utility lfo

[johnnymad]

does anyone have samples of the utility lfo? i've heard great things about it, but i have never actually heard it in action. i'm planning to build one as soon as the parts come in the mail.

[numbernone]

JUST DO IT.

I have built 2 of them and LOVE them. Make sure you max them out with the join and swap for the Vari outputs. Also range switching is a MUST, check out Foniks site for a diagram of how to hook it up, I think my first had something around 2 uf for the slow setting, while the second was maybe 4.7uf for GLACIER speed. These are extremely versatile modulators that you will never tire of.

[johnnymad]

[Luka]

good point on the range switch i am about to do that
i might add a rotary switch and give it a good set of range options

[widdly]

I built three of these on a small piece of perf board.

I left off the right hand side of the schematic ( square and variout), so I can't comment on that part.

I think they are too fast if built straight from the schematic. I have a switch to parallel the 47n with a 470n cap. I one of them I added a 2uf bipolar for really slow settings.

[johnnymad]

just finished building it today. it is a SWEET module. i added the range selection mod as suggested, and i'm glad i did. it makes some awesome sounds when using the vari out with the two lfos in different ranges. thanks for the suggestions!!

[creatorlars]

I just built mine with join/swap switches and I REALLY love this LFO. Way more flexible than my MFOS VCLFO (of course no PWM or VC -- but I was rarely using those anyway.)

[johnnymad]

i thought about building the mfos lfo, but this one seemed to have more to offer. i'm really glad it built it. i may build one of ray's eventually though. the voltage control could come in handy.

[j.dilisio]

I'm thinking of different ways to do the range mod.
Would It work if I had a large cap (470nf-1uf) and a pot in series with the 47nf?
I imagine the pot would act as a course speed while the speed pot would be more of a fine tune.

Does that make any sense?

[j.dilisio]

Ok, I tried it with a 1uf cap and a 200k pot and it seemed to work just fine.
The pots cover different ranges but neither is really any coarser or finer than the other.
The max time of the 1uf is around 30 secs. It would be nice to have something longer.

Here's what I'm thinking..
Replace the original cap with something smaller like a 1nf and wire a 10uf with a pot in series.
This should give it a really wide range(5mins to very fast).
Then maybe even replace the speed pot on the front panel with this new pot.

Here's a question.. is that 200k pot going to cut it with a 10uf cap or should I increase the resistance?

[otherunicorn]

[j.dilisio]

Yeh, I'm not having much luck with it.

Ken, do you know any way of increasing the range without adding switches between cap values?

[otherunicorn]

[j.dilisio]

Thanks Ken,
I'll try messing with these values and post the results.

[j.dilisio]

I ended up switching the 4k7's with 1k resistors and leaving the pot as is.
This extends the range so it goes down to about 25 seconds per cycle.

This feels a lot more musical to me than having to switch between ranges.

[TekniK]

[creatorlars]

[haricots]

I love and use the dual utility LFO all the time however I've always suspected there is something wrong with the join/swap switching on mine. I haven't found a use for this yet because I can only get (slightly) usable modulations when either of the pots are turned to the extreme ends of their rotation. Does this sound like something is wrong or is this how it is supposed to be?

Does anyone have some audio examples of what it should be doing?

Thanks.

[haricots]

**crickets**

Ok, I need to replace the two switches. They are DPDT. However switch action confuses me. Should these be simple On-Off switches or not?

[jean-louise]

[numbertalk]

You don't see DPDT as often (as least I don't) in an On-Off setup (which would actually be a DPST). If you need some basics on switches check this site out: http://www.beavisaudio.com/techpages/Switches/ - could help you determine from a wiring diagram or schematic whether an On-On is required or an On-Off would suffice.

[wmonk]

It chooses between normal mixing, and joining/swapping, so a DPDT is needed. (see wiring diagram on the CGS site).
My problems are the same, should check that one time. I think the problem is that I use the LFO at the power connector side on the right of my panel (LFO2), and the other on the left (LFO1). And on the Bridechamber panel, the one on the LFO on the power connector side is on the right.

[camelneck]

I just finished wiring and testing my module. However, I'm not sure if it is working properly or not.

I've looked at the saw/tri and pulse outputs of each LFO with an oscilloscope and both LFO's are working properly and the waveshapes look
really good.

The problem I'm having though is with the variable outputs. Let me first say that I chose to wire my module as shown in Ken's first wiring diagram which I "think" is representative of the schematic. (In other words, I added the 2 Mix pots, but I didn't add the swap and join switches.)

Anyway, the schematic says that Variable Output #1 should be a mix of the square and tri waveforms produced by LFO #1 as determined by Mix #1 Pot. Similarly, Variable Output #2 should be a mix of the square and tri waveforms produced by LFO #2 as determined by Mix #2 Pot. Thus, variable output #1 is an output of LFO #1 and is independent of LFO #2 while variable output #2 is an output of LFO #2 and is independent of LFO #1.

However, when I tweak either LFO #2's Frequency and Shape pots it also effects Variable Output #1. Thus, variable output #1 is controlled by both LFOs and is not independent of LFO #2 as shown in the schematic. The same goes for Variable Output #2, which is also effected by the shape and frequency pots of either LFO.

Here is my question:

Is the variable outputs of my LFO module working correctly? (Remember, I haven't added the swap and join switches. I wired it as shown in Ken's first wiring diagram.)

Should Variable Output #1 be controlled exclusively by LFO #1 pots (Shape 1, Frequency 1, and Mix #1) or is it also effected by the LFO #2 pots (Shape 1, Frequency 1, and Mix #1)? (Both sets of pots control Variable Output #2 in a similar manner instead of just the LFO #2 pots.)


If Variable Output #1 suppose to be independent of LFO #2, perhaps I need to add some decoupling capacitors to the TL072. Any other suggestions?

David

[Mongo1]

Hi David,

I think you must have it wired incorrectly. The two LFOs are completely independent if you don't have the join or swap stuff in place. I'd recommend just going through and double checking it all.

If you look at each end of the mix pot, you should see the square at one end, and the triangle at the other. They should both come from the same LFO. If they don't there's a wiring error.

You may also want to double check your power and ground connections. It's possible that maybe the ground is bad or something, but I have a hard time believing the thing would work at all if that were the case.

Gary

[camelneck]