It s time for a guest appearance!
Chris Stelloh of Capitalist Death Cult requested a layout for this one a while ago but I couldn't do it at the time so he went off and did his own. The layout is verified and good to go.
It is basically a EHX Bassbals with quite a few mods by PedalPCB. The internal trimpots are now extrenal pots. The Attack, Decay and the the distortion section are addons that wasn't included in the original Bassballs.
hey all - one small note about the capacitor that is at E20 - PedalPCB has it listed as a tantalum cap. I used electrolytic but I imagine that a film box, although bipolar, will work fine too.
ReplyDeleteI'd love to see a vero layout for this version that has a CV IN to control the filter! It has some other modifications listed as well.
Deletehttps://urekarm.tripod.com/synth/fuzzyballs.html
Thanks for the layout Chris. I've never tried a filter like this. The mods make it look interesting. I'll have to take a shot at it.
ReplyDeleteone of my favorite things to build, the noisier and less predictable, the better!
DeleteD1 should be 1N5817. Protection diode right?
ReplyDeleteyes - reverse voltage protection - 1n5819 serves the same function - it has a slightly lower average forward voltage drop than a 1n5817, so I've just gotten in the habit of putting them in any build that doesn't also have a voltage regulator.
DeleteIs this one confirmeD?
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteJust finished this and unfortunately didnt work. Checked all placements, cuts and connections, all seem fine, but no chance.
ReplyDeleteEven though I have built this one up and it has worked, it looks like there was in fact and error with the 470nF cap. the anode needs to go to pin 6 of the LM1458. I'm going to send Anders an updated layout ASAP. Thanks for catching that!
DeleteChris, I just uploaded the updated layout you sent me yesterday. So it is all good now.
DeleteChris, any idea if that 470n cap *must* be polarized? Asking because I'm super lazy and cheap about sourcing part, LOL.
DeleteMy understanding is that a polarized cap is never actually necessary - it's a compromise to fit larger values in smaller packages. You should always be able to sub a non polarized cap.
DeleteThere are still some minor errors though,
Delete100uf should be on B18 and C18, positive side being on C18.
4n7 and 22n caps are vice versa, should be exchanged.
27k resistor on L4 must meet with 2k7 on I9 and go to pin no 7 of IC2.
Even after these, i still couldnt make this work, i literally checked the both pedalpcb and madbean schematics step by step, everything is in the place where they should be, but still no chance. Sad..
So as far as the resistors and film box caps you mentioned, as well as the legs of the dual op amp they are connected to - the reason they don't match perfectly with the schematic is that you can swap sides of a dual as long as you match + input, -input, and output. As far as what you mentioned with the 100uF power filter cap - I'm not really sure why you would do that since the anode needs to connect to the protection diode and the cathode goes to ground. Since I have built this circuit successfully more than once (even with the wrong connection on the 470nF cap) please let me know if you still have no luck with it. I would be happy to build one and send it to you in Turkey!
DeleteI got some progress Chris!
DeleteChanging 4n7 and 22n caps made a significant improvement on fuzz channel, it was clipping before.
Don't know about the 100uf power filter, I've done it according to a suggestion on DSB forum, wasn't my idea :)
Just for taste, I've changed transistors into 2n2222 (metal caps) and now it sounds more natural somehow, with 2n5088 the filter effect was a bit dull, or feint, or I don't know..
I somehow managed to get a sound but I lifted the leg5 of IC1 and fed it with a bias probe with 3 diodes + 100k resistor. Seems like my opamp (which is MC1458P) doesn't work as it supposed to be.
I've been researching about this schematics for days and I've learnt that this circuit overall is not supposed to work under normal conditions lol, it has its own flaw and its something that makes the pedal unique I suppose, as feeding the inverting pin to gnd is something quiet weird. I've ordered LM358 and LM1458 IC's today, I suppose they'll arrive tomorrow and I'll try them and write the results here.
P.S: I'm a guitar player and using a hi-gain active pickups of S.D Blackout, so I've changed the input buffer 2m2 resistor into a 1m and got a better sound, it was a bit weaker before this.
And thanks for your humble offer Chris, your assistance would be more helpful for me to improve myself, my friend! Even if you build one, we can go side-by-side by keeping in touch for comparisons to see what's wrong.
Ok, I call this verified!
DeleteMy orders have arrived and tried both 358 and 1458 (stupid ppl sent me MC1458 again instead of LM-,) and both have worked but I got much better response from MC1458. I believe the one I had was faulty or not a real 1458 even.
Nevertheless, thanks everyone!