Does anyone make a voltage tremolo?

DRodriguez · Post by **DRodriguez** » Tue Apr 04, 2017 6:42 am

Because it would be cool as shit to have a lfo controlled voltage starve. Especially with a random setting

spacelordmother · Post by **spacelordmother** » Tue Apr 04, 2017 8:28 am

Yes, yes, I like this, keep going.

Jwar · Post by **Jwar** » Tue Apr 04, 2017 9:42 am

Is this even feasible with a trem? I didn't think voltage starving had much effect on a lot of modulation?

DRodriguez · Post by **DRodriguez** » Tue Apr 04, 2017 9:49 am

jwar wrote:Is this even feasible with a trem? I didn't think voltage starving had much effect on a lot of modulation?

Not a voltage starved tremolo pedal but a fluctuating voltage starve. Like it starts at 9v then sweeps to like 5v and back to 9v

crochambeau · Post by **crochambeau** » Tue Apr 04, 2017 9:55 am

jwar wrote:Is this even feasible with a trem? I didn't think voltage starving had much effect on a lot of modulation?

It's possible. Recall the CV input to modulate the power rails of the Dirty Doper, feed an oscillator into that and you've assembled a voltage tremolo.

The power rail side of things is easy. Oscillators start easy and get complex as they get more interesting (random voltage, for example).

The big issue is that different circuits are going to react (or not react) to different ranges, so a stand alone voltage tremolo would require the ability for the user to define the low point and the high point of the voltage output - and a two point scaling circuit is adding controls to what otherwise should be a neat and clean package (ie - we're veering into user reachable controls that can easily be set to make the circuit not work, which annoys some people).

Eivind August · Post by **Eivind August** » Tue Apr 04, 2017 11:40 am

^ Sounds like a job for C. Rochambeau, pedal builder extraordinaire!

DRodriguez · Post by **DRodriguez** » Tue Apr 04, 2017 11:51 am

Eivind August wrote:^ Sounds like a job for C. Rochambeau, pedal builder extraordinaire!

Funny you mention that, I just talked with him and he is going to build one.

In case anyone else is interested in joining into the project. Roughly 4 months build time for R&D, planning, staff retreats, and time for noise to be noise.

If you want to be a part of the feature conversation, I'd recommend talking with him and me. But the rough plan would be:

Standard boss 9v jack in and standard boss Xv jack out. I would strongly want CV in for the main oscillator. Definitely want scaling. And would like to do some more complex oscillator options.

crochambeau wrote:Something like a simple timer circuit with square and ramp could come in at the ~$100 mark. Randomization will impact cost tremendously, though quasi-randomization will not. External CV input will keep it interesting, but will also drive up the cost. Scaling is almost imperative in my opinion, and will also affect sticker price - it's a somewhat nasty one in that scaling UP is different than scaling DOWN when we're talking about doing that on top of a user defined starting point; I can cut negative swing out of the power supply though (I'd have to) so it's simpler than a CV processor I've been chewing on.

As it stands, the oscillator portion is going to be the big shifter of end price, as I have a CV mirror power rail circuit already drafted on a small PCB and it's not a big deal.

aen · Post by **aen** » Tue Apr 04, 2017 11:52 am

I do this with the YEP from time to time. The "clock sub" is actually just a jack into the power pin for the oscillators on board. Really all you need is CV tapped into the power input on another circuit. Just dont go blasitng 12 volts into a pedal that takes nine or some such shit.

Dandolin · Post by **Dandolin** » Tue Apr 04, 2017 12:05 pm

I saw exactly what you're talking about from a maker/seller on Reverb. Now I just need to tease it out of my 1000 item watch list....

Edit: shit, sorry, can't find it - - I know it was out there, though. If it's any consolation, it looked a lil fly-by-night....

I like the external lfo into Power Struggle idea.

I also like mont_assy's have-a-care....

multi_s · Post by **multi_s** » Tue Apr 04, 2017 12:41 pm

why dont you just use a power op amp or something similar? get something like the druid tap tempo trem ic and just feed it into a power opamp. voila, tap tempo power starvation. see also how to increase your repair bills.

alexsga · Post by **alexsga** » Tue Apr 04, 2017 12:53 pm

copilot broadcast -> dwarfcraft power struggle

crochambeau · Post by **crochambeau** » Tue Apr 04, 2017 7:27 pm

DRodriguez wrote:[Roughly 4 months build time for R&D, planning, staff retreats, and time for noise to be noise.

It's really mainly the staff retreats, hahahaha.

4 months seems like a safe window to go public with, what with juggling stuff & all.

multi_s wrote:why dont you just use a power op amp or something similar? get something like the druid tap tempo trem ic and just feed it into a power opamp. voila, tap tempo power starvation. see also how to increase your repair bills.

If I can get past my aversion to using anything but jellybean parts this is a great idea, and would do to keep the cost reasonable . Regarding the CV to power rail section, I use a common base BJT (set up like a voltage regulator) being squeezed by a MOSfet to decouple the CV. Bench testing showed surprising linearity, though to be fair I have not run one into destructive test yet (since the circuit it was feeding was less than 100 ma). Obviously a stand alone build would need a bit more working over with the proverbial BFH.

I think scaling will be easier than I suspected, since we're not going through zero on it. Moving has fucked my brain, sorry.

autopilot · Post by **autopilot** » Tue Apr 04, 2017 10:28 pm

i built a expression/cv starve feature in a custom pedal (tesseract), the main thing you have to know is that most devices dont operate (in a cool/musical context) in the same voltage sweep, some get interesting from 9 to 8, others can go to 6, 5 and others kinda only work from a fixed voltage only

jrfox92 · Post by **jrfox92** » Wed Apr 05, 2017 1:07 am

VCA+LFO=tremolo. Right?

PeteeBee · Post by **PeteeBee** » Wed Apr 05, 2017 1:11 am

I don't remember exactly and I'm a little drunk but I feel like you can get close to this sound with the eqd nightwire? It doesn't have cv input so maybe not at all...