Forgot to say that I have the real pedal. Now I prefer the one I've made with your precious help. That, vintage caps and a J201 in place of the 2n5457, maybe... Cheers! And keep the good work!
I have built this. Initially the sound was muffled (I know it's muff clone, but it's still bad) and output level was rather low, about half of usual pedal gain. I checked voltages and Q4 (output boost fet) was 6.5, which I thought was suspicious. I biased it to 4.5 and it was much better, then dialed by ear with waveform preview in DAW and I found a sweet spot at about 2.5v, sound was fuller and output level was the expected one. 2.5 is interesting as it's kind of reversed polarity from 6.5 (9-6.5=2.5). So, replaced 10k resistor that goes to Q4-D with 82k. Then I didn't quite like what color controller does, it's a kind of sweep between HP and LP filters as far as I can see. 3.3n cap with the 39k resistor next it is the high pass and 10n cap at A6 + 39k at C10 is low pass. If you calculate the cutoff frequencies they are quite drastic. Basically my feeling was that the controller was not very usable it would sound bad at any position, especially at extremes, with the first half of the range of no use at all (unless you like to hear only the mud part of the signal). I tried to tackle it, first by modifying the knob balance - adding 5k or more resistor between color 3 and volume 3 pushes the sweep middle point counterclockwise, so the treble part is more present throughout the range. That was a tad better to me. Then lowering resistance of C10 39k would push low pass frequency a bit higher... Then I accidentally bypassed the whole color module and it would sound much, much better to me, so I ended scrapping the whole filter section, connecting volume 3 to H8 (100n cap is output point of previous section). In addition to fuller tone I recovered more output volume (and saved drilling a whole). Couldn't find W25k pot for hot, so used W20k, which seems to work quite fine. With all three knobs fully clockwise it would start to self oscillate and amplify all dirt, adding capacitance next to Q2 tames that, though I liked to have more "air" when not maxed the drive, so I made it a switch. Also adding more than 2n cap acts as low pass, which can be alternative to color knob... I also tried to play with diode types and found something interesting. Adding a germanium diode to D1/D2 couple next to Q2 filters oscillation and low end dirt that gets amplified wit hot and dive maxed out. It also changes the dynamics quite noticeably, there's less sustain (which would be crazy when maxed) with similar level of fuzziness, so to say. I tried bunch of diodes this way (silicon ones had no effect) and settled on salvaged vintage OA79, though N60 were very similar here. I find it cool as option, so there goes another switch. Also polarity made big difference here, for good sound I had the extra diode same polarity as D1. In the end I really like the sound of this one.
Verified. Works great! Thank you!
ReplyDeleteGreat! Much appriciated!
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ReplyDeleteForgot to say that I have the real pedal. Now I prefer the one I've made with your precious help. That, vintage caps and a J201 in place of the 2n5457, maybe... Cheers! And keep the good work!
I have built this. Initially the sound was muffled (I know it's muff clone, but it's still bad) and output level was rather low, about half of usual pedal gain. I checked voltages and Q4 (output boost fet) was 6.5, which I thought was suspicious. I biased it to 4.5 and it was much better, then dialed by ear with waveform preview in DAW and I found a sweet spot at about 2.5v, sound was fuller and output level was the expected one. 2.5 is interesting as it's kind of reversed polarity from 6.5 (9-6.5=2.5). So, replaced 10k resistor that goes to Q4-D with 82k.
ReplyDeleteThen I didn't quite like what color controller does, it's a kind of sweep between HP and LP filters as far as I can see. 3.3n cap with the 39k resistor next it is the high pass and 10n cap at A6 + 39k at C10 is low pass. If you calculate the cutoff frequencies they are quite drastic. Basically my feeling was that the controller was not very usable it would sound bad at any position, especially at extremes, with the first half of the range of no use at all (unless you like to hear only the mud part of the signal). I tried to tackle it, first by modifying the knob balance - adding 5k or more resistor between color 3 and volume 3 pushes the sweep middle point counterclockwise, so the treble part is more present throughout the range. That was a tad better to me. Then lowering resistance of C10 39k would push low pass frequency a bit higher...
Then I accidentally bypassed the whole color module and it would sound much, much better to me, so I ended scrapping the whole filter section, connecting volume 3 to H8 (100n cap is output point of previous section). In addition to fuller tone I recovered more output volume (and saved drilling a whole).
Couldn't find W25k pot for hot, so used W20k, which seems to work quite fine.
With all three knobs fully clockwise it would start to self oscillate and amplify all dirt, adding capacitance next to Q2 tames that, though I liked to have more "air" when not maxed the drive, so I made it a switch. Also adding more than 2n cap acts as low pass, which can be alternative to color knob...
I also tried to play with diode types and found something interesting. Adding a germanium diode to D1/D2 couple next to Q2 filters oscillation and low end dirt that gets amplified wit hot and dive maxed out. It also changes the dynamics quite noticeably, there's less sustain (which would be crazy when maxed) with similar level of fuzziness, so to say. I tried bunch of diodes this way (silicon ones had no effect) and settled on salvaged vintage OA79, though N60 were very similar here. I find it cool as option, so there goes another switch. Also polarity made big difference here, for good sound I had the extra diode same polarity as D1. In the end I really like the sound of this one.
Hi-res image, please!
ReplyDelete