Simply a Rat with some odd component value choices, two switchable gain controls with their own RC filters and a slightly reworked filter control.
Schematic is avaiable HERE.
Simply a Rat with some odd component value choices, two switchable gain controls with their own RC filters and a slightly reworked filter control.
Schematic is avaiable HERE.
I'd like to build this. I am trying to go through the layout from the schematic. I'm not great at it because of all the switching indicated. Could someone who is a little better at schematics check this out before I build it? I'll keep trying but could use a little help if possible.
ReplyDeleteI assume that Ground is actually the bottom row as opposed to the "O" row that is indicated?
Thanks
According to the schematic, should the cap spanning B17 to D17 be a 100n ( C13 on schematic )? It is notated as a 10n on the layout. And row P should be labeled ground instead of row O. Those are the only issues I can find after comparing schematic to layout. I'll check a few more times and then build it.
ReplyDeleteThanks
Yeah, that looks right. The capacitor is there for filtering so it probably wouldn't matter too much but the ground should indeed be on the bottom row.
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DeleteOh yeah - I've seen a 100n added like that in parallel to the 100u for filtering - equals100.1u I think. I believe that a lot of people just leave it out but I've seen arguments in comments pro and con.
DeleteThe only thing I don't really understand ( yet ) is why 6 & 9 and 4 & 7 are used on the channel switch. They and the drive 2&3 go back to a common point so why use both? Redundancy? I'll keep looking at it.
I know its just a modded rat but I just remember a guy demoing one in a local music store back in the late 90s ( I think ). I just remember how good it sounded. Of course he was a pretty good player so I'm probably remembering that more than the pedal. Now I have to build it and see...
Thanks for the reply.
It may not be too interesting to an engineer but some circuits have just a small difference that makes a relatively big sonic difference. I've built several rats. They all have something slightly different that I like about each. Would I pay hundreds of dollars for a 1981 DRV...probably. Haha, no but its a cool little bastard.
DeleteComponent tolerance and drift - even identical circuits have subtle or not so subtle differences indeed.
Delete