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Getting technical with amps/headphones - what do i need to know?

post #1 of 2
10/12/11 at 8:10pm
Thread Starter 

Can someone offer a crash course on what tech specs to look out for when matching amps to headphones? Ohms/watts etc...

 

Also how can I verify the specs of the amps I have - is it as simple as just taking readings with a multimeter?

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post #2 of 2
10/12/11 at 8:25pm

Output impedance under 1/8 of the headphone impedance.

 

About 10x the output needed to drive your headphones to 90dB. This equates to 110dB. This is mostly just to ensure you're able to drive the headphones in the worst, worst case scenarios, like very quiet recordings at high volume. You can find the 90dB numbers in Tyll's data on Inner Fidelity. Obviously this has to be into your headphone's load, not something with higher or lower impedance.

 

Gain settings that won't cause amp clipping with your source. You'll probably be safe if your source has a 2 V line out, but some have considerably higher.

 

Low THD+N, preferably 0.05% or below into your headphone's load. If you can find graphs, it's even better if the amp has more second order harmonics than third order harmonics, but as long as both are low it won't matter.

 

Low IMD. Not sure how low is necessary, but I believe IMD is more audible than THD in most cases. This is rarely published though.

 

Lord Voldemort (NwAvGuy) wrote a guide for Inner Fidelity that detailed suggestions for future amp measurements on the site. It can be used as a summary of what's important to look for, too.

 

You'll get some information from a multimeter (power output for example) but not everything. At best you'll have to use manufacturer published specs and any third-party measurements you can find (from Stereophile for example), along with two large helpings of salt.

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