cool, unique design (by me)

[Marc.yo]

i was sittin here lookin at 555 tutorials and i came up with this


it's a pretty original idea....


here's what it does: u1 (555 in monostable) creates a square wave signal to match your signal. then it sends that square wave into the mixer (u2) along with your original signal to be mixed. so it actually is a doubler. every note you play will have a square wave note of the same pitch right beside it!! the two pitches, the original and the square wave are mixable


warning: the 555 chip is a single note oscillator/timer. this circuit will only work on single note lead lines but is a pretty nifty tool for it's purpose



i haven't come up with values for r1 and c2 yet....volunteers? there are a few calculators out there...idk how to do the values though.

Time= 1.1 x R1 x C2

in seconds

555 chips are readily avaliable from anywhere that sells ICs. so feel free to build this....just credit me please!!!



it's messy, I know. but it's the best I could do

[O]

Any sound clips?

[Marc.yo]

lol....haven't made it yet. i'm picking up a 555 on monday...this is all prototype right now

[gez]

Some things to be aware of:

With a monostable, if you make the time period too long, higher frequencies can go through more than one cycle before they next trigger the monostable.  Consequently, you have to make the time period really short. 

It's much easier to wire up the 555 as a schmidt-trigger for 50:50 duty cycle.  Just wire the trigger and threshold pins together - this is your input.  No cap/resistor needed.

You need to amplify the signal going to the 555.  It's even preferable to square it up, especially if you want to minimise phase-shift.  Don't use a diode clipper to do the squaring as your signal will never meet the 555's trigger thresholds.

The output signal of your 555 will be 9V peak to peak.  You'll need R3 to be a hell of a lot bigger than it is at the moment in order to bring the volume down.  Better to divide down the output of the 555 going into the mixer. 

Does a square wave mixed with the clean signal sound that good?  Personally, I'd say no, but by all means experiment.

[Jaicen_solo]

Reminds me of John Hollis's Crash Sync, maybe you should check that out for ideas.

[Marc.yo]

Some things to be aware of:

With a monostable, if you make the time period too long, higher frequencies can go through more than one cycle before they next trigger the monostable.  Consequently, you have to make the time period really short. 

It's much easier to wire up the 555 as a schmidt-trigger for 50:50 duty cycle.  Just wire the trigger and threshold pins together - this is your input.  No cap/resistor needed.

You need to amplify the signal going to the 555.  It's even preferable to square it up, especially if you want to minimise phase-shift.  Don't use a diode clipper to do the squaring as your signal will never meet the 555's trigger thresholds.

The output signal of your 555 will be 9V peak to peak.  You'll need R3 to be a hell of a lot bigger than it is at the moment in order to bring the volume down.  Better to divide down the output of the 555 going into the mixer. 

Does a square wave mixed with the clean signal sound that good?  Personally, I'd say no, but by all means experiment.

thanks for all of the suggestions! i knew i should amplify it first but I wasn't really aware to square it. thanks for the heads up!

i will work on this....more to come!

[paperhouse]

i'm very interested in clips as well - this sounds like a cool idea

[brett]

Hi
as always, the CMOS TLC555 is much easier to use than the garden-variety 555, which puts lots of spikes onto the power rail.
cheers

[gez]

Hi
as always, the CMOS TLC555 is much easier to use than the garden-variety 555, which puts lots of spikes onto the power rail.
cheers

I'd agree with your choice for reasons of saving power, Brett, but when it comes to comparator fuzz type things I shouldn't think it would matter as the spikes are in sync with the signal.  It would be a different matter with a LFO, however, where said spikes would be very noticeable. 

You're right, though, the CMOS version tends to be a better chip for our purposes.

[gez]

You need to amplify the signal going to the 555.  It's even preferable to square it up, especially if you want to minimise phase-shift.  Don't use a diode clipper to do the squaring as your signal will never meet the 555's trigger thresholds.

Something else I forgot to mention.  As elaborated on in my full post, using the 555 in monostable configuration is a waste of components.  It's simpler to wire up the 555 as a Schmidt Trigger.  If you do this, however, the input signal will have to swing around a central axis of around half supply for 50:50 duty cycle (assuming a pure sine wave test signal).  So, you could either DC couple the input of your 555 Schmidt to the output of a buffer/amp whose output sits at around Vcc/2, or you could AC couple and hold the input of the 555 at half supply using divider bias.