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DIY Stompboxes => Building your own stompbox => Topic started by: madstringbean on November 29, 2009, 06:21:30 PM

Title: good LFO circuit for making your own ring mod?
Post by: madstringbean on November 29, 2009, 06:21:30 PM
Has anyone here built their own ring modulator with a built-in carrier?  If so what LFO circuit do you recommend?  Ideally one that is simple and small. 

My plan is to build a device that is centered around a very simple 4x diode-ring+2x transformer ring mod design but that has a variety of different wacky outputs (a chip from a toy, white noise machine, etc) all of which can be patched in to be used as carrier OR input, so the device can be either a processor or self-contained wacky mini synth, but I want at least one basic LFO among them.

I tried it with a simple 555-chip-based square wave LFO but apparently the "bepbepbepbepbep" that it makes when it's slow was too inconsistent to give the right effect.  I think a triangle or sine wave might be better anyway.

Then I'm thinking I'd just mix everything with diodes?  Does that sound like it should work?
Title: Re: good LFO circuit for making your own ring mod?
Post by: madstringbean on December 01, 2009, 09:19:22 PM
just wanted to bump this up for a second chance... I know one of you must know!...thanks...  ;)
Title: Re: good LFO circuit for making your own ring mod?
Post by: Br4d13y on December 02, 2009, 12:41:00 AM
you could feedback loop another pedal (fuzz/OD) and plug it into the carrier/input

if you want to have lots of options, just make the box with the inputs and output, and plug various things into it



as soon as i get a set of organ pedals, i'm gonna make a ring mod  ;D  its been on my to-do for a while
Title: Re: good LFO circuit for making your own ring mod?
Post by: Top Top on December 02, 2009, 01:27:29 AM
Quote from: madstringbean on November 29, 2009, 06:21:30 PM
Has anyone here built their own ring modulator with a built-in carrier?  If so what LFO circuit do you recommend?  Ideally one that is simple and small. 

My plan is to build a device that is centered around a very simple 4x diode-ring+2x transformer ring mod design but that has a variety of different wacky outputs (a chip from a toy, white noise machine, etc) all of which can be patched in to be used as carrier OR input, so the device can be either a processor or self-contained wacky mini synth, but I want at least one basic LFO among them.

I tried it with a simple 555-chip-based square wave LFO but apparently the "bepbepbepbepbep" that it makes when it's slow was too inconsistent to give the right effect.  I think a triangle or sine wave might be better anyway.

Then I'm thinking I'd just mix everything with diodes?  Does that sound like it should work?

You will want something faster than an LFO. Maybe that is why you had wasn't working. To get that ring modulated sound, you need to have it in the audio range. It may be a little misleading at that point to call it an LFO, as it is no longer LOW frequency...

Most LFOs can be made into audio range oscillators with the change of a capacitor or two.

I'm not sure what you mean about mixing with diodes.

This might be interesting to you...
http://www.all-electric.com/schematic/eticircuits/555-triangle-with-independent-slopes.htm

but if you search around the web, you can probably find tons of oscillator circuits. Sine waves produce the nicest sounding ring modulation to my ears, but a triangle wave will be close.
Title: Re: good LFO circuit for making your own ring mod?
Post by: Mark Hammer on December 02, 2009, 10:16:10 AM
Indeed, sine waves are likely the optimal wave-form to use for RM.  People tend to forget that the origins of RM were with electronic oscillators generating pure tones, modulated by other pure tones, whose harmonic content is relatively constant.  Guitar signals vary not only in bandwidth and envelope, but in harmonic content as well.  Modulating something with a lot of inherent harmonic content, using something with a lot of harmonic content, is not a great idea, since the sideband products tend to be far too numerous.  If one wants to get sounds similar to what synth players produce, then you need to a) filter out a lot of the top end from the guitar, and b) use a modulating wave-form as close to sinusoidal as you can manage.
Title: Re: good LFO circuit for making your own ring mod?
Post by: dthurstan on December 03, 2009, 06:14:36 AM
Hey

If you do a search for sine wave generator you get some great threads. I'm thinking of building this one
http://www.diystompboxes.com/smfforum/index.php?topic=74094.0 (http://www.diystompboxes.com/smfforum/index.php?topic=74094.0) the poor man's signal generator.

Don't know if anyone has built it.