built a magnavibe, not what i expected..

Started by nightendday, November 09, 2012, 01:03:26 AM

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Ben Lyman

Thanks Duck, couldn't get that to make a difference, but probably only because I was doing it all wrong in the first place.

Here's my new experiment:
100k (or choice) *BETWEEN* collector and "L" cap. The amount of depth increases substantially  :)  although the volume also drops  :(
This mod may be the one thing worthy of a make up gain stage but I need you "more-pro" guys to try it and lemme know what you think.

Rather than across the cap (allowing dc flow) I put it in front of OR after, either way sounds the same (I think?)
I guess it is reducing the one signal (from collector) and allowing a little more of the (inverted?) signal from the emitter.
I don't know what it's doing but it turns an otherwise subtle vibrato into something more "in your face"

I'm off to try some lower value resistors right there and see if I can lessen the depth a little bit and find a happy medium.
"I like distortion and I like delay. There... I said it!"
                                                                          -S. Vai

pipporan

Quoteand I saw pipporan, huddling under his umbrella, at the giro.
sorry man, too much rain for my taste;)
and afterall, i never liked the chrono-stages

last 2 questions about magnavibe: about the flashing led, i have to put in 3PDT, right? otherwise it will turn on when i plug the power...?

if i want to put 2 effects in the same box, with indipendent 3pdt switches (in this case they could be EA tremolo i just build and this magnavibe), which one would you put first in the chain? i would think the vibrato...and, putting 2 effects plugging them from the same dc plug, doesnt have any bad effects for power (i dont know, something like there's no enough power for both)??

duck_arse

two in one box - if you do this, you will want to put a supply filter R/C in the supply to the trem, and one in the supply to the vibe, just because it is good practice. if you llok over at AMZ, there is a page about supply filters will explain all. there should be plenty of supply juice for these particular circuits from "a dc plug", no problem.

the flashing led will be flashing all the while the oscillator is running. unless you switch around the led, but that would be daft. and, this type oscillator can be a little slow to start up at certain settings, so you might hit the switch and get .................... tr ... trremm ..... tremolo, like. I'd personally let the oscillator run from when you plug in, and just use dpdt to bypass the signal around the whole fx. others like to leave the trem in-line w/ the signal the whole time, and just stop the osc (there are ways), but again, you might get slow start which you might not like.

otherwise, use a 3pdt for an effect on/off led, and have a seperate led flashing all the time. I did that on my ez-type trem, with a blinking orangs mounted above an on/off red, in a small block of perspex. there is a million ways to do these things .....

I'm not much chop for the individual TT, the team TT slightly more interesting.

and Ben, if you're still reading - does the tour of california pass your house this year?
don't make me draw another line.

Ben Lyman

Quote from: duck_arse on May 18, 2016, 11:41:15 AM
and Ben, if you're still reading - does the tour of california pass your house this year?
About 15 min. away, the final stage is right downtown. I used to live on a dead end street right downtown and any bike race, foot race, parade, etc. would trap us in our houses on that street unless we all moved our cars out the night before
"I like distortion and I like delay. There... I said it!"
                                                                          -S. Vai

pipporan

Quotetwo in one box - if you do this, you will want to put a supply filter R/C in the supply to the trem, and one in the supply to the vibe, just because it is good practice. if you llok over at AMZ, there is a page about supply filters will explain all. there should be plenty of supply juice for these particular circuits from "a dc plug", no problem.

mmmm...too many potential troubles for this, i have plenty of boxes right now, i'll box in an enclosure for each effect:D


duck_arse

nah, easy. you just need to add a resistor and a cap on each of your boards, and many designs/layouts will already have the parts there. pick the builds you think are the right ones for you, show us here, and we'll fix you right up, I'll give you the drum.
don't make me draw another line.

pipporan

from this page:
http://www.muzique.com/lab/filter.htm
what is a choke???do i need it fo my purpose? or it's just about mount a resistor and a cap at the beginning of the circuit?

midwayfair

A choke is a big honkin' inductor used for power filtering.
My band, Midway Fair: www.midwayfair.org. Myself's music and things I make: www.jonpattonmusic.com. DIY pedal demos: www.youtube.com/jonspatton. PCBs of my Bearhug Compressor and Cardinal Harmonic Tremolo are available from http://www.1776effects.com!

duck_arse

this page is the one you really want:

http://www.muzique.com/lab/hum.htm

I always get the links confused. and as midway says, honkin big to be any use, not really for our pedal purposes. and a choke is an inductor, which works, roughly, the opposite way a capacitor does, it chokes-off high freq AC, and allows DC through.
don't make me draw another line.

pipporan

#49
so, final recap should be:
for DC: 100ohm resistor between V+ e V+ input, 220uf cap between V+/V Input and ground
for signal: 100-1k ohms resistor between audio input and board input, and 220pf cap between input and ground...nothing more is required, right?
so, this thing could be helpfull in general, even if i put one effect in one box...and this should help even for the fact that i will use plastic boxes, right?
guys, you are a endless source of infos..i really really appreciate!!!!!!! if you continue like this, there's a serious risk that at the end, i will understand a bit about electronic:)

EDIT: something like this??

duck_arse

there is no need for the filter on the audio input. some circuits include that protection, others don't. the power supply filter is correct.

an easy way with plastic boxes is to cut a thin sheet of Aluminium (or thick, if you like) the same size to fit inside the lid, or in the bottom of the box. then drill all your pot and switch holes in it, and it will provide shielding and some strengthening. as no-one will ever see it, it can be the crappiest bit of sheet you have laying about, all odd holes and off square, etc.

you could even bend it square on one side, to run up the box side, and then mount your jacks through the plate and sidewall.
don't make me draw another line.

Ben Lyman

I assume there are cuts under those resistors?


"I like distortion and I like delay. There... I said it!"
                                                                          -S. Vai

pipporan

QuoteI assume there are cuts under those resistors?

ops :-[ :-[ :-[ :-[