ProCo Rat Modifications

[bwanasonic]

Grab a couple alligator clip leads, a handful of capacitors, and open up your Rat. Clip one lead to the wiper of the volume pot, and the other lead to the ground lug. Now try assorted caps clipped between the leads, while you play and listen to the effect. I settled on 10n (.01uf).


Kerry M

[enigmur]

Will have a go, how do I know which tab is the Wiper on the pot?

I have a few caps from doing my wah I can try out.]

Cheers

[bwanasonic]

As is pretty much always the case ( as far as I know) the center lug on a pot = wiper. The ground lug in this case is lug 1, which when looking at the back of the pot is the rightmost lug. I have found some of my favorite Rat tones by dialing in the volume and tone controls on my guitar, rather than tweaking the Rat itself.

Kerry M

[enigmur]

Oh you are a God!

I put a green cap I got for my wah (Not really sure of the value, possibly 0.22uf) and it sorted it! The filter is a lot more effective now, instead of only finding tones I like in the 9-10 area, it has calmed the whole grindy end down.

Thank you so much! And the mod is so easily removed, so it is perfect.

Yay 

[bwanasonic]

I put a green cap I got for my wah (Not really sure of the value, possibly 0.22uf) and it sorted it!

Glad your having fun. And as I mentioned previously, I was only passing on info I got from this forum.  BTW, those little numbers printed on capacitors are usually much more informative than the color of the cap 

Kerry M

[enigmur]

So I switched out the diodes today and put in 2 sockets, then put two red LED's in.

MAN is this a fantastic pedal now!! It's perfect, such awesome sound. I can have it as a volume boost, slight drive, hard drive, and fuzz all just by adjusting it.

Such an easy and awesome mod!

[wampcat1]

I would HIGHLY suggest reading through some schematic how-to's, or read some of the stuff here in the FAQs or the links above ( |DIY FAQ| |GEO FAQ| |Debugging Page| |Links| |Schematics| |Wiki| |Layouts Gallery| |STORE| |AMPAGE| |GEOFEX| |AMZ| ).

There are a ton more ways to modify it and it really is much easier. I've got some freebie videos at youtube.com where I discuss some circuits - you might look up "sd1 mod" on youtube.com... it will help you decipher schematics to know what to change and what it does.

Hope that helps!

bw

[enigmur]

What are the stock diodes in a Rat?

Just wondering because I discovered my local component shop stocks one type of germanium diode (OA-91) http://www.jaycar.co.nz/productView.asp?ID=ZR1141&CATID=&keywords=germanium&SPECIAL=&form=KEYWORD&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=

Compatible with a Rat or not? If theres a chance it will work Ill go and pick some up, and plug them in.

I might have to go in and get some elect caps this weekend, so I'll see if they have those germs.

[dosmun]

Stock Diodes are:

Rat 1N914
Turbo Rat red 5mm LED's
You Dirty Rat uses those little blue Germanium diodes not sure on the number.

[enigmur]

Thanks for the info, I might just try some anyway.

I have a 1991 vintage reissue, but have put 3mm LED's because I wanted more of an overdrive. Since I have sockets in there now, I see no harm in experimenting.

Just a thought, would differnt LED's effect sound differently? For example 5mm and 3mm, or even different colours, I know that different colours use different voltages.
I might have to play with that at some stage, since I have green and yellow LED's sitting there.