tiny tremoloOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO

[John Lyons]

Hmmm
just off the top of my head, how about a cap in between the chip and the depth pot?
So it has to charge up the cap...slows up the on off of the LED, ramping up a bit...triangle wafeform.
EDIT: Scratch that, the cap will block DC. 

[daverdave]

A larger cap won't make the waveform off the cap any bigger, as it's gonna charge and discharge at 2/3 and 1/3 of the power supply (I think) or the threshold voltages. You could try taking the voltage off it and lighting an LED to see how bright it gets, though I think it'll be smaller than the output of the 555 it might be big enough to drive the optocoupler. I did a 555 timer last year for uni so I'll have a peak at my notes, we had to measure the voltages.

[daverdave]

Yeah, according to my notes, the cap charged to 2/3s of the Vcc, and discharged to 1/3 Vcc. I used a 5V supply for it and got 1.75 pk-pk roughly. So I'm guessing that with a 9V supply, you'd get 3V to 6V at 3V pk-pk. Which would be enough to light it fully I think, but I don't think it'd give you a very wide swing.

[Gurner]

@john i tried a 100uf and it just makes the speed rate longer....havent got a scope to see waves etc..

I'm fortunate enough to have a USB scope, but if I hadn't access to that, I'd be getting stuck into something like this

http://translate.google.com/translate?hl=en&ie=UTF-8&sl=de&tl=en&u=http://www.zeitnitz.de/Christian/index.php%3Fsel%3Dscope_de&prev=_t&rurl=translate.google.com

(really dunno how mso many can get by without seeing the waveforms of their efforts)...

[deadastronaut]

@john i tried a 100uf and it just makes the speed rate longer....havent got a scope to see waves etc..

I'm fortunate enough to have a USB scope, but if I hadn't access to that, I'd be getting stuck into something like this

http://translate.google.com/translate?hl=en&ie=UTF-8&sl=de&tl=en&u=http://www.zeitnitz.de/Christian/index.php%3Fsel%3Dscope_de&prev=_t&rurl=translate.google.com

(really dunno how mso many can get by without seeing the waveforms of their efforts)...

nice one gurner...brilliant...i get by with my ears!..ha ha..thanks for that!..

[Perrow]

Hmmm
just off the top of my head, how about a cap in between the chip and the depth pot?
So it has to charge up the cap...slows up the on off of the LED, ramping up a bit...triangle wafeform.
EDIT: Scratch that, the cap will block DC. 

Small cap in parallel with the led? Steals some power while charging and gives some back when the timer switches off. Problem is that if it works it'd probably need different caps for different speeds.

I'm fortunate enough to have a USB scope, but if I hadn't access to that, I'd be getting stuck into something like this

http://translate.google.com/translate?hl=en&ie=UTF-8&sl=de&tl=en&u=http://www.zeitnitz.de/Christian/index.php%3Fsel%3Dscope_de&prev=_t&rurl=translate.google.com

(really dunno how mso many can get by without seeing the waveforms of their efforts)...

Now that looks like a nice program, thanks for the link.

[tubelectron]

Hi deadastronaut,

Very as interesting as compact trem circuit - I would even give it a name if I release it : SuperCompacTrem !

As I experimented many designs (but not already this "funny" one !), I have a question - I hope I am clear in my description : When you increase the rate, without touching the depth pot, do you notice an attenuation in the overall volume and a loss of the effect depth, compared to the low rate settings ? This is common on photocell LDR trems on Fenders (deluxe & twin reverb for example), due to the recovery time to black high resistance value of the LDR. So have you noticed this problem ? Would you please check accurately and tell me ?

Thanks !

A+!

[deadastronaut]

hi bruno.

the level seems ok to me...fast or slow..no problems...

[Perrow]

So here comes a new pcb design, slightly smaller than the last one

I realised that the design now was a "variable bleed to ground" circuit, so I removed the in and out points and replaced it with a "bleed" point. Doing this will require wiring the 3pdt different than normal, shorting the two normal "to board" and "from board" legs. But that shouldn't be a problem, we were doing it before, going to and from the board but shorted on that board.

Depth pot between signal and board is optional I guess.

[deadastronaut]

Question: if the ldr is going to ground, does that mean the input and output impedence varies with the r of the ldr?
If so, you could potentially drive it with something that needs a high impedence input and get a wah/filter sound out of it?
just an idea that popped into my head.
sounds great btw.
1 chip 1 resistor 1 cap
1 ldr and 2 led's

hi gil.
im sure everyone is very interested in this idea if you could explain it in more detail! thanks rob.

@perrow. dont be surprised if it changes again 

[Perrow]

@perrow. dont be surprised if it changes again 

I won't be when it does 

For another episode in the depth mod variations series: A second, dimmed, led also shining on the ldr 

[Brymus]

Sounds great Rob 
How about a schematic showing the original and changes ?
I just cant wrap my head around vero   
I actually liked the first soundclip better.
But I can see why some would want the depth pot for easing back on the effect.

[deadastronaut]

Sounds great Rob  
How about a schematic showing the original and changes ?
I just cant wrap my head around vero  
I actually liked the first soundclip better.
But I can see why some would want the depth pot for easing back on the effect.

cheers bryan. yeah i like the more choppy feel of it too...nice to have both though!...switchable!!!

i'll give the schematic a go ok. rob.

[deadastronaut]

@bryan heres the schemo's........

[Renegadrian]

WOW Nice circuit there! Thank you!"

[askwho69]

NICE a expensive tremolo becomes simple! wow very bright discovery!!! next Little delay?chorus? etc

[Brymus]

Thanks Rob.
So D1 is the other half of the LDR ?
And on the second schematic should the output be taken after the LDR like the first schematic not before ?

And finally ,so to see if I understand this right this signal is just getting choked as the LED increases the resistance through the LDR.
Basically its like the 555 is working your volume knob really fast (or slow) with the LDR acting as the volume knob.
And the 555 and LED acting as your hand.
Is that about right ?

[Brymus]

Oh and what does the other side of D1 connect to ?
Ground or V+ ?

[John Lyons]

D1's other side connects to ground.
The second schematic's LDR is connected in a different way.
The in/out are shorted to ground when the LDR is "hi" (LED not lit)

In the first schematic the LDR is some megaohms in series with the signal
and the second schematic the resistance of the LDR is to ground (affecting impedance
and essentially shorting the in/out to ground when it's 5K)

[Brymus]

OK
Thanks John
So I was right about the first schematic,how it works choking the signal off.
The second version bleeds the signal off instead of choking it,if I understand now.