Pretty much a stock Rat with two additional switches. The clipping switch selects between the stock silicons and a assymetric MOSFET/Shottky pair. A Earlier units is supposed to have a 1N270 germanium diode in place of the Shottky The Fat switch toggles between stock mode and Fat mode by adding a 6,8uF cap at one of the RC filters and a cap to ground at the gate of the output buffer.
....and a demo by MR. Ian Sheridan.
Hi, I built this, but all I get is clean signal.
ReplyDeleteI put +9v on the top left.
I put ground on bottom left.
I used a 2.2uf electro instead of 2.2nf because I thought that was a typo.
I attached switch 2 to filter 1 and 2.
Any help is appreciated, thank-you!
Add a cut at J10 (just right to pin 5 of the IC, under the 100k).
DeleteIf you have a legit J201 it works fine in this circuit.
Also, I used a J201 instead of the 2N5458...
ReplyDeleteCut added, this is verified and sounds great!
ReplyDeleteAwesome! I'll tag it.
DeletePlayed it on bass today at volume and it sounded radical!
ReplyDeleteTons of volume, lots of tight low end-especially compared to my '87 Rat 2. Switches made meaningful changes.
One thing, Filter adds highs when turned clockwise, I'm not going to bother to change mine though. Thanks fuzzhead!
Just made this. It's a bit late at night to make a video but I can confirm it sounds great.
ReplyDeleteAs per the videos I have seen of the originals the switches don't make a huge difference. The difference is more noticeable when the distortion isn't too high up.
I guess now I need to make the warthog....
Here it is! Thank you Anders!
ReplyDeletehttps://youtu.be/Pwf4JJYQE7E
Thanks for the demo Ian! Sounds great!
DeleteThank you Anders! ☺️☺️☺️
Deletei subbed the 2n5458 for a J112 and im getting a bit of squeezling. this is the only mod ive done. would this cause the squealing?
ReplyDeletethanks
If I'm getting low volume with this, what could be the cause? The only thing I replaced was the 6.8uf capacitor with a 10uf one. For the IC I used OP07CPZ.
ReplyDeleteI Had issues with fake FETs. I use 2n5457 in these and they work great
DeleteInteresting! I'll give that a go.
DeleteHmm swapped for the 2N5457 but seems to be the same. Max volume still seems to be unity.
DeleteIf the only problem is that it's very quiet, but otherwise sounds like it should, then the problem is likely around the JFET output buffer. Check to make sure the 1u electro cap isn't backwards, and that the 1M resistor on the gate pin is properly going to ground (i.e. connected from E13 to B13). Beyond that, make sure there are no solder bridges on the copper side of the vero. Good luck!
DeleteChecked the 1u cap and 1M resistor, and solder bridges, Sebastian. Still no good :( Might have to sit on this one a bit and come back to it. Thanks for the suggestions though!
DeleteBad pot?
ReplyDelete