cheep koreans amps no good -FI

[Lbox88]

Fi haven't showed proof of the amps causing it.... i seen a few post of people saying they can see it on the scope.

not bashing Fi though. they build beast subs and this wont stop me from buying more.

Fi Car Audio Far from the only speakers that burn up.

Where does the noise that the output mosfets are working at go if it is not filtered out? Why do the amplifiers that cost more money in the parts and time to make sure the noise is not there if it isn't an issue? Why is the "sine" wave of these amplifiers have a notch wave form in the top 30% of the wave precisely where it burns the coil in the gap and the lead?

looks to me like distortion at the upper 30% of the sine wave. could be wrong

See how the text looks normal here? You can use the little pink/white eraser thing in the top left corner of the topic reply box to remove text font/color when pulling from other sites.

I would like to know brands also, my DC's are on their 3rd year of running, I'm the 3rd owner, they've been on a korean 5k, 3k, 2k, and 3.5k and still kicking strong with original soft parts.

[Nick580]

I bet FI uses this concern to promote their new line of amps. Jk, Id be down for some AA/ FI power though

[Lbox88]

At this point I think if they ever came out with an amp line they would forever be scrutinized by that facebook post lol.

[Krakin]

I can't understand why everyone is upset, no body has brought up anything to dispute the claims made by Fi.

I am also not saying these claims are true either, but at least they are trying to make their product better to protect more against the alleged high frequency filter problems.

I however can't comprehend how anyone can be upset by the progression of technology, and if this helps lead to a higher quality production of amplifiers then what is the issue?

This is not going to change my opinion of a company that as long as I have can remember has made high quality products.

[Colin - STAPUFT]

Ok... here comes my long late night rant- read it or not, IDC.

I would still like to see more data behind these claims as well. But- I don't think Fi would make a claim like this without good reason- I would just like to see a good write up with some screen shots of this distortion- shown through an O-Scope or some graphic means.

And IF what Fi are saying is true- is anyone surprised that most if not ALL of these Korean build house amps would have the same "problem"? Let me preface this by saying I know diddle about the specific inner workings of an amplifier. I know not all parts are created equal, BUT knowing that all of these companies that use Korean build houses are constantly pushing for a better but somehow less expensive product to compete with everyone else.... that uses possibly the Same Build Houses. I mean honestly- how long did we think this cheap wattage for "only" thi$ much money could go on? Is anyone surprised that when the envelope gets pushed and things begin to break that new limits of technology would be found? 10,000 solid watts for only $2k?? Seriously? And don't misunderstand me- there are differing levels of goodness and badness (says the man who Proudly uses 4 Hifonics Brutus amps).

What I am really interested to see is if this is True -and IF this is a HUGE punch in the face to the way 90% of all class D amplifiers work. Will this send the Class D amplifier industry into a spiraling collapse??? Nah. Not at all.

I know it is cliche- but the difference between good and great is just that little bit. Just that little bit often costs 2-5x as much. You may never ever need the difference between good and great- but if what they claim is true- when you do need that difference and you put it to the test... great works and good goes out for a bonfire. I don't need that difference. This is a hobby. I don't get paid for this mess. lol

/rant.

[gibsonm21]

In regards to what amps were involved, 4 of the cases from the SP4 on fire thread on SSA involved 2 Sundown 3ks, 1 AB amp, and a Kicker.

[iwannabeloud]

From Nick in 2011

I was asked to come here and clear up mis-information..so i'll post. There is nothing wrong with doing the leads like this and it only has issues and develops problems in the following situations.

There are also youtube videos of people driving cars into walls which is clearly the car's fault right? Not the operator?



Cars committing suicide seen here..which is clearly their fault.

http://www.youtube.com/watch?v=W6aCfdxpBdA


There are 3 things that come into play.

1) Those coils that are ".5ohm" are not ".5ohm" in parallel, they are .35ohm dcr. The power supply cannot supply enough current on the rails to the output side stage of the amplifier so it starves itself into trying to make power that it simply cannot make. Kicks out DC voltage and things get very nasty very quickly...which continue to read and I'll explain more.

2) Poorly designed Korean/Chinese amps. For those who do not know the bigger the amplifiers get the more issues you are going to run into. These things are designed and built on a power supply that has a bank that is plugged into a wall on a resistor that is always constant, not a sub-woofer. In order to get efficiency up so you can get more power out of the amp and put in less and less to get efficiency up above 85% or so they ramp up the switching frequency on the power supply of the amplifier itself. This ranges from board to manufacturer..but all of the bigger amps all have the same exact issue. What happens at these frequencies is you are reaching the range of "Microwaves". The amplifier does not filter this stuff out...and you cannot hear it as it is much higher then the frequency range that human ear can detect. Signal goes from the amplifier to the terminal block...the frequency range is outside of what the terminal block is so it continues to the tinsel leads. The tinsel leads have the current and voltage going through them in the first place which already makes heat present and why the spiders are treated with flame retardant coating to prevent it from catching on fire. What happens is the amplifier's switching power supply actually 'Microwaves' the tinsel leads at the frequency in which it is switching at which happens to be very close to the resonant frequency of the size of wire and material of the tinsel leads themselves.

When you throw a piece of aluminum foil in a microwave in your house...or a CD..what happens? There is a HUGE generation of heat because on a molecular level the material itself is vibrating back and forth at that given set of frequencies...which is how a microwave warms your TV dinner up.

3) When you start to drop an amp below 1ohm more heat is being built up because the power supply side of things of the amplifier simply cannot handle the demand that the output stage is wanting to get. When you do not have a subsonic filter...or one that is set improperly...you then start to make this thing that you've just microwaved move...

Take a can of coke, pop it open and bend it back and forth a few millimeters...within it's mechanical limitations that tab will never break. Now if you start to bend it past its mechanical limitations is when you start to get into trouble. This is where the subsonic filter comes in and making sure that you are not playing full power below port tuning frequency of a sub. If you already have something that's hot from running it hard on one of the Korean amps and you start yanking the soft parts past their mechanical limitations more and more heat builds up. This is like driving a car with no brake pads in the calipers. Sure..you got a brake pedal in the car, it does not mean that it's going to do anything to stop you though if the brake pads are not there.

You get to the point where so much heat builds up that the spiders start smoldering...they won't catch on fire until you've clipped the signal to death, vaporized all of the flame retardant spray that the spiders are soaked in and then it smokes. (square wave form, dc voltage out of the amp because the power supply cannot handle what you are doing to it)

It's not the sub, there is absolutely nothing wrong with running those leads like they are. What's going on is an issue of the big cheap Korean amplifiers in and of themselves...and total ill-regard to what a microwave and conductive material does.

Hope this helps you understand...if you run a Crown A6000Gti you'll never have a problem...because it's an A/B amp....the other stuff that is cheap...don't run it below 1ohm or you are going to have nothing but problems because in order to get that big power cheaply and cut out on the parts that are going into the amplifier the switching frequency of the power supply must be ramped way up...in turn microwaving woofer parts.

I won't be returning here, I was asked to post...this is what's happening. There will be no finger pointing as I've already tested all of this stuff and know exactly what is going on. Don't buy an amp that does not have an adjustable subsonic filter unless you have means of adjusting it another way. Don't use bass boost, and finally Don't design an amp on a resistor...and don't wire an amp below 1ohm and you'll never have a problem.

A speaker does what you tell it to do in the environment that you place it in. It is stupid, if you tell it to go wide open..it knows no better.

Regards.

[Smoove]

I dont care what the drama is. I'm keeping my SP4's and not reconing to the new style and they will be fed by RF-BD power so all is good.

If Nick made a post about garbage amps in 2011, then people should have listened. Yes, it's that simple.

[Jessica]

Ok, if it is a power supply switching speed issue, does this effect the PBR line from fosgate. Maybe i don't understand that tech. But i think it uses really high voltage switching really fast right?

Maybe they have the filters to remove the noise, i don't know. Just a question.

[WastedTalent]

so any way to know whats a cheap korean amp and whats not

Do the research and find quality. I could be COMPLETELY wrong here but way I see it? Look at amp costs. RF is pretty high right? I mean can count tons of amps that cost less that either do same power or more. But according to FI, RF are clean.

I also would like some results, some proof, some something. Big accusations of "Our shit has been blowing cause of cheap ass amps". Not saying it's not true as how many people go buy big powerful subs and then run out of money, can't afford good quality amps and go buy the pos amps? And since they're rated at/near the good amps, but we know they don't do rated, at least cleanly, might cause the sub to go poof.