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DIY Stompboxes => Building your own stompbox => Topic started by: Valoosj on September 22, 2008, 05:14:25 PM

Title: Piano+guitar fx = bad?
Post by: Valoosj on September 22, 2008, 05:14:25 PM
A friend of mine that plays in my band asked me to build him something to put in between his piano and the PA. I decided on building him a fuzz face with a phaser and an echo base in between.

After unveiling my plans somebody (Auke Haarsma) mentioned that the loads on a piano are different than those of a guitar, and that the fx would not work.
He pointed out this topic by STM: http://www.diystompboxes.com/smfforum/index.php?topic=39559.0

Would this do the trick for a piano? And if so, can somebody explain the schematic a bit? Do I need 5x TL072 and what does the thing in the bottom left corner mean?

Thanks
Title: Re: Piano+guitar fx = bad?
Post by: frequencycentral on September 22, 2008, 05:48:13 PM
What's the piano exactly?

I generally have my breadboard sitting on top of my Fender Rhodes - the output of which is very 'guitary' in both level and dynamics. It sounds at it's best through a tube guitar amp too. I can also play one handed while tweaking the breadboard - much easier than using a guitar. For me, if it works with the Rhodes it'll work with guitar too. Then I try it with guitar!
Title: Re: Piano+guitar fx = bad?
Post by: Franky on September 22, 2008, 06:24:26 PM
Phasing on a piano, that's the kind of ethereal sound I love.. Delay and (obviously) reverb are good too..

All the modulation effects can be applied (you can even put some distortion, listen to Lights from Archive)..
Title: Re: Piano+guitar fx = bad?
Post by: mth5044 on September 22, 2008, 06:43:02 PM
Quote from: frequencycentral on September 22, 2008, 05:48:13 PM
What's the piano exactly?

I generally have my breadboard sitting on top of my Fender Rhodes - the output of which is very 'guitary' in both level and dynamics. It sounds at it's best through a tube guitar amp too. I can also play one handed while tweaking the breadboard - much easier than using a guitar. For me, if it works with the Rhodes it'll work with guitar too. Then I try it with guitar!

Thats because the rhodes and guitar work the same way. The rhodes hits the little metal thingers that vibrate and are picked up by the same (well, I guess the same) passive pickup that guitars have. I play my rhodes 54 out of guitar amps with guitar pedals, and that is the conclusion I have come up with.

I can only assume by 'piano' you mean keyboard? In my experience, keyboards have much stronger output then a guitar, but can still sound good with guitar pedals. I would guess rack effects would be better for keyboards, due to their level (line level? I forget the terms) stuff. And stuff.
Title: Re: Piano+guitar fx = bad?
Post by: frequencycentral on September 22, 2008, 07:14:50 PM
Quote from: mth5044 on September 22, 2008, 06:43:02 PM
Quote from: frequencycentral on September 22, 2008, 05:48:13 PM
What's the piano exactly?

I generally have my breadboard sitting on top of my Fender Rhodes - the output of which is very 'guitary' in both level and dynamics. It sounds at it's best through a tube guitar amp too. I can also play one handed while tweaking the breadboard - much easier than using a guitar. For me, if it works with the Rhodes it'll work with guitar too. Then I try it with guitar!

Thats because the rhodes and guitar work the same way. The rhodes hits the little metal thingers that vibrate and are picked up by the same (well, I guess the same) passive pickup that guitars have. I play my rhodes 54 out of guitar amps with guitar pedals, and that is the conclusion I have come up with.

Cool! Another Rhodes guy! Mine's a Stage 73 Mk1. I totally tweaked it up. I've also got a Wurlitzer EP200a. Did you build the Dyno-My-Piano preamp yet?
Title: Re: Piano+guitar fx = bad?
Post by: caress on September 22, 2008, 07:16:16 PM
i think you mean acoustic piano?  but if not, i am a keyboardist and use all of my pedals with lots of different kinds of keyboards and tube amps.  wurlitzer, rhodes, digital synths, analog synths, kiddie toy keyboards... the list goes on.

usually the simplest option in my experience is to use a simple pot on the input to drop the signal going into the pedal.  that way, you can leave the keyboard volume up and turn on the effect and you won't over-saturate the opamp, transistors, whatever.  wire it up just like an output pot to ground, but place it before anything else.  you can get a lot of different sounds that way, too.

for example:
if you play a wurlitzer with the volume up and put it through a fuzztone or fuzzface, the "fuzz" control on the pedal won't do anything since the pedal is already being overdriven to the max...
just turn down the input volume and you've got a whole cornucopia of subtle fuzztones!
Title: Re: Piano+guitar fx = bad?
Post by: mth5044 on September 22, 2008, 10:02:24 PM
Quote from: frequencycentral on September 22, 2008, 07:14:50 PM
Cool! Another Rhodes guy! Mine's a Stage 73 Mk1. I totally tweaked it up. I've also got a Wurlitzer EP200a. Did you build the Dyno-My-Piano preamp yet?

Aw man, I always liked the look of the Stage 73. I'm not familiar with the Mk1, but is that the kind that has the amp along with it?

My Rhodes 54 was a hand-me down from my father. He also gave me a Horner Clavinet N. Then from my grandfather I got a Hammond B3 and a shin-ei univibe. I had a picture of the Clavinet ontop of the rhodes at a right angle with the B3, and me doing a Rick Wakman, but that was tragically lost in the computer crash of '05. It was epic. The Rhodes needs a bit of a tune up and the Clavinet is in desperate need of those little sticky things that pluck the metal prongs, but both still get the job done  :icon_mrgreen:

But no, what is this Dyno-my-piano? The way you speak of it, it sounds like I need to do it. Immediatly.
Title: Re: Piano+guitar fx = bad?
Post by: iaresee on September 22, 2008, 10:07:22 PM
Works well for Tori Amos. She runs overdrive off a piezo (I *think* that's what it was) output on her Bosendorfer piano. I'm trying to remember where I read that now. It was a great article talking about recording her latest album at her home studio with her husband. Hmm...maybe an old MOJO?
Title: Re: Piano+guitar fx = bad?
Post by: Auke Haarsma on September 23, 2008, 04:43:23 AM
Quote from: Valoosj on September 22, 2008, 05:14:25 PM
After unveiling my plans somebody (Auke Haarsma) mentioned that the loads on a piano are different than those of a guitar, and that the fx would not work.
He pointed out this topic by STM: http://www.diystompboxes.com/smfforum/index.php?topic=39559.0
Ej Yorick, as mentioned above, I pointed at the difference in signal strength between instrument level (passive guitar pup) and line-level (key/synth).
Title: Re: Piano+guitar fx = bad?
Post by: Valoosj on September 23, 2008, 04:47:42 AM
It is as Auke says, a synth. Sorry for the confusion. So a simple volume pot at the beginning would do it? Or do I need to use the stuff in stm's topic?
Title: Re: Piano+guitar fx = bad?
Post by: Steben on September 23, 2008, 05:10:39 AM
Depends on what has stronger amplitude: the guitar or the piano.
I would say differences of <50% are not important, since different guitars tend to have bigger differences on their own. Most gear is suited for most guitars, so I doubt some millivolts would make them useful or useless.
But of course: a simple pot in the front, labeled "sensitivity" or so, can do the trick.
Title: Re: Piano+guitar fx = bad?
Post by: frokost on September 23, 2008, 05:25:40 AM
Quote from: mth5044 on September 22, 2008, 10:02:24 PM
... the Clavinet is in desperate need of those little sticky things that pluck the metal prongs, but both still get the job done  :icon_mrgreen:

At http://www.clavinet.com you can buy new hammer tips for the clavinet, if you didn't already know.
Title: Re: Piano+guitar fx = bad?
Post by: axg20202 on September 23, 2008, 06:22:30 AM
Quote from: mth5044 on September 22, 2008, 10:02:24 PM

But no, what is this Dyno-my-piano? The way you speak of it, it sounds like I need to do it. Immediatly.

Another Rhodes owner here. Mine is a Stage 73 Mark I (it now contains a clone of the suitcase preamp, which I made). Dyno-My-Piano were a company specialising in Rhodes modifications. The Dyno sound is very distinctive and more bell-like (many workstation keyboards have a Dyno patch, which will give you some idea of what I mean). However, the secret is not just in the Dyno preamp, it is also in the way they used to set up ('voice') the piano. The Dyno preamp can excentuate flaws in the piano setup, so a very well-regulated piano is required. The company also made other modications such as on-board chorus effects (Tri-stereo chorus) etc. You can find out more at the Rhodes Supersite.

http://www.fenderrhodes.com/history/dyno.php (http://www.fenderrhodes.com/history/dyno.php)
Title: Re: Piano+guitar fx = bad?
Post by: Paul Perry (Frostwave) on September 23, 2008, 07:56:12 AM
In my experience keyboards usually have a higher signal than a guitar. And analog synths much more.
But, if you have a level control at the front of the effect, you can drop the signal down.

how well does a piano sound thru a guitar FX? Well it's just the same as a guitar, some FX can handle chords OK, some can't.
I have had a Yamaha concert grand play thru my ring modulator (for a Stockhausen piece). That was via a loop in the mixer, the piano was miked.
Title: Re: Piano+guitar fx = bad?
Post by: earthtonesaudio on September 23, 2008, 10:10:18 AM
Quote from: Valoosj on September 23, 2008, 04:47:42 AM
It is as Auke says, a synth. Sorry for the confusion. So a simple volume pot at the beginning would do it? Or do I need to use the stuff in stm's topic?

Volume pot is the way to go.  Your synth probably has low enough output impedance to drive any guitar effect ever made.  Think of it like this: guitar effects are optimized for low level, high impedance signals.  Your synth has a high level, low impedance output.  Therefore, to make it play well with guitar effects, you need at least a volume attenuator, and preferably also a series resistor to increase the output impedance (to help with the fuzz boxes).
Title: Re: Piano+guitar fx = bad?
Post by: ashcat_lt on September 23, 2008, 02:50:00 PM
I think the issue mentioned here is more that the fuzzface "expects" a relatively high-Z, inductive, input like that of a guitar.  This creates a hi-pass filter that makes it smoother and lest nasty.  The link you posted would change the input-Z seen by the keyboard, but would still present a fairly low-Z to the following pedals.  The synth likely won't respond to that low-Z with the same filtering action you'd get from a guitar, because it doesn't have the inductance and capacitance of the pickups. 

A volume knob is a good idea.  A simple cap to ground LPF might help.  If you want to get all fancy and stuff, try this (http://www.muzique.com/lab/pickups.htm).