Escodebo's PWM

[mr.adambeck]

So I built Time Escobedo's PWM, and I LOVE it!

However, I've noticed that it tracks a lot better, and sounds more "synthy" if I roll the tone knob on my guitar all the way back.  Unfortunately, this is hard to do mid song, and if I don't have the PWM on the entire song, it can be an annoying problem.  So, I thought I'd add a Low-Pass filter to the pedal to simulate having my tone knob rolled back.
The PWM loses some consistency and sustain if the volume on the guitar is down at all, so if I put it at the start of the pedal, it would definitely need a make-up gain stage.  So, I thought maybe it could be added after the 386 instead?  I'm unsure if this would just cause the same problem or not.  Does the 40106 need the volume for consistency or the 386?

I want to breadboard this, but unfortunately, my cheap breadboard doesn't like IC's (they literally keep popping back out of the breadboard!), so I thought I'd ask if anyone thought this would work before I commit this to vero.

[Chrome Dinette]

The 386 is there to make the guitar signal strong enough for the 40106 to do it's thing.  I have built one of these and I would occasionally use it with another distortion ahead of it. 

If you want to build in a losssy tone control, you may want to put it between an additional simple gain stage and the 386.

[mr.adambeck]

Okay, thanks!  Now to find the simplest gain recovery stage...  Any suggestions?  I think I have an LPB board hanging around, but I'd rather build something new if it's simpler, esp since the tone of this stage won't matter (It will be converted to a pulse wave anyways...)

It also hit me how to wire the LFO on a switch!  If I get around to rebuilding this, I'll post a tricked out Vero for everyone.   

[Dan N]

It also hit me how to wire the LFO on a switch!  If I get around to rebuilding this, I'll post a tricked out Vero for everyone.   

The lfo really cuts the volume as one of the knobs (I forget whether it's depth or speed) is turned up. Putting it on a switch may result in more gain recovery fun and games.

[mr.adambeck]

Okay, so I built this, with a tone control, and it sounds great except for one thing:
You can hear the LFO ticking when the PWM bypassed.  I have the LFO wired up on a switch, and if I turn the LFO off, the ticking stops.  Turn it back on and it starts up again.  Any ideas about something I could do to stop this?  I love this effect otherwise.  It's great for Nintendo-ish lo-fi synth sounds!

[mr.adambeck]

Dan N- The LFO doesn't seem to cause any volume drop.  However, I added a treble roll off to the start of the chain to help with tracking, and that may need some gain recovery as the high notes don't seem to ring out very long when the treble is tapered down.

Still can't figure out how to get rid of the LFO ticking.  I used the input grounded 3pdt wiring from GGG...  Would using a different type/brand of 40106 help at all?

[liquids]

heres some thoughts I had when I was expirimenting with it....yet to come back to it, but soon...maybe 

http://www.diystompboxes.com/smfforum/index.php?topic=74333.0


Ticking - tim's circuits are starting points, bare bones projects that get down to the ideas, that you can use as a springboard, it seems to me.  They are often far better when tweaked, standard buffers applied, standard power filtering, gain adjustments etc.   Keep that in mind.

Also, consider, rather than a passive r-c filter, an active one.  If tweaked well, it will have a sharper 'knee' of frequency cut off, so that notes will not be lost in the filtering.   Search here or the internet for a standard low pass sallen-key filter...3-stage versions with lots of filtering (probably more than you need) can often found on octave tracking circuits such as the EH microsynth, boss oc-2, etc.