getting rid of noise in a ring modulator

[timd]

I know some ring mods out there have that extra noise associated with the effect. I'm building one right now that uses a 4066 and a 4093 IC to produce the effect, but I'm looking for a way to kill that extra noise in the circuit with having to use a noise gate pedal. Any suggestions?

[Mark Hammer]

Using a noise gate wouldn't be all THAT terrible if you blended in some straight signal with the sideband products.  The abruptness of the gating is much more apparent when it kills/gates the entire signal.  If it is only gating the sideband components, and the clean signal continues unabated, it's not nearly as noticeable.

[timd]

I was going for an internal pedal noise fix for 2 reasons:

1. I don't own a noise gate pedal yet.

2. I want to be able to add a switch to the pedal that turns the extra noise on and off. There are some great oscillations with this extra noise that can be used for certain purposes, but they are annoying with other applications. I was hoping there might a catch-all noise reduction using only a few components that doesn't kill the volume too much.

[Mark Hammer]

As always, I recommend taking a look at the gate built into the Boss CE-1 and A/DA Flanger for noise control.  It's pretty simple, with a modest parts count (assuming you have some sort of existing input stage that you can take a feed off), and is used to gate in the delay signal (which in your case would be the sideband products) when the input signal exceeds some level.  Again, since the clean signal tends to mask the effects of the gate, you can afford to have an abrupt or gradual gating action, depending on what you like.

[dthurstan]

Hey

I'm working on a transformer & diode ring mod (http://www.diystompboxes.com/smfforum/index.php?topic=94851.0), which makes use of a gate to reduce bleed thru\noise. I lifted the circuit from the stompboxology article here;
http://www.moosapotamus.net/IDEAS/stompboxology/RingMods.htm

This is a great article with lots of information and a great explanation of how a gating circuit works.

[timd]

Thank you both for the great info! Time to study...

[DougH]

Seems to me you could just gate the oscillator itself for the most effective and subtle control. Use an envelope detector on your input signal but gate the oscillator. Unless this is what you guys were already referring to.

[Jaicen_solo]

Seems to me you could just gate the oscillator itself for the most effective and subtle control. Use an envelope detector on your input signal but gate the oscillator. Unless this is what you guys were already referring to.

That's certainly what I would do Doug. However, I think the carrier would have to drop out when the input signal is almost inaudible, but i'm sure that won't be a problem.
As soon as someone puts up a design for how to do this, i'm building a transformer based ring-mod, I just can't get past the bleedthrough.

[timd]

I have studied many layouts, websites and forum posts of both passive and active ring mods in the last few days, and I'm having an issue figuring this out. Some of them (passive) have 2 inputs and one output, but I'm building an active one (1 in, 1 out) run off the standard 9v.

This would be my 4th build, and I don't have electronics schooling -  so I'm not an expert by any means. Here are a couple links that demonstrate this very easy circuit I'm working on.

http://www.youtube.com/watch?v=WJea4HgcRuU&feature=relmfu
http://little-scale.blogspot.com/2007/08/blog-post.html

I've breadboarded both and they are very similar in build and sound. Both use 2 chips (4066 is the same in both) and I would suggest either one to someone just getting into this great hobby for a "confidence boost".

I'm just looking for a way to eliminate the carrier noise in this specific circuit - best case with a switch to regain the "noise" on demand for crazy fun with a few components. I think what I'm looking for is not only how to do it (connect this component to pin 1, etc), but WHY it works...

[Gabriel]

I beleive a noise gate will do the job.

I have build the Boscorelli attack-o-matic, which is very good: fast atack and very sensitive. I tested to shut up the Heliotrope carrier, and works ok.The bad news is that it change the tone a bit (little more brighter), so i have to tune that.

The ideal is to install a noise gate inside of the ring mod, or any noisy-ish effect..

[Quackzed]

maybee a simple crossover diodes type gate?
with a blend could work, easy to try..

in between the oscillator and the circuit splice in...

2 'inline' b2b diodes( ge or shottky or maybee silicon if the oscillator signal is big enough.)
also in parallel with them you  put a 100k trimmer to smooth out the abrupt 'crossover' type gating...
so basically 2 b2b diodes in parallel with a trimmer placed inline not to ground, between the oscillator and the circuit.
if you wanna see how it would work...of IF it would work for what you need, sorry bout the huge link! 

http://www.falstad.com/circuit/#%24+1+4.9999999999999996E-6+5.459815003314424+81+5.0+50%0Av+256+352+256+208+0+3+40.0+0.5+0.0+0.0+0.5%0Ag+256+352+256+400+0%0Aw+352+304+352+352+0%0Aa+352+288+496+288+1+15.0+-15.0+1000000.0%0Aw+496+288+496+352+0%0Ar+352+352+496+352+0+2000.0%0Ar+256+352+352+352+0+1000.0%0Aw+256+208+352+208+0%0Aw+352+208+352+272+0%0AO+592+288+656+288+0%0Aw+496+288+496+272+0%0Aw+560+288+560+272+0%0Ad+560+224+496+224+1+0.4%0Ad+496+240+560+240+1+0.4%0Ar+592+288+592+352+0+10000.0%0Ag+592+352+592+368+0%0Aw+496+240+496+224+0%0Aw+560+272+560+240+0%0Aw+560+240+560+224+0%0Aw+560+288+592+288+0%0Aw+496+272+496+240+0%0A174+496+288+560+288+0+100000.0+0.42080000000000006+Resistance%0Aw+560+288+528+272+0%0Ao+0+16+0+34+0.5846006549323611+9.134385233318143E-5+0+9%0Ao+9+16+0+34+1.5137171177895485+6.103515625E-5+1+-1%0A

[timd]

I beleive a noise gate will do the job.

I have build the Boscorelli attack-o-matic, which is very good: fast atack and very sensitive. I tested to shut up the Heliotrope carrier, and works ok.The bad news is that it change the tone a bit (little more brighter), so i have to tune that.

The ideal is to install a noise gate inside of the ring mod, or any noisy-ish effect..

This is what I ended up with - and you can still hear the carrier signal. I read in another post about the possibility that grounding a pot could fix the issue. right now, only my volume pot is grounded.

[timd]

http://www.diystompboxes.com/smfforum/index.php?topic=99235.0;topicseen

Upon rereading that fix with grounding the pot on the heliotrope - I realized that was your post Gabriel!

[Gabriel]

 

Yes, we are on the same boat sometimes!.

The best to you.

[petey twofinger]

that swirl looks  very nice man .

congrats on your ebay sucess as well .


i intend to try this soon , i scored a pxl2000 for 5 bux , in the box , complete , with 2 chrome cassettes in the package still ! its my second one so i intend to sell this unit , hopefully do well . also , i think omni bot is going to go too

[Om_Audio]

 Interesting box you built there!
My fav ring mod right now is the one in the Line 6 MM4 surprisingly. A wet/dry really helps to tune it to taste.
petey twofinger why do you mention PXL2000? My friend Gerry Fialka has been doing PXL fest here in Los Angeles for over 20 years and I have created submissions last 3 or 4 years. Make one and enter! www.laughtears.com for info.
Now back to your regularly scheduled ring mod discussion!
C

[timd]

Thanks guys! @Gabriel - I tried to ground the pot of the ring mod, but it didn't take away the noise. I'm thinking external components might be needed.