How do you know how much gain you need in your amp?

[panda67]

Is gain directly proportionate to the impedance of the headphones?

 

[d-cee]

probably moreso a combination of impedance and their efficiency

 

[BIG POPPA]

I think it would depend on the cans and the source. With a better source with decent cans gain would not be so critical. An Ipod with music recorded at 128k or so like apple suggests you will need to pay attention to the cans and the gain. It did not sound like I would like it to. My twin sent me an Ipod from Iraq with all the stuff he was listening to, not 2 songs were downloaded the same it seemed like since everybody poached each others music. Also some amps will sound better with an Ipod than others IMO.

 

[Goh]

Are gain setting numbers consistent across different amps? For example, the Go-vibe is available in gains of 2, 3, and 4. Someone told me the Xin Reference gain was 3. Do the Go-vibe "3" and Xin "3" have the same loudness, then?

 

[Negatron]

Gain is not complicated. A gain of 2 means literely that for an input of .5 volt, 1 volt is at the output, thus a gain of 4 would give you 2 volts for the 1/2 volt in.

Using ohm's law you can figure the power used by the headphones.
power out = voltage squared, divided by resistance. So... .5 volt in & 2 volt out into a 120 ohm phone uses 208mW, 300 ohm phone, 83mW.

If the output impedance of the amp is above the load, the power drops accordingly. A cathode follower tube amp with an output impedance of 100 ohms won't reach it's full output into 60 ohm phones.

 

[riceboy]

Quote:

Originally Posted by Negatron /img/forum/go_quote.gif Gain is not complicated. A gain of 2 means literely that for an input of .5 volt, 1 volt is at the output, thus a gain of 4 would give you 2 volts for the 1/2 volt in. Using ohm's law you can figure the power used by the headphones. power out = voltage squared, divided by resistance. So... .5 volt in & 2 volt out into a 120 ohm phone uses 208mW, 300 ohm phone, 83mW. If the output impedance of the amp is above the load, the power drops accordingly. A cathode follower tube amp with an output impedance of 100 ohms won't reach it's full output into 60 ohm phones.

Very interesting. Thanks for the input