A bit hesistant to upload this one since there is an unknown cap value and pot value. But a quite a few people have requested this one so I guess a 95% accurate trace is ok?
Traced by evilarsen, AlexS and myself. It is a Rat based circuit running on 9v/-9v up to 18v/-18v. It is intended for bass but works equally well for heavy down tuned guitar playing. Tonestack is a passive James variant and there is an extra gain/makeup stage before the output.
The diode selector rotary switch has a quite interesting configuration. Many of the diodes are stacked and are asymmetric. Probably the keep an even output level across the switching range?
ohhhh snap. Ive been waiting for this. I havent even looked to see if I had parts, lol, just saw it. i ll be all over this one. Thank you.
ReplyDeleteNow verified. Sounds heavy as...0))))))))))
ReplyDeleteYessssss. Was waiting 2P6T in hand for the verified tag. I know what I'll be doing this weekend.
Delete@fuzzhead what did you end up using for diodes 10 - 14 ?
ReplyDeleteI think it was BAT42s...
Delete...but you might want to experiment with the shottkeys. Some units had germaniums. Also the difference between the shottky setting and op amp/no diode setting is quite small.
Deletehttps://youtu.be/wuhY7UH1QJE
So it might be worth reverse D12 and D14 for more clipping and less headrrom...
I have a pile of D07 germaniums with a .28 - .30 fv. you think theyd be worth trying . I will socket but just curious. Arent BAT42s around .5 ? I need to order some 42s at some point.
DeleteDefinitley worth trying! I think I'm going to do the same before housing this. Lower v. drop sounds like a good idea, I'm not happy with that switch setting ATM...
DeletePopped in some D9K germaniums. Works great. So I guess iether low v. d. shottkys or germaniums is the way to go...
DeleteAwesome, just waiting on some rotary switches.
DeleteCrap, I was going along real good and bam, no LTC1144s. Waiting on another order damn it. As always when I order I ended up buying more shit than I need, lol.
ReplyDeleteYou can actually use a 7660S or MAX1044 if you bridge pin 1 and 8 of IC3. But no 18v! Only 9v or else you'll get some smoke and a funny smell.
DeleteThanks Fuzzhead, I may give that a go just to test it out.
ReplyDeleteThis is killer, sounds great. Socketed some D07 and have some BAT42 and LTC1144s on the way. Sounds great on bass, definitely going on the board and gonna be there a long time. Thank you evilarson, AlexS, Fuzzhead and Ryan for this great job/ layout.
ReplyDeleteMatt
GD012/D07
DeleteSo I should have left this at a 9v pedal. I took the bridge off pin 1&8 and put the LTC1144 in but I had a high pitch whistling. I decided to put the 7660s back in the way it was but now my low end is pretty much gone and on position 4 on the clipping pot the effected signal is slightly less than unity. I did switch the smaller caps to 50v but didn’t change the 47uFs. When I was swapping the chips around I accidentally put a OP07 where I should have put the 7660s. I’m not sure if I popped one of the other caps but position 4 on the clip pot is kinda weak and it seems like it had more lowend before I did all the swapping. Any ideas on where to look. I have changed all the ICs but that didn’t help.
ReplyDeleteProblem solved. Shitty stripboard. One of the joints for the bass pot lifted of the board. Cheap shit. I gotta quit using that.
ReplyDeletePhew! Ok, so how does it sound at 18v?
DeleteIm gonna try ot at 18v tonight. After I found the loose pad and fixed that I had enough for the evening. The owner of Dunwich replied to my thread on Talkbass and suggested the following.Which is pretty much Chinese to me at the moment. I can kinda grasp it. This is what he had to say about the whole.BUT I need to test to see if its still an issue.
ReplyDeleteIf you attach Boost to V+ the Osc frequency increases by a factor of 10. Depending on parasitic capacitance on pin 7 you can increase the OSC above audio band to avoid noise.
Additionally you can also raise the Osc frequency using a cap from Pin 7 to Pin 2
Ok, so I have tested at 9,12 and 18 volts with the LTC1144. The High pitch whistle is still there. You can dial it out by turning the gain and treble pot all the way down but that pretty much defeats the purpose of having it,lol. It does sound pretty good at 12 and 18 but I cant live with that whine and my dog hates me now, lol.
ReplyDeletealso noteworthy. I tried different values for c7 but nothing changed. If I remove it whining stops but no treble pot
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteWhistle / Whine fixed. Using the LTC1144 no cut between pin 1 & 8. I bridged mine. As explained to me. If you connect pin 1 ( boost) to pin 8 ( v+) you increase the osc frequency by 10 thus putting the freq out of hearing range. Working great at 9, 12 & 18 volts. If you do run at 18v you may want to keep the bass pot down a little or you will get some harsh sporadic clipping . Or just crank it a let er rip. I really like this one at 12 and 18 volts. Thank you to all involved.
ReplyDeleteBuilt it with a 7660, and an LM301.. sounds good. Will box
ReplyDeleteThis schematic confuses me as to how the clipping switch works in positions 1,2 and 4.
ReplyDeleteHi, I just noticed d2 and d3 on the layout should have anodes and cathodes reversed to correspond to the schematic. Also, switch 1+2 and switch 8 should be interchanged. In my built pos. 3 and 4 are much lower gain than 1,2, 5 and 6. Also led's do not light up as they should as clipping diodes. Has anyone had the same issues? I used 1n4148 and bat46's. Cheers.
ReplyDeletehey crissp.
DeleteIt appears that Ryan that did a redraw of my original mess of a schematic did some mistakes when it comes to the orientation for some of the diodes and possibly the switching. The layout reflects the original trace and schematic. I will replace the schematic with my original schematic on monday when I get back home from work.
Hopefully that with clear some things out.:-)
My own original schematic is now uploaded. Bear with the switching since the circuitlab software don't have aa rotary switch in the library so I had to create my own....:/ But hopefully you can wrap your head around it:-). (yes, yes, I know, I should start using EAGLE...)
DeleteThanks fuzzhead!
ReplyDeleteis op07 distorting? in a typical rat schematic, the jfet at the end acts as a buffer and to isolate the volume control from the tone stack, yes? what's the purpose of the second opamp, is the volume essentially controlling how much signal is hitting the second stage?
ReplyDeletewondering if i could parse the second opamp schematic into a typical rat with a jfet buffer for an additional gain stage at the end. not even sure if it makes sense..
Hi fuzzhead! Thanks for posting this one. I'm building this today since I finally got some 2P6T's. I think there are only [34] cuts but the pic currently says [39]. Hoping I'm not missing something or need some new glasses. Lol.
ReplyDeleteYou might be missing the cuts under D5, D6,D8,D11 and D12. They're a bit harder to see since they're under components.
DeleteHa! You have the eyes of an eagle, Orion Tonehunt! I just zoomed in and you are right. That definitely saved me some headaches. I should get some glasses. Thank you!!!!
ReplyDeleteThanks again fuzzhead (and Orion for pointing out those cuts!). This was my first build using a rotary and I was a little worried I was going to screw it up...but it was easier than I expected & I feel more confident tackling another one (I've been actively avoiding these builds). I realized as I started soldering that the rotary has numbers on the underside (which was a nice surprise & made it easier to locate the right points).
ReplyDeleteThis is an interesting Rat variation and there is something really cool about watching the LED's light up when it's maxed out. Now I have to figure out what size enclosure I can fit this one in. The rotary dial is pretty chunky. :)
can the trimpots be replaced by potentiometers ?
ReplyDeleteShould be just fine!
Deletei thought so but wanted to be sure. (there's just allready so many wires lol! 22!!) thanks !
Delete