So I got this amp about 4 years ago, had it pushing a boston pro 12.5 4 ohm. it took all of 3 months for my sub to totally stop working. voice coil was FRIED. so i figured I just over ran the sub. Changed it out with another 12.5 4 ohm. this one lasted about 3 weeks, I had the gains turned way low on the amp, and xo set at 85h. after it toasted the second sub I started to suspect the amp. I changed it over to full range speakers. At low volume, it sounds like the speakers are hanging up, the sound is scratchy, and muted. if I turn the volume up to a normal listening level, the sound improves greatly. with the gain set at about 1/3 getting a clean 4v signal from my line driver, I every thing sounds great. and then... the magic smoke leaves the drivers.. I opened the amp, everything looks great. no burnt traces, no signs that anything was ever over heated or abused.
anyone have an idea what might be causing this to kill speakers? For a big amp I am really pleased with its output when it works properly, and makes one hell of a sub amp. I would love to fix it as it was quite pricey in its day, and I have a matching 250 for it as well. any fosgate guys know where to start? I can pop it open for board revisions or to test whatever with my dvom. I dont have a scope.
anyone have an idea what might be causing this to kill speakers? For a big amp I am really pleased with its output when it works properly, and makes one hell of a sub amp. I would love to fix it as it was quite pricey in its day, and I have a matching 250 for it as well. any fosgate guys know where to start? I can pop it open for board revisions or to test whatever with my dvom. I dont have a scope.
Well, you got a three channel amp there meepers lol lol lol
I was sure you had a rail voltage coming out of something there just by the description of the amps SQ. That and the fried Voice coils.
Most All Rockford's fail there outputs in this exact way of passing the power rails to the speakers and producing very nice smoke rings lol lol lol
For what they charge for their amplifier products they could and should have engineered speaker protection relays inside all of there amplifier products, especially there Class D stuff Whew!!! you ain't seen nothing till one of those unload into a voice coil Who-Wee now thats some fireworks
Thank you for your very kind comments, I try to be helpful when possible. I have been doing this a very long time. There a several other people here that I am proud to post with though, as they also have a vast amount of knowledge to share also. I am just glad they let me in to hang around with them as they are some very smart folks in their own right.
Ohm out your output fets in the bad channel, They are gonners my friend, and I would replace everyone of them in that channel. You also have to worry about the driver section of SMD components in front of the bad outputs.
This is a HESHA based amplifier so you must remove the outputs from there MESHA panels. I use special tools unlike the RF techs which use a 150 watt soldering iron mounted on bench press.
I chose to use a Professional rework station, But I have less than 1% failure or my rework of these and my panels look original when I get done.
You can see by the DC readings the good channels have low DC offset on the output, The week one has 12 Milli-volts which tells me that channel has been artificially aged and the damage is displayed as DC offset over 10 milli-volts DC, Anymore and I would say it needs to be reworked also as it is headed around the bend on you already.
I was sure you had a rail voltage coming out of something there just by the description of the amps SQ. That and the fried Voice coils.
Most All Rockford's fail there outputs in this exact way of passing the power rails to the speakers and producing very nice smoke rings lol lol lol
For what they charge for their amplifier products they could and should have engineered speaker protection relays inside all of there amplifier products, especially there Class D stuff Whew!!! you ain't seen nothing till one of those unload into a voice coil Who-Wee now thats some fireworks
Thank you for your very kind comments, I try to be helpful when possible. I have been doing this a very long time. There a several other people here that I am proud to post with though, as they also have a vast amount of knowledge to share also. I am just glad they let me in to hang around with them as they are some very smart folks in their own right.
Ohm out your output fets in the bad channel, They are gonners my friend, and I would replace everyone of them in that channel. You also have to worry about the driver section of SMD components in front of the bad outputs.
This is a HESHA based amplifier so you must remove the outputs from there MESHA panels. I use special tools unlike the RF techs which use a 150 watt soldering iron mounted on bench press.
I chose to use a Professional rework station, But I have less than 1% failure or my rework of these and my panels look original when I get done.
You can see by the DC readings the good channels have low DC offset on the output, The week one has 12 Milli-volts which tells me that channel has been artificially aged and the damage is displayed as DC offset over 10 milli-volts DC, Anymore and I would say it needs to be reworked also as it is headed around the bend on you already.
yeah this forum is a great place and alot of knowledge amongst the members. and unlike most other forums I am or have been a part of, there is very little of people going at it. I still need more practice at the putting things together, but I am quite skilled at taking things apart.
I wish I would have realized there was a problem before having a $400 dollar amp kill $500 in speakers. And I REALLY wish I would have sent it in when it was under warrenty.
Once I pull the cover off, what chips should I check out? Like I said, I couldnt see anything that looked smoked when I took it apart the first time. I can post up pics once its apart as well.
I wish I would have realized there was a problem before having a $400 dollar amp kill $500 in speakers. And I REALLY wish I would have sent it in when it was under warrenty.
Once I pull the cover off, what chips should I check out? Like I said, I couldnt see anything that looked smoked when I took it apart the first time. I can post up pics once its apart as well.
oh yeah, I did not think about the smd components. grr. I am guessing since I ran the rear channel bridged that it would be a good idea to rework both rear channels and not take a chance. I just dont want to drop 200 bucks into this amp to have someone else fix it if I can do the work myself. But I know smd is not a strong suit of mine.
I will pull the case back off and start probing around and see what is gone for sure.
Thanks again for taking the time.. Its way appreciated, and I hope by learning more, I will be able to help others in the future.
I will pull the case back off and start probing around and see what is gone for sure.
Thanks again for taking the time.. Its way appreciated, and I hope by learning more, I will be able to help others in the future.
I post elsewhere also, and I am going to state part of a ongoing post I have made at length elsewhere.
4 Channels amps running bridged for bass line, IS NOT a good idea.
Why and How, I come to this conclusion:
In every 4 channel amp there is a single power supply that is big enough to run all 4 channels to full power at any given moment.
Now armed with this info, does the following make sense to you
When operating a 4 channel bridged to 2 channel it is possible to OVER drive one of your channels and pass 4 times the normal power through that single channel. And if you do pass 4 channels worth of power through that single channel, HOW long do you think it will handle that excessive power level before it goes South on you and possibly taking out your expensive speakers with that single channel being driven way past its Safe Operating Area SOA for short???
If you funnel 4 lanes of traffic down to one lane what happens if the cars don't slow down ???
I have repaired more 4 channel amps than any other type of amplifier, and when I question my clients they were all running them bridged < 25 years of answers in 25 seconds >
I would treat yourself to a new amp and let the four channel either rest or sell it broken on e-bay, Tell the truth when your selling it, but there are a lot of better ways to run a sub then with a 4 channel amp.
I hope this makes sense and helps you to make the best decision for yourself and your stereo
4 Channels amps running bridged for bass line, IS NOT a good idea.
Why and How, I come to this conclusion:
In every 4 channel amp there is a single power supply that is big enough to run all 4 channels to full power at any given moment.
Now armed with this info, does the following make sense to you
When operating a 4 channel bridged to 2 channel it is possible to OVER drive one of your channels and pass 4 times the normal power through that single channel. And if you do pass 4 channels worth of power through that single channel, HOW long do you think it will handle that excessive power level before it goes South on you and possibly taking out your expensive speakers with that single channel being driven way past its Safe Operating Area SOA for short???
If you funnel 4 lanes of traffic down to one lane what happens if the cars don't slow down ???
I have repaired more 4 channel amps than any other type of amplifier, and when I question my clients they were all running them bridged < 25 years of answers in 25 seconds >
I would treat yourself to a new amp and let the four channel either rest or sell it broken on e-bay, Tell the truth when your selling it, but there are a lot of better ways to run a sub then with a 4 channel amp.
I hope this makes sense and helps you to make the best decision for yourself and your stereo
yeah, I hear ya. I figured this was going to be a good work horse amp. I have an A404 in my car running the front stage, And I have an A300 that I need to repair for the sub. I have been running a super old school Radion 150 watt amp to my 10" in my car.
There are a hand full of fets that are getting no readings. I dont want to just run it as a 2channel amp and risk another set of speakers, I rather replace it with another art series or a PC2150 just for sub duty. After taking a look in side, the soldering required for anything but the fets *and I know its usually more then that* is way beyond what I am equipped for. and I am a bit concerned about the mesha boards as well, I would hate to break one. What do you think a competent repair shop would charge to repair? and what is the amp worth? I wish I would have kept my BD1000.
Thanks for all the input. but its sad to say, this one is beyond my skill level for solder and testing.
There are a hand full of fets that are getting no readings. I dont want to just run it as a 2channel amp and risk another set of speakers, I rather replace it with another art series or a PC2150 just for sub duty. After taking a look in side, the soldering required for anything but the fets *and I know its usually more then that* is way beyond what I am equipped for. and I am a bit concerned about the mesha boards as well, I would hate to break one. What do you think a competent repair shop would charge to repair? and what is the amp worth? I wish I would have kept my BD1000.
Thanks for all the input. but its sad to say, this one is beyond my skill level for solder and testing.
Sorry for offtopic. Cecil, I became a strong fan of PG, my M44 amp for components are hands down the best sounding amp I ever had in my life. But what is your recommendation for a sub amp from PG? It would be nice to have at least 500RMS watts at 2 ohms to replace JL 500/1. Thanks in advance!
A old school M-100 will just about cover that, but my favorite would be a 2125 for durability reasons, as it has a 50% higher scale of build inside then the M-100.
for reliability you could always use 2 M-100's but they are surfboards to install.
Most folks don't know that all of these two different series of amps were designed from the same circuit, just with different power supplies for scale factor. This is why all these older PG amps sounded alike and very good. they were the same inside just scaled differently to suit your needs.
Its the same with their other lines also. Everybody sells car amps like this. Start with a great design and just scale it to suit the customer.
Hope this helps
for reliability you could always use 2 M-100's but they are surfboards to install.
Most folks don't know that all of these two different series of amps were designed from the same circuit, just with different power supplies for scale factor. This is why all these older PG amps sounded alike and very good. they were the same inside just scaled differently to suit your needs.
Its the same with their other lines also. Everybody sells car amps like this. Start with a great design and just scale it to suit the customer.
Hope this helps
yeah I have always been a fan of PG. they had some of the sickest demo vehicles on the planet. The nice thing about it is my musical tastes have changed from back in the day. I dont need 3 12's and 1000 watts to be happy. Just nice tight bottom end with my good components in a total stealthy install. The sub is always the hardest thing to hide, and with the high power amps, they are hard to stealth install. I remember this Orion Hcca amp that I had.. it was almost 3 feet long and weighed like 80lbs. My 404 fits under the seat rather well with plenty of ventalation room, the 800a4 is a fairly large amp, especially with the side covers on.
I always loved the old school sound stream amps cuz they were so small and rocked alot of power *at 2ohms*
Pretty much my setup as of now in my xB is as follows:
stock HU with decent Line level converter fed into a PPI Par 245 eq. this goes to the EPX-223 xo, into the a404 and old school Radion 300 watt amp.
Diamond Hex 6.5 components with silk tweets *I liked my boston 6.4 pros better* memphis 10" sub in the floor flush mounted
a404 running the front stage, and the radion going to the sub. I seriously considered changing to the par 650 eq, but it was post sellout from ppi. it would have been nice to have the 2 additional inputs for Ipod and dvd or whatever. it sounds very good, the low end is great for only a single 10. I got a smoking deal on the diamonds, thats the only reason I bought them. After the 800a4 took out my Boston pro 5.5's, I got a set of 6.4 pros, but they required too much work to fit in the doors for a clean install due to depth. I have the factory rears as fill only, and the fader is set to 80% front. I have considered putting in a deq-230 to get the most out of it, but space constraints, and the the fact that its still a factory HU have kept me from doing that.
I always loved the old school sound stream amps cuz they were so small and rocked alot of power *at 2ohms*
Pretty much my setup as of now in my xB is as follows:
stock HU with decent Line level converter fed into a PPI Par 245 eq. this goes to the EPX-223 xo, into the a404 and old school Radion 300 watt amp.
Diamond Hex 6.5 components with silk tweets *I liked my boston 6.4 pros better* memphis 10" sub in the floor flush mounted
a404 running the front stage, and the radion going to the sub. I seriously considered changing to the par 650 eq, but it was post sellout from ppi. it would have been nice to have the 2 additional inputs for Ipod and dvd or whatever. it sounds very good, the low end is great for only a single 10. I got a smoking deal on the diamonds, thats the only reason I bought them. After the 800a4 took out my Boston pro 5.5's, I got a set of 6.4 pros, but they required too much work to fit in the doors for a clean install due to depth. I have the factory rears as fill only, and the fader is set to 80% front. I have considered putting in a deq-230 to get the most out of it, but space constraints, and the the fact that its still a factory HU have kept me from doing that.
valterdaw said:
try to stay at 4 ohms mono and 2 ohms stereo, The amp really does not perform any better at that load level by design. Try to find a MPS2500 for that sort of loading it likes 1 ohm loads, and was built for it. < costs about the same also>
Or better yet do as I do, I have two 12's with and two MS-275 bridged into each one separately. Works great and has been online for 5 years now, and it has a tad over 500 watts RMS, just not as efficient as the JL class D amp , so be prepared to beef the charging system to drive it, as it will be pulling some amps off your system.
The M series were built for the non competing customers that PG wanted to be able to sell to way back when. Remember their first amps were all battleships in battleship grey no less. the M's were for a more civilized audio purest.
Basically same amp, just different power supply, and not intended for low ohm loads. the transistors in the pre-driver overheat and turn funky green in color when you do run low on the amp as a sign its un-happy with what your doing.
I have one in front of me here at the shop right now I keep on the shelf to show people you can't hide what your doing from a real tech. It shows inside the amp where we work, and can't be hidden from us old timers.
meepers said:
Wow thats a lot of equipment to tune up you got there. I can see why you have space issues dang that a lot of toys in one car. I guess i can't say much though I have two 31 band stereo EQ's to tune the system with PG EQ-232's and a separate crossover PG AX-406, and a bass cube , love the bass cube, everybody should have one of these>
And thats just mounted on a custom panel behind my back seat in my Burb. A simple Hu with remote for driving safety. the rest is all hidden like custom 24 DB hand made crossovers, and stuff associated with the drivers.
Small but clean and very clear as i run a Xenon 200.4 on my four corners and at 200 per corner i never hear clipping at the level i like to listen to, i also don't blow tweeters either. never have and I think i never will after reaching the proper size amp to run in linear range and not to clip.
Yeah, I was amazed to find out how much of a difference putting enough power to your speakers can make. I was always afraid that an amp that had higher RMS ratings then the speakers was a bad thing. Then I found out the hard way that an underpowered amp that clips will kill speakers. I have run some pretty junk setups and made them sound good, but I have ALWAYS had great results running my PPI stuff. I just did not like that I needed a separate xo to run off my stock deck. Dont get me wrong, I have had some super nice head units, but they almost never look good in the dash, and they have a way of causing your window to get broken. I dont like sitting on glass, and replacing a $500 hu every few months. My first real head unit was an alpine 7909, that thing was sick. I wish I still had it as they are still going for bank. My most trusted unit of all time was my Pioneer Deh P825. I had that unit for 8 years, it was installed in 12 different cars. I moved up to the 835r, but I really did not like the controls as much, and it did not have the same DSP unit. My last high end deck *still have it* is my alpine cda-7949. I think I am going to dump this unit though as Unlike Pioneer that has a sweet P bus, alpines AI stuff does not all work with it. I will not run my sirius sat unit, it wont play CDR's, and I cannot hook up the full speed Ipod to it. I have been looking at the Ida-x001. since it does not have a CD transport, I can hide the unit under a seat, and mod the face to clip into my center consol with the screen in driver view, but hidden well off. just put a pocket in the factory radio location, and go complete stealth.
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