Technicality

I made some, it was fun and not that hard even though I didn't really know what I was doing. It did take a lot of patience though. It took about 15 minutes at the highest speed my drill would go (fast enough that the bobbin was a blur) to wind one, during which one lapse in concentration can mess it up, in which case its time to start again. Here was my set up [url="http://www.idlecreations.com/loz/pup1.jpg"]http://www.idlecreat...om/loz/pup1.jpg[/url] For counting the winds I had an arduino counting clicks of a little switch which triggered from a bolt taped to the drill. I overwound them both a bit, measured the impedance, and then took some winds off by hand. You could possibly do it without counting, but the taking winds off after measuring process would take a lot longer. The tape around one end of the bobbin is to try and discourage the wire coming off that end and winding round the screw. When this happened at high speed it was a real pain because in a fraction of a second you have a load of winds on it that you need to unwind very carefully. The wire is so thin its really really flimsy. I found that the closer the spool of wire was to the winding mechanism the more likely it was that the wire would snap from the changes in tension due to the bobbin shape. As a result the spool of wire is way way out of the picture out the door across the hallway and in another room. I think I had two failed winds where the wire snapped around the 7 minute mark (before I moved the spool further away). Oh, I also had a way of securing the drill in the on position. Holding the very springy button in for 15 minutes whilst concentrating on winding proved too difficult for me. And they eventually came out like this: [url="http://www.idlecreations.com/loz/pup2.jpg"]http://www.idlecreat...om/loz/pup2.jpg[/url] After this picture I wound string around the windings and potted them for protection. The surrounds are a bit big because I really had no idea how much space the wire would take up. The only things I bought were the wire and magnets, so it was pretty cheap.

This discussion got me thinking about the whole issue for the first time since I built it, so I plugged it in and did some quick tests to look into it further. It turns out the high pass and band pass both seem to sound Ok blended. I'd guess because in both cases you are blending clean signal with bass cut phase shifted signal, and its the bass frequencies that cancel out the worst. Here's a short mp3 of how they sound: Played Clean, Low pass wet, Low pass 50/50 mix, band pass 50/50 mix, high pass 50/50 mix [media]http://idlecreations.com/loz/meatball_test.mp3[/media] This really surprised me. I think I just never noticed it before because I don't experiment much with the high pass and band pass on bass, because the wet signal usually sounds so awful to me on its own. I'm going to have to experiment with them some more though clearly.

I did a bit of reading and experimentation trying to work this all out after I'd built it and discovered the problem. I'm pretty sure that guy is not quite correct. If I remember correctly, the filter in the schematic is called a "state variable filter". The band pass is 180 degrees out of phase (I'd imagine why some envelope pedals have a "mix" mode that mixes the bandpass and clean). The high and low pass however, change phase depending on the frequency. One will be somewhere between 0-180, and the other is somewhere between 180-360 degrees out of phase. Different pitches will generate different phases for these, so an inverter won't cut it. In the end I decided against the headache of trying to cram an extra inverter into an already built pedal just so I could blend the band pass without it thinning out. I'd be very interested to hear how useful you find blending the band pass if you do try it though. If it turns out to be useful I might attempt it.

I used VTL5c3's.

You probably can take it out. I think the bubbling sound only happened to me playing above the lowest octave under fairly specific settings and when I played the notes with exactly the right attack. Before that it didn't seem to do anything whatsoever and I was considering removing it and using the switch for something else. I quite liked the sound though and might want to make it intentionally sometime, so I'm keeping the switch. I think the full build idea to test is a good one, as with a different bass and a different person playing it, it wouldn't surprise me if yours behaved a bit differently to mine.

Yeah, most of the time even when putting something other than bass through it I leave it fully wet. The strange thing about this circuit is that there always seems to be more than one way to get what you want. Changing the intensity and colour can tone down the effect a bit like a blend, and you can get similar sounds at different range settings by adjusting the sensitivity, intensity and colour. Sometimes the bandwidth switch doesn't seem to do anything, and sometimes it toggles between smooth and this bubbly type sound. It definitely feels like a circuit that could get by on less controls, but I wouldn't know which to take out due to the way they all interact. Good luck with your build. For all its eccentricities I found the results to be more than worth the trouble, there are some fantastic sounds you can get out of it.

Here's a little recording I did with my build back when I made it a month or so ago (amateur musician who doesn't really know what they are doing alert!): [media]http://www.youtube.com/watch?v=qSW4jEA6efo[/media] My box is a bit bigger than a 1590B, and it was a real squeeze to fit everything in. I saved a bit of space by using small slide switches instead of the rotary switch, but I had no space left at all when it was done. Without space for the battery it could have been a bit smaller though (the top section above the controls is basically just the battery). The main problem is squeezing all those pots into the box means everything else needs to be very flat. There is a mod you can do to the Colour pot that really improves the useful range for it. Worth looking up if you find (like I did) that only a few degrees near one extreme was useful. Here's my take on the controls after having mucked about with it a fair bit: I find the blend pretty useless for bass. The filter changes phase with frequency, so when you blend the clean in with it you get the same kind of effect as when you wire pickups out of phase (the sound thins considerably). I never really use the Hi pass/Band pass for bass. Since the blend doesn't really work I can't get much use from them. [Edit: It turns out the blend does work better in band/hi pass, and I just completely failed to notice this] I do use the up/down occasionally. You can get some interesting sounds out of it. All the other controls are fairly essential apart from maybe the sensitivity, which you can adjust by increasing the volume on the bass, and decreasing it on the amp to match. If you are using other pedals though that may not be an option. If I wanted to make another one even smaller and just for bass, I'd remove the blend, battery, hi/lo/band switch and maybe sensitivity and the up/down if I absolutely had to, and then go shopping for the smallest shallowest pots and switches I could find. Oh also this is where I got all the harder to find parts (very reasonable postage): [url="http://doctortweek.co.uk/"]http://doctortweek.co.uk/[/url] Hope this helps.

Sounds exactly like a ground loop problem to me. Seperating the power to the problem pedal should fix it.