| MatthewS |
There I was.. staring at the makeshift page for cops towing, a towing company that sells what they yank out of the cars. Located in Oregon, and it only happend to make it's way in front of me because I was googling to find a particular amplifier model to disect and study (more on that later)
Scrolling down the amplifier page I seen a small, blurry picture and could barely make out 'Audio Control system90' and whole bunch of adjustment knobs on the top. I remember thinking at first 'Equalizers don't belong here..'
It was going for about 90 bucks and it looked fancy so I hobbled by google again and dug up what little I could find on it (it's rare.. google it I dare ya!)
Apparently the System90 was an amplifier line produced with several models that included various goodies like EQ lineout's, PFM (programable match filters), etc.
Deciding that I just had to have a peek inside it knowing AC's quality reputation, I contacted cops and asked if they would ship. The answer was yes.
Low and behold.. the Audio Control System90, Model 50.. Disected for cleaning and viewing pleasure.
Specs:
Four channel Bridgeable power amplifier
Four channel Equalization
18db/per octave crossovers
Programmable Frequency Match (PFM)
Selectable low pass / full range output
Speaker level inputs
50 watts x 4 or 150 watts x 2
PS stage -
6x IRFZ34N
TL494 PWM
Isolated transformer
AUDIO stage (per ch) -
TIP35/36C matched output pair
MPSW56/06 Pre-drive
External damping diodes
Overall Dimensions - 13"l x 5.6"w x 2.5"h
NOTES: Has 4 IRFZ34N's mounted to sinks center of amplifier board, and in vicinity are two LM393's.. Any ideas what they did here?
Let me know what you thin of it.. for 90 bucks I know I didn't go wrong.
- Matt |
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| Eva |
| Those four IRFZ34 could be used for output current sensing. There don't seem to be any emitter resistors on output transistors. |
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| MatthewS |
| quote: | Originally posted by Eva
Those four IRFZ34 could be used for output current sensing. There don't seem to be any emitter resistors on output transistors. |
Thats a good shot! But if you look REALLY closely at the one pic that is a closeup on the mosfets I mentioned, and look at were each channel card you can see mounts right angel to the PCB you will see tucked away and partially hidden emitter resistors.
Any other guesses?
- Matt |
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| ppia600 |
| Nice amp, from back when they were made by people who didn't really care how they looked. Quality was what mattered. I see some rectifiers but not the emitter resistors, maybe I'm not looking close enough? |
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| MatthewS |
| quote: | Originally posted by ppia600
Nice amp, from back when they were made by people who didn't really care how they looked. Quality was what mattered. I see some rectifiers but not the emitter resistors, maybe I'm not looking close enough? |
See the red arrows.. :D
- Matt |
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| ppia600 |
| Oops, I thought those were for the audio output transistors..? |
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| MatthewS |
| quote: | Originally posted by ppia600
Oops, I thought those were for the audio output transistors..? |
The previous poster termed them emitter resistors on the outputs.. Not the same thing?
Am I stuck on semantics here? someone help me understand, maybe it's me.
- Matt |
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| ppia600 |
| I'm sure the outputs use emitter resistors, I have no clue what those mosfets in the center are though. If Eva said they are for current sensing, I'm sure that's the case. Maybe he didn't notice the emitter resistors on the output transistors, though. Is there a pair for every channel? |
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| 1moreamp |
Evening,
Nice Old School amp from Audio Control, I was looking over your pics, perhaps you should visit Amp-guts and post them there along with the others from this era in Car audio. I am sure everyone would appreciate you efforts...:)
Thanks for the peek :) |
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| MatthewS |
| quote: | Originally posted by ppia600
I'm sure the outputs use emitter resistors, I have no clue what those mosfets in the center are though. If Eva said they are for current sensing, I'm sure that's the case. Maybe he didn't notice the emitter resistors on the output transistors, though. Is there a pair for every channel? |
Yeah, one pair per channel. The 'cards' appear to be part of the modular design and seem to host the entire channel on each of them. Thats what I gathered at a glance anyway, I wanted to take the time to really dig into tracing the routes on those mosfets but just didn't have the time.
| quote: | Originally posted by 1moreamp
Evening,
Nice Old School amp from Audio Control, I was looking over your pics, perhaps you should visit Amp-guts and post them there along with the others from this era in Car audio. I am sure everyone would appreciate you efforts...:)
Thanks for the peek :) |
Thank you, I didn't need another amp but I couldn't pass it up. I have actually been trying to get a good pic set for amps that are not on the ampguts site and I'm slowly submitting them. The last amp I submitted a few weeks ago has not made it's way up yet. Not sure what the update scedule looks like over there.
- Matt |
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| tsmith1315 |
I'm jealous, that's a very cool amp.
I wonder why it's a rare bird. Were they too pricey? too much in one package? too far from conventional designs? scary to one who didn't know what to do with it? |
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| MatthewS |
| quote: | Originally posted by tsmith1315
I'm jealous, that's a very cool amp.
I wonder why it's a rare bird. Were they too pricey? too much in one package? too far from conventional designs? scary to one who didn't know what to do with it? |
Well, if you Google the system90 series not much shows up, especially for the model 50. You get a good share of hits, but when you dig deeper you find very little of the results. What I have been able to surmise is that at one time AC tried to integrate their processing goodies into a package with certain purpose built amplifiers. For example the system90 model 11 was a center channel amplifier. It didn't do DTS or anything, just a small sumed mono amplifier for center channel purposes. Then there was the model 20 and 40 which I didn't dig into, and then my model 50 which appears to be the cadillac of them all.
My guess is that they didn't hit target sales to keep the line going because the system90 line only had a few models and there didn't seem to be any new lines after that which suggests it was pulled early in life. Speculation of course. Given AC's quality standards and on-shore manufacturing I would say the price probably scared a lot of end users away, which only left the super techies with the money that knew what to do with it. Then of course there was also the crowd who liked AC's processing but wanted to use their own amps with it and that probably ate up half the sales potential with the super techies with the money.
So what probably ended up happening to most of them was they ended up in SQ installs that entailed buyers with the money, and a loyalty to AC products. Or loyal AC users who were excited to try the new line of amps. All speculation, again. What we need here is somebody from audio control to chime in :D
- Matt |
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| EnvisionAudio |
| quote: | Originally posted by MatthewS
Or loyal AC users who were excited to try the new line of amps. All speculation, again. What we need here is somebody from audio control to chime in :D
- Matt |
How about a former AudioControl dealer?
They were very expensive, low powered and not reliable. I remember them well.... :rolleyes: |
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| tsmith1315 |
Envision Audio:| quote: | | They were very expensive, low powered and not reliable. I remember them well.... |
Can you attribute anything in particular to their unreliabilty?
I like the layout and have considered using a similar format for signal processing. But having large vertical board 'modules' in a vibration prone environment is worrysome.
Did your customers have a reasonable interest in them, aside from the exclusive pricing? |
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| EnvisionAudio |
| quote: | Originally posted by tsmith1315
Envision Audio:
Can you attribute anything in particular to their unreliabilty?
I like the layout and have considered using a similar format for signal processing. But having large vertical board 'modules' in a vibration prone environment is worrysome.
Did your customers have a reasonable interest in them, aside from the exclusive pricing? |
Not really - we sold them to individuals with zero trunk space in cars like MGs and Porsches. Even higher end customers then were still looking for separates in their larger cars. It might have done better with more power, but then it wouldn't be as small. It was 40W x 4 for $650 retail (I think our price was a bit over $600). Compared to buying a 4 channel Alpine and an Audiocontrol EQLs, most people went for the "more stuff the same money". I think brand recognition for Audio Control wasn't in the amplifier business - and they had no presence in the competition circuit except for signal processing. It was confusing to many people!
IIRC, the return rate was ridiculous. Since they were warranty repairs, we never repaired them. I have worked on them personally in the past few years, and their biggest trouble is popped outputs. Something about lack of heatsinking and using a pair of TO-220 parts at 2 ohms comes to mind as a very bad idea...:D |
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| ppia600 |
Quoted from Envision audio:
"Not really - we sold them to individuals with zero trunk space in cars like MGs and Porsches. Even higher end customers then were still looking for separates in their larger cars. It might have done better with more power, but then it wouldn't be as small. It was 40W x 4 for $650 retail (I think our price was a bit over $600). Compared to buying a 4 channel Alpine and an Audiocontrol EQLs, most people went for the "more stuff the same money". I think brand recognition for Audio Control wasn't in the amplifier business - and they had no presence in the competition circuit except for signal processing. It was confusing to many people!
IIRC, the return rate was ridiculous. Since they were warranty repairs, we never repaired them. I have worked on them personally in the past few years, and their biggest trouble is popped outputs. Something about lack of heatsinking and using a pair of TO-220 parts at 2 ohms comes to mind as a very bad idea..."
Did they all use to220? The op says his has the tip35/36 style... |
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| EnvisionAudio |
| quote: | Originally posted by ppia600
Did they all use to220? The op says his has the tip35/36 style... [/B] |
It could have been...ok, I see what you're saying. Heh.
Used properly, ventilated properly (mount it with fins vertical) it will last a long time. |
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| ppia600 |
| quote: | Originally posted by EnvisionAudio
It could have been...ok, I see what you're saying. Heh.
Used properly, ventilated properly (mount it with fins vertical) it will last a long time. |
Just mount it in a silicone dampened enclosure with some forced air ventilation and a fresh air inlet from outside the trunk then, lol? I actually thought about building a sealed amp enclosure and having one inlet vent and one outlet vent totally isolated from trunk air volume to keep the amps super cool, never got around to building it though. And of course some filter screens to keep the fans from sucking in small animals haha
:smash: |
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| MatthewS |
Wanna sell it? I was considering using a center channel in my next install.. would be neat to have matched products like that from the old days.
| quote: | Originally posted by EnvisionAudio
How about a former AudioControl dealer?
They were very expensive, low powered and not reliable. I remember them well.... :rolleyes: |
I have a 87 vette I was going to do a SQL install in and am seriously considering keeping this one. I was going to flush the amps anyways and use forced cooling in the panel gap so heat wouldn't be a big deal. The design should yield rated power, albeit low. But I was going to use all four channels on front stage, which was going to be split between the dash and door areas because the kicks in that car are virtually undoable (barely enough foot space as it is)
Doing this allows me independant control of each area and EQ control between the dash and doors, so it should be a tweakers paradise for me. I hooked it up and it has TONS of boost/cut in the EQ and sounds really flat when everything is centered. I reall liked some of the things they done with the design, and hey! I got PLENTY of tip35/36c pairs in the bin ;)
I think it'll be a sweetheart in the application I'm contemplating.. anything other then the negatives you listed I'd care to know? Have an old manual laying around for it? :D
- Matt |
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| EnvisionAudio |
| quote: | Originally posted by MatthewS
Wanna sell it? I was considering using a center channel in my next install.. would be neat to have matched products like that from the old days.
I have a 87 vette I was going to do a SQL install in and am seriously considering keeping this one. I was going to flush the amps anyways and use forced cooling in the panel gap so heat wouldn't be a big deal. The design should yield rated power, albeit low. But I was going to use all four channels on front stage, which was going to be split between the dash and door areas because the kicks in that car are virtually undoable (barely enough foot space as it is)
Doing this allows me independant control of each area and EQ control between the dash and doors, so it should be a tweakers paradise for me. I hooked it up and it has TONS of boost/cut in the EQ and sounds really flat when everything is centered. I reall liked some of the things they done with the design, and hey! I got PLENTY of tip35/36c pairs in the bin ;)
I think it'll be a sweetheart in the application I'm contemplating.. anything other then the negatives you listed I'd care to know? Have an old manual laying around for it? :D
- Matt |
You, like most "Old School" collectors are not type of customer that's going to blow up this amp. I can pretty much guarantee it.
No, I don't have a manual...but audiocontrol has it FOR SALE on their website. No clue why they can't or won't scan it into a PDF.
http://www.mobileaudiocontrol.com/p...oduct_id=228095 |
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| marko |
| i think someone should scan the manual and post it on here! i got a system90 #11 model in blue!! it needs a remote cable which i can build but need to know the wire config 1st... |
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| tsmith1315 |
Envision:| quote: | | I think brand recognition for Audio Control wasn't in the amplifier business - and they had no presence in the competition circuit except for signal processing. It was confusing to many people! |
Makes sense, especially when there were so many proven amps already on the market. Many folks serious enough to spend that kind of dough want to pick and choose items individually for their merit.
Envision again:| quote: | | Something about lack of heatsinking and using a pair of TO-220 parts at 2 ohms comes to mind as a very bad idea... |
Yeparoo, even if they're TO-218's :D
So, do ya'll think an item similar to this would be valid in any segment of today's market?
MatthewS:| quote: | | I have a 87 vette I was going to do a SQL install in and am seriously considering keeping this one. |
Keep us posted of progress? I don't know about everyone else, but I think we have room for a few more system projects and pics in here. |
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| djQUAN |
| quote: | Originally posted by tsmith1315
So, do ya'll think an item similar to this would be valid in any segment of today's market? |
not sure. most kids these days want chrome and lots of PMPO. :rolleyes:
ofcourse, there are guys like us that want better sound quality in our gears. |
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| ppia600 |
| quote: | Originally posted by tsmith1315
So, do ya'll think an item similar to this would be valid in any segment of today's market?
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I'm not sure considering the advancement in on board signal processing decks are capable nowadays. I don't prefer any additional external components if it can be done in the same unit without adding any additional noise or distortion. Some people do like knobs to play with though. :smash: |
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| yesterdaysyouth |
| sure would, 125 + shipping and it's yours! |
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| rail19 |
| I OWN A MODEL 50 AND A MODEL 25, WENT TO THE IASCA WORLDS FINALS WITH THEM IN DALLAS. DON'T COMPETE ANYMORE AND THE CAR THEY WERE IN HAS BEEN SOLD. ALSO HAVE SPECS. |
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| jol50 |
| I always liked having the crossover in front, I fiddle with it all the time. But have a new DSP HU to put in now and not sure how I will like it, since it will be too complicated to do much adjustment on the run. For that reason I was never interested in an amp or any other trunk mount EQ/crossover. Do like the idea of having it in the HU, simple and less chance of noise/etc. |
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| Cal Weldon |
Rail,
Please don't post in CAPS.
Thank you. |
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