TREMMY TREMOLO

[midwayfair]

Try just using the Tremulus Lune's depth control (voltage divider between +9v, pin 7, and R6). It's already almost identical to the Lune's oscillator anyway, and then you can take advantage of the complete sweep of the vactrol instead of the max of maybe 50% attenuation you currently have. Of course, then it'll basically just be a two-knob Lune with the first stage inverting ...

You probably want a pF cap in the second op amp to head off ticking; you might also notice a difference with a buffer in front. And you may want a treble bypass across R8 (try something like 4.7nF and a 47K in series) to correct some of the treble loss you're no doubt getting with that input section.

cheers john,

i just tried the 'lune' depth' but am not getting any depth control now...

am i right in thinking that the ldr would then go direct from IC1A pin 1.pin 6 IC2A?..

diagram?...i'm lost..

Well, you don't need to remove R16. It's setting the op amp gain to unity. You could remove it if your depth is too HIGH.

If your LED isn't blinking, something's hooked up wrong. It should divide between the output of the op amp and +9V.

If your LED is blinking but you aren't getting any volume attenuation ... well, there I'm just confused. Your LDR's resistances should divide with the op amp feedback resistor. :/

[samhay]

Perhaps take a look at the Shoot the Moon tremolo, which is a Tremus Lune-lite: http://juansolo.demon.co.uk/stompage/schematics/Grind%20Customs/STM_V1_Schematic.png

[deadastronaut]

cheer guys, well i tried again with the shoot the moon setup,

both leds hardly flashing...,( r16 then ldr )...

the leds are hardly dimming, hence no trem really...

i copied it exactly...hmmmmm....i get the theory for it working that way , but it just isn't oscillating as widely in this case...e.g led on/off


edit i moved the leds in series and it seems better...

i now have depth but very ittle control, all bunched up one end of the 1k pot....

[samhay]

^the leds are hardly dimming

Are you using superbright LEDs? If so, try some regulars.

[deadastronaut]

hi sam, yeah using brights, seems ok now , i just had to put them in series rather than parallel..

getting proper depth now, but 1k control seems moody...either on or off really

[samhay]

Yep - it works when you hook several LEDs up from the op-amp output to ground. The sweep is not great though as it is tricky to set the max and min depth. You also probably want the LEDs to be fully on at minimum depth, which is tricky unless you play with the op-amp DC bias.

The reason the Lune/Moon depth control is a bit more complicated is that the depth control and sweep works much better this way if it is set up properly (at least as far as I have found). With ultrabright LEDs you need to decrease the current by perhaps 10x, so try scaling the resistors up by ~10x.

Edit - but if your depth control is still parallel to the LDR, ignore most of what I said and try playing with the taper of the depth pot.

[deadastronaut]

yeah i'll dig out a 1kA pot if i have one and try it in reverse...

it does seem more choppy though...

the blue led is choppier than the red as i said before...both have a nice haracter...like mike said switchable..

unless theres an easy mod to have siney and squarey..


edit: one thing i notice, when i have distortion on and guitar turned down i get a whooshing sound, not a tick or thump...hmmmm...

it goes when i turn guitar up..

[samhay]

Are the bl**dy whoosh - If it changes when you turn the rate knob, then you are likely hearing the LFO/LEDs.
If you want a square wave, tap the non-inverting input of the LFO op-amp and send this to the LFO buffer via a SPDT (to switch out the triangle you have there already).

[deadastronaut]

 the whoosh is really bad  when depth is low/off...(distortion on/guitar vol off)

i'll try that tap lark after the whoosh issue..

edit: got rid of the whoosh with a 2.2k to ground from ldr led...cool. silent now. (cut trem depth a little...hmmm..


edit: got it, no more whoosh....

[deadastronaut]

rght, i'm a happy bunny (but not blue ) no more whooshy whoosh...

but before i draw up a new improved schemo,

this tapety tap tap  off shape lark...

i tried a jump lead from pin 3 to 6/7 is that what you meant?..

[duck_arse]

spdt switch wise, pin 5 to common, pin 3 to square end, and whatever you currently have connected to pin 5 to the triange end. that's if I'm reading anything correctly.

[samhay]

^i tried a jump lead from pin 3 to 6/7 is that what you meant?..

As the other da said (I think). Pin 3 goes to pin 5 and you switch out the connection between pin 5 and lug 3 of the speed pot.

[deadastronaut]

yep got it now,

nice... square and triangle...very cool addition. cheers guys.

i just realised my work lights affecting the ldr, like a  total f...... dumbass...i put a tiny pinhole in the heatshrink ages ago to see/make sure  the led was working ha ha. 

proper good now..when dark.

[deadastronaut]

ok heres what i have now..



and  a normal clip...

https://dl.dropboxusercontent.com/u/7464107/tremmytremolo666.mp3

and having fun with the swell side of things....

https://dl.dropboxusercontent.com/u/7464107/tremmyverb.mp3

[samhay]

Cool.
You don't need R10 or R11. Actually, why not make the first op-amp non-inverting and save on a little noise?

[deadastronaut]

cool, removed R10/11

i'm all for lowering noise....diagram?

[armdnrdy]

A couple of things.

What are you using for the LDR?

And...a bit of advice for Eagle:

Schematics are much easier to read (especially busy circuits) if you use symbols instead of wires to make power connections.

You'll find V+ symbols in one of the "supply" libraries.
You can also find VR symbols which you can place at the confluence of the resistors of the voltage divider.
You can then set a symbol anywhere on the schematic for VR with no lines.

I used to leave the ground symbol name in place for all of my GND symbol placements.
Sometimes the name will get in the way of something else and would be better off not shown....after all, we know that the symbol is ground.
Delete the GND name by right clicking on the GND symbol, left click on "smash", right click on the GND symbol name, and hit delete.
The name will disappear.....like magic! 

If you should want the name to be viable again, click on the symbol, and hit "unsmash".

[deadastronaut]

LDR ; led on 24k led off 2k on . is what i get..


eagle: yeah i still need to learn untold stuff with it, especially the power side of things, to keep it tidy..

i either get no power and grounds to the board , or lots of pads everywhere...i need to sort out the 'references' rather than pads...

[armdnrdy]

LDR ; led on 24k led off 2k on . is what i get..

i either get no power and grounds to the board , or lots of pads everywhere...i need to sort out the 'references' rather than pads...

Which model # LDR?

It sounds like you are using the GM supply power which lays a pad.

Look for the libraries supply, supply0, supply1, supply2. These libraries are not in the GM libraries. Scroll down in the library to the S section.

[deadastronaut]

ldr  :  same as this..

http://www.evelta.com/ldr-5mm


ok i'll check that out, cheers man.