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Feedback - try this at home?
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RJ Guitars



Joined: 14 Nov 2006
Posts: 1647
Location: White Rock, New Mexico

PostPosted: Sun Apr 08, 2007 2:22 am    Post subject: Feedback - try this at home? Reply with quote

Feedback without extreme volume - is it possible?

Has anyone tried this??

http://www.marksmart.net/gearhack/feedbackgen/feedbackgen.html

it seems like a clever yet simple idea. I love my Les Paul but it just doesn't want to feedback... is it possible that this just might bring her to life without the Marshall turned up to 11? Smile

rj

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surfsup



Joined: 29 Nov 2010
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Location: Chicagoland

PostPosted: Fri Mar 23, 2012 12:08 pm    Post subject: Reply with quote

Four years later, I'm wondering if anyone tried this yet, as well?
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LeftyStrat



Joined: 14 Jan 2005
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Location: Seattle, WA

PostPosted: Fri Mar 23, 2012 3:34 pm    Post subject: Reply with quote

Glad you resurrected this. I hadn't seen it.

I've done the Fenandes-style as an experiment, but it was more for smooth sustain.

The clips in that link give some great organic feedback.

I think something like a tactile transducer might work even better:

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-375

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Reeltarded



Joined: 14 Feb 2009
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PostPosted: Fri Mar 23, 2012 6:16 pm    Post subject: Reply with quote

Yes I have played a couple different guitars with a driver attached to make your back hurt even more. I'd rather hurt my ears!
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vibratoking



Joined: 10 Nov 2009
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PostPosted: Fri Mar 23, 2012 8:45 pm    Post subject: Reply with quote

I am not sure about removing my neck pickup or clamping that big box to the end of my guitar.

That tactile thing looks interesting. I tried to find some real data for it, but haven't had any luck yet
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LeftyStrat



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PostPosted: Fri Mar 23, 2012 8:51 pm    Post subject: Reply with quote

Here's an even smaller and cheaper one. Only handles 2 watts:

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=297-2101

Maybe something like an LM386 to drive it. It's small enough to fit in the control cavity.

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RJ Guitars



Joined: 14 Nov 2006
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Location: White Rock, New Mexico

PostPosted: Fri Mar 23, 2012 9:30 pm    Post subject: Reply with quote

I am greatly pleased to see life come out of this thread... it was interesting to me at the time but apparently that extra sustain isn't what everyone was needing when I made that original post.

I recall back in the late 70's bands like Linda Rhodstat's and England Dan & John Ford Coley were doing all these songs with guitars featuring long ringing sustain and I was mystified how they got that clean sounding sustain at the time. I built a couple sustain pedals, bought sustain pedals, put a brass nut on the guitar, etc.. but the sound was never there.

Eventually the physics of it all sank in that sustain is an interaction with the guitar, not just a modification of the signal after the fact.... four years later I still wish I had followed up on this. If anyone comes up with a good little driver circuit for it I would be very interested in giving this a shot. Looks like there are lots of drivers to use.

rj

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Zippy



Joined: 25 Apr 2006
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PostPosted: Fri Mar 23, 2012 9:50 pm    Post subject: Reply with quote

Ever hear of the Fernandes "Sustainer" (1980's)? As I recall, it was a Strat-a-like guitar with some built-in doohickey (did I spell that right?).
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LeftyStrat



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PostPosted: Fri Mar 23, 2012 9:57 pm    Post subject: Reply with quote

Well it's sort of serendipitous that the thread got bumped a day after I saw the sale at parts express for the bass shakers. I originally investigated them for use as a reactive amp load that could be muted by not hard mounting it to anything, and while at it I looked at the broader category of "tactile transducers."

Then this thread revives and made me think of the full range tactile transducers.

I've alway been a fan of the eBow, as well as the amazing Moog guitar. I had followed the long thread on some board whose name escapes me now about building a home brew Fernandes-style driver. But it just had too many downsides for me. (The neck pickup on a strat is a little bit of heaven for me).

Seeing this thread is certainly enough motivation for giving it another go.

I had planned on making an order with parts express (once I can figure out which Neo 12 inch is best for guitar), so I certainly plan on having a few of those transducers thrown in. I may have an LM386 laying around, as well as one of the speakers the guy in the link used. So I may have something to report as soon as this weekend.

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Reeltarded



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PostPosted: Fri Mar 23, 2012 10:50 pm    Post subject: Reply with quote

You can bury a sustainiac into a strat without it showing. Wink

The first person I ever heard of feeding his guitar a speaker was Frank Zappa. I use volume! You think a Firebird is neck heavy? You should try a guitar with 9#'s clamped to the headstock.

Ebow is the key to life, and sustainiacs are just polyphonic ebows. Smile

Zappa also had HotDots installed in the neck, neck joint, and body of the Monterey fire victim.

Why do I know so much about Zappa? Dunno. I hate the noises. I like music!

I don't know much about dancing, that's why I sing this song. One of my
legs is shorter than the other and boffa my feets too long...

-dons me now my fire ap-parel falalalala la la la laaaaaaaaah...-

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Last edited by Reeltarded on Fri Mar 23, 2012 10:59 pm; edited 1 time in total
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LeftyStrat



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PostPosted: Fri Mar 23, 2012 10:55 pm    Post subject: Reply with quote

Those tactile's are an inch in diameter and weigh near nothing. If I can get feedback at lower volumes into any amp, I don't need to know what the magic is in Tony's #102. Very Happy
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Reeltarded



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PostPosted: Fri Mar 23, 2012 11:17 pm    Post subject: Reply with quote

Servo drive a semi-solid tele made of pawlonia.
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fperron_kt88



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PostPosted: Fri Mar 23, 2012 11:40 pm    Post subject: Reply with quote

I experimented with a system similar to the sustainor around the summer of 2008. I used a dimarzio hotrail as an actuator. The pickup was rewired with thicker enameled wire (something like AWG 24-28, IIRC) and driven with an COTS 1W amp (probably using an LM386 of some sort, as previously suggested above). The modified pickup was installed in the neck cavity.

I found that it gave me the chord sustaining features I was looking for. I later played a moog guitar and I realized the stream of thought as already been explored by some other folks! It also came clear that the name of the game was to integrate the whole thing into a simple package, which was left for further experiments in my case...

I thought at first that the idea of using a mechanical coupling (as is described by the OP) was the way to go to closely mimick a real guitar listening to itself in the acoustic field of a raging marshall stack. But, I went with an eq and compression device instead using the magnetically coupled device. It needed some tweaking to get going, but it worked.

The tweaking was with the processing that you apply to the signal before you inject-it back into the string (either with mechanical or electrical/magnetic coupling). Delays, gain, eq, compression, clipping... It all adds up to a very complex feedback loop. Fun, fun, fun!

What I dig and find very clever with the OP experiment is the experimentation with flangers and other delay devices. Never thought of that!

It would have been interesting to put a dsp in that loop to try and figure out an eq/gain/phase/compression curve(s) that would bring each note close to saturation... trying to mimick what you guys really do with these dumble circuits to have all the notes of the neck transition into nice overtones... this very project might come back to life in the future... who knows!

Fun thread!

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selloutrr



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PostPosted: Sat Mar 24, 2012 3:05 am    Post subject: Reply with quote

is this similar to the feedback circuit used in the Fernandes guitar? It generates a tone of wide band feedback (but ramps up slowly and only generates a wide band feedback). If so I have to say... It was neat the first time and got old after the second or third flip of the switch. You can hear it all over the Velvet Revolver album, so no one else used it.
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LeftyStrat



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PostPosted: Sat Mar 24, 2012 3:15 am    Post subject: Reply with quote

selloutrr wrote:
is this similar to the feedback circuit used in the Fernandes guitar? It generates a tone of wide band feedback (but ramps up slowly and only generates a wide band feedback). If so I have to say... It was neat the first time and got old after the second or third flip of the switch. You can hear it all over the Velvet Revolver album, so no one else used it.


The Fernandes is electromagnetic, basically using a pickup as a magnetic driver of the strings. The link in the OP is a mechanical solution equivalent to putting a speaker or mechanical vibrator on the guitar. Listen to the clips, especially the HappyBirthdayJimi clip. It sounds much more like acoustic Hendrix-at-Woodstock feedback than the Fernandes infinite sustain feedback.

The guy basically turned a small speaker into what is now more efficiently manufactured as a tactile transducer, coupled to the body of his guitar.

The solution linked to in the op is more about mimicking acoustic feedback at a lower volume than creating infinite sustain.

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