# old school mods Rockford Fosgate PA1 (pics)



## drumcrusher (May 4, 2008)

hey guys. for anyone interested, ive been refurbishing/modding an old school fosgate PA1. this is the first, non HD version. i think its a little easier to work on, because it doesnt have the proprietary fosgate parts that rockford started using with the hd products. i think these were made up until around 1991 or 92.
i bought it off of ebay, from a guy that sells a bunch of overpriced old school amps as a (for parts only) buy. it was cool to find out that the guy just had the gain cranked up so high on it that it distorted horribly, making it sound effed up. but, once i figured that out, the only thing wrong with it was a slightly scratchy volume pot, and short power wires.
i went ahead and put new longer wires in it, then proceeded to tear the whole thing apart as i have the habit of doing lately.
i cleaned the noisy pot so that it isnt making that gawd aweful noise anymore. the 10uf caps were replace with elna silmic2's for the most part, but used multiple nichicons parrallelled in the power supply. the two input channels used 1uf caps, so i replaced them with some Tecate polyester caps, and bypassed them with either wima or ero 1837 polyprop's. the 1837's are pretty well known in the hifi community as having excellent sound quality. those are all .01uf. i havent messed with the films that came stock in the eq. i need to get my hands on the schematics to see where it may help to upgrade those. i also replaced the 1uf caps at the output RCA's with some of the blue polys from radioshack. they are actually pretty decent too.
i replacedthe 2 oppamps at the input stage with sockets so i can listen to different opamps side by side. its nice to be able to switch channels easily to listen for any differences. i first tried two opa132 singles mounted on a brown dog adapter, but that did nothing but create problems. not sure what the problem was, but i quickly replaced them with a single opa2132 and had much better results. compared to the stock opamps they seem much smoother and had better detail.i just got a couple of opa227's and plan on trying them out. they were cheaper tha. the 2132's, but many have said that they are better, with less bloated bass notes.
so thats where im at right now. i think i may have a listen to the ops227's tonight. ill keep you posted on how they work out...


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## drumcrusher (May 4, 2008)

a slightly less blurry pic...


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## PPI_GUY (Dec 20, 2007)

Sir, you have a PM.


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## drumcrusher (May 4, 2008)

and you have one back good sir. 
yours is like mine right? and not the hd version? i actually have schematics for the PA1 HD, i have never looked inside the HD, mainly because people want an arm and a leg for them (or for the PA1 for that matter). i lucked up by finding this one for parts. i payed $35 plus shipping i think.


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## HiloDB1 (Feb 25, 2011)

You're just on a roll arent you


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## drumcrusher (May 4, 2008)

haha. yea man, you should see the floor in my house. my girlfriend is getting a little irritated about not having a path to the rest of the house because of all of the electronics. good thing shes not paying rent.


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## drumcrusher (May 4, 2008)

hey hilo, i just noticed that you own a shop. do you do installs? just curious, i just got an old bimmer. its an 87 735i. its in real good shape. been trying to get a system going in it. these damn german cars are a pain sometimes. have you ever done any installs on the old e23 bodies? havent come up with much online.


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