Anyhoo, screw the idjits keep posting here. I enjoy reading about your projects. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
joetama
5,000+ posts
The British Ear
The Pro-PA and Home-Audio world is messed up my friend. There are only a few companies or people out there anymore willing to try new things because most guys that are in that are about as smart as a bag or rocks. All I have to say is thank god for people like John Meyer, John Bowers, D. B. Keele, G. A. Briggs, Bob Heil, and many others. With out people like these guys we would still be listening to crank phonograph players. What drives audio revolutions is to imagine a way to make something sound better, have more functions, be more reliable, and so on. The big 2 in Pro-PA (Electro-Voice and JBL) are now just followers to other companies (Meyer Sound, Martin Audio, Adamson, Nexo, VDOS) who use engineering and logic to make a better product.
Another great thing about audio is there is never a right or wrong answer to most things, it is the ultimate to each his own type situation. People need to understand they DO NOT know everything about audio. Because when someone thinks they know everything they can not learn anymore. People need to be more open to new ideas, topics, or whatever else.
My point being even if you know a lot you have to respect other people that know a lot and be willing to teach the people who don’t. For example, I personally wouldn’t go with quite as big of a system as thylantyr in my house. HOWEVER, I respect him because he is experimenting and trying new things. I bet his system sounds pretty danm good because he has a lot of good ideas. So, keep at it man just don’t go def lol.
Another great thing about audio is there is never a right or wrong answer to most things, it is the ultimate to each his own type situation. People need to understand they DO NOT know everything about audio. Because when someone thinks they know everything they can not learn anymore. People need to be more open to new ideas, topics, or whatever else.
My point being even if you know a lot you have to respect other people that know a lot and be willing to teach the people who don’t. For example, I personally wouldn’t go with quite as big of a system as thylantyr in my house. HOWEVER, I respect him because he is experimenting and trying new things. I bet his system sounds pretty danm good because he has a lot of good ideas. So, keep at it man just don’t go def lol.
- Thread Starter
- #18
Want to laugh out loud ? One guy said....
"How the hell can you still hear?
And btw- I wouldnt call your thing a "line array." More of a column speaker with a shit ton of cheapie drivers in them. And, if you're not pushing the tweeters hard, why not just run amp stereo?
I dont know about some people..."
Evan
Harford Sound
http://www.harfordsound.com
/////
I went to that website and found this;
http://home.comcast.net/~riotweb/harfordsound/about.htm
Harford Sound was formed back in 1999 by lead engineer Evan Kirkendall. He set out with one goal in mind: To provide great quality live sound at a great low price. Harford Sound is dedicated to bring you the highest quality live sound possible. We have a lot of experience working with other bands in the local music scene. You can't go wrong with Harford Sound- send an email for a quote today!
////
Evan posted that comment, a lead engineer that doesn't know what a line array is..... //content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif//content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif :laugh: //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif :laugh: //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif
BTW, read this if interested about arrays.
http://www.audiodiycentral.com/resource/pdf/nflawp.pdf
BTW, that forum svcks anyways, I rarely go there, they want you to enter you real name to post...
Tom Araya --> singer for Slayer //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
- Thread Starter
- #19
On the other hand, on CAF home audio, a small place in cyber hidden from
the masses, I spend my time there posting weird stuff and many times mocking
product for fun. A few chime in on the punishment.. Then you get the people
who counter and don't understand the clowing... Some of the clowning is
for fun, some is for punishment, mix the two and we have funishment.
There is alot of funnay in that forum, but it only goes back a few pages of
history unless you search archives.
Usually, I'm anti-mod because it's retarded because the claims made.
The claims people make are invalid, just personal opinion without scientific test. ie,
I upgraded my CD player components with more expensive capacitors
and the sound was amazing. I say 'prove it with ABX testing'...
When I do a mod, in this case, I'm not making power boost claims like
someone else would do. I'm not saying the SQ is better either. I'm saying
I'm boosting rail capacitance to have more stored energy //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif Perhaps improve
ripple and stabilize the rail voltage better under heavy load.
D@mn it don't give me more chit to read. It's just gonna make me want to build something else //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
- Thread Starter
- #21
Lucky me, based on experience, I decided to torture the PLX amp on the test bench to get a baseline of what it can and can't do. It would be dumb to
just blindly do a mod, then bench test it without previous data to compare with right?
So.. the drama unfolds... read how the PLX went up in smoke here {before mod}.
http://www.caraudioforum.com/vbb3/showthread.php?t=235998
This is a good lesson for modders. If I were to mod the amp and then run it
through the torture test, it would have blown up and it would have me
scratching my head -> Did the mod do this? WTF ?
Now I have an idea on what the amp can't do well -> continuous sine wave
testing w/abnormal load, but this is no surprise as pro amps aren't really rated to do this, look at
the chassis they are in, it's small. These amps are more for music not playing
test tones and taking torture. There are exceptions to the rule, if you want to
buy a 4RU proamp beast that weights 150 pounds like a Crest 10001.. /LOL
The plan is to repair the amp {parts on order}, redo the test with a normal
load, not abnormal, and see if the amp is happy and take some readings.
Then, make a prototype cap bank that just sits on the test bench and taps
into the rails via wire taps.
Another test/measurement I want to do... I snagged two 30,000uF caps
[200V] to do another experiment on the input power supply {the amp has two
supplies} to make it 'stiffer' {car audio term}... I want to compare voltage sag
with and without the extra input caps. These caps are big, 3" x 9" so they won't
fit inside the amp but I can get some data from it.
I guess I'm just curious on how the switcher behaves under different conditions.
SMPS vs. Conventional Power Supply
SMPS = switch mode power supply aka high frequency switching power suppy, found in
alot of electronics today. Small transformer, high power because the transformer is being
turned on/off much faster than household 60hz AC {switchers for audio can be 50khz - 300khz},
but 100khz plus or minus is more common.
So which design is better? Car audio needs SMPS because the battery is 12v. The SMPS has to support
high current draw, hence you see many parallel transistors driving the transformer. The transformer is
small compared to a traditional 60hz transformer in a conventional power supply.
SMPS has more parts and the transistors are prone to failure if you exceed it's design, in this case
the PLX amp using only two transistors to switch the coil and it went -- kaboom -- during torture.
Conventional supply -> big azz transformer, lots of power supply capacitors, and a few diodes.
Anyone can make this in a garage blind folded, it's that easy. SMPS is not easy to DIY, there is more
science involved to get it right.
A conventional supply is so simply and dumb, fat and heavy that it's really like a tank.. You can abuse
the hell out of these with no issue other than the transformer getting hot, but it takes a long time
to smoke a transformer. If the diodes you uses are beefy, they can take alot of punishment.
Caps really don't go bad if you load down the power supply hard.
SMPS is more sensitive because anything can cause the transistors that switch the transformer
to smoke. Usually one does the 'push', one does the 'pull', but they alternate .. if both are turned on
for whatever reason, smoke.
Even though we like smaller product, lighter weight, sometimes the good old concentional power supply
is just too good to ignore if you design a product to be abused.
just blindly do a mod, then bench test it without previous data to compare with right?
So.. the drama unfolds... read how the PLX went up in smoke here {before mod}.
http://www.caraudioforum.com/vbb3/showthread.php?t=235998
This is a good lesson for modders. If I were to mod the amp and then run it
through the torture test, it would have blown up and it would have me
scratching my head -> Did the mod do this? WTF ?
Now I have an idea on what the amp can't do well -> continuous sine wave
testing w/abnormal load, but this is no surprise as pro amps aren't really rated to do this, look at
the chassis they are in, it's small. These amps are more for music not playing
test tones and taking torture. There are exceptions to the rule, if you want to
buy a 4RU proamp beast that weights 150 pounds like a Crest 10001.. /LOL
The plan is to repair the amp {parts on order}, redo the test with a normal
load, not abnormal, and see if the amp is happy and take some readings.
Then, make a prototype cap bank that just sits on the test bench and taps
into the rails via wire taps.
Another test/measurement I want to do... I snagged two 30,000uF caps
[200V] to do another experiment on the input power supply {the amp has two
supplies} to make it 'stiffer' {car audio term}... I want to compare voltage sag
with and without the extra input caps. These caps are big, 3" x 9" so they won't
fit inside the amp but I can get some data from it.
I guess I'm just curious on how the switcher behaves under different conditions.
SMPS vs. Conventional Power Supply
SMPS = switch mode power supply aka high frequency switching power suppy, found in
alot of electronics today. Small transformer, high power because the transformer is being
turned on/off much faster than household 60hz AC {switchers for audio can be 50khz - 300khz},
but 100khz plus or minus is more common.
So which design is better? Car audio needs SMPS because the battery is 12v. The SMPS has to support
high current draw, hence you see many parallel transistors driving the transformer. The transformer is
small compared to a traditional 60hz transformer in a conventional power supply.
SMPS has more parts and the transistors are prone to failure if you exceed it's design, in this case
the PLX amp using only two transistors to switch the coil and it went -- kaboom -- during torture.
Conventional supply -> big azz transformer, lots of power supply capacitors, and a few diodes.
Anyone can make this in a garage blind folded, it's that easy. SMPS is not easy to DIY, there is more
science involved to get it right.
A conventional supply is so simply and dumb, fat and heavy that it's really like a tank.. You can abuse
the hell out of these with no issue other than the transformer getting hot, but it takes a long time
to smoke a transformer. If the diodes you uses are beefy, they can take alot of punishment.
Caps really don't go bad if you load down the power supply hard.
SMPS is more sensitive because anything can cause the transistors that switch the transformer
to smoke. Usually one does the 'push', one does the 'pull', but they alternate .. if both are turned on
for whatever reason, smoke.
Even though we like smaller product, lighter weight, sometimes the good old concentional power supply
is just too good to ignore if you design a product to be abused.
joetama
5,000+ posts
The British Ear
Finally got back to the posts and I have one question, did you look at his pictures???? How do we say "amateur" hour? The company I work for got out of the sound reinforcement business because of yahoo's like this one who think they can do a better job with shitty equipment and less knowledge than my right nut, oh and wait charge 1/3 of what the job is worth. I have used better equipment on 70V/140V line dime store paging systems for Sporting and Motor sport events. Too many "amateurs" confuse Curvilinear Line Arrays with the theoretical sense of a Line Array, INFACT a column speaker technically under the strictest of principles is a Line Array (but backwards with a few different parts and terms). In the worlds of Jack Nicholson "Why can't we all just get along?"
BTW--- Look close in the Pics at his EQ, do you think they are hooked up or just there to look pretty??
joetama
5,000+ posts
The British Ear
From reading that sounds like you entered the wonderful work of DC to the output.... Or more commonly know as the magic thing that lets the smoke out of the chips....
ngsm13
5,000+ posts
BSEE
LOL @ that evan kid.
NG
NG
- Thread Starter
- #25
PLX3402 repair & mod
New thread;
http://www.caraudioforum.com/vbb3/showthread.php?p=1841744#post1841744
New thread;
http://www.caraudioforum.com/vbb3/showthread.php?p=1841744#post1841744
wow ok, i have a broke pioneer gm-5100t, if i send it to u can u mod it fix it do whatever u want?? i just want to see what u can do to it
Zach
Zach
- Thread Starter
- #27
I'm already booked with tons of projects ... electronics, audio, homestead, job,
woodworking, //content.invisioncic.com/y282845/emoticons/smokin.gif.f1dc8d2acb1809e863ebd6a47eaa0d45.gif , etc.
ahh ok thanks man, well id love to know how to fix my amp if u ever have time to explain and dont mind ... i have put in quite a few gate operators, so i am new to amps, but not circuit boards
Zach
- Thread Starter
- #29
Car amplifier have power transistor as the main failure mode.
Output stage - could be bipolar or mosfet transistors, the big ones attached to
the heatsink. They usually short out when blown, sometimes they look charred.
Power supply - 99.9% chance it's mosfet, the big ones attached to the heatsink.
99% chance that if the power supply blows, the whole bank of transistors
are blown as they are in parallel. All it takes is one to fail and that one takes
down the others, people in a boat analogy. One guy cuts a hole in the boat,
everyone sinks. /hehe
If the output stage has a bad transistor, check the small signal 'predriver' transistor
to make sure it's ok. Oddly enough, I never found one to be bad when I did
amp repair and the odds of them going bad too is pretty good.
It's rare to find a 'signal processing' problem.
So.. you need to look up NPN and PNP transistors and how to measure
them with a DMM using the diode check.
Mosfets you can use the Ohms settings.
Also, when measuring transistors in a circuit, the readings can be skewed, ie
hypothetical -> you have four output stage transistors in parallel and you
measure a short. Are they all bad? You don't know because they are in parallel.
Basically, if you find a short, you have to remove all the transistors and measure
them seperately to really know if they are toast.
Transistors can 'open circuit' also which means they are bad but you don't
measure a short. Usually they are shorted.
Another tip. Suppose your power supply is toast, it has 10 transistors. You
are not sure if all transistors are toast, but you find out each transistor cost
only a buck. Well then, buy 10 or more and replace the whole bank, it's
only $10. That eliminates all the doubt.
Then, you have to re-install the transistors back making sure the case doesn't
short to the heatsink as most amplifiers {few exceptions} have electrical
isolated transistors from the heatsinks via mica insulator, but also they have
the white heatsink compound for good thermal transfer.
Never test your amp with transistors NOT mounted to heatsinks. A transistor
case not attached can only dissipate maybe 2 watts. With heatsink, it dissipates
alot more heat. So.. a person doing a repair but didn't attach the transistor
to the heatsink can blow up the amp again.
After you install new transistors, use the DMM to make sure the case is
not shorted to the heatsink.
There are some amps that do have the transistors mounted to the metal
without insulation, you have to look at the mechanical design when you remove
the transistor. Does it have a mica insulator? if not, maybe it's one of those
amps OR .. maybe someone who tried to repair the amp screwed up and forgot
it, hence it ain't working and is toast.
After the repair is done, most people will tell you to use a current limiting power supply
but most people don't have one, instead just install a very low amperage fuse, maybe a
few amps or so to see if the amp turns on without blowing the fuse. If the fuse blows,
maybe the repair is not good yet. If the fuse hasn't blown, perhaps a good sign. Trying
playing tunes with a small speaker at very low volume.
Output stage - could be bipolar or mosfet transistors, the big ones attached to
the heatsink. They usually short out when blown, sometimes they look charred.
Power supply - 99.9% chance it's mosfet, the big ones attached to the heatsink.
99% chance that if the power supply blows, the whole bank of transistors
are blown as they are in parallel. All it takes is one to fail and that one takes
down the others, people in a boat analogy. One guy cuts a hole in the boat,
everyone sinks. /hehe
If the output stage has a bad transistor, check the small signal 'predriver' transistor
to make sure it's ok. Oddly enough, I never found one to be bad when I did
amp repair and the odds of them going bad too is pretty good.
It's rare to find a 'signal processing' problem.
So.. you need to look up NPN and PNP transistors and how to measure
them with a DMM using the diode check.
Mosfets you can use the Ohms settings.
Also, when measuring transistors in a circuit, the readings can be skewed, ie
hypothetical -> you have four output stage transistors in parallel and you
measure a short. Are they all bad? You don't know because they are in parallel.
Basically, if you find a short, you have to remove all the transistors and measure
them seperately to really know if they are toast.
Transistors can 'open circuit' also which means they are bad but you don't
measure a short. Usually they are shorted.
Another tip. Suppose your power supply is toast, it has 10 transistors. You
are not sure if all transistors are toast, but you find out each transistor cost
only a buck. Well then, buy 10 or more and replace the whole bank, it's
only $10. That eliminates all the doubt.
Then, you have to re-install the transistors back making sure the case doesn't
short to the heatsink as most amplifiers {few exceptions} have electrical
isolated transistors from the heatsinks via mica insulator, but also they have
the white heatsink compound for good thermal transfer.
Never test your amp with transistors NOT mounted to heatsinks. A transistor
case not attached can only dissipate maybe 2 watts. With heatsink, it dissipates
alot more heat. So.. a person doing a repair but didn't attach the transistor
to the heatsink can blow up the amp again.
After you install new transistors, use the DMM to make sure the case is
not shorted to the heatsink.
There are some amps that do have the transistors mounted to the metal
without insulation, you have to look at the mechanical design when you remove
the transistor. Does it have a mica insulator? if not, maybe it's one of those
amps OR .. maybe someone who tried to repair the amp screwed up and forgot
it, hence it ain't working and is toast.
After the repair is done, most people will tell you to use a current limiting power supply
but most people don't have one, instead just install a very low amperage fuse, maybe a
few amps or so to see if the amp turns on without blowing the fuse. If the fuse blows,
maybe the repair is not good yet. If the fuse hasn't blown, perhaps a good sign. Trying
playing tunes with a small speaker at very low volume.
- Thread Starter
- #30
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