suggestion for a simple phaser pedal?

[loki]

hi guys, i was just looking around for some phasers schematics, but seems like i didn't find what i'm looking for...

all i need is a simple phaser, with just a speed and depth knob... but these could be even fixed, 'cause i always use phasers with one setting.... going up and down veeeery slowly... a la Extreme's "there is no god" to give you an idea.
so, i've ran into MXR 45 and 90 schematics, as well as the ross phaser, small stone, DOD phasor 201... but they're all too complicated

i'm looking for a simple thing, i've also noticed the Runoffgrove Phozer, simple.... but listening to the soundclips, i think maybe it's not what i need

somebody has more suggestions?
thanks!

[Ge_Whiz]

Phasers are not simple circuits compared with distortions and boosters, and that's the simple answer. They don't come much easier than the 45. If this is too complicated, you need to build a few more distortion pedals to gain experience, then maybe a ROG EA trem, and work up to the phaser slowly. Or go out and buy one. Sorry.

[StephenGiles]

It depends how you build - on PCB most of the work has been done for you in the design of the board. On stripboard, however, you do all the work yourself, but with a phaser, once you have got the pattern right for the first couple of stages, the rest is easy. However, I've been building on stripboard since 1975 so it's easy for me to say, but it does provide a good grounding in getting stuff to work. The first phaser I built was the Univox microphase, from a circuit that turned out to be wrong, so it didn't work until I bought one and reverse engineered it. I got my version going in the end. I don't think anyone will progress much building fuzz boxes all the time.
Stephen

[Mark Hammer]

At the very least, any phaser will require:
1) A low frequency oscillator to generate the cyclical sweep
2) An input splitter stage to separate the straight and to-be-phase-shifted paths
3) The phase-shifting section/s
4) A means of recombining the straight and shifted signals

There certainly more and less complicated ways of doing this, but the P45 is getting very close to the barest bones way of doing so.  It uses only one op-amp for the LFO (most designs will use two), uses passive dry/wet mixing instead of an op-amp, and only uses two phase shift stages (absolute minimum).  Very very hard to make it simpler than that.

The hard part will always be obtaining suitable control elements, whether they be FETs, LDR, or OTA chips.  It's not impossible, just harder than strolling into a Radio Shack and buying a variety pack of 1/4w resistors.

In general, the quality of the sound will absolutely depend on the complexity of the circuit.  In the case of distortions, it is easily possible to make the effect more intense by changing a component value here or there to increase gain or clipping amount.  In the case of phasers, effect intensity necessitates adding more stages and more circuitry, and there is often little way around it.

[Fret Wire]

Not technically a phaser, but check this out
http://www.runoffgroove.com/phozer.html

sound clips:
http://www.runoffgroove.com/salvo.html#phozer

[loki]

thanks guys for your answers...

i actually don't want to build a stompbox, but a circuit to mount onboard on my bass, so the main concern was about the complexity of the circuit, also because i use breadboards, not PCBs...
so far i've built a ts-808, a big muff, a MXR microamp, and a Pulsar Trem. those were easy to breadboard... but if you're telling me the Phase 45 is the simplest of them all i'll check for it and i'll study how to match FETs
thanks again!

[Mark Hammer]

Ah, some context, finally....

1) I generally try to discourage people from installing effects on their instruments because of how it forces you to go with the simplest possible form with less than the controls you might like.  There is also the issue of changing batteries, but that is more fixable than the problem oif being stuck with one or MAYBE two knobs.

2) The sonic quality of any phaser will be a product of WHERE the notch/es is/are located in the spectrum.  If this is for bass, you might want to tune the notch location downwards.  Depending on the circuit chosen, that might involve adjusting the bias trimpot, selecting resistance-to-ground values differently, or changing the cap values for each phase shift stage.

3) Whenever you have more than one pickup on a stringed instrument there will be some cancellation produced by the interaction of the two pickups.  I routinely find that if I have a way of playing the volume control for one pickup with my little finger when both pickups are on, it is easy to produce a phaser-like effect, similar to a P45, as the amount and location of the cancellation moves around.  Depending on how, and how often, you want to produce the effect, it may even be possible to do what you want just be having separate volume controls (i.e., no extra circuitry, no perfboarding, no design choice and NO BATTERIES!).

4) Single swept bandpass filters can do a credible job of sounding like simple phasers, even though they aren't phasers per se.  Check out the Phozer.

[loki]

thanks mark...

i considered the instrument's control cavity narrowness, and being myself a batteries-hater, i thought about drilling an additional hole near the jack plug for a 9v power jack that should power the circuit(s) i might install and also, with a charge pump, the 18v needed for the active PU electronics.
i thought that since i have already the instrument cable dangling, wrapping a power cable around it shouldn't be much of a trouble, and plus both end to the pedalboard, so it would be much like having the instrument cable only.... this seems to me a perfect solution to get rid of any battery.

as for the controls... i am really a one-setup guy... that is when i found a sound i like out of a stompbox, it pretty much stays the same always...
but even if i mount a say 5-knobs circuit, i could choose one or maybe 2 of them (let's say "critical" ones) and drill holes for them, living the others in the cavity or substituting them with trimpots..

i've already tried what you suggested about the volume swell, yes, the sound is ok, but it's not exactly what i'm looking for (that is a jet-like phaser).

so i think i should experiment modding existing phasers for bass... i'll ask an enginneer friend's help.
thanks!

[vdm]

hey mate,

im not sure how the power cable would go... something tells me it would cause a problem... but that's just my silly intuition...

one thing i'd like to add is that if you are using a distortion or fuzz pedal in your effects, you might want to consider that phase before a distortion is usually not nearly as nice as phase after distortion.

so this could be another reason to keep it as a pedal.

oh and btw. i think if you have built a ts808 and a big muff you certainly have the ability to stick the components together... i made a P45 on perfboard when my previous biggest build was a bluesbreaker..it fired up first go too.... but maybe im just lucky :twisted:

gd luck!
trent

[bioroids]

thanks mark...

i considered the instrument's control cavity narrowness, and being myself a batteries-hater, i thought about drilling an additional hole near the jack plug for a 9v power jack that should power the circuit(s) i might install and also, with a charge pump, the 18v needed for the active PU electronics.
i thought that since i have already the instrument cable dangling, wrapping a power cable around it shouldn't be much of a trouble, and plus both end to the pedalboard, so it would be much like having the instrument cable only.... this seems to me a perfect solution to get rid of any battery.

as for the controls... i am really a one-setup guy... that is when i found a sound i like out of a stompbox, it pretty much stays the same always...
but even if i mount a say 5-knobs circuit, i could choose one or maybe 2 of them (let's say "critical" ones) and drill holes for them, living the others in the cavity or substituting them with trimpots..

i've already tried what you suggested about the volume swell, yes, the sound is ok, but it's not exactly what i'm looking for (that is a jet-like phaser).

so i think i should experiment modding existing phasers for bass... i'll ask an enginneer friend's help.
thanks!

You may wanna try some kind of phantom power,  like the used on recording mics. That way you can get the power thru the instrument cable. You may need to use a "phantom powering" stompbox as your first on the chain.

Just thinking out loud, but if properly designed it should work great.

Luck

Miguel

PS: are you sure you need a phaser at all? I think "jet effects" can only be obtained with flangers

[Mark Hammer]

PS: are you sure you need a phaser at all? I think "jet effects" can only be obtained with flangers

Yes and no.  Phasers that have many stages (let's say at least 12), a harmonically rich input signal, and a means of sweeping those notches way up into the high audio band can sound quite jet-like in their character.  Admittedly, a properly-designed flanger will do this MUCH better, but don't confuse what a plain 4-stage phaser with simple LFO can do and what a more complex one can do.

Mike/Vsat's 24-stage phaser does a pretty damn credible job, I must say.  Of course, you wouldn't really want to build one in your guitar, and I'd hesitate to call it "simple".