Hello everyone

Have you ever lain in bed at night, tortured by your unrequited dreams of making a random tremolo pedal that will screw your audio signal up in a variety of uncontrollable chaotic ways? While using very few parts? You have? Well, I am about to make your day

For the first time in how ever many years I've been on this forum I am about to astound / impress / surprise you by actually designing my first circuit (instead of asking for help after I break other people's designs). I've made a random stuttering tremolo. It actually works. I was wondering how to get a random tremolo effect and was looking at circuits where clever people use microprocessors to generate randomness that modulates the brightness of LED / LDR combos but that was too smart for my limited brain. And I thought, how can I, a man of extremely limited electrical knowledge realise my dreams? By cheating of course! All I needed was an LED that already had a random flicker to it... yes you guessed it, those really tragic candle flame LEDs! They are perfect (well they'll do for a start anyway). So this is the nearest I will probably ever get to creative genius You saw it first folks!

Hopefully the below link goes to an mp3 of me gently playing and gradually adjusting the one pot on the circuit to remove more and more audio. This recording only has two LEDs / LDRs in it (I've run out of a lot of parts recently and had to wait to today to get paid before I could order more, so the next iteration of this will have 4 LED/LDRs, each with their own pot to control the amount of sound they erode.) The circuit works with two homademade vactrols, so I'm sure it will work with 4!

https://drive.google.com/file/d/1OTF2-Z9_XFuKUvo3IM4qoyw9OXyUtqnT/view?usp=sharing

Schematic for your amusement.



The pot starves the LEDs of power (the 78L05 is there to stop the LEDs exploding; it's hard to find any datasheets for these flicker LEDs - all of which came from random ebay sellers - and the one I did find said they shouldn't be fed more than 5V, so that's what I've done). I originally had a 100ohm resistor just after the 78L05 because I thought there should be a little extra protection, but it got so hot that I swapped it for a 470ohm... so the maximum brightness is dimmed a little, but the resistor no longer burns my skin if I touch it! The voltage starving doesn't change the rate the LEDs flicker at sadly (in the above mp3 I'm using a slow change RGB disco LED and a bright green candle flicker LED) I've not been able to achieve that at all, but with less current some of the colours of the RGB LEDs no longer light up so that adds variety to the tremolo, or with the standard candle LEDs they tend to turn off more and struggle to light up which adds sawtooth to the tremolo. I have found that two of the same LEDs can be used with a different LDR each - if they both get powered on at the same time they stay identical in their flicker timing for a few seconds and then slowly drift apart. I'm not sure if there is a way to 'boot' multiple LEDs of the same type with different start times to make the tremolo pattern even more unique... so that might be something interesting to explore if you only have one type of candle flame LED.

I've tried four different LEDs. The traditional orange LED candle flame is the least interesting - it rarely turns off and modulates too gently. I discovered that it can be made more interesting (audio wise) if you put a standard red LED in series after it - the orange LED then loses current to the red LED, causing it to stutter much more and make interesting patterns. The bright green candle LED gives smooth slow volume undulations, the slow RGB Disco LED (which is not slow) makes the fast patterns and gets more chaotic as it is starved, and a slow RGB colour change LED is not so interesting with full current but becomes more random with less current because it is unable to generate some of the colours in the spectrum and so turns off at times.

I added a 10K resistor after the input audio jack because I think Duck got me to do that on a previous circuit although I can't remember why it was important...sorry Duck.

Any thoughts about stuff I should add to this circuit to make it work better / different / be friends with other pedals etc would be great. A way to cut down the background hum when the audio is cut out? This is only on breadboard at the moment with insulation tape wrapped around the vactrols (and recorded with the lights off) so there is bound to be some light leakage at present, so this might disappear if things are soldered together.

Stuff to do - add a boost circuit after the LDRs and before the audio out jack (probably a DOD 210 preamp - they are tiny!). Maybe add a blend pot so that there is always some original audio to be mixed in? Add a switch to each LDR to take them in and out of the circuit as desired and a pot for each LED so they can be starved at different amounts. It's a shame they have to be kept inside a box for the final version; they look like a crazy disco rave migraine inducing light pattern at the moment! Maybe it's better that way...

If anyone knows a way to make these LEDs actually change the rate they modulate at I would be very grateful. I've tried adding capacitors to ground from the LEDs (thinking that I've used caps to slow down tremolos before) but that did nothing, and I can't find any info about this online.

Enjoy your weekend!

Cute!

This won't help you. But in the 1970s I ran an ARP 2500 synth with very good random voltage, including a heavily high-cut filtered rumble/wobble. Run that to a VCA (or VCO) and you got your random modulation. Not a lot of control of "speed" unless you added a filter. (In your scheme this filter has to be a light-filter and that's not a stock part.)
http://www.guitarfool.com/ARP2500/1016.html
http://www.guitarfool.com/ARP2500/1036.html

https://youtu.be/ZNa-JHPnpgM?t=127

That is the coolest thing ever.          Or at least, the coolest thing this Saturday.  So far...

May I be so bold as to suggest a name for this wonder of engineering?

The Moidulator!

Quote from: PRR on August 30, 2024, 10:44:54 PMCute!

This won't help you. But in the 1970s I ran an ARP 2500 synth with very good random voltage, including a heavily high-cut filtered rumble/wobble. Run that to a VCA (or VCO) and you got your random modulation. Not a lot of control of "speed" unless you added a filter. (In your scheme this filter has to be a light-filter and that's not a stock part.)
http://www.guitarfool.com/ARP2500/1016.html
http://www.guitarfool.com/ARP2500/1036.html

Thanks! Glad you like it

Wow, an ARP synth is one of those pieces of kit I would love to play with. Those schematics you posted links to are just a bit too complex for me at the moment though! I've got more ideas to adjust this circuit so I'm reading up about them to see if they sound plausible and will hopefully get built at some point in hte distant future... I need to get on with this circuit first!

Quote from: bluebunny on August 31, 2024, 04:48:16 AMThat is the coolest thing ever.          Or at least, the coolest thing this Saturday.  So far...

May I be so bold as to suggest a name for this wonder of engineering?

The Moidulator!

Thanks Marc I will admit I was totally astounded with myself that this actually worked (and first time) and yes I did indeed think it was one of the coolest things to ever happen to me. I have to say your naming idea is both flattering and genius! I think it has to be! I have some plans for a more complex version of this circuit which sound great in my head, and if that ever gets made it can be the Son of Moidulator! Thanks for your suggestion. Hopefully I can get some time tomorrow to update the circuit - I added a third LED/LDR combo and that worked, and it sounds better than the two LED/LDR version I posted above.

I am thinking I need to get rid of the background hum if possible, and also try different LDR types... the best ones so far are some unlabelled random bag I got from Ebay years ago that I don't really know what spec they are. I've tried some 9K - 20K and some 9K - 24K LDRs and they didn't work so well - I think I need to find an LDR with a much lower bright range 1K - 20k? something liike that to get the most contrast between audio on and off based on LED brightness. Time to read through some data sheets I guess. I was wondering whether it was worth placing a resistor in parallel with an LDR to lower its resistance, but I presume that would also lower the maximum resistanc when the LED is off as well, so that might not be the best way to approach the issue. Some thinking is required!

Do a couple voltage followers either end to buffer. You could mix in caps in series/to ground with your ldrs for lpfs and hpfs. Yes, parallel with the max resistance you want given a light tight Lee should have such high resistance it'll be about that; as an aficionado of cheap let, don't trust the info with them.

You can use negative feedback (I believe) to remove frequencies from the signal too. Once you add in op amps (properly biased) I'm sure you can go lots of ways!

Oh! Also a small current limiting resistor after the flickering led (trim pot instead?) could help adjust the on off ratios.

Since most of the cells are cadmium sulphide and most of the remaining ones are cadmium selenide, this could be difficult to find in the future as cadmium is one of the thsree RoHS banned metals (along with mercury and lead).  There may be only a limited supply of these devices available.

From some admittedly old catalogs that only carried RCA and Philips photocells, the light to dark ratio was much greater than those moid was looking at.  The RCA NSL62 is a 0.25 inch unit with a 100 footcandle resistance of 770 ohms, a 1 footcandle resistance of 28 Kohm and a dark resistance of 10 megohms.  It may be that for tremolo frequencies, you can't get to the 10 megohm resistance in time but you should be able to get better than 9K - 20K with good light shielding.

I dunno nuffin baht these candles wot you speek of. but, we are told, when leds cycle, they have "circuitry" inside, and they are inherently noisy. it might be that you can't get them noise free.

but, we always tell, leds in parallel get a current limit resistor each, because they won't current share otherwise. that single 470R resistor might be what makes it all work, it might be what causes them buzzes. maybe those candle things don't need a current limit, who nose, not me.

but you could try a 470R in series with each of the led things, all connected back to the VR1 wiper. what's the worst could happen - smoked pot? burnt finger?

that's three buts.

Quote from: Matthew Sanford on August 31, 2024, 07:16:03 PMDo a couple voltage followers either end to buffer. You could mix in caps in series/to ground with your ldrs for lpfs and hpfs.

Thanks Matthew - do you mean adding something like a TL072 to the circuit so the audio would come from the jack in to the first opamp on the TL072, then pass through all the LED/LDR part of the circuit and before it hits the audio out jack, it would go through the second op amp on the TL072? Or have I got that totally confused? (quite possible!)

Quote from: Matthew Sanford on August 31, 2024, 07:16:03 PMYes, parallel with the max resistance you want given a light tight Lee should have such high resistance it'll be about that; as an aficionado of cheap let, don't trust the info with them.

Sorry I don't understand any of that, I think you just went way over my technical knowledge there!

Quote from: Matthew Sanford on August 31, 2024, 07:16:03 PMYou can use negative feedback (I believe) to remove frequencies from the signal too. Once you add in op amps (properly biased) I'm sure you can go lots of ways!

Oh! Also a small current limiting resistor after the flickering led (trim pot instead?) could help adjust the on off ratios.

That's interesting - I thought the CLR would go between the power and the flickering LED (like I have it at the moment) but you think it should go between the cathode of the LED and the ground of the circuit? Or do you mean in addition to the 470R I've got (that is in place because I was worrying about 5V going straight to an LED)

Quote from: amptramp on September 01, 2024, 09:24:30 AMSince most of the cells are cadmium sulphide and most of the remaining ones are cadmium selenide, this could be difficult to find in the future as cadmium is one of the thsree RoHS banned metals (along with mercury and lead).  There may be only a limited supply of these devices available.

I had heard that LDRs are going to be difficult to find in future which is a real shame. I wonder if there will be anything to replace them?

Quote from: amptramp on September 01, 2024, 09:24:30 AMFrom some admittedly old catalogs that only carried RCA and Philips photocells, the light to dark ratio was much greater than those moid was looking at.  The RCA NSL62 is a 0.25 inch unit with a 100 footcandle resistance of 770 ohms, a 1 footcandle resistance of 28 Kohm and a dark resistance of 10 megohms.  It may be that for tremolo frequencies, you can't get to the 10 megohm resistance in time but you should be able to get better than 9K - 20K with good light shielding.

THanks Amptramp. Those values sound really good, however I couldn't find any mention of an NSL62 at any of the component stores (or even on ebay!) so I guess they are sadly long gone. I did spend some time looking at a lot of different LDRs and found three possible candidates to try that I can get from Mouser in the UK

NSL-6110 light resistance 1.34K - 2.66K,  dark resistance  11M


NORPS-12 light resistance 5.4K - 12.6K,  dark resistance  1M


NSL-06S53 light resistance  5.4K - 100K,  dark resistance  20M

Do any of those sound promising? To me the NSL-6110 looks really good, but would it be worth buying samples of all of them? They're not cheap sadly (nothing like the GL series LDRs which can be bought for very small sums) and I need to order £33 worth of stuff to get free postage (but four of each of those LDRs is almost £30 so that's not too hard!)

Quote from: duck_arse on September 01, 2024, 10:57:39 AMI dunno nuffin baht these candles wot you speek of. but, we are told, when leds cycle, they have "circuitry" inside, and they are inherently noisy. it might be that you can't get them noise free.

Ahhh it never occured to me that that might be the issue - I was assuming it was the DC power on the breadboard... I thought it might be a good idea to add in some of the components that ElectricDruid puts in the power sections of his schematics? I noticed that his optical tremolo had a 78L05 in the power section so thought some of those components around it might be a good place to start:

Quote from: duck_arse on September 01, 2024, 10:57:39 AMbut, we always tell, leds in parallel get a current limit resistor each, because they won't current share otherwise. that single 470R resistor might be what makes it all work, it might be what causes them buzzes. maybe those candle things don't need a current limit, who nose, not me.

but you could try a 470R in series with each of the led things, all connected back to the VR1 wiper. what's the worst could happen - smoked pot? burnt finger?

that's three buts.

But I love the way you butt in! I will give that lot a try. I didn't know that LEDs in parallel needed CLRs each, so thanks for warning me. I think it's time to re-arrange the mess on my breadboard! I'll be back

One possibly interesting note - I was comparing recordings I made of the circuit with two and three LED/LDR combos in it, and the circuit with three LED/LDRs is less noisy than the one with two. When I get more parts I will try four of them! I've no idea why this should be, but maybe more = better in this case. The tremolo effect sounds more random with three LEDs that's for sure.

Quote from: moid on September 01, 2024, 05:03:45 PMAhhh it never occured to me that that might be the issue - I was assuming it was the DC power on the breadboard... I thought it might be a good idea to add in some of the components that ElectricDruid puts in the power sections of his schematics? I noticed that his optical tremolo had a 78L05 in the power section so thought some of those components around it might be a good place to start:

The reason for the 78L05 is that the LFO I used is a PIC microprocessor-based thing, the StompLFO. That needs 5V to run. There's no other reason for the 5V supply to be there, but since I *had* to have a separate power supply for the digital section of the circuit (the page you haven't shown) I used it for the LEDs and anything else not directly audio-related. Even so, I had trouble on the first version of the PCB because of ticking caused by ground currents. The solution was to separate the ground paths for the two sections too, so digital/LED ground currents don't flow in the same paths as the audio grounds.

Incidentally, I notice now that the schematic page you showed misleadingly says "1 of 1" instead of "1 of 2". My bad, sorry. That second page is important too!

HTH

For limiting ldr response, look at this snip Electric Druid's FilterFx (I hope Tom doesn't mind)



Actually look at the project page. He references the thread here on it's development, good info on filtering and a great pedal was made! Yes on the TL072, coupling caps with bias voltage to + in and output tied to - in. See Druid schematics for the guidance that has led me, as you did for the power (good on ya). You could have global feedback or op amps through the middle, see the resonance and lp/bp/hp for example. I didn't see your clr, sorry, but you could put a 1k trimpot instead/in addition to play with different levels. And if you want volume tremelo, a voltage dividing output volume pot (1 to ground, 2 out, 3 to signal) with the ldr parallel with pins 1&2 (and turn it down a little to put some resistance the non-ldr side

I love it, brilliant out of the box new use! You might optocouple power to get led noise out, but I don't know how exactly

A few ideas:

1. You could try to arrange several light sources so they only need one LDR. Use some sort of small light tight container where you have an LDR in one spot. Then arrange all the flickering leds to point the brightest spot of their light towards the LDR.

2. Play around wiht the value of your R2. It should affect the depth of the effect, especially if you put a buffer or another effect in front of the Moidulator. With a passive guitar straight in to the R2 it might not make as big difference.

> It's a shame they have to be kept inside a box for the final version; they look like a crazy disco rave migraine inducing light pattern at the moment!

You could have two of each LED: one inside with its respective LDR, and one outside for the light-show! 

Quote from: moid on September 01, 2024, 05:03:45 PM

Quote from: amptramp on September 01, 2024, 09:24:30 AMSince most of the cells are cadmium sulphide and most of the remaining ones are cadmium selenide, this could be difficult to find in the future as cadmium is one of the thsree RoHS banned metals (along with mercury and lead).  There may be only a limited supply of these devices available.

I had heard that LDRs are going to be difficult to find in future which is a real shame. I wonder if there will be anything to replace them?

Chase Bliss have recently announced that they're dropping 5 pedals from their range because of vactrol problems. They're selling the remaining stock in the US, where this stuff isn't controlled yet.

I exchanged a few emails with Joel Korte at Chase Bliss, and it seems the catalyst for this is that the *UK* authorities are cracking down on vactrols. Although the UK left the EU (and so the EU's RoHS directive no longer applies in the UK) most EU environmental legislation was rolled-over into UK law on exit so that businesses didn't have a completely-changed legal framework to deal with overnight. He said he's been in contact with several UK pedalmakers who have also had problems.

Whether genuine non-cadmium LDRs are technically possible at some point in the future is a physical chemistry question that I'm not qualified to answer.

This is timely for me since I was about to order more vatrols for the Druid shop, but if the "RoHS" claim on those products is not actually true when independently tested then there's really no point, so I'm holding off until I've found out what the UK's Office of Product Safety and Standards has found out about vactrols.

I wonder if there would be a way for phototransistors to act as a replacement for LDR's as they're much easier to find and don't have the Cadmium that Europe doesn't like. I have a 3d printer and I'm planning on making my own vactrols with that (just to be less janky than shrink wrap and duct tape)
Phototransistors and LDR's are not really interchangeable but I'm sure things can be done circuitry wise to make it more similar

Quote from: ElectricDruid on September 01, 2024, 06:37:51 PM

Quote from: moid on September 01, 2024, 05:03:45 PMAhhh it never occured to me that that might be the issue - I was assuming it was the DC power on the breadboard... I thought it might be a good idea to add in some of the components that ElectricDruid puts in the power sections of his schematics? I noticed that his optical tremolo had a 78L05 in the power section so thought some of those components around it might be a good place to start:

The reason for the 78L05 is that the LFO I used is a PIC microprocessor-based thing, the StompLFO. That needs 5V to run. There's no other reason for the 5V supply to be there, but since I *had* to have a separate power supply for the digital section of the circuit (the page you haven't shown) I used it for the LEDs and anything else not directly audio-related. Even so, I had trouble on the first version of the PCB because of ticking caused by ground currents. The solution was to separate the ground paths for the two sections too, so digital/LED ground currents don't flow in the same paths as the audio grounds.

Incidentally, I notice now that the schematic page you showed misleadingly says "1 of 1" instead of "1 of 2". My bad, sorry. That second page is important too!

HTH

Thanks Tom! In that case I might leave my 78L05 where it is and not add the other parts you did unless I get noise issues. I'm using the 78L05 bcause I found a datasheet for a candle flame LED that said that it should not be fed more than 5V, so I used that and a resistor to make sure nothing went bang!

It is going to be digital in the end. Go ahead and develop a GOOD ADC board, compute the optimum gain function, apply it to your bytes. Latency can be 20 MICROseconds which is quite short.

Hello everyone

Sorry about the delay in replying, term started up again and life got busy And then my asthma decided I should have a bad time on top. Yay. Anyway I finally got some new components and have made a new circuit (somewhere further down this thread) with new weird issues and questions to ask you chaps. I will answer the great posts you all made first though!

Quote from: Matthew Sanford on September 01, 2024, 06:53:54 PMFor limiting ldr response, look at this snip Electric Druid's FilterFx (I hope Tom doesn't mind)



Actually look at the project page. He references the thread here on it's development, good info on filtering and a great pedal was made! Yes on the TL072, coupling caps with bias voltage to + in and output tied to - in. See Druid schematics for the guidance that has led me, as you did for the power (good on ya). You could have global feedback or op amps through the middle, see the resonance and lp/bp/hp for example. I didn't see your clr, sorry, but you could put a 1k trimpot instead/in addition to play with different levels. And if you want volume tremelo, a voltage dividing output volume pot (1 to ground, 2 out, 3 to signal) with the ldr parallel with pins 1&2 (and turn it down a little to put some resistance the non-ldr side

I love it, brilliant out of the box new use! You might optocouple power to get led noise out, but I don't know how exactly

Thanks Matthew! I don't think I want to limit the LDRs though, more maximise them? Or maybe I don't understand what you're telling me (sorry). Later down in this thread I will put a revised schematic (I rebuilt the circuit today) although that was to make it easier to adjust on breadboard and get more control in. I haven't got to your ideas yet. I really like the idea of the volume tremolo control but I don;t understand what you wrote in terms of how to implement it sorry - could I not just have a pot at the end of circuit (assuming some sort of buffer /splitter at the start that sends out once audio line to the tremolo and one just dry audio) with dry audio going into lug 1, tremolo audio on lug 3 and then lug 2 to output jack?

I've no idea how to use an octocouple (I don't think I own one anyway) and I have new / different noise issues now - will post them later in the thread

Quote from: Elektrojänis on September 03, 2024, 05:37:25 AMA few ideas:

1. You could try to arrange several light sources so they only need one LDR. Use some sort of small light tight container where you have an LDR in one spot. Then arrange all the flickering leds to point the brightest spot of their light towards the LDR.

2. Play around wiht the value of your R2. It should affect the depth of the effect, especially if you put a buffer or another effect in front of the Moidulator. With a passive guitar straight in to the R2 it might not make as big difference.

Thanks! What would be the benefit of only having one LDR? Would that reduce noise then?

I haven't got to R2 yet, but I will try that. I noticed a difference in the audio quality if I plugged the guitar into a boost pedal first, then into the tremolo - there's more of a dynamic range when the tremolo is at fullstrength. I will try to change R2 to see what happens. Would it be better to have a pedal with a buffer in it (like a Boss pedal) to test with or will any boost pedal work (my boost is not a Boss pedal so I have no idea if it has a buffer at all - it's a Caline Orange Burst which is a clone of the Xotic BB Preamp pedal.

Quote from: bluebunny on September 03, 2024, 09:00:00 AM> It's a shame they have to be kept inside a box for the final version; they look like a crazy disco rave migraine inducing light pattern at the moment!

You could have two of each LED: one inside with its respective LDR, and one outside for the light-show! 

Thanks Marc. If I have two LEDs of the same flicker type together they seem to drift out of synch with each other... also I thought they looked dimmer... I think that was when they were in series, maybe it would be different in parallel? I tried that before I rebuilt the circuit and haven't tried again since. They are a bit migraine inducing, so it might be best to stick them inside the box after all!

Quote from: ElectricDruid on September 03, 2024, 10:33:02 AMChase Bliss have recently announced that they're dropping 5 pedals from their range because of vactrol problems. They're selling the remaining stock in the US, where this stuff isn't controlled yet.

I exchanged a few emails with Joel Korte at Chase Bliss, and it seems the catalyst for this is that the *UK* authorities are cracking down on vactrols. Although the UK left the EU (and so the EU's RoHS directive no longer applies in the UK) most EU environmental legislation was rolled-over into UK law on exit so that businesses didn't have a completely-changed legal framework to deal with overnight. He said he's been in contact with several UK pedalmakers who have also had problems.

Whether genuine non-cadmium LDRs are technically possible at some point in the future is a physical chemistry question that I'm not qualified to answer.

This is timely for me since I was about to order more vatrols for the Druid shop, but if the "RoHS" claim on those products is not actually true when independently tested then there's really no point, so I'm holding off until I've found out what the UK's Office of Product Safety and Standards has found out about vactrols.

Thanks for the info Tom. I did some research as well and apparently there are LDRs without cadmium or anything dodgy in them - they are GeCu (Germanium Copper) and they are supposed to be extremely sensitive and cope with huge brightness ranges, so I thought, wow this is just what we need! Then I did some more research. They are infrared only (OK, not the end of the world, infrared LEDs are easy to get), they are designed for astronomers to measure light with and cost around £65 - £175 each!!! Oh, and if that price range wasn't the killer, apparently they really only operate well when chilled to 77 degrees Kelvin... so any pedal using them would need some impressive liquid nitrogen cooling - I bet this is very 'audiophile', but not very practical

Quote from: Transistor-Transistor on September 03, 2024, 01:34:03 PMI wonder if there would be a way for phototransistors to act as a replacement for LDR's as they're much easier to find and don't have the Cadmium that Europe doesn't like. I have a 3d printer and I'm planning on making my own vactrols with that (just to be less janky than shrink wrap and duct tape)
Phototransistors and LDR's are not really interchangeable but I'm sure things can be done circuitry wise to make it more similar

Thanks Transistor-Transistor - I also looked into phototransistors but they seem to be for modulating current? Can that be used to modulate resistance? They don't have any banned materials in them which sounds good.

Quote from: PRR on September 04, 2024, 01:13:35 AMIt is going to be digital in the end. Go ahead and develop a GOOD ADC board, compute the optimum gain function, apply it to your bytes. Latency can be 20 MICROseconds which is quite short.

I don't know if my brain is ready for digital yet; I'm still struggling with analogue! As my colleagues who understand coding will tell you - they wouldn't trust me to count from 0 to 1 and get it right; I think digital might be a while (unless it gets a lot easier in future and doesn't require coding)

OK time to bring you uptodate with changes to the circuit. I rebuilt the whole thing on breadboard because it was a mess. It still works (yay!) and each LED has it's own CLR and potentiometer.



You'll notice that the first two LEDs have large CLRs, while the other two have small ones (220ohms). There' a sad story about that. I'm not sure if you remember that I said the circuit was rather warm when it only had a 100R resistor in it? And I replaced the 100R with a 470R and that seemed to cool things down? Well I rebuilt the circuit and thought I would try 220ohm resistors on each LED. After a few minutes I thought, that's odd, some parts of the breadboard feel rather warm... and then I stuck my finger on the top of the 78L05. I suspect you're probably all shaking your heads at this point... was it hot? Bloody hell it was hot!



Anyway after swearing furiously, I unplugged the power, let the 78L05 cool down and swapped it for a larger 7805 which worked fine and didn't get above 45 degrees C. I presume the heat issue was caused by too much current being used by the circuit? And later on, I changed the value of some of the resistors and the heat went away completely, so I was able to swap back to a 78L05.

While testing the circuit I discovered that two of the LEDs (the candle flame ones - D1 and D2) play electronic music when the pots are turned so that the LEDs are at full brightness! Which was cool, but also bloody irritating when you don't want them to sing over the guitar (they are louder than the guitar) and they also sound a bit crap...

If you want to hear them singing, they start to do it at about 1 minute 15 into this recording (I got Moid Junior to play some better guitar for you to hear)

https://drive.google.com/file/d/1hKsF0WjY57h8zJ_EIMMpLsqamwt4s6g1/view?usp=sharing


Throughout the above recording I slowly turn all the pots to maximum so you hear stronger tremolo.

To get rid of the techno noises I had to increase the CLR on those two LEDs. The values  I used were the smallest I could use that still removed almost all of their audio; the downside is those LEDs are nowhere near as bright now and so do not affect the circuit as well as they did when I used a 220ohm resistor on them. If there is a better way to do this so I can have brighter LEDs please let me know.

I also got my son to play into my caline orange burst pedal (Clean Boost), and then that went into the tremolo, without the techno noise - that sounds like this:

https://drive.google.com/file/d/1zrPVpDEWfrAwSCHqDtIEFaLX0p0ZjYCd/view?usp=sharing

Throughout the above recording I slowly turn all the pots to maximum so you hear stronger tremolo.

At the moment it seems that unless playing with R2 give a massive change in depth to the tremolo (I will test this), I think I need to buy some more sensitive LDRs, because the tremolo is not as strong as I would like it to be.

Hope you're all having a good weekend