The blog needs more modulation, so here's the classic EHX Small Clone chorus. Made famous by Kurt Cobain, the Small Clone has a wide range of chorus tones. I've laid it out two ways, one stock, and one with the Depth switch replaced with a pot. You can probably squeeze this into a 1590B, but I'd stick with a 125B if you want the board mounted to the pot(s). Schematic for reference.
Amazing! Please, make a EHX Bad Stone Layout (or some phase with 3+ controls).
ReplyDeleteMutron Phasor Il in a 125b please 🙏
DeleteThanks. The first pic don't amplify clicking on it.
ReplyDeleteyep, the top pic without the depth pot doesn't enlarge.
ReplyDeleteHi, how can I adapt the MN3207 to this? in a real way without assumptions
ReplyDeleteIf you are interested, go to the top of facebook. I put the MN3207 project there. Verified.
DeleteCAN YOU INSERT THE LINK FOR THE CONVERSION FROM MN3007 TO MN3207? THIS PROJECT IS NOT WITH MN3207.
DeleteIn my beginnings as a guitarist, I bought this pedal and I loved it, I had to get rid of it, but now that David presents this circuit, feel free to build it. Sounds great, verified they can rate it. Thanks, David.
ReplyDeleteI forgot to say that I did the depth switch version.
DeleteThe real problem on this schematic is that getting a MN3007 is not that easy and makes the construction of this pedal not very interesting considering that a second hand small clone cost about 70 bucks.
ReplyDeleteThere's the MN3207, but the pinout is not compatible.
It would be excellent with adaptation to MN3207
DeleteDavid has a 3007 to 3207 conversion in a post MXR.
DeleteI think It doesn't work for this one, read the comments
DeleteIt looks like PCB project from tonepad.com :D
ReplyDeleteVerified with the depth potentiometer!! thanks for your great work!! (not long ago I sent you a message on IG for the arion sch, in case you wanted to take a look) bye!!
ReplyDeletein the diagram the potentiometer rate from c1m the pins 1 and 2 of the potentiometer are not connected together but in the layout instead it is an error or not?
ReplyDeleteI follow the layout (both connected) and works
DeleteHey guys,sorry if this is not a report for this particular build, but I want to give you some advise. I have made several small clones from tonepad and madbean. Always check the 4047 because a bad chip can fry your 3007(they get pretty hot). It happened to me a couple of times. Just Google "4047 test circuit" (the one with 3 leds) you have to see all leds blinking but if they are all on or dimmed, you have a bad chip. I always do this because I import them from Banzai and to wait for another is a pain in the ...
ReplyDeleteHello, thanks for your designs, they are great, could I ask you for this please? https://www.diystompboxes.com/smfforum/index.php?topic=114973.0
ReplyDeleteThis Small Clone pedal is kicking my butt..... I tried both modded and unmodded on perfboard and get only a dry signal through no chorus affect at all. Iv'e gone over it a hundred times and can't find any problems with my traces. Iv'e gone through and rechecked that all components are right several times. Iv'e searched google for voltage readings to test for the ic's and couldn't find anything. I can see with a multimeter that the LFO is working. I am just stumped here. Any help would be greatly appreciated.
ReplyDeleteDave
hhhmmm got it figured out.... so the cheap mn3007's I got on ebay are marked as mn3007 but are actually mn3207's changed some traces and added a couple jumpers moved the 39k on pins 7 and 8 from positive to ground. now it works great.... sounds really good.
DeleteThanks for all your great work.... I have alot of fun building pedals but sometimes ya hit a snag and it gets to be more frustrating than fun.
hello, i have the same problem with the mn3007. Just have to move the R39k to the ground?
Deleteon a mn3207 pin 1 is ground and pins 4 and 5 connect to positive and on the mn3007 pin 1 is positive and pins 4 and 5 go to ground. I changed some of the traces and had to add a jumper and move that 39k resistor on pins 7 and 8 to ground instead of positive. I actually redrew this for a mn3207 but I have no way to upload a pic.
Deletehi Dave, could you upload pics of your mods? i have same problem with my 3207, thanks
DeleteI tried use 3007 to 3207 conversion pcb from mxr, but still nothing.
Deletenot sure if I can do this. this is a link to a blog I created with the mn3207 layout. https://mn3207smallclone.blogspot.com/2023/04/blog-post.html I have not verified it. I built the original one thinking my chips were mn3007 and then I modified it from that, and redrew it in DIY layout creator.
DeleteDo you think you could post the 3207 pcb layout (not the perf layout) so it would be easy to eatch?, I have done it with eagle but I guess you could do it already with DIY layout creator since you already has the file.
DeleteHas anyone used an NTE1641 in place of the MN3007? Online forums claim that they're interchangeable, but I'm only getting a clean signal through my circuit and I'm wondering if that's the culprit.
ReplyDeleteFrom the data sheet it looks like the NTE1641 would be the same pinout as the MN3207 so that would most likely be your problem.
DeleteThis is a reworked layout for using a MN3207 https://mn3207smallclone.blogspot.com/2023/04/blog-post.html
DeleteMaybe I'm not interpreting something correctly, but on every datasheet I've seen the MN3007 and MN3207 have the same pinout (gnd on 1, etc -- see https://www.experimentalistsanonymous.com/diy/Datasheets/MN3007.pdf). Am I reading the pinout incorrectly?
DeleteIt's really confusing because everywhere I look online it says that the NTE1641 is the same chip as MN3007, just rebranded.
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DeleteHad to go back and look at the layouts again. to make it work pins 4 and 5 go to the positive voltage and pin 1 connects to ground with that 39k resistor. that is with the MN3207 and the datasheet I looked at for the NTE1641 is the same as the MN3207.
DeleteIf you look at the layout here you see that pins 4 and 5 go to ground and pin 1 go's to positive voltage.
Resoldered with your layout and still no effect 😭 checked the traces over and I’m confident there’s no mistakes, although I haven’t included the 10k resistor you have between ground and pin 1 of the LM358 since it wasn’t in the original and I wasn’t sure. Could omitting that single resistor possibly cause there to be no effect at all and just dry signal?
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Deleteyes sorry it’s the depth pot one. The trimpot doesn’t have any effect. Pin 1 goes to ground like in your diagram, pin 2 goes to pin 11 of the 4047. It’s just very strange to me that I’m getting a totally clean signal no matter how I adjust the pots.
DeleteI'm sorry I'm getting confused.... Had to delete my last post cause it had some incorrect info and I can't edit it.
ReplyDeletePins 7-8 on the MN3207 connect to a 39k resistor and then to ground. the original with a MN3007 the 39k went to positive. If you have a volt meter you can check to see if the pins on the ic's are getting power. you can look up the data sheets and it will tell you what pins should have 9volts and what pins are ground.
I get 1.6V when I measure pins 4 and 5, pin 1 is ground
DeleteI opened mine up and took some voltage readings on the MN3207 ....pots turned all the way up.(not sure if that makes any difference)
Deletepin 1 - 0volts (grnd)
pin 2 - 4.2 volts
pin 3 - 4.5 volts
pin 4 - 8.5 volts
pin 5 - 8.5 volts
pin 6 - 4.2 volts
pin 7 - 5.7 volts
pin 8 - 5.7 volts
double check that you don't have something bridged/shorted in your traces.... make sure diodes are in the right way. It is kind of a big circuit and easy to miss a solder joint, double check all that.
Yeah all my pins have less than 2V. So I was checking the diodes like you suggested, and I noticed that your layout has a 914 instead of the 4148 in the original, and the orientation is flipped. My diode is still oriented like in the original - before I desolder I wanted to make sure that’s not a mistake? Thanks a million for your help btw
DeleteGood catch it is backwards on my layout.... it needs to be turned around. As far as the type of diode either one should work. I changed it when I was trouble shooting my original one and just left it. My working pedal has a 914 in it. I'll get my layout changed.
DeleteDarn I was hoping yours was correct, would’ve been an easy fix! I’ll have to figure out why my 3207 isn’t getting enough power.
DeleteSo I've got about 5.5V going into C of Q3, and I read 1.8V on E of Q3, which is the same trace that is feeding pins 4+5 of the 3207 and pins 4+5+6+14 of the 4047. The 5.5V going in is correct I believe? Might there be something wrong with that transistor?
DeleteYou should have 9 volts going into C of Q3. on mine it read 9 volts in on C and 8.5 volts out.
DeleteAfter much fiddling around, I figured out that the voltage drop happens only when I actually include the NTE1641 in the circuit. Whenever it's not included in the circuit I read 9V. I wonder if having it wired backwards earlier may have fried it or something? Either way it seems that the problem is the IC itself, and I'm thinking I might just get an actual MN3207 now that I have it reconfigured with your layout.
DeleteThe MN3207 is pretty easy to get and fairly cheap. I know I had a tough time figuring out why mine didn't work at first and couldn't find any voltage specs or nothing. I will say though this is my favorite sounding chorus pedal. I looked on smallbear and they sell mn3007's but there like $15 each.
DeleteThat was the problem! Putting an actual MN3207 in solved it and it works great now. Thanks for all your help!
Deletehi i built the MN3007 AND MN3207 and both work fine with Depth mod
ReplyDeleteI suggest doing everything again and with a positive and open mind, strictly following the layout that does work.
ReplyDeleteuse original ic
ReplyDeleteThat 100k trim is just for signal level?
ReplyDeletethe trim pot is for setting the bias on the LFO.
DeleteHow do I know the right setting? Should I just tweak it till it oscillates?
Deleteyeah .... i would just turn all the way counter clockwise and slowly turn it up till ya get some chorus affect.
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ReplyDeleteI don't know how active this thread still is, but do these pedals need matched transistors to work? I'm just getting clean tone, it only modulates when I turn the potentiometer but when I leave it alone it stops.
ReplyDeleteis it possible to get a version that works with the SAD1024 chip
ReplyDelete