can someone please explain the function of "gate" and "trigger" on circuits such as ADSR?

thanks
vito

thank you colin.

hi all,

i found this scheme online - http://personal.inet.fi/koti/holmberg/images/shape.jpg

can the ICs there be any old opamp?

what's meant by "1/2Vcc"? how do i supply .5v?

lastly, what does the "SPDT MUX" switch do?

thanks
-vito

great, that looks just fine. a couple questions though:

there is a symbol on the schematic that looks like a Venn diagram (two circles overlapping) - what kind of component/connection is this?

would anybody be so kind as to rig up a PCB layout for me? i've never done such an elaborate project before (most of my experiences have been in modifying circuits, not so much building them from scratch) and i'd like to etch a PCB for this particular project. i'd be most grateful for any help in this regard.

thanks, colin. do you recommend a passive or active low pass filter? how would i check for the correct impedance, and correct it if need be?

*bump*

i've concluded that i'd like to add an ADSR envelope to the keyboard, as well as a low-pass filter.

are these components capable of being added onto the signal after it's been processed, as it's about to go through to the speaker? or must they act earlier in the signal chain?

thanks colin, that might be the way to go. coaxial cable makes me think of the rather stiff cable used for TVs, is that what you meant? i can't imagine using that as a patch cable for a bent keyboard

does anybody know of an online resource from which i could purchase RCA patch cables? i'm looking for cables around a foot long.

hi all,
i just got a Wurlitzer Music Learning Module on the cheap at the local thrift store. it's got a decent sound, but the only control on it is volume and i'm interested in adding perhaps a filter to it, or an envelope, or anything that'll allow me to customize the sound. i'd normally just dive in and poke around with a couple probes but i don't want to fry it.

does anyone have experience with one of these MLMs? any information that'll point me in the right direction is appreciated.

i want to do it for all the controls on the pedal and for each pedal.

if someone wants to draw up a quick schematic of how i could implement the 4066 it would be greatly appreciated...

thanks Colin, i'm reading up about the 4066 and it looks like the way to go. it's very hard to visualize how it would all work together without a pedal in front of me so i'll wait til i'm back home to continue planning it out.

switching between the pots with a DPDT sounds simple enough... could you elaborate on "SPDT and a bunch of 4016's or 4066's"? i don't have much experience using ICs so i don't really know what that means

i had an idea to allow me to change the controls on my pedals on the fly without bending down to turn the knobs... i would normally just go ahead and try the idea out to see if it would work but i'm not home right now and don't have access to my pedals. here's the idea:

i would solder wires to the contact points of one of the pots. those wires would extend up to a box (or some kind of enclosure) where they would connect to another pot. this way i could keep the pedal on the floor and still use it as a stomp box, but would be able to control it standing up... however i don't know if the second pot would affect it correctly if it were just soldered over the preexisting pot. i don't want to take out the original pot but rather just connect another one to the same place and be able to use them interchangeably.

i hope i articulated this idea well enough for you guys to understand it... anyway, is it possible? it would be so helpful because i like to change my sound around as i play and bending down to do it is annoying and inefficient.

thanks
littlewing

does anybody have info regarding the ph50? i just picked one up outside someone's house that was going to be thrown out. some of the buttons don't work or only work when i press very hard and i can't seem to get the MIDI to work, so i'd like to try to modify/bend it... are there any known mods out there? any help is appreciated

thanks
littlewing