tiny tremoloOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO

[Gurner]

Just to chime i a little here (I find this thread fascinating...and don't take this the wrong way, the probs encountered are to be embraced/welcomed as we all learn from the quest to solve).....

ok, just wanted to float a concept here - IMHO, this 'tremolo' is actually more akin to a kill switch vs a traditional tremolo.

(warning: oversimplification for the sake of putting a point across ensues!)

kill switch - swings between inifinte resistance  &  a dead short....the load as seen by the source changes (a lot!) - current is  the affected one here.

traditional tremolo - swings between full voltage and no voltage - or variations within those limits (think 'potentiometer' moving up and down quickly - the wiper being the output), the load as seen by the signal source stays the same - voltage is the affected one here.

the ldr in the tiny tremolo is acting like a polite kill switch...it's not infinite, nor is it short....but bounces back and forth somewhere in between these boundaries. There'll always be some source  signal loading  (albeit not too much impact at the dark end of thing, *if* a high dark resistance ldr is used), equally the signal will never fully get down to nothing...close but not fully killed  (IMHO it's a bit of an aural illusion.... a similar analogy being an optical illusion to do with your TV ....when it is switched off the screen is actually only dark grey...but when you turn it on, there and watch something you'll swear there 'appear' to be deep, deep blacks in there!)

Anyway, I'm rambling....I'll get me coat!

[artifus]

i hadn't actually really looked at the circuit yet!    will do now. had only really glanced at it and assumed the ldr was acting as a volume pot. will look again.

[Gurner]

i hadn't actually really looked at the circuit yet!    will do now. had only really glanced at it and assumed the ldr was acting as a volume pot. will look again.

It's defintely not acting like a volume pot (which is a potential divider - with three connections, these being input, wiper & ground) ...the LDR is acting like a rheostat (remember an ldr only has two connections, so it can't act like a traditional volume pot on its own) - to help you visualize, I drew up an equivalent cct - see my reply 337 on this earlier page...

http://www.diystompboxes.com/smfforum/index.php?topic=87322.320

with the guitar volume pot fully turned up, there's no potential divider - so the ldr simply acts like the aformentioned kill switch - the pickup signal 'stacks its hand'  when the ldr's resistance is too low for the pickup's output drive ability .....turn your guitar's volume knob down a bit an then there will be a 'top resistance' present in the ldr feed chain, and the overall vol pot/ldr chain willl begin to act partially like a potential divider (ie a vol control - but probably not anywhere like the volume extremeties you'd likely want)...but in this scenario you've lost signal level as presented to your amp.

It's a conundrum....but as I've said before, if it gives you the required outcome/effect who cares?!

[artifus]

am i being completely stupid in thinking that placing a small value resistor in line would solve this?

[Gurner]

am i being completely stupid in thinking that placing a small value resistor in line would solve this?

alas no, it'll sort of help out (but not to any degree of satisfaction IMHO) and there is a 'cost' (loss of signal magnitude).

What you've said can be emulated very simply & quickly....

.....turn your guitar's volume knob down a bit an then there will be a 'top resistance' present in the ldr feed chain, and the overall vol pot/ldr chain willl begin to act partially like a potential divider (ie a vol control - but probably not anywhere like the volume extremeties you'd likely want)...but in this scenario you've lost signal level as presented to your amp.

[artifus]

thanks for the info. possibly related re ticking - been playing with led/ldr combo's a bit recently and noticed ticking can happen in completely isolated circuits (eg waving a flashing bike light near an independently powered guitar processing ldr circuit) depending on proximity of led/ldr. is there any kind of interference that could be being picked up from the charge arcing in the led or am i thinking out of my hat, so to speak? or is it just the sound of the ldr 'gulping' at the sudden change in resistance? (and ldr response time)

[Gurner]

thanks for the info. possibly related re ticking - been playing with led/ldr combo's a bit recently and noticed ticking can happen in completely isolated circuits (eg waving a flashing bike light near a ldr circuit) depending on proximity of led/ldr. is there any kind of interference that could be being picked up from the charge arcing in the led or am i thinking out of my hat, so to speak?

I've mixed thoughts on the ticking - I guess someone really needs to isolate if it's the LDR side or the circuit side  that's the cause of the ticking (or possibly a bit of both!)

In order to do that, somewhere in or around that reply #337 I suggested emulating the LDR with a manual 1M pot (configured as a two connector rheostat & *not* as a traditional volume knob!) & turning it fully high/low as fast as possible while strimming the guitar via an amp (no mean feat!)   - at least this way it can be seen if a lot of folk's ticking problems are related to the pickup current being whacked about by the wildly rapidly differing load the LDR presents - because the only way of getting to the bottom of the ticking problem is to establish where the problem is coming from in the first place! (although the gnat in the ' LDR switching pickup current too fastly" ointment argument is those who don't have ticking problems!)

[artifus]

(although the gnat in the ' LDR switching pickup current too fastly" ointment argument is those who don't have ticking problems!)

oops, editing for clarity as you posted... re above quote - everyone is presenting slightly different loads (gtr/pickup) to the circuit, no?

[Gurner]

(although the gnat in the ' LDR switching pickup current too fastly" ointment argument is those who don't have ticking problems!)

oops, editing for clarity as you posted... re above quote - everyone is presenting slightly different loads (gtr/pickup) to the circuit, no?

I tend to look at it the other way round   - everyone is presenting a similar 'wildly variating load' (the LDR) to their pickup with this circuit - and therefore (by & large) are likely to experience the same results (or issues)

[artifus]

ok... so much to learn... i've most recently experienced this ldr ticking sound when playing with filters - specifically ray wilsons 741 odd filter from the wsg but also with other, mostly simple passive, volume and tone circuits involving ldr's and completely disconnected flashing led circuits.

*edit* i don't have a scope or simulator and so tend to (ahem) work on a 'live' breadboard connected to gtr and amp at all times so i can hear component changes and listen to different parts of the circuit by probing with the output jack.

[deadastronaut]

tend to (ahem) work on a 'live' breadboard connected to gtr and amp at all times so i can hear component changes and listen to different parts of the circuit by probing with the output jack.

me too...

@gurner...good explanation, aural illusion etc...


ok,so ive had a little drink think...

a booster at the in/out should solve this shouldnt it?..as long as the boost is clean and  can push out unity level when slow and more than unity level when fast where it needs it...  it should be ok...do you think?

or am i being a  dumbass again... ...(yes rob you are..again!)..

guess i'll just bread a boost and run it into the pedal and see how it goes...its quick enough to try...report back soon...

[deadastronaut]

right, ive got a nice clean boost together...sounds nice..brightens it slightly too..great.

but...

where to put it in the scheme of things..because it only needs it on the actual on....not off..hmm..

and the way it has to be wired , there is no place to do it..without it being switched too!..i guess!..hmmmm again...

more thinking i think...

hmmmm....might just leave as is after all...

[Perrow]

right, ive got a nice clean boost together...sounds nice..brightens it slightly too..great.

but...

where to put it in the scheme of things..because it only needs it on the actual on....not off..hmm..

and the way it has to be wired , there is no place to do it..without it being switched too!..i guess!..hmmmm again...

more thinking i think...

hmmmm....might just leave as is after all...

Well, we could go the whole nine yards and make it true bypass

[deadastronaut]

ha ha...

i just thought, if the output went to a toggle then it could go

> out
-
>boost..volume pot...

hmmm...means a pot and a switch though!...i dont know...spent too long on this to be arsed i think...just a thought though!..

[mrsuspend]

I just breadboarded the fader version using an NE555 and it's blinking away merrily on my desk  
Just wondering what voltages you are feeding your led(s), with the 2k2 resistor applied my rather slow multimeter swings between 1 and just under 2 volts.
It seems a bit faint but I don't want to burn the LED out...?

/Magnus

[Perrow]

I just breadboarded the fader version using an NE555 and it's blinking away merrily on my desk  
Just wondering what voltages you are feeding your led(s), with the 2k2 resistor applied my rather slow multimeter swings between 1 and just under 2 volts.
It seems a bit faint but I don't want to burn the LED out...?

/Magnus

With a 2.2k my 555 didn't blink, had to go down to 820R. Killed two leds in the process, while testing without resistors

[mrsuspend]

With a 2.2k my 555 didn't blink, had to go down to 820R. Killed two leds in the process, while testing without resistors

Thanks Perrow, which layout was that?
I did mine according to Rob's own LED Fader schematic. As this is feeding 9v to the IC and the transistor separately they could get different voltages although I don't know what I would achieve 
Now I've just stuck the 2k2 immediately after the battery so the whole board is getting the reduced voltage. The LED  does seem a bit faint although it might work, I haven't tried the ldr/audio yet.

/Magnus

[deadastronaut]

With a 2.2k my 555 didn't blink, had to go down to 820R. Killed two leds in the process, while testing without resistors

Thanks Perrow, which layout was that?
I did mine according to Rob's own LED Fader schematic. As this is feeding 9v to the IC and the transistor separately they could get different voltages although I don't know what I would achieve  
Now I've just stuck the 2k2 immediately after the battery so the whole board is getting the reduced voltage. The LED  does seem a bit faint although it might work, I haven't tried the ldr/audio yet.

/Magnus

hi magnus,

i was using a 'hi bright' clear lens  green and blue...at same time as i am now on the pulsewah too...works ok...

using the led fader circuit in my gallery..

[Perrow]

Thanks Perrow, which layout was that?
I did mine according to Rob's own LED Fader schematic. As this is feeding 9v to the IC and the transistor separately they could get different voltages although I don't know what I would achieve 
Now I've just stuck the 2k2 immediately after the battery so the whole board is getting the reduced voltage. The LED  does seem a bit faint although it might work, I haven't tried the ldr/audio yet.

/Magnus

It's still on my breadboard, sort of like any of the layouts posted in this thread Been messing around with it a bit since I had some trouble coming to the conclusion that the 2.2k was the problem.

[mrsuspend]

Well, I've tested the fader version now (in the dark, very atmospheric) and...

It works very well!  
No ticking when the grounds were all properly connected. And this with an NE555 too...
I tried a few LEDs and it seems clear blue has the least volume drop, however the non-clear red had the smoothest slow action. Guess I'll just have to try a slew of them and find the best compromise.
I did find the speed range a bit on the fast side so I swapped the 4k7 pot for a 10k and stuck a 1k resistor in the path to put a cap on the top speed.

/Magnus