hi guys
i need ur help on this one. i know its not a madbean project but i know many of u have built this with great success
ive some problems with the madsphere build
ive built everything up as described in the doc. wiring is the same
and it works basically
but:
when i turn the up / down switch the signal is off. when i then reduce the insensity pot, the signal comes back but on lower vol and brighter
on some settings there is a vol drop but i guess thats normal?
and the led doesnt work at all. should show the modulation right?
any input appreciated. :-)
Where did you get your LM1458 IC from?
got it from musikding
but its a mcp1458p. can that be the issue? ive read somewhere that not every ic works but i thought every 1458
i think i order a lm1458n from ebay
ok im really stuck here...
i bought an LM1458N from ebay and it doesnt work either.
altough i get some sound through the pedal, the following problems occur:
-) signal vol very low
-) up/down switch only works on one position, on the other the signal is off (comes back when i turn the instensity down)
-) the LED is off on the up/down position where i get a sound, on the other up/down position the LED lights but doesnt blink
-) the quack sound is increasing when i hit the guitar harder... that not normal right? when i pick the notes soft, the effect is only very minimal
i tried:
-) LM1458N instead of MCP145P
-) measure everything around the 1458 and the up/down switch. connections are all working as they should
-) removed the LED
-) changed the Rled from 2k2 to 300R
when theres a modulation problem where do i have to search / start?
any hints.
-) 3PDT wiring is correct
-) send / return switching works
can a contact failure be the problem? or a wrong part value?
Thanks! i appreciate any help here
I had a "somewhat" similar problem with my full size build (the up/down working only in one position and other odd happenings)
It turns out that my V+ (9V) was shorting to Ground because my LED lead for the on/off was contacting a metal bezel.
Check to see if you are getting voltage on your ground. IF not, it would be good to post some voltage readings and good pics of your build (BOTH PCB sides, wiring, switch, etc.)
at least it sounds like it generally works... in the up position the led is dark and when you strum it should light up. in the down position it lights up all the time and when strumming it will dim. also, it is normal that the quack is stronger when hitting the strings harder, the sensitivity controls how hard you have to strum.
unfortunately, no idea where to start looking though
Thanks !
at least i could fix the volume drop problem. i soldered in 7.5k instead of 1.5k :/ i swapped them and now it has normal volume
ok that means the LED generally works, but it doesnt light up or dim when strumming.
ok strange though, because sensitivity is all the way turned up.
i checked now all parts, and they are all correct. so it must be a contact failure with up/down switch. i measured it, and its connected correct, but yeah maybe the problem lies somewhere else.
I have a similar problem now: in one position of the up/down the pedal seem to generally work, in the other i get a strange noise, like its directly connected to 9V or so .... ill check everything for that ;)
ill keep u updated
Did you use the recommended VTL 5C3s, or did you roll your own? Mine barely worked with the VTL 5C3s, but 2 green LEDs and Tayda LDRs made it sing!
dont use proper vactrols, use green led and 2M dark photocells
try a different 1458 chip
even try other dual op amps. despite what taylor says, others do work, eg 5532
Thanks
at the moment i use everything as in the Musicpcb BOM.
I use the VTL5C3
ok i can try that. would photocells work, that i bought from smallbear for the univibe?
i have some lying around
i tried so far a MC1458P, LM1458N and a RC4558P, none of them has made any difference
i guessed that, saw no reason why other opamps shouldnt work
Check your ground to see if it is getting ANY voltage. Mine was bleeding the LED voltage onto the ground circuit and was doing EXACTLY what you are describing now.
unfortunately it doesnt look like this is the cause. ground looks ok.
i checked back all connections around the up/down switch and everything should be working as designed...
i couldnt find any mistakes
down position works, up doesnt.
When the up/down switch engages the 9V to the Led resistors and the LED cathodes to the intensity pot, then the signal is off. but the voltage is there, because the LED is also on.
Everything else works.
as the higher voltage is pointing to the OUtput of the 1458, i wonder if this is able to work in any way...
the up / down switch doesnt swap the 1458 to the other direction...
any suggestions what i can try?
the VTL5C3 work, and dont seem to be a problem
I'm not totally convinced your pedal isn't working properly. Turn down basically EVERYTHING in up mode. Decay, threshold, make the attack longer, go to low mode, turn the sweep down, turn your guitar volume down, etc. Up mode in anything Mutron-based is annoyingly difficult to get working properly.
thanks for the tip, jon
when i turn down the intensity, i get a lower sound in the up position. but thats only working in some positions of the rotary switches.
when i turn everything up, and i chnage the filter switch to the highest frequency, i get a noisy signal, like some voltage gets directly connected to the signal path.
maybe i dont know the circuit not well enough, but i barely can find any infos on the web on this one, that helps me out here.
i watched a demo of youtube of the meatsphere, where this strange behaviour didnt occur (up/down switch)
You are using the Meatsphere PCB from Taylor right?
Stupid question but..... Did you solder the Rotary switches on the correct side of the PCB?
It has happened before... :-\
yes, i use the PCB from musicpcb.com
not a stupid question, since I wanted to do it wrong before soldering :)
but they are on the side without the part numbers
Ill post some pictures when im at home, maybe that clears something up :)
here are some pics of my build...
let me know if you need better pics
(http://i.imgur.com/enfKuor.jpg)
(http://i.imgur.com/3TIYflM.jpg)
(http://i.imgur.com/EGTsZCg.jpg)
(http://i.imgur.com/0GrmMEq.jpg)
maybe it helps, i guess not, but i hope...
What kind of rotaries are those? I know the PCB is supposed to work on the Alpha/Lorlin style 3P4T but.... some other companies rotate and make contact differently.
i used these:
http://www.musikding.de/Rotary-switch-3P4T-sealed-pcb?lang=eng
i doubt the switch is the problem, it does what it should according to the schematic.
It connects the diodes correctly to either 9V or ground
Looking carefully at your pics.
The first resistor directly below the Blend pot. It looks like that could be a 10ohm resistor. Can you verify that it is a 100Kohm as it should be?
Also, can you explain how the shunted jack is wired? Something does not look right with it. When the plug is removed (I am assuming that is the Pedal1 jack) the Tip should be grounded. It looks like you wired it so that it does not change when the plug is removed.
EDIT: OK... Looks like it is the Send/Return loop. Be sure that it is wired according to the build doc.
EDIT2: Can you post a bit better pic of your stomp switch and its wiring?
send - return works, when theres nothing plugged in to the return, there is a direct connection from send to return
hmm good point ill check the resistor, but it should be 100k (the lights just very bad, and the orange looks brown)
ill post a pic of the switch later
thanks dude for your analysis ;)
Quote from: luks999 on December 10, 2014, 11:27:57 AM
hmm good point ill check the resistor, but it should be 100k (the lights just very bad, and the orange looks brown)
In the pictures, it looks like the resistor is marked Brown, Black, Black,
Gold, Brown. This indicates a 10 ohm/1% resistor. It could be the lighting though.
Another alternative is to make a post on DIYStompboxes. Taylor (he runs MusicPCB) is a frequent visitor on there and has a LOT more knowledge on this.
yesterday i soldered in a new one to be sure, but that was not the problem...
The wiring of the 3PDT is working too, i measured it too
Thanks Govmt_Lacky for your help! :) i will do that
Hi!
I've build the meatsphere a few weeks ago, boxed it and spend some time experimenting on it (damn good sounds in there).
But there's not enough sensitivity when playing single not with my strat.
Reducing the value of the 4K7 resistor (after "sens" pot) may alter balance frequency response (am I right?).
So I'd like to increase sensitivity using feedback loop of the op-amp.
Anyone can help me on this?
Thank you (hope you'll understand my frenchie english)