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[1 4.9 - 5.3]

I just tested my LowRider build and it almost works, but there seem to be some problems with the 2nd Octave Down. Clean, Oct Up and 1st Oct Down work perfectly fine. The 2nd Octave Down is very much louder than the other channels and when idle (not playing) there's some weird ticking going on. It's not a constant tick, but it does seem to have some regularity to it. Kinda like the pedal sending out Morse code (tr-tr-tr-tr stop tr-tr-tr or something like that). This happens even with my hands on the strings and I can sometimes briefly shut it up by moving my hand slightly, but then it starts again. This would suggest to me some grounding problem? I think my IC readings support this idea, see below.

I've checked the IC voltages with the ones in this topic. Below are my values (half supply is about 5V), the ones I think are off/peculiar are in bold typeface. What I find odd is that it only manifests (at least audibly) on the 2nd octave, yet my readings of the 4013 ICs quite different with the reference ones. Is this consistent?

IC1:  TL072 checks out fine

IC2:  LM324
1  4.9 - 5.3 (periodically goes up and down)
2  5.1
3  5.1
4  9.5
5  5.1
6  5
7  4.9
8  2 mV (stays steady at this and doesn't go down to 0)
9  5
10  5.1
11  0
12  5
13  5.1
14  3.9 - 4.6 (periodically goes up and down)

IC 3:  CD4013 (9, 12 and 13 are really disturbing here, compared to the reference).
1  0
2  9.5
3  0
4  3.9 - 4.6 (periodically goes up and down)
5  0
6  0
7  0
8  0
9  0
10  0
11  9.5
12  0
13  9.5
14  9.5

IC 4:  CD4013 (lots of differences here)
1  0
2  9.5
3  0
4  0
5  9.5
6  0
7  0
8  0
9  0
10  0
11  0
12  0
13  9.5
14  9.1

IC5:  TL074 checks out fine

IC6:  TL074 checks out fine

Any suggestions?

*Edit*: Just to clarify, when playing everything is fine, also on the 2nd octave down. But when I stop playing it makes noise, sometimes intermittent like Morse code, sometimes a constant chop-chop-chop like there's a helicopter in the room, and it's quite loud. It's seems periodic, which makes me suspect something with the clock? At the moment it's a pedal that literally demands you keep playing

Could some of the bass afficionados here tell me how well suited is the Weener Wah for use with bass? Much obliged

Ok, so I built this high octane Blues Driver for a friend, working on 18V using an ICL 7660 S CPAZ like in a Road Rage. So I get a phone call two days ago that his chorus pedal is making weird ticking noises in combination with it. I can best describe it as a birdlike chirping, like waking up on a nice spring morning. Cool yet undesired. I made a recording of it whilst fiddling the depth and speed knobs:

Recording

This happened with his DOD Super Stereo Chorus FX68 (sadly, no schematic is available, though there is one for the FX67) but not with an Arion Stereo Chorus SCH-1.

This is the schematic for the Blues Breaker:


Anyone ever experienced something similar or have any clues/tests/suggestions?

Ok, this is a bit of a long shot, but I'm hoping someone can help me out. I've been working on a modified Blues Breaker circuit, running on 18V, and designed a PCB for it that I had fabbed by OSH Park. I tried the circuit before hand on a bread board but it was oscillating, which I thought was caused by long wires to the IC. But I just fired up my prototype and it's oscillating as well.

I tried audioprobing the circuit and the oscillation is all through the circuit, the pitch responds to turning any of the controls. Interestingly, I got the loudest sine tone when touching the input jack, so I suspect that something is going wrong right in the beginning of the circuit. This is supported by the IC voltages:

Pin 1: 9V
Pin 2: 9V
Pin 3: 8V
Pin 4: 0V
Pin 5: 9V
Pin 6: 9V
Pin 7: 9V
Pin 8: 18V

Notice Pin 3 with a 1V drop compared to the others. I'd expect 9V there?

I really don't know what to look for. Everything seems to be connected properly as far as I can tell with my DMM. I checked the schematic that I made to the one at GGG and the Morning Glory project, and I don't see any faults (but may of course be wrong). Any and all suggestions welcome.

Schematic


Board

I've addressed a similar issue on DIYSB months ago, but it has come up again and maybe (hopefully) someone here has some interesting views to contribute.

I've build a modded Wampler Plexi Drive for a friend a while ago. The circuit is basically three cascaded J201 stages with filtering between stages. The mods are some clipping diodes between 2nd and 3rd stage and a 'boost', which switches a bypass capacitor in/out of the first stage and a pot in series with the level pot to get a rhythm and solo setting. Here is the first stage of the effect (with the switchable cap):



Now there's two weird issues that keep coming back. Any and all ideas much appreciated.

-Circuit runs fine on 9V and 18V of a Voodoo Labs PP2+ or a OneSpot. My friend likes to run it at 12V with the PP2+. This works fine in normal mode, but when he switches to the boost (increase level and bypass cap) this induces a sort of low pitched hum, that slowly oscillates at about 1 Hz (I would describe it as 'hovering'). Sometimes it goes away for a short while, then it comes back. Like something charging up? I hoped to solve this by using a Road Rage with a 12V regulator, but no luck. No problems at 9V or 18V, just 12V (and possibly 15V).

-He likes to stack a booster in front of the Plexi. Now this is sort of a quest for more gain where no more can be found, AFAIK, but he likes it. He uses quite hot pickups in a Les Paul and it seems the high output levels can completely swipe the JFET out of operation until the signal dies of to a lower level. I have remedied this somewhat by lowering the input cap to filter out more low frequency content, but on certain setups the signal is still cut off. Can somebody explain the mechanism behind this? It's like a sudden dive bomb going to complete silence then slowly coming back up again. Why doesn't the JFET just clip the waveform off? Can a really large signal at the gate (say a few volts) upset the bias operating point of the device or something?

Thanks mucho in advance!

I just placed my second order with OSH Park and found out that they now also ship free internationally (used to be $8 standard mail), not just in the USA! I had been saving up a few designs to combine the shipping, but no need for that now!

Thought I'd share

Not sure if this is the right subforum, between general, tech and mods there seems to be a bit of a bleed through. Anyway, here it goes.

I build a NPN Mangler/Fuzz Face with some excellent OC type transistors. I totally love the pedal, but I noticed it's a bit picky running of power supplies (I loathe batteries, not an option for me). It mostly works fine on its own, but daisy chaining in any way induces noise. It works well with a Visual Sound One Spot, but there's a background whine when using a Godlyke Powerall (similar to what I noticed when using it with a Mosfet Boost aka Thunderpuss).

This got me thinking about better power filtering options in the Mangler (and Thunderpuss). One idea that I've seen a lot lately is using a film cap in addition to the electrolytic cap because they apparently don't work equally well on all frequency bands. What value would be appropriate? About 100nF would be my guess. Is higher better?

Also, usually there's also a small resistor used for power filtering, like 100R. Will this mess with the function of the 470R resistor in the FF circuit and would lowering it to 10R still have some filtering function?

Also, I've understood from Brian that a RoadRage would take care of some filtering when using PNP transistors and having them work at 9V. Is there a way to utilize the Road Rage for +9V? (I'm guessing that this won't work with a 9V regulator?)

Anyway, any other tips and insights into filtering the power in this type of circuit are very much appreciated.

Quick question: I'm designing a PCB for a Fuzz Face type circuit. If I use the Road Rage board to power it (pos. ground with -9V), is the power to the effect already filtered and rev. polarity protected? Put differently: is it still useful/sensible to incorporate those parts on the FF pcb?

I'm in the process of building a (second) Neutrino, the Burst version. I was wondering the following things:

1. The documentation states that D1 and D3 represent two diodes, to implement asymmetric clipping without a jumper. What's the original intent for symmetric clipping: one or two diodes in each direction? (I know, in the end it's about taste, just wondering).

2. The burst uses a 500k level pot, while the black version uses a 100k (and different electrolytic caps in front of it). What difference does that make? Is it the same as with guitars? (higher value pots pass more highs)?

I'm building a Mudbunny and was going for Civil War specs from the descriptions I've read. It should be a bit smoother than a Green Russian. The main difference in specs as listed in the project documents are C2, C5 and C8.

Civil War: 430 pF
Green Russian: 470 pF

I didn't have any 430s, only 470s. I did some more research and that's where the confusion starts. On DIYstompboxes forum I read that higher values (like 560 pF) sound smoother than lower values. That seems to be in contradiction with the Madbean Civil War specs.

Could anyone shed a little light on this?

I've built both the Slambox and the Thunderpuss from MB. The circuits work well, but I've noticed that they are both very picky about their power supply, either daisy chained or not. Sometimes I get a whistling noise from one of them when on a power supply, other times it's like a flanging sound. I've only had reliable results with an isolated power supply like the PP2+. Today a friend of mine checked out a slambox with a Godlyke Power All adapter, huge whistling noise. With a Boss adapter, the noise got considerably less, but still there faintly in the background.

I know that simple power supplies can cause noise and adding pedals in a daisy chain makes problems worse...but what strikes me as odd is that its primarily the mosfet boosts that seem to be affected by this. Haven't had these problems with higher gain pedals such as the AMZ Mini Booster, MB Grapevine or Neutrinos.

Anybody recognize this? What's the cause and what's the fix? Does it come with the mosfet territory?