Feedback circuitry on acoustic amp -- why?

dennisg
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Tue Mar 02, 2010 2:20 pm

I have a Roland AC-60 acoustic guitar amp, which I really like. One thing about it confuses me, though: it has anti-feedback circuitry. I understand why a guitar player/singer would want to suppress feedback, but why is it selectable on an amp? Why isn't it just wired in to the circuitry without the need for the user to turn it on and off? Why wouldn't I want it on all the time? Does having it on degrade the signal somehow?


MarkM
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Tue Mar 02, 2010 2:40 pm

Dennis,

Good question. I'm certainly no expert but you may want to induce feedback from time to time like in the begining of the Beatles song I Feel Fine. Just a thought.


MarkM


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neverfoundthetime
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Tue Mar 02, 2010 2:43 pm

No idea Dennis, but that's the amp I want to get. Seems like you'd recommend it.


dennisg
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Tue Mar 02, 2010 2:55 pm

neverfoundthetime wrote:
No idea Dennis, but that's the amp I want to get. Seems like you'd recommend it.
Absolutely, Chris. If what you want is sparkling clean acoustic guitar sound, it's a great amp for that.


Moondog
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Tue Mar 02, 2010 3:03 pm

I know the need for feedback on an Electric guitar, many great guitarist use it, but an acoustic? It could be fun experimenting with it.





Mike


Chasplaya
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Wed Mar 03, 2010 12:13 am

Many amps come with what's called "Notch Filtering, mine does an Ashdown Radiator 100w, smaller in size than your Roland." What this does is isolate a narrow band of frequencies that cause the amp to feedback (or warble) at certain pitches. This is at worst, a nice bonus, and at best a complete necessity. The more "acoustic" in character your set-up is, the more you'll be dealing with the ravages of feedback.


dennisg
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Wed Mar 03, 2010 8:45 am

Chasplaya wrote:
Many amps come with what's called "Notch Filtering, mine does an Ashdown Radiator 100w, smaller in size than your Roland." What this does is isolate a narrow band of frequencies that cause the amp to feedback (or warble) at certain pitches. This is at worst, a nice bonus, and at best a complete necessity. The more "acoustic" in character your set-up is, the more you'll be dealing with the ravages of feedback.
Thanks. I understand the need for feedback circuitry -- what I don't understand is why it's selectable.


thereshopeyet
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Wed Mar 03, 2010 12:02 pm

Thanks


dennisg
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Wed Mar 03, 2010 1:20 pm

THY,

Yep, that does help. Thanks.


Catman
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Thu Mar 04, 2010 5:28 am

Just to clarify, the anti-feedback circuit is a narrow notch filter at the feedback frequency. If it is active, it suppresses the feedback, but it also suppresses the guitar's output at that frequency.

So if you are in a situation where there is no feedback problem, disable the filter.

David


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