in the pre-amp section, both the riser and main board, that's probably what I was going to say. Try spraying those out with cleaner like DeOxit and trying it again. If still nothing, you definitely have an output fault. I am slightly rusty now, but I used to be entangled in the amp repair industry pretty well, Even had a contact on the inside of Kicker so I could get proprietary parts sent to me all day long, such as the crossover and gain pots, they frequently went bad, and they are fairly specific. So I bought a handful of them at a time from Kicker's repair center.

[@prodigalus]

hello. i have a couple Samsung subwoofers that interface via wifi to a soundbar.. but i don't have the soundbar. is there any way to hack these active subwoofers? they have no aux input, but there has to be a way to bypass the need for the soundbar? any thoughts?

[@easyamp123]

@13:00 diodes don't flip anything they only block the flow of current in a particular direction. you have two windings per diode (which are two diodes in one package on that board) that are out of phase with each other so you always have two peaks and dips per cycle, the diode bridge only combines the two separate windings peaks and dips two form a signal much closer to dc but at twice the switching frequency and the caps do the rest.

[@barevids]

Thanks!

[@stuartmp1974]

Wow. What a awesome, Well comentated repair video. So looking for to watching part 2. Learnt so much for this. Thank you for sharing your knowledge.

[@American_Made]

great description of what's goin on.

[@HeartOfGermany]

Pretty good Video. Just a small mistake: You definitely do not need the same batch of Mosfets. First, the same batch does not vary more than the same part of different batches. Second, Mosfets in parallel do not need to be matched at all. Mosfets don't fight. They are just resistors. If one mosfet heats up more due to more current, it will get higher resistance, which limits the current and will make the other mosfets take more current - it basically just does stabilize itselfe. On BJTs it is more critical, because if they heat up, they conduct even better, which will heat them up even more! That's why BJT amps with paralell transistors will always be connected with small resistors, to balance the load much better. Still there it is not that critical. I recently did just solder a cheap ass transistor into an amp which had completely different values, yet it works like a charm - but keep in mind, it was a single transstor per channel per rail of course. The different gain will then just get corrected by the OpAmp circuit which always is there for Class AB.

[@barevids]

From my practical experience, having tried fets from different batches and found they hear up, to then replace with all same batch and stay cold, I go by this being worth doing even if it "should in paper" be okay. I covered the reasons why in another comment reply further down

[@fredgarvin9262]

MOSFETS are transconductors whos gain is determined by gate charge. You are right. They will share current very well. BJT's have varying gain characteristics and hence should be matched when used in parallel.

[@alvinramosadante]

Nice tutorial, thanks for sharing.

[@SheikhN-bible-syndrome]

In my understanding (correct me if I'm wrong) ac voltage is when the polarity reverses back and forth and what you explained was a square wave telling the mosfet to turn "on and off on off" which is different than "plus minus plus minus"

[@ScramTek]

If a signal is alternating between ‘On and Off’ then it is, by definition, and Alternating Current (AC) signal. Similarly, whether it is On/Off or Plus/Minus is irrelevant. They’re both Alternating Current signals..

[@edgarhoey8733]

Your videos have helped me so much thank you

[@berniedofitas1891]

Great explanation! Thumbs up!

[@adamsdiyandrandomvids5379]

What are the 2 bars or rails that are behind the power ground input that go from side to side