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Vintage ProCo RAT mini-Restoration Thread

A

Armchair Bronco

Jun 10, 2008
54
0
Seattle, WA
#1
Here's a mini-Restoration thread I've been posting here and there of a vintage ProCo RAT I recently purchased. The RAT was one of the "bassline" pedals that defined Nirvana's tone in the early days. It was Novoselic's favorite pedal by a mile, and Cobain also used one in addition to his trusty DS-1.

***

Last week, I purchased an early 1980's vintage ProCo RAT from someone at work. Here it is:

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This is a low serial number ProCo "The Rat" and I originally thought it was from 1983 or so:

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More than 25 years ago, the original owner disconnected the internal 9-volt input jack, carefully bent it out of the way, and installed in its place a Radio Shack "Battery Eliminator" wall adapter.

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He fed the adapter wire through the jack opening, re-soldered it together, and connected it to the 9-volt battery connector. He then used duct tape to seal up all the original parts. Nice work for a 17 or 18 year old to take the time to keep all of the original parts around.

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I used small scissors to cut away the crumbly, sticky duct tape to expose the original components. Here the battery clip cover has popped off. I cleaned off the goo with some lighter fluid and re-attached it to the 9-volt connector.

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Then it was time to "cut the umbilical cord".

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Next, I took the duct tape off the original power jack. Yay! All the original hardware was still there. It was bent up to move it away from the jack opening, so I'd have to bend it back down.

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Now I was able to get a good look at the pots. If I'm not mistaken 7-digit number 1378150 on the pots means the following:

137 = CTS
81 = Year
50 = Week

So the pots at least were made during December of 1981. I was a freshman at the University of Colorado at Boulder then.

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I removed the 2 input jacks and then carefully coaxed the power jack back into alignment. When everything was lined up correctly, I re-installed all 3 jacks and tightened up the hex nuts.

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Here's the exterior of the "restored" RAT.

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#4
vigor&kandor said:
how much bass loss is there?
Click to expand...

Well, the "word on the street" is that in general you lose a lot of low end with the RAT. A lot of bassists seem to prefer the Turbo RAT.

In my case, I use this primarily with my guitars. My only bass is an SX short-scale bass, so it doesn't have much low end to begin with.

I did notice that the RAT really accentuated the scratchiness of the cheap pots on the SX bass. The distortion didn't sound very good through my Roland Cube 30 bass amp (no surpirse there), but I still haven't tried it through my Ampeg BA-112. I'll bet it would sound a lot better through a cleaner bass amp like the 112.
 
#9
True. Should have written that I guess that he/she's asking for the OpAmp. ;)
Transistors, in this case JFETs, should be BF245A. Though different ones (2N5457/2N5458 or maybe a MPF102) here shouldn't make that much of a difference since they are only there for buffering (the first one) and a fixed volume boost/lowering of the output impedance.

/Edit: For those interested in Rats: Try a LM301 in there. They are basically the same as the LM308N but muuuuch cheaper (something like 0.40€ compared to around 3.5€). I couldn't hear a difference between the two in my Rat.
 
#11
dune2k said:
True. Should have written that I guess that he/she's asking for the OpAmp. ;)
Transistors, in this case JFETs, should be BF245A. Though different ones (2N5457/2N5458 or maybe a MPF102) here shouldn't make that much of a difference since they are only there for buffering (the first one) and a fixed volume boost/lowering of the output impedance.

/Edit: For those interested in Rats: Try a LM301 in there. They are basically the same as the LM308N but muuuuch cheaper (something like 0.40EUR compared to around 3.5EUR). I couldn't hear a difference between the two in my Rat.
Click to expand...

I hear a slight gain difference b/w the two opamps. I use the 308 in my Rat Tail and the 301 in my Dark Driving.
 

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