How to bypass or adjust or modify an over current protection circuit on JVC 7042s receiver?

Most AVRs can do only some 50W per channel or alternatively some 100W into two channels 8 ohms. You could easily see this limitation from the similar heatsink sizes that most AVRs use, irrespective of brand.

To get good sound out of an AVR, run bi-amp stereo with a compression driver for HF duty, subwoofer amp separate. Do not use 4 ohm speakers, car / plate amps are more suitable for such things. Alternatively use a professional amplifier supporting 2 ohms load.
 
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Hello, let me start with I picked up this nice condition JVC receiver because it hosts a 130w per channel amplifier. However when I start turn the volume up and I get to an almost perfect level of "loud" but not "distorting" (it's not even nearing distortion, so I can tell there is still lots of room for more volume...) but when I pump it up a bit more the over current protection kicks in.
Of course, it is doing its job as designed.
have about 14 other receivers here all around 100w to 110w and they all drive these same speakers much louder with more punch).
Those receivers can drive 4 ohm loads, JVC CAN NOT.
Not hard to understand.
To boot, User Manual and probably back panel says so clearly.
Are you trying to invent a square wheel?
I can tell whoever set this protection circuit up must have leaned towards safety over performance, because the heatsinks are not even hot.
GOOD protection circuit.
And it is not "thermal" which is often sssllloooowwww but probably monitoring SOA or at least peak current.
State of the art.
It might also have thermal protection of course.
I opened it up and I thought I saw "temperature sensors" thermistor's near the amp chips, with the "left channel" one being bent very close to the amp IC (I bent it back like the others) and I assumed ok now I'll get more volume. But I got the same cut out at around the exact same volume. So I installed a large PC fan on the heatsink to keep it cool... and it cut off at the same volume (I might add this is not digital/display volume on the unit - but the same audible volume).
Main protection is NOT Thermal but current/load dependent.
So there is something causing the cut off to cut out long before it's technical abilities are overloaded/tapped.
How do you know?
JVC Engineers know more than all of us combined plus they have LOBG EXPERIENCE, decades of manufacturing hundreds of thousands or even Millions of Audio devices ... who can think about outsmarting them?
A few here have an equivalent or higher level, yet nobody is suggesting to grossly overload amplifiers.
I'd like to figure out where the over-current protection circuit might be, and possibly remove it and or change it's value so it does not cut out so soon before the peak performance of this unit has had a chance.
CRAZY idea.
Same as blocking sprinklers in a room so you can light a barbecue inside, bear the curtains and drapes, etc.
I might add some key points:
The speakers I am using are in A+B combination (4 sp6 use only 8 or 16ohm speakers at each terminal, however both pairs of my speakers being used are 4ohms.
Crazy idea.

Technically speaking I get away with using these same speakers on other receivers fine
Read what you wrote: on OTHER receivers.

(making sure to always use a good fan to keep the heatsink cool) and there is no issue driving them hard for extended periods. I have one Sony 110w which only has Speaker A terminals and it's got a hard switch to select 4ohm or 8ohm, so I set it to 4ohm and installed the 2x 4ohm speakers totalling 2ohms and ran it for 10mins, the heatsink got so hot I panicked and installed a permanent fan. Now it runs fine 2ohm speakers testing for a solid hour at loud volume, no issues (and stays just warm now).
So out of all these other receivers I've run these same speakers off - this is the only unit having "issues" and I think it's simply because they set the cut off limit too low.
To each his own, those are all different.
 
Oh well this is just another typical forum, you post for help and suggestions on "DIY" and all they do is drop a "don't DIY"
SHOW where anybody said that, chapter and verse or STFU.
The whole Forum is based in DIYing.

Now if you post harebrained ideas such as disabling Safety features, yes, nobody will encourage that.
or "it's possible but not worth it, so don't do it" then...
Nobody said it is worth it.

oh then all the negative commenters come rolling in,
Maybe there is a reason your ideas do not get traction.
just to run me down or mock me for no logical reason other than they enjoy it.
Think "not burning down your amplifier/home" instead.
Great welcome.... this is site is looking like all the rest
You got same answers elsewhere?
Maybe there is a reason behind that.
"come here to share build ideas" but instead people just hoard them.
You are building nothing, just dangerously modding commercially built stuff.
What aspect of your DIYing am I missing?
It's so typical of online forums where people "know how" but never actually discuss "how to's" or sit down with you to say "hey I like your idea can I offer some help with the design?", but I guess that's because everyone hoards it for "profit"...
I know NO other DIY/Audio Forum which is as generous as did one: circuits, schematics, build plans, calibration, measurement, simulation, use of dedicated software, PCB artwork, Gerbers, how-to design build and calibrate crossovers, transformers, cabinets, the works.
A TREASURE TROVE all under one roof.
FWIW I came here to LEARN and am learning something useful and new every day, go figure.
How is anyone going to learn if the teachers teach it wrong,
How would YOU know something is right or wrong?
and when you ask "what does it mean" they are like what do you mean? It means exactly E=R/I! But that's NOT what I mean...
Questions in general are answered properly but this is a Public Forum, you can't DEMAND it to replace Electronics101 or do your homework for you.
Knowledge requires personal effort.
and when I ask in a way I need to hear it said to learn, all they do is argue "watch a video" "read some books" etc... but the problem with these all is the same - they never use these "arbitrary values" to actually affecting something real. So in my mind these "arbitray values" have no value and there for I do not store/memorize and it's lost. Sad because I spent 5 years taking electronics classes... and I still can't grasp the "concept" because it's never applied to "cause & effect".....they assume all you need to do is memorize the math and you'll know it (conceptually). No I need to know it (conceptually) before I can apply the math to a concept. I can't apply math to "no concept" and expect to understand a "concept"....
With due respect, start again.
Each and every time you will pick something new, something will "click", etc.
I have dog eared books which I have read 10-20 times.
Each reread is worth it.
Even/specially old Classics, think Beranek's 1954 😲 Acoustics, same by Olsen (1948 😲), early 70's Op Amp and Active filter books, general Electronics theory, general PHYSICS books, any dealing with "basic principles" plus all the stuff which came later.
So ok, let's get on with the running me down further, until I am modded or banned, for whatever silly reason they see fitting.
Why do you react that way?
You wanted to do something dangerous, were advised against it, nothing personal.
 
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I find it rather odd that when I want to do a project, and I post about in online the absolute FIRST thing I am constantly met with is "discouragement". And why is it no one ever actually offers actual inputs on forums? Oh they'll tell you their opinions but no actual "if I was you I'd design it like this" and leave examples... it's as if everyone wants to hoard their ideas rather than share them openly. Like how big bran manufactures act, like they need to safeguard this knowledge so they can have a competative advatage over their advisary companies. Could you imagine what sort of tech we could have if we stopped competing and all just openly shared and discussed ideas!?

Also I must say I find it rather funny, how people here reacted to my comments/posts. It's like if I said "it's really bright in here" and a bunch of you chimed in and said "oh you're going to go blind because any level of brightness will blind you! To be safe just keep the level down super low or wear sunglasses indoors just to be super sure your not damaging your eyes!"
... like really how can you tell being halfway across the world how "bright" over here is to me??

Secondly you can't compare "loud" on a cheap $50 Fisher Reciver to a $3000 Receiver with a high end DAC connected with nice $400 Op-Amps installed on it.... A alot has changed since the 70's.. but there is also the quality of an amp, there are in fact some epic amplifiers from these generations of past... but many sources sucked back then (tapes, 8 tracks, LP's) and all of these were also downgraided by the recording industry at the time not having the tech like we do now for recording and mastering. In fact I download a lot of 24 Bit recorded FLAC (lossless audio) albums from bandcamp... (and the sound card I am saving up for currently now supports 32Bit audio at an unreal 384bit sampling rate!).
Also amps list their specs like "this receiver is 130watter with 0.09% THD at that wattage..." where as others say "hey we also have a 130watt amp in our receiver! But when you look at their specs they are achiving that wattage with 10% THD..." that's when you know you're going to get a distorted expereince with possible hearing damage on an amp that has 10% THD, if you play it at loud volumes. Shoot I dislike anything near 0.9% THD... I don't tend to buy it or use. I need clean power that is "distorion free". Also you guy's need to keep in mind the speakers I am using (you never asked how big or small they are if they are like PA speakers or 6inch woofers or 15inch woofers) I mean I'm not listeing to "stadium horn tweeters or raid sirens here" ... in fact I've even begun making my own custom built speakers (reading up on woofer specs, mids, tweeters, cross overs cut offs etc).

oh you guys "it's too loud you'll damage your hearing!" Listen, I've been at this for around 4 decades and I can still hear all the tones in a hearing test fine... so I must know what I am doing. In fact there is a reason why I've not damaged my hearing....

However, before I get into that.... I will share a story of, the only "real hearing damage" I believe I suffered. And please note this was back in the 90's when tech and amps in headphones really were much poorer compared to todays tech/gear. So back in the early 90's I picked up a really nice pair of Audio Technica or similar barnd over ear headphones (that looked much like the Beyerdynamic DT 990 Pros with the fuzzy ear piece that went around the ears). Whatever they were, they sounded amazing so soft and smooth. But a few days, later and my father upgraded his reciver, and picked up some Cerwin Vega AT-10's... a day or two later, he was out, so I plugged these headphones into his new reciver and was listening to stuff. Then I think he came home, so I took them off we chatted a bit and then turned the speakers on and started jamming to some tunes on the new speakers. Suddenly I hear this "crackling beat" faintly, and I look in that direction, and I see my headphones are still plugged in, I grabbed them and sure enough they were on at the same time as the speakers! (All our previous recivers when you put speakers on - the headphones shut off - but on this receiver it ran both at the same time! Which is rare/unusual most recivers no will click over a relay when you plug headphones in that automatically shut speakers off) either way, my headphones were blown, and I had just bought them (was $200 or $300). So my dad took them back to the dealer to claim warrenty "they are defective"... the store owner smelt "BS" I think, but my dad had purchased a lot of gear from him previously. So he took them and said ok I'll claim the warrenty. Some time passed, and he never called us back about claiming the warrenty.. so we called he gave us a story "yeah soon". Then afew weeks later we called back yet another story... my dad got ticked off and we went down there in person. The headphones were still sitting on the owners desk where he had left them previously... so seeing us he got up and said "I tell you what here's a pair of Nikko headphones to try, if you like them you can take them as an exhange" he put me on some reciver with the FM radio on to test them. I stood there and immediatly I could tell these were faulty headphones, one side was 2x louder than the other side. It suddenly dawned on me "There were not in a box, he took them out of his office where mine were.... I think these are another pair of returned headphones! And he's also not honored or called in the warrenty on these from another customer & now trying to pawn them off on me". As I stood there listening I was feeling like "no I don't want these they are faulty" but I looked up and my dad finally seeing "justice" was encouraging me, even egging me on to "well take them, at least it's something back" he just had that look .... "WELL??? Like come on, take them! Let's go (like we won)". I wanted to say "but they are faulty too..." however I was scared (I was a young teen) and both these adult men were hovering above me pressuring me to take them. I contemplated speaking the truth about these headphones and saying these are faulty too... but I pictured that is going to cause the store owner to say "are you accusing me of trying to scam you!" and this would start some huge argument in the store (over me) with my dad yelling at the store owner, and us getting kicked out and me getting nothing, so I just shut up and took them. (I wanted to wait for the owner to just send them in under warrenty when he got around to it) but my dad was impatient. And so they were OK if I listened at home on my receiver because I could adjust the balance to make them sound "equal". However... when I was at home I listened to music on speakers and thus the main thing I wanted these headphones for was to use these for walking to school and back or going for bike rides to the park on my portable CD Player. And of course the Left side was much quieter than the right... and there was no balance to adjust, so to hear the left side I had to turn it up more than usual and this made the right side overly loud vs the left and the left sounded "normal". Sadly it was the only pair I had, and I used them often... years later I noticed that all sounds (like answering the phone) was quieter in my right ear now vs the left (since that right earphone was so much louder than the left). I swear to this day that my dad pressuing the store owner coupled with the guy "pushing his scam deal on me" to get rid of a nuisance customer, caused me hearing damage.
That is the only thing I've ever noticed about my hearing that is "off" but as time has gone on I think my brain (being malleable) it has wired it up so that to compensate for this, my right ear is just more "sensitive or more aware" light hightened awareness. Because now it sounds more "balanced" even tho I can tell if I balance headphones "prefect" then reverse them one side is louder than the other. And that is because my level of audible sound is less in one ear than the other.... you know that ear can still hear the same tones that my left ear can (it's just quieter).

Also please note, I grew up with a 60's hippie dad, whom was a music junkie, he had these massive 12inch woofer speakers hung from the ceiling, where he would blast the radio, or play LP's... (you know typical classic rock, The Doors, Alan Parsons, Jefferson Airplane, Iron Butterfly, Pink Floyd into all the great 80's tunes "every body wants to rule the world" and harder rock too like Van Halen, AC/DC ... to softer things like Genesis and Yes, well just about everything he played). And so I was constantly listening to music for hours per day, in fact from the moment I was born and brought home... I would constantly sleep by the speakers or ask to wear those massive black and white over ear headphones with the volume knob on them then fall asleep listening to music. I mean I was just a child but you could tell I loved music and felt so much comfort in it. You'd think I'd have some sort of hearing loss after decades of music pounding in my home....
Yet to this day, I'm the only one who's always notices faint sounds or errors in recordings... or if someone's mic is clipping ever so slightly on a live stream I will point it out. And everyone else will be like "I don't hear anything" and as it keeps happening I keep pointing it out and I often get people arguing with me "the sound is fine for me, maybe it's your gear!" etc and I keep pointing it out until someone who was disagreeing with me suddenly says "ooooh wait I heard it that time I get what he's complaining about, but come on man it's so slight it's not worth mentioning). But hey I am a perfectionist in many respects, and among them, I do audio editing, and remastering of older recordings... I've even sat down and by ear removed all the pops n clicks from a LP recording.

I also have trouble sleeping because I get woken up by the slightest sounds. For example someone in the kitchen crinkling a chip bag or running the water... or a car passing outside on the street, it seems I'm very senstive to sound. And if an ambulance goes down the same street I am on whaling it's siren I have to cover my ears as it's a "peircing noise" that distorts in my ear and hurts my ears, while others look at me like I am insane for covering my ears. But it's like I can "feel it hurting" as if my body "tells me" hey this is "bad levels/tones". I get the same pain when I go to a rock concert... it's just too shrill and hurts my hears so much, that I have to put ear plugs in.
So I think with decades of sound being all around me I have just very sentive and aware of the slightest detail in audio and I can pick up the slightest begining of distortion when playing back music loud I hit that "oh there it is the beat is breaking up turn it down" and my body "tells" me when something is damaging my ears and when it's not. I'm just that senstive.

.... and as if all that wasn't long enough.... but let's also add how not only you but others have made fun of my crying to music, but I guess you'll never understand the way music touches my soul, to me it's like the single most important thing in the entire Universe. It seems to regenerate my soul, which in turn regenerates my body... music is more important to me than anything else. Sometimes music touches me so epicly that I will pour and I mean pour tears of sheer joy all down my face onto my shirt soaking it. It's like pure "ecstasy" "bliss" "euphoria" "my heaven"... I've been forced to go without music for years until recently... and I noticed a lot of changes in my body and health... lacking passion and motivation and meaning and purpose and drive. I once had a "sort of g/f" who would come over and specifically ask me to play some music because she wanted to sit and watch me get all filled up with emotions and cry tears of joy. She had never seen anyone do that... and you know my mom says she gets "rushes" from music which I do as well.
 
Sad because I spent 5 years taking electronics classes... and I still can't grasp the "concept" because it's never applied to "cause & effect".....they assume all you need to do is memorize the math and you'll know it (conceptually)." You were either asleep or did not attend lectures or practical or both. You wasted 5 years of your life, I am sorry.
 
There must be a forum somewhere on the internet for your particular craving. You will not find this here I am afraid. everyone here is probably already or striving to audiophile nirvana. You on the other hand are not. Try bridging two of the largest Crown amps you can find (as many pairs as you can afford) and then set up a public address speaker system with as many horn drivers as you can afford. Turn all the gain settings fully clockwise, sit back and blow your mind.

BTW I am so surprised that JMFahey afforded you the time and effort he put into your request. In my opinion you are not worthy of it.
 
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I am wondering what school you went too for 5 years to learn the little you know about electronics?
If you read a proper book on audio power amp design such as Bob Cordell’s book, it will teach you what you need to know and answer your questions. All for ~$100, probably a lot less than what you paid for your so called education in electronics.
I graduated from a three year electronics course at Centennial College way back in 1980, it did not teach me much about audio power amplifier design.
 
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stv

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Joined 2005
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You could try to connect the two 4 Ohm speakers in series each and attach them to the amp. By doing so you would be able to use the full power provided by the amp without tge current mimiter engaging and without danger of overheating/damaging the output devices.
However if the speakers in series are not identical there will be some sound colorations due to differing impedance changes.

Edit:
The problem with adjusting the current limiter is, you will reach and exceed the output devices' and the power supply's current capabilities.
That can damage the amp but also, you don't get the rated power, but less.
 
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