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Post subject: Please educate me: Negative Feedback (NFB) (Pro Jr amp)
Posted: Tue Jan 19, 2010 2:26 pm
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Aspiring Musician
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so what's the story with the NFB thing?
what does it do for an amp, such as the Pro Jr, and why is it there?
what are the advantages of using it?

give me the details, i would like to learn about this.

i read about some people disconnecting the NFB wire in their Pro Jr...what effect would this have overall? what is the reason for doing this?

thanks for the info.!


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Post subject: Re: Please educate me: Negative Feedback (NFB) (Pro Jr amp)
Posted: Tue Jan 19, 2010 6:36 pm
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msvolpe wrote:
so what's the story with the NFB thing?
what does it do for an amp, such as the Pro Jr, and why is it there?
what are the advantages of using it?

give me the details, i would like to learn about this.

i read about some people disconnecting the NFB wire in their Pro Jr...what effect would this have overall? what is the reason for doing this?

thanks for the info.!


Oversimplified and in plain English, it is an electronic pressure regulator. It's purpose is to increase the amp's overall stability and response and to keep distortion down. In other words, it is to keep the amp from blowing up and out while attempting to maintain the amp sounding its best at the same time. Frankly, I personally have no use for such a circuit and would disconnect it in a heart beat. Of course, this is merely, IMO as YMMV.

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Post subject:
Posted: Tue Jan 19, 2010 7:02 pm
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Here's a pretty in depth explanation that's easy to understand.

http://www.aikenamps.com/NegativeFeedback.htm

Dumping it would be more of an advantage. You'll get a smoother transition to natural distortion as well as a wider frequency response. If it doesn't work out for you, just put it back.


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Post subject:
Posted: Tue Jan 19, 2010 11:44 pm
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Professional Musician
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Yeah Volpe, the negative feedback loop circuit is an interesting part of the power section. If you disconnect it, there should be an increase in amplitude and rawness, but a decrease in bandwidth. Compared to a Deluxe Reverb, your amp has very little negative feedback applied to the signal. So the results may not be very pronounced, but I haven't tried it on this particular amp. If you're looking for a growling mid range heavy amp, then this might be the ticket. There is a rule of thumb that says: for everything you add, there is something you loose from the amp. Actually, I increase the feedback resistor in my personal amps and add a capacitor across the shunt resistor. That gives me great picking dynamics and a nice bandwidth. It's just a matter of what you like. Art

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Post subject:
Posted: Wed Jan 20, 2010 9:53 am
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Aspiring Musician
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Joined: Mon Jul 16, 2007 9:58 pm
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i'm not even sure if i would want to do it yet, so here i am asking about it haha. i heard people talking about it, and got curious. its hard to understand alot of the descriptions online that i found.

thanks


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