Help with tremolo design

[llmdcll]

So I've "designed" a little tremolo circuit using an led flasher with two LEDs flashing off of one another. I rigged it up with two Ldrs and an output for each led/ldr combo. So it's also a panner with two amps hooked up and each led has a pot to control the time it flashes. When one is off the other is on. It's only really usable at the higher speeds to be the tremolo effect. I wired it up in a dumb way so that when ever the pedal has power the lights flash. I plan on going back in and hooking the grounds of the led to the stomp so that the lights are off until the pedal is on but I'm worried about that creating a pop when engaged. I haven't done this yet but I've only been using the pedal about a week or so and now even with the pots at max speed the tremolo effect is getting slower and slower so the LEDs are flashing way slower that they should/were flashing. Could this be from the LEDs getting burnt out already from always being on? I'm gonna open it up and mess with it tonight but the reason for the topic is I would like to just make a very simple tremolo effect. I've seen many led/ldr circuits and some other designs with more transistors. I would like to stray away from led/ldr but it seems to be pretty simple. As a super beginner I've made the killswitch using a momentary switch conecting the signal to ground when pressed to achieve the killswitch but could there be a very simple way to make something similar to that with something automaticly sending the signal to ground and a way to control the speed of it happening? I'm trying to think of simple but decent sounding ways to get the tremolo sound any help would be amazing.

[llmdcll]

So after opening the enclosure and messing with the board it seems that I have a cold joint some where or something weird going on the the pot I was able to get it flash at the correct speed by shaking the wires I'm gonna try to reflow some joints and see how it goes. I just feel like there is an easier way to get this effect without the led/ldr set up.

[MaxPower]

The simplest tremolo circuit I've seen is the EA Tremolo.

[duck_arse]

llmd, I dunno how familiar you are wit de workins of the 555, but if you go to this page, you'll find loads of stuff.
http://home.cogeco.ca/~rpaisley4/LM555.html

specifically #14, 23, 31 and 38. one of the quirks of the 555 is that its duty cycle changes as you change the frequency, unless you design it otherwise. this may be an effect you are seeing with your tremolo, it maybe needs more like 50% duty cycle.

let us know how you get on.

[PRR]

>> simple but decent sounding ways to get the tremolo sound
> The simplest tremolo circuit I've seen is the EA Tremolo.

That's what I was thinking. Dozens of wiser minds have sought decent *simple* tremolos. It would seem to be smart to plagiarize STUDY (and copy) that work, rather than beat your own path through the jungle.

> I was able to get it flash at the correct speed by shaking the wires

Probably best to look good, find and fix ALL your dubious joints. (Bad joints are one of the top 3 problems in ALL electrical work.)

[GibsonGM]

+1

One of the first things I ever "designed" was an octave effect based on opamps.  I used oh, maybe 5 opamps, 30 resistors, a ton of diodes, and posted it here a long time ago.  Got some good feedback that I learned from ("why such a terribly low pulldown resistor value??" and so on --didn't know WHY you'd want to think about that pulldown resistor, at the time). 

Anyway: It WORKED!!!!!   

But you know - I could've done the same thing using existing designs to plagi....study....and would have ended up with a better-performing, much less gormy and clunky circuit.  As I designed it, in my naivete, there were so many basic errors as to make it a no-go for any sort of use on stage, or to sell.   Neat test of theory that I'd been reading about, and exciting, but in the end -- mostly useless, ha ha....

EA Trem will get you going on the basics, and you can improve it to your heart's content!   

[llmdcll]

I reflowed a joint for the first "speed" pot. It is working again as it did before. I'm going to look more into the ea trem. I've been cloning more and more pedals and learning a lot and I'm addicted now as many other people on this website. I've learned a ton through cloning and I'm trying to work on really understanding the technical side and working through trial and error to try to design some of my own creations. Granted there have been many many people before me who have done it better but I find at least trying to "design" my own little creations is more fun and it makes me feel a little better than straight cloning a big market pedal. Although I'm not really designing anything. I used a schematic from the led flasher from a kit that I bought here from Micro Center. I'm just north of Cincinnati, Ohio and that's one of the only stores that sell some sort of diy stuff that I'm looking for besides from ratshack. I made my own vero layout but that's not hard and I still "stole" the design from someone else. I rigged the ldrs through some caps to ground to change the sound a little and it sounds more modulated then used an ehx lpb after as I was worried about volume drop with the signal only going through the ldrs with caps to ground. I still have much to learn and from what I've read it seems hard to really create new designs. I've read that most circuits are just using basic electronics and I'm fully aware how pedal company's are always slighting changing other designs and using them as their own. I'm ready to dive deeper in the pedal world and I'm trying to take steps to better understand how circuits work and how to try to come up with something at least semi orginal. Thank you for the input I'll have to do some do some serious research to learn more about this beautiful hobby.

[aron]

I liked the EA tremolo when I built it. It was a nice little circuit.

[anotherjim]

I just finished my own Tremolo.
Mid-way simple - but still 2 dual opamps and a home made vactrol.
The hard part was getting the depth control right - I wanted min depth to be full (normal) volume but still have a smooth sinusoidal "dipping" as the depth increases.
Ideally, it would be good if at deep modulation, there was (automatically) a bit of volume boost as the perceived effect obviously gets quieter - but life is too short and I only wanted 2 controls
Anyway, 1 dual amp is the LFO, the other is 2 voltage followers with the vactrol in between.

[llmdcll]

I'm probably gonna build the ea sometime soon. I was worried about the flashing led circuits because I was worried about them burning out but I'm leaning more towards the flashing LEDs because there are a lot more options with led colors, ldrs, and filters and other possibilities. I've read the giant thread on the tiny tremolo and I really like the modding possibilities with that circuit. I'm gonna start trying to use other ics because the ticking on the 555's is really bad I've found some solutions for it but I'm experimenting with other flashing led circuits. I like the transistor version in my first one because the ticking isn't noticeable but I'm still working on stuff thank you for the input

[deadastronaut]

^ you can use an opamp to make an lfo, with flashing leds ,  much better/quieter option than the 555 way..

[llmdcll]

Haha yeah I read like every page of the tiny tremolooooo thread I learned a lot from that thread. I'm loving your designs by the way I've seen the chasm reverb and that delay with the alien on it your work is beautiful!

[Transmogrifox]

Speaking of the EA Tremolo -- one of my favorite designs.  Years ago I posted a schematic for the rEAgenerated Tremolo, which was basically the EA with some mods to improve the depth.  It was on geocities, which went the way of the buffalo and I have never reposted anywhere.

If there is interest I can repost  and hopefully photobucket won't go away.  I think I want to revisit this to simplify...IIRC I had more components than necessary to accomplish the same end.

[thelonious]

If there is interest I can repost

Sure, would love to see that!

[Transmogrifox]

Here's the "part II", a little different from the first but should be nearly equivalent.  "R2" is 470 ohm here, but original shows 180.  If you want more gain change it back to 180.  This also works by replacing "M1" with a 2N5089 BJT.  Decrease R2 if substituting BJT -- a BJT increases the gain.

The main deviation of this circuit from the original is in the addition of Q2 and the biasing related to making this work.  It functions as a high-impedance current source so the AC gain is practically nil when the JFET is substantially turned off.

[thelonious]

Nice. Thanks for this!