tiny tremoloOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO

[Gurner]

I don't understand how it couldn't work. The LDR, as he has it wired, is simply bleeding a variable amount of the signal to ground based on the resistance of the LDR. Pretty simple stuff, this is the way a volume pot works....

Thats not my take - IMHO, a volume pot works as a potential divider....as it is drawn in the schematic above that LDR is acting as a rheostat - without some form of in line (series) resistance preceding it, it cant/wont work as a potential divider.

Think about it..... if your AC signal coming in is 500mv & the LDR is 1M , then 500mV is dropped across 1M, if the LDR then drops to 10k that same 500mV is still dropped across 10k - so, the signal voltage remains the same at the top of the LDR .....what changes with the LDR changing resistance is the current through the LDR to ground (& might account for why there is so much clicking going on for some?)

If you roll the volume pot off a little on the guitar then that provides the necessary in series resistance for the LDR/rheostat to work as a potential divider.

[deadastronaut]

hi guys, just found these low power cmos 555's...

anyone got any ideas if theses would be better?...very low power...pin for pin replacement too...

http://pdf1.alldatasheet.com/datasheet-pdf/view/25485/STMICROELECTRONICS/TS555.html

[Barcode80]

I don't understand how it couldn't work. The LDR, as he has it wired, is simply bleeding a variable amount of the signal to ground based on the resistance of the LDR. Pretty simple stuff, this is the way a volume pot works....

Thats not my take - IMHO, a volume pot works as a potential divider....as it is drawn in the schematic above that LDR is acting as a rheostat - without some form of in line (series) resistance preceding it, it cant/wont work as a potential divider.

Think about it..... if your AC signal coming in is 500mv & the LDR is 1M , then 500mV is dropped across 1M, if the LDR then drops to 10k that same 500mV is still dropped across 10k - so, the signal voltage remains the same at the top of the LDR .....what changes with the LDR changing resistance is the current through the LDR to ground (& might account for why there is so much clicking going on for some?)

If you roll the volume pot off a little on the guitar then that provides the necessary in series resistance for the LDR/rheostat to work as a potential divider.

Either way, what he drew does work though, at least as he has reported.

[deadastronaut]

any successfully built and boxed ones?...

thought i would have seen a few boxed by now...

ive still been working on my pulsewah, so havent completed the single trem yet!...busy...

todays analysis:

ok ive just breaded this tiny trem yet again ... , and tried the ldr to signal ground...noisey as hell...because when the led goes off there is no 'signal' ground i guess.

with the ldr to power ground its much much cleaner.....but has a slight thump when ldr/on/off...enough thump not to call it finished and boxed up..

edit:

just put a 100r/220 on the ldr's led to ground...yes!.any thump,seems to have gone...its sounding good...which some are using for depth control.(which i never bothered with but thought i would try)

but i would add this 100r in there anyway (after the depth)so the thump is eliminated anyway..even with a depth pot ...im using cmos555 btw..very clean too.

[Barcode80]

I'm planning on building and boxing soon. I just got a couple cmos 555's so that I could.

[deadastronaut]

I'm planning on building and boxing soon. I just got a couple cmos 555's so that I could.

hi patrick, ,cool,look forward to seeing/hearing it.. been messing around with this a lot today, ive got it running really nice...except!

if i turn the gain right up on my mixer there is a tiny click...not audible at all in normal level situations..but it is there at extreme levels...(just thinking of distortion pedals in front etc)

its just bugging me on how to get rid of it...and finally box this and get it out of my head at last!!!!...

ive set it up with the in/out into one side of ldr..other ldr side to ground..

im using a 5k depth pot with a 100r to ground off the 1 lug...seems really good as a depth control..

apart from this minor problem..can you try yours with the level on ya amp right up...see if its the same!..? cheers . rob.

[MoKoLoKo]

any successfully built and boxed ones?...

One here!!

Despite the separate ground, I have some ticking, I'm waiting to a CMOS 555 to change it, I hope it fix it.



I know, it's REALLY crappy

And some more soundclips --> http://www.soundclick.com/bands/page_songInfo.cfm?bandID=1036831&songID=10032818

There isn't ticking in the recording because I put some noise reduction filter in the clip, put the tick exists

Another problem is that ticking is not too loud, but it sounds too in bypass! And I don't know why, the stompbox is true bypass, with a 3pdt 

[thomasthebuzzard]

sometimes oscillation sneaks in through ground somehow. For stuff like this i will connect the ground of the board to where the led connects to the stomp switch. This shut the power to the whole unit of. I know this is a brutal way to do it but it works effectively. It only works well with some effects though. This one should be fine. Also I know that there is a way to do this better. I just don't know how. You can probably find something on the forum though about how to stop that.

[Scruffie]

Input Ground True Bypassing is what you want.

[thomasthebuzzard]

True that!

[deadastronaut]

yay!....moko is the first.....you win the prize!......


anyway...i still have this on a tiny breadboard.

i had to turn the gain right up on my mixer to hear any click which under normal recording circumstances you wouldnt have it nowhere near that level......

i noticed the other day that the ticking goes when i turned the guitar volume down,(try it) so i figured something on the input might help!!!!..and it did!.

i tried a 1M resistor on the input to ground...with a 10nf  to ground also..and yep it removed the tick....a lot lot better!..

like this.......btw i'm using cmos555....

input_________________________
                    /              /
                    \              /
               1m /             /  10nf

give it a try!......it might help you!... rob.

[Perrow]

i tried a 1M resistor on the input to ground...with a 10nf  to ground also..and yep it removed the tick....a lot lot better!..

And I have to ask, inline or bleed? Or both?

[deadastronaut]

as above ^^^^^^^^

like a pull down resistor plus cap...

[Perrow]

I meant the LDR, do you have that inline or bleed?

[deadastronaut]

oh right....i have my ldr straight to ground...in /out on other side of ldr...with the the 1m/10n to ground...connected to the in/outs...

[Perrow]

i.e. "parallell" to the ldr if I understand it correctly. I'll see if I can modify the PCB to include this, will have to wait 'til after work (started working yesterday after being unemloyed for the last 6 months ).

[deadastronaut]

congratulations on getting a job...especially nowadays..

heres the pdf of it...try it first before you pcb it...ok.

http://dl.dropbox.com/u/7464107/tiny%20trem%20..pdf

[Gurner]

I keep coming back to this thread as I'm curious about the clicking.

I'm still puzzled as to how this is all working (I'm not doubting it does...I just can't quite wrap my head around why it does!)

Here's the equivalent circuit...



Now becuase the LDR is acting as a rheostat vs a potential divider (like say your guitar volume knob), can the guitar pickups internal DC resisistance be considered the top part of pseudo potential divider (the rheostat being the lower part)....or, since the pickup is the signal 'source'. must it not be brought into play in this respect.

[deadastronaut]

hi gurner, sorry im not too au fait with rheostats and some terminology...still learning etc...

basically the guitar in and out is connected to one side of the ldr......other side of ldr  to ground....led flashing turns it on/off...thats it!.....

sorry if this is an obvious answer....but im still a dumbass noob.....

[Manny]

Hi Gurner 

I don't have a cap or pot wired to mine, mine is like this:

IN-----------OUT
        |
      LDR
        |
      GND

The way I see it is that while the LDR has low resistance , more current flows to ground causing the signal to be cut. While the LDR has high resistance less current flows to ground allowing the signal to pass through to OUT.