old ppi amp
Hello, I'm brand new here and I can't email people yet, else I wouldn't have bothered everyone publicly about this... I'm looking for a specific part for an old ppi a1200, a U3 driver board I believe it's called. The guy in my town who fixes amps, god bless him, is great at what he does, but not the most creative when it comes to finding obscure parts and stuff. He called PPI and they said they don't make the part anymore, whatever that means, so he threw up his hands and tried to get me to buy some performance technique amp he has in the shop...
I've seen a few posts from people saying they have parts to repair these amps, but as I said, I can't contact people without making a few posts, so if anyone sees this and has that part, please drop me a line!
so in short, HELP! I don't have the scratch to buy a new quality amp for my subs! Don't make me get some pos from auto zone!!
Hello, I'm brand new here and I can't email people yet, else I wouldn't have bothered everyone publicly about this... I'm looking for a specific part for an old ppi a1200, a U3 driver board I believe it's called. The guy in my town who fixes amps, god bless him, is great at what he does, but not the most creative when it comes to finding obscure parts and stuff. He called PPI and they said they don't make the part anymore, whatever that means, so he threw up his hands and tried to get me to buy some performance technique amp he has in the shop...
I've seen a few posts from people saying they have parts to repair these amps, but as I said, I can't contact people without making a few posts, so if anyone sees this and has that part, please drop me a line!
so in short, HELP! I don't have the scratch to buy a new quality amp for my subs! Don't make me get some pos from auto zone!!
Re: old ppi amp
So whats the deal with this driver board? why do you need a knew one? Is this thing really not fixable? Im guessing its like one of those boards you find in some Fosgate amps with all the transistors mounted on it? Do you still have this board? Can you put up some pics? If its one of those boards like in the Fosgate amps i talked about, this would be very easy to diy a board, home etch.
Also welcome to DiyAudio. Beware
You may just loose your girlfriend over this website. 
paul_strings said:Hello, I'm brand new here and I can't email people yet, else I wouldn't have bothered everyone publicly about this... I'm looking for a specific part for an old ppi a1200, a U3 driver board I believe it's called. The guy in my town who fixes amps, god bless him, is great at what he does, but not the most creative when it comes to finding obscure parts and stuff. He called PPI and they said they don't make the part anymore, whatever that means, so he threw up his hands and tried to get me to buy some performance technique amp he has in the shop...
I've seen a few posts from people saying they have parts to repair these amps, but as I said, I can't contact people without making a few posts, so if anyone sees this and has that part, please drop me a line!
so in short, HELP! I don't have the scratch to buy a new quality amp for my subs! Don't make me get some pos from auto zone!!
So whats the deal with this driver board? why do you need a knew one? Is this thing really not fixable? Im guessing its like one of those boards you find in some Fosgate amps with all the transistors mounted on it? Do you still have this board? Can you put up some pics? If its one of those boards like in the Fosgate amps i talked about, this would be very easy to diy a board, home etch.
Also welcome to DiyAudio. Beware
You may just loose your girlfriend over this website. Alright, now we're talking...
Yes, I believe it may be what you mentioned... like a little daughterboard with a few transistors on it... Now, I know next to nothing about electronics, just what I've picked up through osmosis during years of playing music... I've used amplifiers a lot, but don't really understand them. Especially high powered solid state devices like this one... I'm a little more comfortable with old tube amps, but still not really at all useful.
That said, I was led to believe by my friend that was working on it, that the little board does more or less the job of a power tube in the output stage of a tube amp, and those transistors were possibly a couple of fet's. I don't know why the driver board itself can't be fixed, but I was referred to this guy very highly by some people I trust, and can only assume he knows what he is doing when he says he needs to replace it... However I can't see how it could be impossible to fix unless it uses some proprietary IC that's not manufactured anymore, and it doesn't seem like the kind of thing that would be in an amp of this age (the amp is like 15 years old)
I don't have a proper digital camera, but I'll see if I can take the amp apart and recognize the board, and get a useful picture with my camera phone.
And as intriguing as I find the prospect of making a diy replacement, I've never done anything like that before, and I don't know if I trust myself to do it right the first time, especially with such a high power device... I would hate to blow out the transformer, or the power supply that he just fixed...
back in a few...
Yes, I believe it may be what you mentioned... like a little daughterboard with a few transistors on it... Now, I know next to nothing about electronics, just what I've picked up through osmosis during years of playing music... I've used amplifiers a lot, but don't really understand them. Especially high powered solid state devices like this one... I'm a little more comfortable with old tube amps, but still not really at all useful.
That said, I was led to believe by my friend that was working on it, that the little board does more or less the job of a power tube in the output stage of a tube amp, and those transistors were possibly a couple of fet's. I don't know why the driver board itself can't be fixed, but I was referred to this guy very highly by some people I trust, and can only assume he knows what he is doing when he says he needs to replace it... However I can't see how it could be impossible to fix unless it uses some proprietary IC that's not manufactured anymore, and it doesn't seem like the kind of thing that would be in an amp of this age (the amp is like 15 years old)
I don't have a proper digital camera, but I'll see if I can take the amp apart and recognize the board, and get a useful picture with my camera phone.
And as intriguing as I find the prospect of making a diy replacement, I've never done anything like that before, and I don't know if I trust myself to do it right the first time, especially with such a high power device... I would hate to blow out the transformer, or the power supply that he just fixed...
back in a few...
Aww crumb... Okay for one thing, I think the guy thought I was dumber than I looked, and the board he showed me was maybe just for size reference, and looks nothing like the thing labeled U3 on the amp, which appears to be some kind of integrated circuit...
Additionally my camera phone isn't cutting it... Maybe tomorow I can borrow a decent camera, until then let's see if these shots do any good... It's a little disorienting because there's a similar looking chip next to it, that has the same number on the back but appears to have a different configuration on the front, and is labeled differently, but here's the front view (it's the one in the forground)
here's the rear view (it's now the one in the bg)
and here's a top view
Is this the kind of thing that can be fabricated? I noticed someone earlier in this discussion had a problem with a similar part for an a600 amp and was planning on making a replacement, but I wouldn't know where to start...
Additionally my camera phone isn't cutting it... Maybe tomorow I can borrow a decent camera, until then let's see if these shots do any good... It's a little disorienting because there's a similar looking chip next to it, that has the same number on the back but appears to have a different configuration on the front, and is labeled differently, but here's the front view (it's the one in the forground)
An externally hosted image should be here but it was not working when we last tested it.
here's the rear view (it's now the one in the bg)
An externally hosted image should be here but it was not working when we last tested it.
and here's a top view
An externally hosted image should be here but it was not working when we last tested it.
Is this the kind of thing that can be fabricated? I noticed someone earlier in this discussion had a problem with a similar part for an a600 amp and was planning on making a replacement, but I wouldn't know where to start...
It looks like you have one transistor missing (bottom right-hand corner). If the board will accept solder, you can replace the missing transistor. If it was defective, the one directly above it has likely failed also.
If you're going to try to solder it, try to get some suggestions from justonemoreamp. He seems to have a lot of experiance with these boards. I've had some that would readily accept new solder and some that would not accept solder no matter what I tried (various iron temps, extra flux, silver bearing solder...).
If you're going to try to reproduce it, you could do so in a program like Cadsoft's Eagle. I was going to do it but I couldn't find a suitable connector to fit the holes in the main board so each connection would have to be made by a tiny piece of wire. That would be OK for a one-off piece but not for something the try to sell to others. The reproduction would probably be easier with through-hole components instead of SMD components.
Someone posted a full schematic for the board here but now I can't find it. Maybe someone else can remember enough about the post to locate it.
If you're going to try to solder it, try to get some suggestions from justonemoreamp. He seems to have a lot of experiance with these boards. I've had some that would readily accept new solder and some that would not accept solder no matter what I tried (various iron temps, extra flux, silver bearing solder...).
If you're going to try to reproduce it, you could do so in a program like Cadsoft's Eagle. I was going to do it but I couldn't find a suitable connector to fit the holes in the main board so each connection would have to be made by a tiny piece of wire. That would be OK for a one-off piece but not for something the try to sell to others. The reproduction would probably be easier with through-hole components instead of SMD components.
Someone posted a full schematic for the board here but now I can't find it. Maybe someone else can remember enough about the post to locate it.
Very often, if those small boards are not burned or cracked, nothing is wrong with the components (SMD transistor and capacitors). Those boards get malfunctioned just because of aged/cracked solder. Resolder all the solderable points, including the pins that hold the small pcb to the main pcb, and the small boards will work fine again.
paul i have a few of those boards that im not using. But they were taken from a fosgate. I dont know if maybe they are like a standard board that a purchase from the same manufacturer or not. but if you can get a schema of the amp and you email your address i'll send them to you. Maybe they will work?
paul_strings said:Aww crumb... Okay for one thing, I think the guy thought I was dumber than I looked, and the board he showed me was maybe just for size reference, and looks nothing like the thing labeled U3 on the amp, which appears to be some kind of integrated circuit...
Additionally my camera phone isn't cutting it... Maybe tomorow I can borrow a decent camera, until then let's see if these shots do any good... It's a little disorienting because there's a similar looking chip next to it, that has the same number on the back but appears to have a different configuration on the front, and is labeled differently, but here's the front view (it's the one in the forground)
Is this the kind of thing that can be fabricated? I noticed someone earlier in this discussion had a problem with a similar part for an a600 amp and was planning on making a replacement, but I wouldn't know where to start...
I know those amps inside and out. There is no need to fabricate anything for those boards and the parts are easily obtainable. The only time you'd need to replace the whole board was if it was cracked. The guy probably doesn't know how to rework those types of boards so he throws up his hands. It's disturbing to know that those kinds of people are "amplifier technicians"...but I know many like this.
I'm sending you a response email to yours sent to me. I might have those transistors in stock.
justonemoreamp said:NOPE ! not the same company, product or design. It won't work lol lol Would not be any better if it did as RF does not stock those old parts either anymore
i know they aren't the same company. but that doesnt mean a company doesnt make those boards in mass and sell them to other companies to implement into their designs. no? they look alike. same material, and means of mounting to the mother board. and really i dont think i've seen that type of material anywhere else. the pcb on those little boards are like a hard glass type material. i wouldnt be surprised if they were the same.
as a matter of fact looking at the pic closer, im almost tempted to put money on that they are the same boards. I dont know, but something tells me that these two companies probably shop at the same store in China. I'll take some pics tomorrow when i get home.
On the other hand if it were something more like the discrete type of boards that i've seen mounted in the same fashion but in a Lanzar amp i wouldnt have even suggest it.
Oh man, i cant wait to find out.
and i love the outcome possibilities. im gonna make a fool of myself. HaHa. EnvisionAudio, so all fogates are hex and all ppi are bi?
impsick said:
i know they aren't the same company. but that doesnt mean a company doesnt make those boards in mass and sell them to other companies to implement into their designs. no? they look alike. same material, and means of mounting to the mother board. and really i dont think i've seen that type of material anywhere else. the pcb on those little boards are like a hard glass type material. i wouldnt be surprised if they were the same.
as a matter of fact looking at the pic closer, im almost tempted to put money on that they are the same boards. I dont know, but something tells me that these two companies probably shop at the same store in China. I'll take some pics tomorrow when i get home.
On the other hand if it were something more like the discrete type of boards that i've seen mounted in the same fashion but in a Lanzar amp i wouldnt have even suggest it.
Oh man, i cant wait to find out.
EnvisionAudio, so all fogates are hex and all ppi are bi?
well I got 32 years inside these that says your gonna have fun, but end up empty handed. And Fosgate made Bi-polar way back in their early dazes before the Punch HD line some of their amps used PPI outputs like the Punch 150 PRE HD version. From HD on till now nothing but MosFet outputsGod I feel old now, Good night all ....
32 years, i aint got nothin on that. 
but what do the little boards have to do with output? i mean to me they look like just something for signal conditioning, or eq'n. I dont know though, i sure as hell aint got 32 years in audio, so like i said i'll probably make a fool of myself. i haven't been home yet but i'll get some pics.
on the other hand, those boards, that i have just have some transistors, opamps, and comparators on them. so im confused on what that may have to do with output. unless we are talking about different things.
but what do the little boards have to do with output? i mean to me they look like just something for signal conditioning, or eq'n. I dont know though, i sure as hell aint got 32 years in audio, so like i said i'll probably make a fool of myself. i haven't been home yet but i'll get some pics.
on the other hand, those boards, that i have just have some transistors, opamps, and comparators on them. so im confused on what that may have to do with output. unless we are talking about different things.
impsick said:32 years, i aint got nothin on that.
but what do the little boards have to do with output? i mean to me they look like just something for signal conditioning, or eq'n. I dont know though, i sure as hell aint got 32 years in audio, so like i said i'll probably make a fool of myself. i haven't been home yet but i'll get some pics.
on the other hand, those boards, that i have just have some transistors, opamps, and comparators on them. so im confused on what that may have to do with output. unless we are talking about different things.
Those hybrid boards are the main amp stage in those amplifiers. The boards have capacitance and resistance designed into the traces so if they blow they are relatively difficult to trace down. Even when I was at PPI we did not stock those boards.
I am sure PPI farmed them out to a part manufacturer. Who I have no idea.
Autotek, Rockford Fosgate, Hifonics, PPI, Memphis, and boat load of others all build their amp channel drivers separate and install it to run the drivers and outputs.
So its not a unusual thing to do. In fact it simplifies the manufacturing process, and the in house repair process.
You also need to understand that all these companies built one basic amplifier design, and then Scaled it up or down to suit the buyers need and pocket book.
Remember scaling a amp design simplifies manufacture and streamlines costs so book keepers can count the coin better. Just about everybody, everywhere does this exact same thing. You the consumer never generally will ever see or know anything about this, as most folks are not tech savy to modern manufacturing methods and typical engineering involved with bring a complete product line to market.
Autotek, Rockford Fosgate, Hifonics, PPI, Memphis, and boat load of others all build their amp channel drivers separate and install it to run the drivers and outputs.
So its not a unusual thing to do. In fact it simplifies the manufacturing process, and the in house repair process.
You also need to understand that all these companies built one basic amplifier design, and then Scaled it up or down to suit the buyers need and pocket book.
Remember scaling a amp design simplifies manufacture and streamlines costs so book keepers can count the coin better. Just about everybody, everywhere does this exact same thing. You the consumer never generally will ever see or know anything about this, as most folks are not tech savy to modern manufacturing methods and typical engineering involved with bring a complete product line to market.
impsick said:
Uhm, that's not what I said. I said that the Rockfords that YOU are referencing and the PPI that WE are talking about are different in nearly every possible way.
That "hard glass material" is alumina ceramic.
justonemoreamp said:
Hi Cecil.
I have a good reason to believe that these hybrid devices came from Delco back in the 1980s. Delco was responsible for much of the hybrid cricuitry design then and possessed the laser technology responsible for the film resistors on the boards. My guess is that the links existed between Delco and the automotive industry with the early cross-marketing of aftermarket and factory autosound installations.
It would be most amusing to watch the faces of the general car audio population when amplifier "guts" are laid out in schematics - not just open-bottom pictures. Gee-whiz Mr. Specialized Amp Manufacturer, why are your circuits EXACTLY THE SAME AS the low buck amps?!
Oh, the laughter ensues.
You know, I've always sort of suspected something like that... There's a belief amongst many purists that the circuits involved in musical instrument amplification were sort of "perfected" in the very early days with vacuum tubes and paper-and-oil capacitors, and that everything since has been a result of incorporating new materials and manufacturing processes in order to streamline production. I can certainy agree that in the realm of electric guitar, tubes are the deal, because part of the sound most guitarists are looking for is created by the unique way in which tubes clip, but for high wattage applications where clean power, headroom and reliability are the most relevant factors, it seem like things have come a long way in the solid state realm, and things like these substrate boards, while they may fail on occasion, in general require far less maintenance than the power stage in an old tube circuit. As I understand it, the main difference in price of production of various solid state car power amplifiers would be the power supply and transformer, and whatever other circuitry is in there like a crossover or bass boost...
So, even just from my rudimentary knowlege of this sort of thing, it would take some pretty serious convincing to get me to buy a brand new power amp in the price range of a zapco or something like that...
I think the main reason I like that old ppi so much is that it is heavy, and has hefty enough fuses, transformer and capacitors to look like it could actually deliver the kind of wattage it claims, as a class ab amp. Plus it was pretty inexpensive to get used, even though it needs a little work... It will still probably be a lot less than I would pay for a new american made amp of comparable power...
Thanks so much for all of your guys' discussion and input, it's been very illuminating! It looks like one of the u3 driver boards IS missing a transistor as was stated earlier, and hopefully will be salvageable, although I don't think I'm gonna try to do it myself just yet
This is a great forum, it's inspired me to ask my mom to dig out my dad's old soldering equipment...
respek!
-p-
So, even just from my rudimentary knowlege of this sort of thing, it would take some pretty serious convincing to get me to buy a brand new power amp in the price range of a zapco or something like that...
I think the main reason I like that old ppi so much is that it is heavy, and has hefty enough fuses, transformer and capacitors to look like it could actually deliver the kind of wattage it claims, as a class ab amp. Plus it was pretty inexpensive to get used, even though it needs a little work... It will still probably be a lot less than I would pay for a new american made amp of comparable power...
Thanks so much for all of your guys' discussion and input, it's been very illuminating! It looks like one of the u3 driver boards IS missing a transistor as was stated earlier, and hopefully will be salvageable, although I don't think I'm gonna try to do it myself just yet
This is a great forum, it's inspired me to ask my mom to dig out my dad's old soldering equipment...
respek!
-p-
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