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Q: High gain? Low gain? Quality difference?

post #1 of 12
3/7/11 at 2:11pm
Thread Starter 

So I have E9 and it has high and low gain switch.  I know what the switch does but is there a quality difference between the two? I never understood a point of having the two when I can easily just use high gain unless there is any SQ difference, which I must say don't see any.

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Gear mentioned in this thread:

FiiO E9 Desktop Headphone Amplifier and Dock for E7 USB DAC
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post #2 of 12
3/7/11 at 2:51pm

Hmm... same circuit, a pair of resistors swapped out for another set of different value... question is about "sound quality"? confused.gif

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post #3 of 12
3/7/11 at 2:59pm
Thread Starter 

Yes, the question is about "sound quality." Sorry for sounding like a noob but that's because I am when it comes to amps. So why is there high/low gain if there is no difference other than one having low resistance and the other high resistance?

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post #4 of 12
3/7/11 at 7:05pm

Because really low impedance, high sensitivity cans like Grados are way too loud with most high-gain settings on amps.

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post #5 of 12
3/7/11 at 7:33pm

I thought high gain was always technically worse in terms of distortion, not taking into account stability.

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post #6 of 12
3/7/11 at 7:36pm

Quote:
Originally Posted by atothex View Post

I thought high gain was always technically worse in terms of distortion, not taking into account stability.


x2.  I was under the impression that gain adds noise.  My amp, when at the low gain setting with the volume pot at 0, is completely silent, but when at high gain setting with the volume pot at 0, there's a slight hiss.

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post #7 of 12
3/7/11 at 7:41pm
Thread Starter 

So there is a difference in SQ, it seems like? I wondered why when you can easily adjust the volume to compensate for an increase with low imp. phones there is high and low gain...

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post #8 of 12
3/7/11 at 7:43pm

Indeed - when you have higher gain, you have a higher amplification factor, and thus any noise will be amplified more

 

Unless stability becomes an issue, you always want to use the lowest gain possible, with the pot as high as possible.  by doing so, you will have no wasted, excess gain that you compensate for via the pot

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post #9 of 12
3/7/11 at 7:57pm
Thread Starter 

Exactly the answer I was looking for! Thank you!

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post #10 of 12
3/7/11 at 8:06pm

Low gain sounded better to me in most cases, even with HD650. And I want to learn why.

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post #11 of 12
3/7/11 at 8:53pm
Thread Starter 

Been searching about this topic but it's surprisingly difficult to find more scientific reasons but I did find this from Wikipedia:

 

Gain

In electronics, gain is a measure of the ability of a circuit (often an amplifier) to increase the power or amplitude of a signal from the input to the output. It is usually defined as the mean ratio of the signal output of a system to the signal input of the same system.

 

Noise

Amplifiers generate random voltage at the output even when there is no signal applied. This can be due to thermal noise and flicker noise of the devices. For applications with high gain or high bandwidth, noise becomes a very important consideration.

 

It looks like when gain is increased noise is introduced (or amplify what was existing like El_Doug said) into the system.

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post #12 of 12
3/7/11 at 9:28pm

Many potentiometers have channel imbalances at the low end of the scale, making adjustments difficult with high-gain outputs with low-impedance headphones.  Additionally, stepped attenuators often offer limited levels of adjustments on the lower volume spectrum.

 

You should seriously try some Grados, or low-impedance IEMs, out of a high output amplifier with a stepped attenuator, and then you will see why hi/low gain adjustments are needed.
 

Quote:
Originally Posted by Dougeefresh View Post

So there is a difference in SQ, it seems like? I wondered why when you can easily adjust the volume to compensate for an increase with low imp. phones there is high and low gain...



 

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Gear mentioned in this thread:

FiiO E9 Desktop Headphone Amplifier and Dock for E7 USB DAC
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