Do You Actually Need a Headphone Amp? A Per-Headphone Breakdown
How to determine whether your headphones need a dedicated amp, based on impedance and sensitivity specs.
How to Decide If You Need an Amp
The short answer: it depends on the headphone. Not every headphone needs an amp, and adding one doesn’t automatically improve sound quality. The deciding factors are impedance and sensitivity.
Understanding Impedance and Sensitivity
Impedance (ohms): The electrical resistance of the headphone. Higher impedance means the amp needs to deliver more voltage.
Sensitivity (dB/mW or dB/Vrms): How much volume the headphone produces for a given amount of power. Higher sensitivity means easier to drive.
These two specs together give you a good picture of whether an amp is necessary.
Headphone-by-Headphone Assessment
No Amp Needed (A dongle DAC or built-in DAC/amp is sufficient)
| Headphone | Impedance | Sensitivity |
|---|---|---|
| Sony MDR-7506 | 63 ohms | 106 dB |
| Audio-Technica ATH-M50x | 38 ohms | 99 dB |
| AKG K371 | 32 ohms | 114 dB |
Low-impedance, high-sensitivity headphones can reach adequate volume even from a smartphone. Adding a dedicated amp yields only marginal improvements.
Amp Recommended (A desktop amp unlocks their full potential)
| Headphone | Impedance | Sensitivity |
|---|---|---|
| Sennheiser HD600 | 300 ohms | 97 dB |
| beyerdynamic DT 880 (600-ohm version) | 600 ohms | 96 dB |
| HiFiMAN Sundara | 37 ohms | 94 dB |
The HD600 and DT 880 600-ohm are high-impedance and demand voltage. The Sundara has low impedance but also low sensitivity, and as a planar magnetic it’s current-hungry. All of these benefit from a dedicated amp in terms of bass control and soundstage.
Amp Essential (Without a proper amp, you’re hearing less than half of what they can do)
| Headphone | Impedance | Sensitivity |
|---|---|---|
| HiFiMAN HE6se V2 | 50 ohms | 83.5 dB |
| Audeze LCD-4 | 200 ohms | 97 dB |
These are power-hungry — some owners even drive them from speaker amps. A high-output desktop amp is a must.
What About IEMs?
Most IEMs are high-sensitivity and low-impedance, so an amp is unnecessary. In fact, pairing them with a high-output amp can introduce audible noise. A DAC/amp combo on Low gain or a portable amp designed for IEMs is the right choice.
What an Amp Changes — and What It Doesn’t
What changes
- Volume headroom
- Bass control and definition
- Soundstage width
- Dynamic expression
What doesn’t change
- The headphone’s inherent tonal character (bright/dark, etc.)
- Its fundamental frequency response
- Resolution beyond the headphone’s physical limits
Budget Allocation
As a rule of thumb, spending about as much on the amp as you did on the headphone is reasonable. If you’re pairing a $400 headphone with an $800 amp, you’d likely get a bigger improvement by upgrading the headphone itself first.
Conclusion
Whether you need an amp depends entirely on your headphones. Check the impedance and sensitivity, determine whether your headphones actually benefit from a desktop amp, and then decide whether the investment makes sense.