mikeaj
Headphoneus Supremus
- Joined
- Jan 10, 2010
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Quote:
I agree that amps are overstated and often relegated to mythical status, but there are some good reasons in terms of audio performance (not just features/connectivity/being shiny) to have external amplification, with some headphones especially.
If you've got like a Beyerdynamics DT 880 600 ohms, it will take about 0.5 V rms to reach 90 dB SPL. See Tyll's measurements:
http://www.innerfidelity.com/headphone-data-sheet-downloads
If you have a portable player, it can probably do about 0.5 V rms max. 90 dB max peaks are kind of low for a lot of people, for music that has a wide dynamic range. (Granted, most music released today is victimized by the loudness wars and brickwalled mostly like -10 dBfs and above, if not higher.) Anyway, higher impedances are easier to drive than lower impedances...at least until you run out of output voltage.
If your source has high output impedance, this can cause huge impedance interactions with low-impedance headphones (usually balanced armature IEMs), particularly those that have impedance that varies a lot over frequency. Grab an amplifier with a low output impedance, and you'll no longer have the wacky FR shift created by the distribution of the source and load impedances over frequency.
Some integrated amps may have poor performance even when driven in a "reasonable" voltage and current range for the device, but the difference here between a poor amp and great amp is probably overstated. However, there is some room for improvement that a dedicated amp can bring. That is, the difference is probably small unless you prefer tube distortions or other inaccuracies/additives and consider that to be an improvement--perfectly fine by me, but let's just be clear about our objectives.
People are often counseled that buying an expensive high impedance headphone is a waste without amplification. It is the single biggest fallacy that permeates this community. Good headphones sound good, even plugged directly into a portable.
I agree that amps are overstated and often relegated to mythical status, but there are some good reasons in terms of audio performance (not just features/connectivity/being shiny) to have external amplification, with some headphones especially.
If you've got like a Beyerdynamics DT 880 600 ohms, it will take about 0.5 V rms to reach 90 dB SPL. See Tyll's measurements:
http://www.innerfidelity.com/headphone-data-sheet-downloads
If you have a portable player, it can probably do about 0.5 V rms max. 90 dB max peaks are kind of low for a lot of people, for music that has a wide dynamic range. (Granted, most music released today is victimized by the loudness wars and brickwalled mostly like -10 dBfs and above, if not higher.) Anyway, higher impedances are easier to drive than lower impedances...at least until you run out of output voltage.
If your source has high output impedance, this can cause huge impedance interactions with low-impedance headphones (usually balanced armature IEMs), particularly those that have impedance that varies a lot over frequency. Grab an amplifier with a low output impedance, and you'll no longer have the wacky FR shift created by the distribution of the source and load impedances over frequency.
Some integrated amps may have poor performance even when driven in a "reasonable" voltage and current range for the device, but the difference here between a poor amp and great amp is probably overstated. However, there is some room for improvement that a dedicated amp can bring. That is, the difference is probably small unless you prefer tube distortions or other inaccuracies/additives and consider that to be an improvement--perfectly fine by me, but let's just be clear about our objectives.