Well judging from the lack of replies so far, either there haven't been many views or so far everyone else is as clueless as I. I'm going to try and zoom in on the boards of my amp and the A600.2's and see if there are any differences in the resistors and capacitors in the input and op amp areas. It will be kind of difficult to check capacitor values for sure. I wonder if there are any other online sites with any of the original ppi designers/engineers lurking around??
I'm not sure anyone here with schematics evem believes this is an actual pro mos 50. It appears to be the older design with fewer caps in the 12v section, like the older art series. I remember back in the 90's reading in CA&E magazine, ppi bragging about using more smaller uF caps to drop esr in the later versions. I have no trouble believing this amp is authentic, after seeing all of the variations in graphic designs they came out with. After all, they were an american company and surely someone had to have the freedom to mess around a few times and make some variants.
I'm hoping someone has a little more insight as to the design of the input and pre driver sections to maybe steer me in the right direction to find the reason for the low frequency loss. I'm sure the original reason was to limit ultra low notes to save energy for the higher bass notes primarily for spl. Its been done in many other amps since then. I consider level low frequency output an important part of sound quality, and I'd rather have a lower powered amp with solid low end than use a higher powered version with a limited low end for example. There ARE important musical components that happen below the 25-30hz range IMO.
I'm hoping someone has a little more insight as to the design of the input and pre driver sections to maybe steer me in the right direction to find the reason for the low frequency loss. I'm sure the original reason was to limit ultra low notes to save energy for the higher bass notes primarily for spl. Its been done in many other amps since then. I consider level low frequency output an important part of sound quality, and I'd rather have a lower powered amp with solid low end than use a higher powered version with a limited low end for example. There ARE important musical components that happen below the 25-30hz range IMO.
I agree it is an oddity as we have pointed out before, as the rail voltages are some what different there some major differences in the intended use.
I wouldn't be real impressed in using amps that have a non-switchable sub sonic filter, it is ok to have a sub sonic but it has to be controllable...
I wouldn't be real impressed in using amps that have a non-switchable sub sonic filter, it is ok to have a sub sonic but it has to be controllable...
Well I'm taking the test cd I was using with the earthquake last night and going to see what the pro mos does at work. (can't crank the stereo at home, don't want to annoy the neighbors like they do me🙄 ) I'm going to see how low it actually plays before the weird drop off. Well, off to work..
I tested the ppi today and it puts out about 42 volts (45v @ the rails) when running full power into 2 ohms. I reinstalled the earthquake into the car and at some notes it produces about 72 volts (81v @ the rails) into 2 ohms. Definately louder, I'm not sure the sq is as good though, I'm going to have to run it with the crossover all the way up to 200hz and play around with the deck's lpf..
And that was without audible distortion on the ppi. So the guy who sold it to me wasn't lying when he told me it was 800 watts.🙂 (definately won't be selling that any time soon.) I never even added it up for the ppi. That earthquake is a monster, and so small. Tomorrow I'm going to try to remember and adjust the crossover, its kind of touchy I believe has a 24 db slope. Its really difficult to cross over just right to match the slope of the mids and highs, especially since I'm only running the front door set right now. 😱 Weird also that the pro mos has fewer caps in the 12v filter section, yet it has the power/mute and low impedance lights like the later model arts. My art600.2 has the power/mute and low impedance light but the art600 I used to have didn't have the mute capability. Luckily my deck is really quiet though so I don't need the ppi acm.
Well, I've decided to sell the ppi and use the earthquake to run my subs. I just can't get over how powerful the phd2 is. I'm also trying to scrounge up extra $ for my engine stuff. The ppi is going to be up on ebay if anyone's interested. 🙂
Well, now there's a guy on ebay (not a bidder) arguing me via email that the amp is a pro mos 50 and that it only puts out 400 watts. He is adiment and almost seems to be trying to prove something to me. I stated in the auction that the amp produces "approximately 600 watts" and that it runs from 35 to 40 volts continuous output clean so people that know can calculate the wattage themselves. This one guy has already asked me the rev number of the board and although I've already told him, he plans on taking his amps apart to check. He also told me he "thought" he had a pro mos 50 until he pulled it apart and the board had a sticker that said a600.2 on it. What a clown
Ok.... Seriously, is someone here playing a prank on me? The guy keeps emailing me telling me "its not a pro mos 50, its just an a600.2 in a pro mos sink" and "the revision number doesn't match the one on ampguts...." etc.. I've already explained the amp runs at 1 ohms stereo with no problem as its been in my car for a while that way and he still keeps on. He acts like I'm trying to rip people off and seems to want me to agree with him that the amp is some kind of fake. I really don't know what to tell him at this point.
The stupid part is that he can't seem to get it into his head that mine is an older (92) version and the amguts version is a 96.. there are bound to be changes for improvement. And actually I'm pretty positive the one on ampguts is using the same output transistors and might even be using the same 50v caps in the power supply because ppi just didn't feel like ordering lower voltage caps for these. Why can't this guy just realize the amp has a lower power supply voltage and is therefore capable of running at lower impedance? After it was explained to me here on diy, I caught on quickly and I'm not the sharpest pin in the cushion.
People, sheesh
I'll be sooooooooooo glad when that auction is finally over
The stupid part is that he can't seem to get it into his head that mine is an older (92) version and the amguts version is a 96.. there are bound to be changes for improvement. And actually I'm pretty positive the one on ampguts is using the same output transistors and might even be using the same 50v caps in the power supply because ppi just didn't feel like ordering lower voltage caps for these. Why can't this guy just realize the amp has a lower power supply voltage and is therefore capable of running at lower impedance? After it was explained to me here on diy, I caught on quickly and I'm not the sharpest pin in the cushion.
People, sheesh
I'll be sooooooooooo glad when that auction is finally over
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