I have a PHD2 I bought new from a guy around a year ago. It was great and had way more power than I needed. One day at work the guys and I were bored and we wanted to smoke a speaker for fun. (yeah, I know STUPID ME) Anyways, we screwed this 6" woofer to my back deck, just to see how much bass it would produce before we smoked it. Well, as soon as the speaker burned, the coil must have shorted to the frame and then to ground through the back dash. The amp shut the entire car down it was drawing so much current. I had to go under the hood and disconnect its main fuse.
After sending it to Earthquake in Cali., and spending much dinero to repair it (I had attempted to repair it by replacing every power supply and output transistor with the original part numbers but it still wouldn't come on) I got it back almost two months later. They somehow kept forgetting to send it back to me. Now when I turn the volume up high enough to pound the 12" mtx 7500's it seems to automatically turn the volume down a little even though the car's voltage isn't dropping much and the subs are aok. It never did this before I fried it on the cheezy 6" woofer. The only thing I noticed different on the amp board is a diode soldered across two of the legs of the power supply pwm IC, or at least that's what it looks like. Of course the IC has the part number ground off so I couldn't change it when I attempted to repair it myself. (that was the only part they changed, besides replacing the ones I changed with the SAME part number transistors
)
-Does anyone know why they soldered that diode across the top of the pwm ic? Is it some sort of power limiter to protect the amp from me running too low of a load?
-If so, can I just remove it? I never run lower than 2 ohms nominal load, I just made the mistake of having the amp ground to the car's body ground one time. I tried getting ahold of the techs at earthquake to ask about the IC and the diode but couldn't.
-The amp never did this before they repaired it and I want it back to normal. I told them about it and they said "It tested aok and made full power" I was like, yeah, whatever. Thanks
After sending it to Earthquake in Cali., and spending much dinero to repair it (I had attempted to repair it by replacing every power supply and output transistor with the original part numbers but it still wouldn't come on) I got it back almost two months later. They somehow kept forgetting to send it back to me. Now when I turn the volume up high enough to pound the 12" mtx 7500's it seems to automatically turn the volume down a little even though the car's voltage isn't dropping much and the subs are aok. It never did this before I fried it on the cheezy 6" woofer. The only thing I noticed different on the amp board is a diode soldered across two of the legs of the power supply pwm IC, or at least that's what it looks like. Of course the IC has the part number ground off so I couldn't change it when I attempted to repair it myself. (that was the only part they changed, besides replacing the ones I changed with the SAME part number transistors
) -Does anyone know why they soldered that diode across the top of the pwm ic? Is it some sort of power limiter to protect the amp from me running too low of a load?
-If so, can I just remove it? I never run lower than 2 ohms nominal load, I just made the mistake of having the amp ground to the car's body ground one time. I tried getting ahold of the techs at earthquake to ask about the IC and the diode but couldn't.
-The amp never did this before they repaired it and I want it back to normal. I told them about it and they said "It tested aok and made full power" I was like, yeah, whatever. Thanks
I'll have to remove the amp from under my seat tomorrow at work.
I'll get a picture or two but I'm not sure if I can post them yet, maybe my donation helped. The IC is on a socket so it can easily be replaced. Kind of like earthquake knew it is a trouble maker part in the circuit, or maybe swappable to maket the amp 1 ohm stable?? I don't know, but I'm still kind of aggravated that they only changed that IC and removed every original matched fairchild mosfet and diode I replaced, because they "had" to. They could have just swapped the IC, I did a flawless job swapping the transistors IMO.
I'll get a picture or two but I'm not sure if I can post them yet, maybe my donation helped. The IC is on a socket so it can easily be replaced. Kind of like earthquake knew it is a trouble maker part in the circuit, or maybe swappable to maket the amp 1 ohm stable?? I don't know, but I'm still kind of aggravated that they only changed that IC and removed every original matched fairchild mosfet and diode I replaced, because they "had" to. They could have just swapped the IC, I did a flawless job swapping the transistors IMO.That's an HIP4080AIP. All manufacturers put them in sockets because they fail virtually every time the FETs fail.
They likely replaced the FETs because not all FETs are created equal. The same part number does not mean the same performance/operation. They used parts that they had confidence in.
They likely replaced the FETs because not all FETs are created equal. The same part number does not mean the same performance/operation. They used parts that they had confidence in.
Well they were all the same exact brand and part numbers verbatim. I made sure to ask that the date codes were at least matched. I think they did it for warranty purposes, but it was such a waste, if I'd known it was a 3 dollar IC I could have saved almost $200.
I just need to find out why they put the diode on there, I have a feeling that is the culprit and they may have done it to protect me from myself. I just wish I could find more information about it. This is the first place I have found anyone with good knowledge on these things. I love this place!! Thanks Perry
I just need to find out why they put the diode on there, I have a feeling that is the culprit and they may have done it to protect me from myself. I just wish I could find more information about it. This is the first place I have found anyone with good knowledge on these things. I love this place!!
Thanks PerryYou can't rely on the exact part number and manufacturer. For example, the IRF3710 that was made a few years ago isn't the same as the one made now. I worked many hours on a few amps trying to find a defective component. I finally determined that the FETs were the problem (same part number and same manufacturer). I had to use a different FET to get the amp working. In another class D amp, RFP40N10s caused the same problem.
There was a thread about this recently.
Justonemoreamp mentioned that he worked on a lot of the PHD2s (if I'm not mistaken). Maybe he can provide some information about the amp.
There was a thread about this recently.
Justonemoreamp mentioned that he worked on a lot of the PHD2s (if I'm not mistaken). Maybe he can provide some information about the amp.
/\There's the underside, the IC (ic 4) is to the upper right corner on the left side of the choke.
An externally hosted image should be here but it was not working when we last tested it.
/\Here's a closer view, it actually has two zeners, I thought there was only one.
What would the HIP4080 cross to with say an NTE part? I'm just trying to find the pinout so I can see what's up with the diodes. I should have tried to read the part numbers of the diodes but my vision sucks.
The cathodes appear to be on the BHO and AHO leads (20 and 11) and the anodes appear to be on the BHS and AHS (19 and 12).
The cathodes appear to be on the BHO and AHO leads (20 and 11) and the anodes appear to be on the BHS and AHS (19 and 12).
justonemoreamp said:I have rebuilt 5 or 6 PHD2's no biggy. Simple HIP4080AIP full bridge output, with dual power supplies. Power supply uses FET drivers IC's that are usual scratched off like the HIP4080AIP output bridge driver.
Earthquake is a local company here in the SF bay area. Some of there stuff was built in Hayward about 12 minutes drive from here.
Let me know if I can be of help, there are several others here also very adept at these amps. Plus you can look in the class D section of this forum for many others that know about these also.
Hope this helps
Well that should at least prove it is a HIP4080.
It's interesting, I know I have seen a pic of that IC with the diodes 3 or 4 years ago when I was into SPL stuff. The pic was part of someones explanation of the "mod" earthquake does to these amps. I can't remember any of what the guy said, but I know it had to do with the diodes.
If they weren't there before, I say just remove them.
http://www.intersil.com/data/fn/fn3658.pdf
The part number is important on the diode.
If you need a magnifying glass, the one in the attached photo is very good and very powerful. There will be several sellers on ebay that have them.
The part number is important on the diode.
If you need a magnifying glass, the one in the attached photo is very good and very powerful. There will be several sellers on ebay that have them.
Attachments
I emailed justonemoreamp about the diodes. I'm thinking they put them in so the amp could run loads lower than 2 ohms.. maybe thinking I was abusing the amp in some way. Little do they know if I somehow grounded the main output rail directly to the car chassis again, (NOT going to happen) those diodes aren't going to do squat. The speaker output fuse didn't even blow because it was protecting the opposite lead, haha.
Now that I think about it, the amp doesn't seem as loud either. Either its been optimized for 1ohm and I'm only running 2ohm, or maybe just my ears being worn out, haha
Now that I think about it, the amp doesn't seem as loud either. Either its been optimized for 1ohm and I'm only running 2ohm, or maybe just my ears being worn out, haha
After a bit more research, it seems that those diodes are used on other amps. They appear to be used as protection for the gates of the high-side FETs. They are likely 1N5246 zeners (16v zeners). The diodes are essentially connected between the gate and the source of the high-side FETs.
The total high-side gate drive voltage is the peak to peak voltage on the source of the high-side FET plus the Vcc/Vdd (regulated 12v) input to the 4080. This would give you a drive voltage (Vgs) of ~12v. Since these diodes are used on other amps, maybe there is some situation where the drive voltage goes too high and destroys the high-side FETs.
They can not limit power. You should not remove them.
The total high-side gate drive voltage is the peak to peak voltage on the source of the high-side FET plus the Vcc/Vdd (regulated 12v) input to the 4080. This would give you a drive voltage (Vgs) of ~12v. Since these diodes are used on other amps, maybe there is some situation where the drive voltage goes too high and destroys the high-side FETs.
They can not limit power. You should not remove them.
Hi Perry, Sorry I am late I have been backed up at the shop. Working 7 days a week now just to get caught up
Those diodes will not affect your power output. They are being used to protect the chip I believe. ALL HIP-4080 amps have them socketed, due to extremely high failure rate of the chip. MHO
I actually think they fail while being assembled and have to be replaced before the amp even leaves the line. I just rebuilt two MMATS 1400.1's and everything went well on the first one, and then on the second one I had the amp fail on first fire up because of a defective "NEW"" HIP-4080AIP chip. I see 30 to 50% bad New chips all the time.
Had to replace half the outputs and the driver chip for a second time just to get the amp repaired and tested.
As for your amp no holding sustained power, well that could be caused by many issues.
I had a client bring this exact same amp into my shop a few months back complaining that Earthquake had repaired it wrong and it was not making power. And that they had replaced a resistor across the outputs and it was robbing the amp of power.
Well it was a 5 watt sand block resistor so if it was absorbing more than 5 watts I assured him it would have burnt up long ago with the power level this amp is capable of.
Anyway long story made a little shorter I found that he had his Subsonic filter set so high that he had a 15 hertz bandwidth of bass between 45 and 60 hertz being reproduced DUH!!!!!
I see no change inside your amp that you should worry about. I live near Earthquake out here in the SF bay area. I am not that familiar with their tech setup, But I doubt that they did not test your amp before sending it back to you.
I test all my amps that I work on and I am a independent service person. I have to spend money and time doing this as its my rep on the line. And no matter how hard you try to do your best work It all must be qualified and tested before the customer gets the serviced work back into their hands. It would cost me my rep and my license and my way of making a living if I did not.
Now back to your amp. Are you measuring the voltage drop at the terminals of the amp when your "testing" your SPL output. Thats where you will see if the juice is dropping off to the amp.
And are you using a SPL meter to measure this test level ?
There are a ton of variables YOU could be inducing to cause this issue.
You can order the HIP chip from many vendors, and since its in a socket all you need do is swap it at a anti-static work station< for safe practices.
This should relieve you of your thoughts of less that professional behavior from your factory repair guys. And it cost you about 5 bucks a copy to stop this line of thinking from bothering you in your pursuit of SPL.
Another thing you can try is to find someone local to you that can test and qualify the amp on a bench. That should also prove weather the amp is capable of sustained output or not.
And I must agree with Perry about the Fet issue he raised. I find I must test all incoming devices to make sure I don't get clones and bad products sold to me. I really don't know how others do it But SoundStream and PG and even Agilent has to test all incoming parts prior to building anything nowadays.
So if you think your gonna get by without doing the same well thats a hit or miss situation my friend. And when its a miss, its a miss in your neck, and other fine parts of your anatomy.
All parts must be checked, it doubles my work load but luckily I have a personal curve tracer at my right on my bench. I can't begin to tell you how much it has saved me over the last 5 years. And yes i throw away good unused parts that fail curve tracing.
Get your amp benched locally by someone that will test before your eye's and has a pro setup to do this testing with. This will at least make sure its a amp issue.
Tech's are people, and we are all prone to make mistakes. Maybe they missed something, and maybe its your setup in your car ?????
I would have to see your amp in my hands on my bench setup to be able to resolve this issue any faster for you, as i need to make the amp fail to find this hidden issue. And yes I have a 250 amp power supply and a 2000 watt dummy load to load the amp with.
PS Earthquake has flat rates like most amp companies, How much money did they charge you for this service ?
Those diodes will not affect your power output. They are being used to protect the chip I believe. ALL HIP-4080 amps have them socketed, due to extremely high failure rate of the chip. MHO
I actually think they fail while being assembled and have to be replaced before the amp even leaves the line. I just rebuilt two MMATS 1400.1's and everything went well on the first one, and then on the second one I had the amp fail on first fire up because of a defective "NEW"" HIP-4080AIP chip. I see 30 to 50% bad New chips all the time.
Had to replace half the outputs and the driver chip for a second time just to get the amp repaired and tested.
As for your amp no holding sustained power, well that could be caused by many issues.
I had a client bring this exact same amp into my shop a few months back complaining that Earthquake had repaired it wrong and it was not making power. And that they had replaced a resistor across the outputs and it was robbing the amp of power.
Well it was a 5 watt sand block resistor so if it was absorbing more than 5 watts I assured him it would have burnt up long ago with the power level this amp is capable of.
Anyway long story made a little shorter I found that he had his Subsonic filter set so high that he had a 15 hertz bandwidth of bass between 45 and 60 hertz being reproduced DUH!!!!!
I see no change inside your amp that you should worry about. I live near Earthquake out here in the SF bay area. I am not that familiar with their tech setup, But I doubt that they did not test your amp before sending it back to you.
I test all my amps that I work on and I am a independent service person. I have to spend money and time doing this as its my rep on the line. And no matter how hard you try to do your best work It all must be qualified and tested before the customer gets the serviced work back into their hands. It would cost me my rep and my license and my way of making a living if I did not.
Now back to your amp. Are you measuring the voltage drop at the terminals of the amp when your "testing" your SPL output. Thats where you will see if the juice is dropping off to the amp.
And are you using a SPL meter to measure this test level ?
There are a ton of variables YOU could be inducing to cause this issue.
You can order the HIP chip from many vendors, and since its in a socket all you need do is swap it at a anti-static work station< for safe practices.
This should relieve you of your thoughts of less that professional behavior from your factory repair guys. And it cost you about 5 bucks a copy to stop this line of thinking from bothering you in your pursuit of SPL.
Another thing you can try is to find someone local to you that can test and qualify the amp on a bench. That should also prove weather the amp is capable of sustained output or not.
And I must agree with Perry about the Fet issue he raised. I find I must test all incoming devices to make sure I don't get clones and bad products sold to me. I really don't know how others do it But SoundStream and PG and even Agilent has to test all incoming parts prior to building anything nowadays.
So if you think your gonna get by without doing the same well thats a hit or miss situation my friend. And when its a miss, its a miss in your neck, and other fine parts of your anatomy.
All parts must be checked, it doubles my work load but luckily I have a personal curve tracer at my right on my bench. I can't begin to tell you how much it has saved me over the last 5 years. And yes i throw away good unused parts that fail curve tracing.
Get your amp benched locally by someone that will test before your eye's and has a pro setup to do this testing with. This will at least make sure its a amp issue.
Tech's are people, and we are all prone to make mistakes. Maybe they missed something, and maybe its your setup in your car ?????
I would have to see your amp in my hands on my bench setup to be able to resolve this issue any faster for you, as i need to make the amp fail to find this hidden issue. And yes I have a 250 amp power supply and a 2000 watt dummy load to load the amp with.
PS Earthquake has flat rates like most amp companies, How much money did they charge you for this service ?
I do believe it was close to $200. I looked over the board and I could only see the output and power supply transistors were replaced. And of course the IC I am speaking of. The diodes appeared to be original. No, my subsonic filter is not on, that is how I've had it since I first bought it. I was already aware of the switch as I did a little research on the amp before I bought it.
I've been experimenting and learning about car and home audio since the late 80's, and installing it professionally since the late 90's. I can easily tell the difference in wattage/power output/spl of this amp since the repair. I even tested the average ac output voltage at the speaker terminals and the ones on a friend's mtx 1000d and the earthquake exceeded the mtx by about 15 volts. This was with the same speakers and in the same car. Nothing in my car was changed from when the amp was originally installed before the damage, as I wasn't even using my subwoofers at the time and the wiring is more than adequately sized considering the amp is under the seat, only a few feet from the battery. Regardless, nothing except the amp had changed when I got it back and noticed the lower output.
It is totally obvious that the volume/output/voltage/wattage is being limited and I've let several co workers sit in and listen to what it does. Today I measured the average voltage output around 38 volts at the 2 ohm load, that seems kind of low. The protection lights do not come on or even flicker when it happens and I have a power supply connected to the car to keep the voltage stable. The power on the amp's 12 leads never drops below 13 volts. My first check was low battery voltage, but that tested fine. Second was woofer voice coil damage, they both measure fine.
I've been experimenting and learning about car and home audio since the late 80's, and installing it professionally since the late 90's. I can easily tell the difference in wattage/power output/spl of this amp since the repair. I even tested the average ac output voltage at the speaker terminals and the ones on a friend's mtx 1000d and the earthquake exceeded the mtx by about 15 volts. This was with the same speakers and in the same car. Nothing in my car was changed from when the amp was originally installed before the damage, as I wasn't even using my subwoofers at the time and the wiring is more than adequately sized considering the amp is under the seat, only a few feet from the battery. Regardless, nothing except the amp had changed when I got it back and noticed the lower output.
It is totally obvious that the volume/output/voltage/wattage is being limited and I've let several co workers sit in and listen to what it does. Today I measured the average voltage output around 38 volts at the 2 ohm load, that seems kind of low. The protection lights do not come on or even flicker when it happens and I have a power supply connected to the car to keep the voltage stable. The power on the amp's 12 leads never drops below 13 volts. My first check was low battery voltage, but that tested fine. Second was woofer voice coil damage, they both measure fine.
I wonder if your fet driver in the power supply is going south on you. You did replace the main power supply fets Correct???
If you did they usually take out the fet driver when they go south. About 2 to 3 bucks to replace. TC4424 I think is the part number but don't hold me to that as I am getting older and forgetful. I think i have a few in stock, its a Microchip part as I recollect.
Other than that I would need to bench your amp and do a power test to see whats dropping out. Your troubles are not a easy to fix as they are only represented only under load. I would be checking the fet drive signal under load with a scope, and also checking into the drive circuits with a scope to find this issue.
The parts you want to replace are cheap enough <less than20 bucks> so you can try that if you like, but the symptoms indicate a drop in either the power supply or the drive signal areas...
If you did they usually take out the fet driver when they go south. About 2 to 3 bucks to replace. TC4424 I think is the part number but don't hold me to that as I am getting older and forgetful. I think i have a few in stock, its a Microchip part as I recollect.
Other than that I would need to bench your amp and do a power test to see whats dropping out. Your troubles are not a easy to fix as they are only represented only under load. I would be checking the fet drive signal under load with a scope, and also checking into the drive circuits with a scope to find this issue.
The parts you want to replace are cheap enough <less than20 bucks> so you can try that if you like, but the symptoms indicate a drop in either the power supply or the drive signal areas...
Measuring the rail voltage at idle (no sighal), at various B+ voltages and at various power output levels may tell you if the power supply is working properly.
If they were having reliability issues, they may have lowered the rail voltage. This would allow the amp to drive lower impedance loads more reliably.The lower rail voltage would reduce the power output into lighter loads.
If they were having reliability issues, they may have lowered the rail voltage. This would allow the amp to drive lower impedance loads more reliably.The lower rail voltage would reduce the power output into lighter loads.
Is the rail voltage supposed to remain constant under all loads? I could probably easily take the seat out, unscrew the amp and take off the bottom cover and test it in the car without removing cables. I'd guess the rail voltage to be not much less than the rail capacitors maximum ratings, and the idle voltage should be the normal voltage if the possibility of sagging at hight output were the issue. Hmm, I thought "class d" amps varied the power supply voltage side too, confusing stuff to me.?? I'll use a nice constant frequency/amplitude continuous bass note and watch the voltage at various headunit volume levels. And like jusonemoreamp said, the fet driver IC would be a cheap check, hopefully it isn't too static sensitive so I can get it in safely. Well I guess I'll have to do this checking after my next day off, I have to change my strut mounts, add some lowering springs and change the front cv's Wednesday. Thanks for the help guys, I definately need it haha.
Thanks for the help guys, I definately need it haha.Most (maybe all) of the amps using the 4080 IC use regulated supplies. It should remain constant. It may fall a bit if the B+ voltage drops too far or at max power into the lowest impedance load.
The rail voltage is going to be 80v or less. The chip can't take more than that. Some manufacturers use voltage as low as ~65v with this IC.
As you draw more power from the amp (lower impedances or higher volume), the gate voltage (as read with a multimeter set to DCV) will increase as the pulse width increases. When the pulse width reaches its maximum possible duty cycle, the gate voltage will not be able to go higher. At that point, expect the rail voltage to begin dropping.
You must be very careful when probing the various points when the amp is on. One slip and you could destroy all that was previously destroyed and possibly more. I'd suggest sharpening the points on your probes. It will make them less likely to slip.
The rail voltage is going to be 80v or less. The chip can't take more than that. Some manufacturers use voltage as low as ~65v with this IC.
As you draw more power from the amp (lower impedances or higher volume), the gate voltage (as read with a multimeter set to DCV) will increase as the pulse width increases. When the pulse width reaches its maximum possible duty cycle, the gate voltage will not be able to go higher. At that point, expect the rail voltage to begin dropping.
You must be very careful when probing the various points when the amp is on. One slip and you could destroy all that was previously destroyed and possibly more. I'd suggest sharpening the points on your probes. It will make them less likely to slip.
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