Passive tremolo video. Let me know what you think?

newfish · October 19, 2007, 05:12:19 AM

Is anyone else having problems looking at the schematic for this fine piece of design?

Tried both from home and work, running Firefox 2 with the acrobat plugin.
Do I have to use Internet Exploder?

~arph · October 19, 2007, 06:26:07 AM

No problems here with firefox 2.. I'm not sure what link you mean, but the fading eyes schematic shows up fine (I believe it's just a gif)

newfish · October 19, 2007, 06:32:26 AM

Hmm - I've been trying to follow Darron's link (optical-tremolo.pdf) - not the flashing eyes one.

~arph · October 19, 2007, 09:14:41 AM

ah, no problem opening that either. I sent it to you by email.

Regards,

Arnoud

newfish · October 19, 2007, 11:48:41 AM

Brilliant - received with many thanks.

~arph · October 19, 2007, 11:51:08 AM

Tip: check the specs of your LDR. Usually they have a wavelength (color) range where they perform the best. For instance in my tremolo (called 'pacemaker', more info soon. It has envelope sensitive rate, like the ripplet, but switchable and more controllable) I use ultrabright green LED's to get the (specified 10k) resistance down to about 450 ohms. If you don't have/know the specs my advise is to experiment with different types and colors of LED's to find your best match.

Regards,

Arnoud

darron · October 19, 2007, 12:13:38 PM

Quote from: JasonG on October 18, 2007, 02:54:33 PM
I just finished bread bording it. Subed in a 10 uf cap and had to use 2 LRD's to get the depth I wanted. I used to have a Boss tremolo. This trem puts that to shame. Now to put it in a box. :-)

hey congrats! the 10uf cap will just change the rate range. thanks for giving it a shot

darron · October 19, 2007, 12:19:50 PM

Quote from: ~arph on October 19, 2007, 11:51:08 AM
Tip: check the specs of your LDR. Usually they have a wavelength (color) range where they perform the best. For instance in my tremolo (called 'pacemaker', more info soon. It has envelope sensitive rate, like the ripplet, but switchable and more controllable) I use ultrabright green LED's to get the (specified 10k) resistance down to about 450 ohms. If you don't have/know the specs my advise is to experiment with different types and colors of LED's to find your best match.

Regards,

Arnoud

hey ~arph. red and green seem to be the key colours to play with don't they? none of the places where i can buy an LDR give any tech. data such as that, so it's a bit of playing around. 450 ohms sounds like it could be much more effective, so maybe i will experiment even further and see what i can get.

thanks for your tip (:

edit: P.S. guys: if you have trouble opening the PDF, for some reason it might just help if you save it to your desktop and open it from there. so right click the link and 'save as' or ctrl click on mac

ItZaLLgOOd · October 20, 2007, 07:39:55 PM

the schematic link doesn't work for me.

foxfire · October 20, 2007, 07:54:27 PM

Quote from: ItZaLLgOOd on October 20, 2007, 07:39:55 PM
the schematic link doesn't work for me.

check your email.

darron · October 20, 2007, 08:22:45 PM

Quote from: foxfire on October 20, 2007, 07:54:27 PM
Quote from: ItZaLLgOOd on October 20, 2007, 07:39:55 PM
the schematic link doesn't work for me.

check your email.

thanks foxfire.

for some reason the pdf's don't open on some computers until you save them and open them instead of going right to the url.

i make the pdfs by making an EPS (standard vector format) in flash, opening it in preview (mac) and saving it. i suppose i could move over to adobe acrobat. any ideas guys?

darron · October 21, 2007, 07:01:53 AM

does anybody know if this particular opamp needs reversed polarity protection? i just finished designing a PCB layout and didn't include anything. that's the only active device, and the led's are obviously sorting themselves out...

darron · October 25, 2007, 08:49:05 AM

the 470 ohm resistor could probably be eliminated on reflection. i put it in there for safe measure not knowing what LEDs people might be using. regarding polarity protection, a friend has told me that the 4558 chip does need it. i tried frying one chip by running it backwards for a few minutes. i did smell a little bit but continued working. you might very well hear the difference if you tried the chip again for audio. maybe this could be a good conditioning method for a distortion? (:

i noticed the TS circuit on tonepad doesn't have protection. hmmmm.....

any thoughts?

thanks for your feedback guys. i really do appreciate it. hopefully this can be the start of many new designs from me, getting increasingly more complicated. i certainly have some ideas for cool things that i'm sitting on anyway.

darron

Jim Jones · October 30, 2007, 08:41:33 AM

Hi Darron,

I perfed this up on the weekend and it worked straight away. I only had 10uF electro's on hand so that's what I used although I think I'll parallel another 10uF in there to get the speed more in line. The circuit works quite well although it's not quite as complex a sound as the bias-vary tremolo built into my amp.

Good job and thanks for posting!

Jim

darron · October 30, 2007, 08:52:21 AM

hey. thanks heaps for giving it a shot Jim. it looks like it's a hard effect to stuff up unless you get a LDR that's not well suited. i haven't tested it with buffered pedals infront or behind, did you find that it still works well? not being an active decide which changes gain etc. it probably won't work with things other than guitar well. did you get the square wave switch mod in there too?

thanks again for letting me know. i'm really pleased (:

darron

ItZaLLgOOd · October 30, 2007, 09:09:55 AM

I breadboarded it last week but I didn't get any pulse to the LEDs. The depth pot controlled the brightness but I did something wrong with the rate section. I went over it several times but I didn't see anything obvious. I'm new to the breadboard so I'm sure that I missed something. Maybe a bad IC?? I'm going to start fresh and try again later this week.

darron · October 30, 2007, 09:14:34 AM

Quote from: ItZaLLgOOd on October 30, 2007, 09:09:55 AM
I breadboarded it last week but I didn't get any pulse to the LEDs. The depth pot controlled the brightness but I did something wrong with the rate section. I went over it several times but I didn't see anything obvious. I'm new to the breadboard so I'm sure that I missed something. Maybe a bad IC?? I'm going to start fresh and try again later this week.

did you try playing with the pulse trimpot? at one point it will actually not let the LED flash and will just lock it into being lit constantly.

ItZaLLgOOd · October 30, 2007, 11:06:00 AM

Yeah I tried messing around with it with no success. The trimpot actually didn't do anything. I pulled it off the board and nothing changed. I always have trouble with what should be the easy stuff.

I'll get it. I just need to slow down and take my time. Thanks for the help.

darron · October 30, 2007, 04:12:27 PM

Quote from: ItZaLLgOOd on October 30, 2007, 11:06:00 AM
Yeah I tried messing around with it with no success. The trimpot actually didn't do anything. I pulled it off the board and nothing changed. I always have trouble with what should be the easy stuff. I'll get it. I just need to slow down and take my time. Thanks for the help.

the trimpot will need to be in there for the pulse to work, or a resistor of roughly the right value. i'll measure where mine is. if it's easy then take some photos and i'll trace it visually.

JasonG · October 30, 2007, 04:23:41 PM

Maby I should have said " I changed the 22uf cap to 10 in order to make the rate knob more usable ( half of the sweep is way to slow to be usable) and I added 2 ldrs to get the depth I wanted " I stumbled upon some 2k-450k ldrs and I am using one of them now with an ultra bright Led. I am getting a slight tick because the voltage is changing too fast. They were older ldr's so my guess is the ultra bright leds were not out when they where made so I am going to experiment some more.

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Passive tremolo video. Let me know what you think?