Tremulus Lune Aux LFO for Level, Not Rate

[FunkyGibbon]

Hi,

I have a Tremulus Lune on my list, and looking at some of the Tremulus Lune projects that use extra LFOs, I thought it would be fun to use one to control the level, in sync with the main LFO, instead of controlling the rate as most of the Aux LFO projects seem to.

Obviously "in sync" might be a major technical problem.

What I want to do is have LFO 2 oscillate with a triangle wave at exactly half the rate of LFO 1. It's only control will be 'depth', and it simply reduces the height of every second PEAK of the first LFO, and therefore reduces the volume of every second 'beat'. This will give a rhythm of:

"loud-soft-loud-soft-loud"

for the PEAK volume points or 'beats'.

The LDR of LFO 2 could simply sit in series with the LDR of LFO 1.

Is there a way to have LFO 2 controlled by the 'speed' and 'fine' knobs of LFO 1 (dual gang pots) BUT have it run at exactly half the rate?

If this is possible, what values in LFO 1 might need to change in order to accommodate the interaction effects of LFO 2?

(Presume I'm talking about the current Tonepad version).

Thanks.

[FunkyGibbon]

Sorry that I'm (partially) answering my own question, but this may be simpler than I had thought.

1. The Commonsound speed doubling mod simply adds another 100uF cap to ground in parallel with the one already connected to pin 3 of the 'smoothness' pot. This doubles the capacitance to 200uF, if I understand correctly.

SOOO... to have LFO 2 oscillate at half the speed of LFO 1, they should both be controlled by the same dual gang pots for 'speed' and 'fine', and LFO 2 should have half the capacitance from lug 3 on 'smoothness' to ground compared to LFO 1. The new values for the Commonsound and Tonepad versions are 10uF in that position, so I should simply find three 10uF caps with close to the same value, placing one in LFO 1, and two in series in LFO 2. Then, LFO 2 should oscillate at half the speed of LFO 1. I would need a pot for depth, but trimmers for spacing and smoothness, so I can set them to some combination that gives close to a triangle wave. All I would need than is a DPDT switch to switch off LFO 2 (as per the Commonsound 'Kill Stomp').

2. If I make LFO 2 completely separate from LFO 1, there is no need for any value to change in LFO 1 (I think!).

Is the 'symmetry' mod required to get a trianlge wave? I haven't been able to figure that out from all the posts I've read.

If I use the Commonsound 'Kill Stomp' method to turn off LFO 2, will this reset the phase of LFO 2?

Am I right in assuming that when I power-up the pedal, LFO 1 and LFO 2 will be in phase, or is this completely wrong and their phase will be random?

Will this work?

Is the timing of each LFO likely to be so unstable as to make this a waste of time anyway?!


Thanks.

[FunkyGibbon]

I'm sorry to bump, but does anyone have any suggestions?

[MikeH]

I'm really bad with this sort of thing but- it would seem to me if you're using capacitors to control the LFO rates, and you want one to go twice as fast, yes, it makes sense that doubling the capacitor in the second one would make it oscillate at half the rate.  The problem will be syncing.  A 100uf capacitor is not exactly 100uf, nor will a 200uf be 200uf (if you can even find one).  Tantalums will be tighter, but not tight enough.  Even if they start at the exact same time, I'd think they will be out of sync pretty quickly.

You could build the Vanishing point though.  It will give you that LOUD soft LOUD soft sound

[FunkyGibbon]

I'd not seen that before, but it looks very promising.

In fact, it looks so useful I might make a separate Vanishing Point unit, that could plug into the Tremulus Lune, as well as other stuff.

Thanks, MikeH!

[JKowalski]

They will start at a completely random phase. You could build the LFO's digitally, there are simple methods to sync digital clocks and multiply their frequency.