built a magnavibe, not what i expected..

[pipporan]

these are new pics:
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i cant do with better qualities, sorry, i just have the notebook's camera to make them...

i took the layout (and schematic) from here:
http://revolutiondeux.blogspot.it/2012/01/bigfoot-fx-magnavibe.html
i followed it exactly, with no expections, exact components, exact layout...

you can see i just put the wires in pot's holes, without soldering them

this is not allowed. connections must be soldered, not poked. if you only want temporary, you can use alligator clips on leads, but just poking won't work. also:

Quote

    you can see i just put the wires in pot's holes, without soldering them

this is not allowed. those holes you have the wires poked into are not for us to use. they are mechanicals for the lugs, and we solder the wires to the lugs so the mechanicals don't get loose - bad connections - useless pot. also, wires soldered all the way up there can short to the body of the pot, another bad thing.

now i soldered the wires to the pot's lugs...and the random blinking has stopped, so it was due to the wires not well connected to the "speed" pot...

so, now all your wires are soldered, and your led is flashing ....... you need to have your LDR completely in the dark. any light, even reflections off the BB will shift the vibeing to some extent. put a box over it, or a 35mm film can, something to block the light.

the led just stays on, always bright, with no blinking...i've tried to put the circuit in complete darkness, the audio signal goes out from the circuit, perfectly clean, but no vibrato effect goes out from that (because the led is not blinking)...

maybe could it be the used capacitors that i put in the circuit? i think in next days i will rebuild the circuit in a new board, with ALL new components

[Ben Lyman]

one more thing we can't get a clear view of is the pots. If there is a loose strand or solder bridge between any of those lugs it can cause the 9v to flow straight thru the pot. Also if the pot is defective/damaged or wired incorrectly this can happen, make sure pots have their wipers soldered to the correct adjacent lugs.

[Kipper4]

I'm perplexed the layout has 9 rows down. Your board has 10.
Have you probed it with an Audio probe. To see what's happening with the signal ?
Maybe it's time to do some transistor voltages too.

[duck_arse]

erm, I think you've built the board upside down.

when looking at a board layout, you look down onto the tops of the components, with the board underneath them, and the copper tracks underneath that. so you just poke the parts thu the holes until your board, viewed from above (cause you can't see the components from underneath, the copper side, of the board) looks exactly like the one in the diagram.

[also, when I say solder with confidence, you do then need to meter-measure all the wired connections before you power on, but you can do that with confidence too.]

[pipporan]

one more thing we can't get a clear view of is the pots. If there is a loose strand or solder bridge between any of those lugs it can cause the 9v to flow straight thru the pot. Also if the pot is defective/damaged or wired incorrectly this can happen, make sure pots have their wipers soldered to the correct adjacent lugs.

the pots now are well soldered, i'm sure of it, no unwanted bridges between the lugs, the pots are all bran new, of the right resistance, ecc ecc ecc

I'm perplexed the layout has 9 rows down. Your board has 10.

when looking at a board layout, you look down onto the tops of the components, with the board underneath them, and the copper tracks underneath that. so you just poke the parts thu the holes until your board, viewed from above (cause you can't see the components from underneath, the copper side, of the board) looks exactly like the one in the diagram.

my board is a little different from the original because i made a mistake and made a cut track on the last row, so i used the 10th row to make a bridge between the 2 parts of the 9th row that i divided for my mistake...you see the board like in a specular (mirror) view because when i cut tracks i did it looking at the back of the board (the part of the strips), without thinking that verything would be t his contrary (and very difficoult to view and debug) (as you say, duck_arse: lack of experience:-( )

Have you probed it with an Audio probe. To see what's happening with the signal ?

i didnt use an audio probe because the signal exit from the output correctly, there's no vibrato effect just because the led is always on instead of flashing...

i think i will spare time desoldering everything and rebuilding a new board...:-(

[pipporan]

ok, just a fast update: i've just finish to rebuild it, i've just conncted the power, and the led's flashing!!!!!!!
now i'll try with the sound:D, but i'm confident it will work

guys, i really want to say a thing: i'm 35, i've been atteding forums online about lot of stuff (motorcycles, poker, informatic, music, RVs, etc etc etc), but i NEVER had an welcome like this: i had no active post in ts forum, and lot of people immediately tried to help me, with lots of differents advice...i'm impressed, and afterall, very very grateful!!!

P.S. i think it will happen soon that i will ask again for some other pedal:)

[pipporan]

ah, just 2 thing:
for anyone else who will build this pedal, i suggest super-bright RED led: the effect is more intense with red than with any other colours...
the second one: how could i do to have the EXTERNAL led flashing too??

[duck_arse]

the very most simple way to have a rate led external is to wire another led in series with the first one. it will go dim to follow the depth setting as well. it can go between the 1k8 and the depth pot if that is easier, as long as it is in series somewhere in that string of parts.

I have two questions for you - did you try a different value for the "Lyman cap" - and - is the giro passing your house this year?

and good work on the getting to work.

[pipporan]

ok, so i could put for example here (where i painted on the image the 2 green "X")??and then simply add a resistor?there is no problems of too much power consumption?

did you try a different value for the "Lyman cap"

sorry my friend, you have to specify which is the lyman cap (and what it does:D)...anyway, i havent changed nothing, to be sure it works:)

is the giro passing your house this year?

EXACTLY!!!!!
the tenth stage pass really close to florence, but afterall, the NINTH stage (15th may, it's an individual stage, very short) goes from RADDA IN CHIANTI to GREVE IN CHIANTI...maybe you know "CHIANTI" zone, it's one of the first toscan region to be famous (famous for the wine from centuries)...well, that's where i come from:)
where are you from, duck?

[Ben Lyman]

I believe it's probably that 100nF on the far right of the picture, I replaced mine with a 10nF, IIRC. It might be dependent on the type of LDR/LED combo you use, but for me it seemed to modulate the upper frequencies better and gave a nice shimmery effect.

[duck_arse]

no, not that green crossed link. I think it easiest to cut the top trace, say at A10. then wire the new led Anode to A9 and the Kathode to A11. there is no other additions, no extra resistor needed, just the new led.

the lyman cap is the 100nF on the lyman left, yes. I thought it sounded best at 5n6, but this will vary with your particular build and taste.

and I expect you to be on the street waving that day, pipporan, so I can see when I'm watching on teevee here in sydney, australia. (I ask all european members if the grand tours are passing, you're the first to say EXACTLY!!!!!)

[Ben Lyman]

You might also try a small resistor (say 8k2 to 22k ish) across the so called "Lyman cap" and it should introduce a bit of volume modulation along with the pitch bending. 

[pipporan]

I believe it's probably that 100nF on the far right of the picture, I replaced mine with a 10nF, IIRC

the lyman cap is the 100nF on the lyman left, yes. I thought it sounded best at 5n6, but this will vary with your particular build and taste.

You might also try a small resistor (say 8k2 to 22k ish) across the so called "Lyman cap" and it should introduce a bit of volume modulation along with the pitch bending.

ok, so i think that before boxing it, i will put sockets instead of lyman cap, so i can try some options...

I think it easiest to cut the top trace, say at A10. then wire the new led Anode to A9 and the Kathode to A11. there is no other additions, no extra resistor needed, just the new led.

perfect, if it's so easy to have it blinking, that's what i will do!

and I expect you to be on the street waving that day, pipporan, so I can see when I'm watching on teevee here in sydney, australia. (I ask all european members if the grand tours are passing, you're the first to say EXACTLY!!!!!)

wow from sidney...from the other side of the planet...do you follow the big cycling tours?
i always followed them, until marco pantani died, then i stopped...it was the only sportman that ever gave me some emotions..after him, i lost interest in it...i just look some of the high mountains stag of giro d'italia and tour de france...are they (the big tours) very famous in australia?

[pipporan]

I think it easiest to cut the top trace, say at A10. then wire the new led Anode to A9 and the Kathode to A11. there is no other additions, no extra resistor needed, just the new led.

no, wait: but if i cut the top trace, i cut the circuit from 1.8k resistor to 9v... or will be the led to close the circuit again?

[Ben Lyman]

I BB'd a magna vibe last night so I could futz around with it.
I still like the 10nF for that shimmery sound.
I also tried a variable resistor across the cap to find a nice mix of vibrato/tremolo. I like a 51k parallel to my 10nF.
I also added a second LED parallel to the LED inside my vactrol so I could watch the depth/rate. It did not affect the circuit in a bad way either, in fact the effect actually intensified. I tried a few different types of LEDs as visuals and each one had a different affect on my vactrol action, some neg/some pos but I think it sounded best when I used two matching LEDs. This will be a nice addition to the top of the pedal as a visual for the user, the icing on the cake is that it also intensifies the effect! Well... for me anyway. I suppose it all depends on what value LDR, LED, etc.
I am using a clear brite LED in shrink wrap about 1/4" away from and facing a Tayda (Waitrony?) LDR spec'd at 500k dark but I measured it sealed up dark at 967k.

[duck_arse]

cut the trace, the led, as you say, closes the circuit. it is all in series, you see.

and, I'm glad to see you say deeper, Mr L, because it is something I have thought was a real thing for a while now. the extra 1V6 across the extra led means the both leds turn off a little sooner for a little longer, so the ldr can relax in the dark, have a smoke, put it's feet up for a while .....

I tried (blind hacking) the magnavibe with a valve phase splitting tonight, but all I got was a nice tremolo. last time I bb'd the magna w/ kipper's help, I added a switch to switch to trem mode, but I also have a gainer frontend and an output buffer stage.

follow the grand tours - yes, kind of. the local teevee has been showing every stage of le tour for a few years now, and it is a nice way to while away the cold winter nights on telly. they are now showing all the giro and the veulta, as well as the spring classics. I like the cobbles races.

[Ben Lyman]

...the extra 1V6 across the extra led means the both leds turn off a little sooner for a little longer...

Yes! Thanks Duck, that's what I have been trying to say is the problem with this circuit but I don't know enough, let alone how to fix it. The LED *NEEDS* to go darker and stay darker a little longer. So, how else can we apply a little 1V6 across it if we don't feel like using another LED? Probably a diode, right? This could very well be the missing element to the Magnavibe.

Here's one more thing I discovered recently on my BB: I put a second LDR in SERIES with the first to double the (dark) resistance and faced it to my second LED.
So that's: Two LDR's in series facing two LED's in parallel. The effect is very intense and I got a nice volume boost out of it, plus placing my 51k across the "L" cap adds a nice subtle volume modulation to the pitch bending as I noted before, making a nice simulation of rotary speaker, albeit mono.

[Kipper4]

Last night I tried the 50k // with the "L" cap and yer it was nice. Great mod Ben.
I did get some ticking though as you know Ben but that was probably the mismatched led I put in parallel with the vactrol. I should have paid more attention to the details.
After a lot of tinkering with the Magnavibe over the last few months I'm gonna have to put it back on the breadboard and try the double vactrol thing though.
Thanks again. Your a diamond as is D A.

I'll try it tomorrow afternoon when I get back from lake swimming.
That'll be a new one for me. The grandkids are tri athletes and want me to come and enjoy the fun.
As long as they don't expect me to keep up.
Only problem is there's a cycle race in the city we have to go through to get there. Grrr.
Bonus Is we get to have a picnic after alfresco after.
Sorry duck........
Carry on.

[Ben Lyman]

Ah yes, you are right Rich! Bad ticking when I max the depth and speed, bummer. I had to scrap that mod for now and go back to dialing in the vactrols, two sounds great.

[duck_arse]

you blokes - yer mixing the DC from the collector wit der DC from the emitter. put a whacking big cap (to pass all freqs) in between the collector and the so-called L cap, then hang your Lyman resistor across the L cap, and report back.

[edit :] oh, and kipper - don't forget to "lard up" for your swim, to keep warm. I think the pro's favour goose fat.

and I saw pipporan, huddling under his umbrella, at the giro.