Passive Pedal - Tone, Overdrive and Phaser

[jpr_musicman]

Hi guys, i've been pondering making a passive pedal for a while (i don't want to rely on batteries whilst i'm away), mainly for tone control. I think, although awaiting parts to try out my design, i've worked out the eq section. This will be somewhat like a varitone, but with extra resistors set inside the box to level the settings. A schematic of sorts below.

I was thinking about what other effects i've used on my cheap Zoom B1, which are very occasional overdrive, phaser, and 'sub bass' (octave down). I think i've worked out how to do a simple overdrive circuit using diodes, sub bass is clearly not possible passively (right?) but i recall reading somewhere that it was possible to make a passive phaser, although i can't find any schematics, or even mention of it around. Does anyone know how to make a passive phaser? Any thoughts on the pedal?



C1=0.033uf   C2=0.01uf   C3=0.0033uf   C4=0.01uf   C5=0.1uf
(Bass Boost)  (Heavy    )    (Slap                           )    (Thin    )


hmm, pic didn't work, here's the link - https://skydrive.live.com/embedphoto.aspx/stuff/eq%20schematic.jpg?cid=2f644d6c76e2837f&sc=photos%22

[rockhorst]

(i don't want to rely on batteries whilst i'm away)

I don't think anyone should (want to) rely on batteries...Using a stompbox implies using an amp, so why not stick a dedicated power supply in an empty socket as well? Even if you could build ear pleasing passive phasers, distortions and tone controls and string 'em together, I think you would at least want to stick a buffer after them, which certainly can not be done passively.

Just my 2cts...hope you find the schematic you're looking for though, if it indeed exists.

[darron]

this guy in australia makes heaps of passive pedals... just like what you're talking about... no shematics

i suppose it helps to have them following a buffered pedal???


http://www.cavepassivepedals.com.au/

[jpr_musicman]

Thanks for your replies guys. I've seen the cave pedals, and they look great, that's where i saw the passive phaser (tubular waves). I was sorely tempted, however i don't really want a range of pedals (i'm a sucker for minimal) I'm aiming for one tiddly pedal with lots crammed into it. Also their tone control (Furry Tongue), doesn't do quite what i'm after (i got the components for my diy one today, so i'll have a go and see if it even works, or i missed the mark entirely) Their series of 'Grunt's sound great i think.

I'm never using my rig is the problem with power, turn up and plug in normally, that's why i want to avoid mains power (routing round for an available socket can be a pain, i know i'm being fussy, but eh)

I'm not really clear on buffer pedals, i need to do some more research on them.

James

[darron]

maybe you could setup some phantom powering! ie a module in your amp that sends the +9v down the cable to the amp and then on the pedal board splices it out. the power is able to be isolated from the signal as the signal is AC and the power is DC.

i'm sceptical about passive effects... the sound samples are surprisingly good for something that i thought would just be a gimmick. well, the signal straight out of your guitar is very weak. think of the pickups as a form of generator making a small voltage. the more that you load it down the more your tone gets sucked down (you lose higher frequencies first). i assume that these passive pedals will sound better if you have buffered pedals before and/ after. IE a boss pedal uses buffered switching (not true bypass in this case) and reprocesses the signal so that it doesn't get loaded down.