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Parts that came with amp: What do they do?

post #1 of 8
6/10/11 at 4:32pm
Thread Starter 

IMG_0001.JPG

 

So these came with my Audio-gd NFB-12. What are they for and what do I do with them?

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post #2 of 8
6/10/11 at 5:27pm

It looks like jumpers. Maybe there is some adjustements that used them.

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post #3 of 8
6/10/11 at 5:32pm

i agree with FortuneSound. if i had to GUESS (heavy emphasis!) i would say they are used to adjust gain. if you look directly on the PCB, there should be some raised pins in pairs of two, the jumpers should slide over them, adjusting the settings.

 

now, i could be completely wrong- i would check the instructions or with the manufacturer about them. be sure of what your doing before you do it, so you don't fry any components! good luck!

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post #4 of 8
6/10/11 at 7:35pm

Those sure look like jumpers alright. 

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post #5 of 8
6/11/11 at 12:22am

They are definately jumbers. I would read the manual as there should be different options possibly for open or closed circuits, different gain settings, etc

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post #6 of 8
6/11/11 at 5:49am
Like people said: they are jumpers and are most often used for adjusting gain.

However most amps don't need more than 1-3 jumpers, and yet they supply quite a lot.
My Little Dot MKIV SE needs 3 jumpers, i got about 10
My Audio-GD NFB-12 needs 1 jumper, i got about 30.

On the NFB-12 they are used for switching between variable and line-out and variable only. Remove the screws on the top and remove the lid, and you will see a jumper glued (at least it was glued in my case) to two pins. You can move it so that it's either connected with the middle+the right pin, or the left+the right pin.
Here's a picture of what i mean:
500
Edited by Tilpo - 6/11/11 at 5:54am
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post #7 of 8
6/11/11 at 5:32pm
Thread Starter 

Thanks Tilpo, I saw that on their site a couple times, but had no idea what it was... :P

 

But follow-up question: What does switching it do? I don't understand what the difference between fixed and variable outs. As far as I know, I've got 3 settings on my NFB-12, HP, Fixed and variable; and HP is the only one that "works".

Are the fixed and variable settings for driving something other than headphones?

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post #8 of 8
6/12/11 at 1:49am
Quote:
Originally Posted by 2enty3 View Post

Thanks Tilpo, I saw that on their site a couple times, but had no idea what it was... :P

 

But follow-up question: What does switching it do? I don't understand what the difference between fixed and variable outs. As far as I know, I've got 3 settings on my NFB-12, HP, Fixed and variable; and HP is the only one that "works".

Are the fixed and variable settings for driving something other than headphones?

Fixed/Variable is for the RCA outputs at the back. They are used to drive another amplifier.

You can use the NFB-12 either as a pre-amp, in which case you want variable output. (i.e. you have control over the volume knob).
Or you can use it as a DAC only, in which case you feed the RCA signal to an other amp. In that case you want fixed output, as then it will bypass the volume knob. Bypassing the volume knob increases the sound quality, and if you have a better amp with a better volume knob anyway, there is no need to use it.
For example I have set the jumper to the left (as seen on the diagram) and set the output to fixed. This is because I use the RCA cables and feed the output to a better amp, the Little Dot MKIV SE.
But since you only use the headphone output of the device, you shouldn't really bother about the fixed/variables outputs. They are only if you want to connect

For some reason the people over at Audio-GD found it necessary to have the ability to disable fixed output, although their reasons aren't exactly clear to me.
Edited by Tilpo - 6/12/11 at 1:52am
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