hi guys, building a funny cat, waiting on some 23k30a's to come in... but i DO have j201, mpf102, 2n5457, 2n5458, j112's kicking around...
would any of them be a reasonable substitute? or should i just be patient and wait for the proper fets to arrive?
and... any cool circuit perturbations/molestations/mods worth trying on the beast?
it was a "kit" containing a build doc and two pcbs that appear to be based on RG's project on geo, by 3pdt.com which no longer bothers with anything online or anything. he suggested adding a buffer before the circuit to hold oscillations down...
anyone got a decent suggestion for a buffer circuit for this monstrosity? i figure i may as well just build it in, maybe with a switch rather than find room for yet another pedal on my live board if i diggit.
thanks peeps!!!!!
I've used the 23k30 interchangeably with BF245A, BF245B, 2N5457, J201 and 2N4303 without any trouble. Not for this circuit but for others (glides and distortions)
cool, thanks kev! i'll ust socket the sucker and have a play with what i've got. ;)
Sockets would let you get on with it. Might sub, might not. In the Q-Tripper, the subs won't function, you have to use the real deal. Hope this isn't that way.
Guessing.. start with the 2N5457 or the J201.. as they have different gains....
or i COULD develop some PATIENCE and wait a couple days ;)
Quote from: pinkjimiphoton on February 19, 2019, 05:17:57 PM
or i COULD develop some PATIENCE and wait a couple days ;)
Screw that.
hahahahahah marc, you know me too well , brother ;)
:icon_mrgreen:
The K30 is acting the same way a FET does with the EA tremolo: as a variable resistance that sets gain. Only in this case, the drain-source resistance is varying at the speed of the ripple in the envelope coming through the diode. And as is often the case, when there is too much ripple in a gate, compressor, or filter, people often report it as sounding distorted. Roland/Boss put the ripple to productive use here. You can vary the audibility of that ripple-driven "soft distortion" with pretty much any FET whose drain-source resistance responds to what the very simple rectifier is feeding the gate. If you can't hear any distortion, then consider upping the value of the 470k feedback resistor in that stage, or maybe place a 1M fixed resistor in parallel with the drain and source pins.
Having built a few of these, I recommend separating the functions of the rotary switch. One set of contacts simply selects between three different gain settings for the rectifier that feeds the filter. Replace the 47k and 22k resistors in that part of the switch with a 15k fixed resistor in series with a 100k variable resistor. That'll get you all the drive range you need.
The other part of the switch selects between a minimally smoothed and better-smoothed version of the envelope, which you can do with a toggle. Really, the unit is more complicated than it needs to be.
thanks mark!
i WOULD try that, but already installed the rotary switch to the board, and as i've learned from past outings, un-soldering them can be a real bummer!
i'll have a play with it once i get it up n running.. i have no prob snipping leads and soldering to them if i have to, i'm fairly old school and grew up reading jack darr ;)
My notes show R10 should be 15k (not 47k).
Someone confirmed this at one point.
The main thing to notice is there is a 15k on the original PCB but no 15k on the schematic.
thanks rob, there's no schematic with this thing, of course ;)
i'll have to take a look and see, i'll try and scan the build doc to upload it
man, i musta been half way to zombie-woof land last nite, i stuck the rotary switch in, but never got around to solderin.....ooh, shiney!
:icon_mrgreen:
A group of us on this group traced through this thing 15 or so years ago,
Schematic and Layout,
http://geofex.com/ entry date 2/3/03
http://geofex.com/PCB_layouts/Layouts/funnycat.pdf
The original unit has funky epoxied modules we worked out what was inside and RG put up a modernized version with opamps. Inside the epoxied modules were real transistors and resistors.
http://moosapotamus.net/ideas/roland-funny-cat-pictures/
Just found this one with no epoxy (real or copy/repair?),
http://www.effectsdatabase.com/model/roland/funnycat#
http://files.effectsdatabase.com/gear/pics/roland_funnycat_005.jpg
FYI, on the non-epoxied modules I think I can see 33k when originally we thought it might be 100k.
Maybe that explains why R10 was left at 47k?
It's a long time ago!
I hadn't realized that Roland had been using discrete op-amps long before the BD-2.
QuoteI hadn't realized that Roland had been using discrete op-amps long before the BD-2.
Another one was the "ROD-10 Roland Overdrive Distortion" from the mid 80's. It used discrete opamps but not modules.
The Funny Cat was '73, quite early,
https://www.soundonsound.com/music-business/history-roland-part-1
These things are logic gates from the 60's made my Philips. They were used in industry. Check out the size of those things.
(https://i.postimg.cc/qh7SkrY8/norbit.png) (https://postimg.cc/qh7SkrY8)
When you cut away the epoxy there were BC107's (TO-18 metal cans) and real resistors inside.
of COURSE, the "us distributor" that would have my parts by "friday the 22nd" ...which is the whole reason i chose the damn vendor... is now saying the damn fets won't be here til march sometime.
went back to bitch, they changed the listing. ebay has gotta lay off the damn molly!!
grrrrr....
so still i wait to mess with it. i DO have to scan the docs that came with it and upload, but i am <of course> fairly lazy.
gonna start on either tom's flangelicious flanger tonite, or nick's foxx phaser i guess.
i need a break from that ovation for a couple days, but am so close to finishing up the last details i really should focus on it and get it done so i can close it up and get some video of both it and the standalone fuzzular.
but... see above lol
Quote from: Rob Strand on February 20, 2019, 04:06:54 PM
QuoteI hadn't realized that Roland had been using discrete op-amps long before the BD-2.
Another one was the "ROD-10 Roland Overdrive Distortion" from the mid 80's. It used discrete opamps but not modules.
I have an ROD-10, and although it does use discrete o-amps similar to what is used in the BD-2, they are not epoxied modules like the Funny Cat.
ok, STILL waiting for the dang fets. so i tried what's here. it works with 2n5457, 2n5458, j113, bs170.... but none super well.
the volume is pretty low. ya gotta really whack the bejesus out of it to get it to really fire.
i tried a bunch of different fets. also tried them backwards. in every single case, it made the unit come to life fuzz wise, and oscillate like crazy. but right way in, it has no balls at all.
the fuzz side is about halfway to unity.
the filter side is kinda touchy to get it to really quack well. of course, the guy who made the board closed his shit down didn't include a schematic and obviously messed the whole project up... stuff backwards from how it should hook up, etc
he says to use only two transistors, not three... there's pads for the other one but cautions not to use it.
i ended up using a 5532 for the second stage opamp, and a lower gain one left over from the ibanez echo clone i built... name escapes me at the moment.
1458 has better distortion, but won't quack. i tried every dual oa i had here, nothing really special stood out.
looking at rg's schem doesn't help a whole lot, as the guy (3pdt.com) seems to have taken some liberties with the circuit, tho it appears to be based on rg's project
so.....
it needs to be louder... any suggestions?
it needs the fuzz to not suck so badly....
any suggestions for a good voltage range to shoot for with the fet?
will swapping out the 1n914's for ge make the sensitivity work better?
is there a preferable opamp for the fuzz side?
i will scan the build doc and upload it here. its a dual sided board, so some of it isn't much help unfortunately. as shown in the doc, pots are attached with flying leads. i just soldered on solid core wire to the pins, added shrink wrap and then used the extended 9mm pots to reach the holes in the enclosure. the led's were marked in the build doc as oriented backwards, which, of course, they weren't. so i had to take it apart to fix that part, which was precarious as hell cuz i used ribbon cable which always breaks if ya move it more than a couple times.
but it IS working, and sounds pretty much like shit. the autowah side is ok, nothing spectacular, but the fuzz side doesn't sustain as i expected and sounds a lot weaker and shittier than the demos i've heard.
advice appreciated!!!!
Keep in mind that different FETs will provide different "on" drain-source resistances. And since the d-s resistance is part of what sets the gain of the distortion stage (and here I am referring to RG's op-amp based translation of the circuit), if the d-s resistance of the one you're using is high, then the gain will be low, unless you increase the feedback resistance as well.
mark,
is that what ya meant by making the d/g resistor 1m?
or should i go for the weakest fets i have?
remember, for all the crap i've done and messed with, for the most part, i know nothing about electronics, so i appreciate you explaining stuff to my moronic arse! ;)
ok, got this puppy meowin' like a kitten on acid at the bottom of a canyon beneath an ocean on europa now. yeah. much nicer.
turns out the "kit" or "pcb's" shitty instructions not including a damned schematic proper TO this particular variant sure didn't help any.
as it turns out, i did socket the jfet socket, and i did try a whole bunch of them. some barely worked like a severely mis-biased transistor kinda horrible blat. some, reversed, would KINDA work, but the whole thing would shriek uncontrollably.
that was when my dumb ass figured out that MAYBe the pinout i was assuming was wrong. i was sure the silkscreening on the pcb was wrong anyways.
so i tried the one freakin fet i hadn't tried yet. a NOS radio shack n channel jfet marked
M 3821
pinout
1 s
2 d
3 g
I =0.66ma
vgs=0.46v
and popped it in, reversed from the silkscreening on the kit. bingo.
it still oscillated, but the fuzz suddenly kicked on, and actually sounds really good. the knobs don't need to be pegged to get it to pass signal, either, let me tell ya what. holy shit. plenty-o-bawlz now. about 9:00 on the fuzz level and the filter sensitivity is good with a les paul, and it sustains much better.
i used a 1458 for u1, on the left, and a 5532 for u2 on the right. seemed to give the best balance of volume, quack, distortion and headroom.
the "kit", if ya got the "new version pcb with 9 pin header" like i did has some @#$%ed-up instructions.
for one, they have the switch and pots mounted on the component side of the board, which is dumb. hopefully this will save some other poor soul a lot of wtf'ing...
flip the damn board over, mount it to the solder side, and solder from the component side.
also, mount the pots with the body of the pots facing toward where the pcb cutouts are, and the terminals roughly in line with the big switch.
its spaced for 9mm board mount pots, but they won't compete with the height of the switch. so take a little solid core wire or resistor leads or whatever, and solder them to the pins of the pots. if ya get them alpha styles with the snap in bullshit on them, snap off the long parts that would mount in the pcb, you won't need them. don't mess up the metal backplate however or the pot may get f'd up.
anyways, once ya solder longer leads to them, i like about a 1 inch extension, stick a tiny piece of shrinkwrap or electrical tape or bubble gum or some kinda shit and insulate the leads a little. ya wanna ballpark 'em so that when stuck in the pcb holes, it about matches up with the switch.
mount them to the board first, no solder, then to the case and sock 'em down snug. that way ya don't have to try and fish 'em thru afterwards.
the switch stopper thing is gonna wanna fall off on ya, and make the switch have too many stops. save yourself a heap o time and put a little piece of masking tape on the mother@#$%er so the washer/stop thing doesn't fall off. i know i swear a lot, but that's ok, cuz i'm a @#$%in electrician ;)
the led's are actually backwards from as advised too. they as well should mount to the same side as the freakin switch and two pots so the damn led's will show up thru the holes you gotta figure out where to drill for in the damn case ;) cuz there's no help in the build doc for that, either, of course.
the pots, if inserted to the board as described, wil sit far enough above the board to not short to it, and from the front of the pedal, will turn clockwise for more.
speaking of which, turn your guitar way down when testing til ya figure out where the sweet spots are on the controls of the pedal, so ya don't spend a day gnashing your teeth over the non-working pos like i did. it works. but, like the people i so often find amusing, i did what i always think they do... peg the damn pedal and expect it to NOT be unruly un-toneful and potentially hideous sounding.
with the guitar about half way up, when ya turn it on, its much more forgiving of the eardrum bleed.
the way the 9 pin connector thing for the footswitching board is a mite @#$%ed up too. as shown in the build doc, it only would work if you have all the components facing the bottom of the case. people wanna see shit inside! not just the damn solder blobules! ;)
to be able to have the power jack as close to the input jack and switching as possible, i had to actually twist the damn ribbon cable i used between the footswitching and main boards like a dang mobius strip. the connections are, of course, backwards if ya are dumb like me and don't think it thru when ya set out to correct someone else's mistaken vision ;)
hahahha... did i really just write that? ooopsies.. i am a ...anyways..
the whole mess works great now. i didn't bother with tantalums. i did use poly chicklets cuz i like to say poly chicklets instead of the mylar caps specc'd, too, and mono ceramics for the rest, and regular ceramics for the pf's. i don't see the diff tonally with tantalums really, and always thought their main use was to save space over much larger electros.
i don't think a buffer before the circuit is necessary now, like i'd read about searching on the circuit. its got plenty of balls.
rolling back your guitar volume and tone knobs can help a lot.
cranked up, expect it to oscillate and possibly be microphonic-ish
a 3904 is fine for the single q to the left of the board.
but anyways, now its working, sounds really cool, much better than the crappy demos i've heard on youtube, and no singing, either.
i'll get some video for me droogies soon, its gotta be a while since the last epi-pen-o-sode of bring on the stupid...
and when i click "post" i'll scan the damn build doc for to save some other poor bastard a bit of aggravation in the future. yes, i was bad, and rebellious, and put stuff together different from the cheezy ass build doc... but there was no reason to do it the way shown. i mean, why socket shit if ya gotta pull it out of the damn case to swap any components out? its ridiculous. plus, its just.... not sexy that way. its gotta have the sex appeal under the dang hood, right? when ya open the hood of a muscle car, its SEXY. when ya open the hood of my crappy suv, its a big sheet of plastic covering shit so you don't get in trouble monkeying with it. about as sexy as a chastity belt and a nun with a big freekin' ruler.
anyways. jesus. its 142 am again. i never sleep. be right back. lol
(https://i.postimg.cc/HcFzr8HY/3pdt-fc-1.png) (https://postimg.cc/HcFzr8HY)
(https://i.postimg.cc/rztgvjCK/3pdt-fc-2.png) (https://postimg.cc/rztgvjCK)
(https://i.postimg.cc/BXTpvvz3/3pdt-fc-3.png) (https://postimg.cc/BXTpvvz3)
there's the build doc
Quotethere's the build doc
Be interesting to compare that parts list with RG's project (the link I posted above).
i intend to do just that, near as i can figure, he took RG's project and re-jigged the pcb layout, but other than that i believe its the same as RG's modded circuit.
it really sounds good now tho. i am surprised at the change between last nite and the day before. really went from unuseable without a booster or fuzz before it as so often reported to totally useful and kickass! ;)
messed with this thing some more. it was oscillating like crazy. so i decided to try and snub it with a cap or two.
on the pic of the pcb from the project, the node at r16 to the bottom left of the board and the pad marked Sw, solder one leg of a 3.3n ceramic cap to ground.. i used the jack ground cuz it was convenient.
also add another 3.3n cap between pins 3 and 4 of u2, that should eliminate the oscillation completely and knock out most of the noise while de-harshing the filter and distortion slightly. it will now quack right on its own, with or without the sds circuit engaged, and it mellows out the distortion a little bit, too. i can get the full range of both pots useably.
for what its worth, it looks like r 16 on this would be r15 on RG's schematic, and it looks like r15 and r14 are swapped, so its the 22k going to the switch instead of the 220k. i dunno how that affects the circuit, but may be why its got a good bit more distortion balls to it than Mark said his had.
it really kinda sounds like a cat now. the distortion can stand on its own, and the filter is nice and meeee-owwwwweeeeeyyy
in case anyone else ever runs into the oscillation nitemare dealio... and if ya need more volume from the sds, add them two caps, and swap them two resistors.
peace!
here's a super shitty pic from my uber shitty phone, i circled the two added parts and where they go.... hopefully will help some other poor sucker some day. ;)
(https://i.postimg.cc/2VHhTJJg/funkat.jpg) (https://postimg.cc/2VHhTJJg)