Pro Co Rat Pedal 1991 odd chip?

[blasterkid]

Hey I am getting back into all my gear and noticed something odd going through all my pedals today. I have a 1991 Rat pedal. I noticed the chip is in fact a lm308 but it's ending code is not the "n" but a p. I have googled everywhere and not seen anyone mention it...so I was confused on is that the "308" which reads in full lm308p it definitely says on the board rat re-issue 1991 and I am the only owner of it...

 

thanks for your time and hopefully someone can help me figure this out.

 

over the pots reads "Grape" printed so not a "woodcutter" and then a few handwritten VN VN / JC or JK

 

if you want pics...later today I can snap a few...it's the light tan board inside.

[Mr.Grumpy]

I think the letter code at the end of the part number signifies the manufacturer or something. I'm pretty sure it's not important; why are you concerned about it? If you want to get all OCD about this, you could un-solder the factory chip and put in a chip socket, and then try several different types of LM308s.

[WRGKMC]

The chip is a common op amp. Depending on how long they been around different manufacturers make the same chip. The P is simply the manufacturers identification code in this case. Its a Texas Instruments chip as you can see in the list below.

 

Manufacturers do make improvements to existing designs and customize them to specific tasks. Some can be low quality for cheap multi purpose applications and higher revisions can be for higher fidelity applications. There can be several revision levels from the same manufacturer and you simply have to have the data sheets from each manufacturer to understand what the differences are. This is getting into Electronic Engineering territory and even if you had the sheets they simply would not be understood by a laymen looking at the differences.

 

I used to use the TTL and cross reference manuals on a daily basis as a tech. The toughest part of the job wasn't finding the bad parts (in analog gear) nor was it replacing the parts. The toughest part was cross referencing part numbers between manufactures to finding suitable replacement parts. Many times manufacturers quit making parts or have newer replacements that cost less or fail less. They may give them a completely new number.

 

Again, how an Op Amp might sound in a circuit requires audio test tools like frequency generators, oscilloscopes and the brain in back of them to analyze those components in actual circuits.

 

Even if you do know what the differences are it still comes down to a component working in a circuit with many other components of varying grades. The only true test for an amateur is to use your ears. Even then one guitar can sound very different from another depending on what amp you're using.

 

Since yours is in a overdrive pedal, high fidelity isn't a major requirement because you're overdriving it anyway.

Low noise and the ability to operate safely at saturated levels would be a more likely requirement. The Chip is a Texas Instruments chip which used to be one of the best US chip manufacturers in the world. I'd likely stick with it over others unless you're having some kind of problem.

 

You can see how many different suffixes there are on these chips. They been around a long time and many different versions made.

 

 

[blasterkid]

I think the letter code at the end of the part number signifies the manufacturer or something. I'm pretty sure it's not important; why are you concerned about it? If you want to get all OCD about this' date=' you could un-solder the factory chip and put in a chip socket, and then try several different types of LM308s.[/quote']

 

sorry I don't want to come across like I am OCD on it. It's what I have (meaning the pedal) . When I went to research the pedal you see these posts or youtube videos from people going "oh it's got this or that...THIS is the one you want etc..." so you check to see what you have and I just couldn't find any information on my chip. I have my old gig bag with all my gear and never really bonded with this pedal...but enough time has gone by I want to really try things and have more patience with what's here...see what I like now, what sounds I can get out of things now...it's less pressure because I am not in a band, playing shows and all that/

 

thank you for the help on this!

 

[blasterkid]

Thank you very much for all that information WRGKMC .I think coming back to this end of things a little older and basically for fun and experimenting...it's a neat spot to be in. anything goes as they say! I'd like to get more into the nuts and bolts this time around.

 

[WRGKMC]

I'm not sure I understand what you just said there. It sounds pretty incoherent.

 

The chip is the same as all the other. I wouldn't be surprised if one manufacturer in china makes them all and simply brands them for other manufacturers.

 

As far as people posting on sites about one chip version or another, most are populated by people who believe in what I call voodoo electronics. Its amazing just how many so called experts you come across posting on sites who have zero technical education. Many think because they read something some place it has some value in professional circles.

 

The fact is unless you can verify differences between one component and another using mathematics, test tools like scopes, meters, frequency analyzers the differences between one component and another doesn't exist and what gets passed around between amateurs is nothing short of science fiction.

 

Electricity has been an invisible force during most of the time man has known it to exist. Its only been in recent history where man has been able to use a nuclear microscope and see electrons actually moving through different substances to fill in the missing pieces of the puzzle. This is in fact how our computers have gotten to the speeds we now enjoy. By seeing the electrons move through silicone thy were able to see impurities blocking electron movement causing heat and errors and refine the materials used even more and make better components.

 

In audio anything from noise, levels, gain, frequency, saturation etc can all be seen using the proper test tools and understood by someone with the proper education in using those tools. I spend years matching transistors to get balanced circuits in high end high fi gear and musical equipment when doing repairs.

You'd use things like a load line analysis circuit to test the quality of the transistors to get a close match so each channel sounded the same.

 

Today the production of new components is much better. It would be rare to find much a difference between one pedal made with the same components and another, no less be able to hear a difference.

 

But what if there was a small difference in treble or bass frequencies between one and another?

Its 1/4dB difference in the output going to make a difference once that signal is passed through a chain of other effects, and amp and speaker into a room and reflected around?

 

Most amps have tone controls that let you compensate for those valiances.

Then you have the actual people listening to the music. Does anyone in their right mind think they will notice the difference between one op amp and another? No way.

 

If the voodoo electronics gives you a placebo effect and makes you think you're getting better tone and therefore play better, then you might perform better and have people notice you're more into playing. That's it in most cases however. Your casual listener does not have ears so refined. They only know when the players are in a groove or not and whether the musical tone is painful to they're ears of feels good. That's about it.

 

The quest for a magic circuit that's going to give you god like tone is in the end is no different then people who believe in UFO's or Bigfoot. Yes there can be differences but in most cases its not where you're going to get the mojo to win an audience. In fact getting your mojo from any man made object is the worth thing you can rely on because you'll always bump your head on a glass ceiling and go no farther.

 

Musical mojo comes from within each of us - not from a physical object. (so does most of the tone you produce)