Saturday, September 10, 2011

Vintage Fosgate Car Amps - PR 220 & PR-250 Pre-Rockford


Fosgate PR-250II and PR 220 Vintage Car Audio Amplifiers


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I decided to dig out some real dinosaurs in the car audio world....the Fosgate "The Punch" PR 220 and PR-250 Type II amplifiers. These amps were produced by Fosgate Electronics, Inc. in the late 1970's before Rockford joined Fosgate. I believe the PR-250 was 1978 or 1979 and this model was also produced in 1980 as a Rockford Fosgate PR-250II (logo was different than the one pictured above). The PR 220 was also late 1970's, found in the 1978 and 1979 Car Stereo Directory issues of Audio magazine, but not in the 1976 issue. I don't have the 1977 issue to see if they are listed there...

These amplifiers were state of the art at the time they were produced. Just think, in the late 1970's, many people were still rocking 8 tracks and a cassette player was "high-end". I don't believe there were many (if any) head units with pre-outs at the time. You definitely were lucky to have one of these back then. Don't forget, 3-way 6x9's were considered high-end at this time! Take your PR-250, power up the Sony tape deck and Jensen or Sparkomatic 6x9's and you were rockin'!!

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Another view of the Fosgate "The Punch" PR-250 Type II / PreAmp & PR 220 Amplifiers

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The Fosgate PR-250 Type II had a matching Pre-Amp, which controlled the unit's volume, bass and treble controls. The volume knob was a smooth rotating potentiometer, while the bass and treble controls had a "clicking" type potentiometer (meaning you had only a certain number of positions, by turning these knobs, it would click into position). The PR-250's pre-amp had only two connections, both DIN style plugs. One DIN cable would be integrated in with your head unit and the other would carry the signal from the pre-amp to the PR-250 amp. Then, you would need some speakers capable of handling 50 watts RMS per channel, not the easiest task in the late 70's...The PR-250 was also bridgeable or capable of handling loads more demanding than 4 ohms.

The Fosgate PR 220 was much simpler and less powerful than the 250. It was rated at 20 watts x 2 channels into 4 ohms, no options for bridging or lower ohm loads. It also came without a pre-amp, all controls (bass and treble) were on the amp itself by 3-way sliders. Your options were low/mid/high for bass and treble adjustments. Again, speaker level inputs were the only signal source allowed into the amp and since most head units were only good for a couple of watts, the 20 watt PR 220 was a decent upgrade and would drive efficient speakers to loud (at the time) levels, around 110dB. Fosgate had a warning in the manual, "Sound levels of 110 dB have been recorded inside a car using the PR-220 and High Efficiency speakers. This is loud enough to lead to permanent loss of hearing after long periods of exposure. So use common sense.."

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Photo (c) 2011 - Dereck Willis - OldSchoolStereo.com

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So, you know me, I'm good for putting up video demo's right? Well yes, I have posted an overview of the amps below. That said, don't get too excited about seeing these amps in action as I'm a little hesitant to power them up. The PR 220 at least needed to pull power from the head unit for the remote turn on.

Quote by tomtomjr, one of if not the US's largest Fosgate/Rockford Fosgate collector and radio/amp technician:

" ...ALSO, on the turn on remote wire (red) , you will need to draw power from it to turn on the amp. We used to use a 12V light bulb and a switch. Put the remote wire (red) to the positive of the bulb, then the switch between the 12V ground and the 12V ground of the bulb. Flip the switch, and it will come on. These have the power-draw on the remote wire rather than the power input like modern amps... Hope this info helps........Tom"


See the video demo in 720p HD or embedded below:

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3 comments:

Greg Sweet said...

That PR 220 looks exactly like the old Sanyo 100W amps that we modified back in the 80's by soldering big Mallory capacitors to the board.

A1RJ said...

Hoping for some help. I have a Rockford Fosgate RF4.6X also A punch 45 the headunit is a Pioneer Supertuner DEH P5800MP Installing in an old VW bug so want to use only one sub woofer A 10 inch Pioneer 350W and than front and rear speakers.Not to hip on car audio system layouts. A1RJ PS have two of the old Fosgate 250 like you have pictured died when car flooded you pay postage and next time at get to my shop I'll send them.

dwillis said...

@A1RJ It would probably work best to use the 4.6x to power the front and rear speakers and use the Punch 45 fr the subwoofer. The 4.6x has built-in crossovers, they should be set for high-pass. Good for you, the P8500M has 3 pre-amp outputs. You'll need to run 3 sets of RCA wires (2 for 4.6x, 1 for P45). The P8500M has a built-in crossover for the subwoofer, so you shouldn't need anything else. As for the subwoofer location, I've seen them done in the front trunk or rear deck. Also, I know the doors are pretty shallow in the old Bugs, so you'll either need to use the kick panels for your front speakers or build out a mount for the doors. Send me an email if you have specific questions. Either oldschoolstereo or bigdwiz at gmail dot com

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