Which headphone amp is technically superior? Help

I don't have the electronics accumen to figure out which of these two amps has better specifications. My headphones are Sennheiser HD600s.

The reason is that there are two amps at the same price with two different specs and I am trying to figure out which amp is objectively superior. I understand there are other factors such as component quality at work that determine which sounds better, but right now I need someone to explain the difference in the technical specs. Thanks!


Power output 150mW/600ohms
Headphone connection>32 ohms
Output impedance 20ohms
Signal to noise 94dB ref. full output
Frequency response 20Hz - 20kHz/0,2dB (10Hz - 120kHz/-1dB)
THD 0,005%
Headphone jack 3-pole ¼" (6,3mm Ø ) phono socket
Power supply type Mains-fed outboard power supply
Output voltage 16V/500mA AC
Power consumption 16V/120mA AC
Dimension W x H x D 130 x 79 x 133mm
Weight 1.000g without power supply


Power output 700mW/30ohms, 110mW/300ohms
Headphone connection > 30 ohms
Signal to noise 110dB (115dB - A weighted) at full output
Frequency response 20Hz – 20kHz/-0,03dB
THD (IMD) 0,003%/30ohms, 0,007%/300ohms
Gain 12dB
Headphone jacks 3-pole ¼" (6,3mm Ø) phono socket
Power supply type Mains-fed outboard power supply
Output voltage 16V/1.000mA AC
Power consumption 16V/230mA AC
Dimension W x H x D 103 x 72 x 151mm
Weight 1.080g without power supply
The Senns are pretty efficient so you probably don't really need the extra power of Amp Two; however, it might later be useful if you bought some less efficient cans like the AKG 701s.

With cans you hear every bit of noise, so if I had to make a choice I'd go with the high signal to noise ration of Two. That said, if you can listen with your own cans, do that a buy based on the best subjective sound.

Like loudspeakers, but maybe more so, cans have incredibly distorted frequency response curves and actual perceived response will vary widely from user to user, thanks to different ears shapes, etc. So, worrying about the last iota of amp frequency response is a futile diversion. With cans and there amps you really need to listen.

Break-in/burn-in is very critical with cans. The close proximity of the drivers to your ears will really highlight any hardness that new equipment tends to show.

I agree with all dcstep has said. I don't believe that specifications will tell you anything about a headphone amp, how it sounds or if you will like it. The combination of headphones and amps is so critical and the synergy between the two is everything. I also am wrestling with trying to choose a headphone amp for my Senn 600s. I like the ASL tube amp I have now and want another amp for another room. I like the tubes but also want something different. My conclusion is that I have to buy a used amp and try it even if I have to sell it later. That way I don't lose too much money. Head=Fi is an alternative source of information and sales of used headphone amps. You may find an answer there.
Dcstep, I don't understand why you are saying that amp 2 is more powerfull than amp 1. Amp 1 has more power than Amp 2 as indicated by 150mw into 600 ohms, while amp 2 has but 110w into 300 ohms. I suspect that amp 1 is capable of more than the 700mw into 30 ohms of amp 2.

At any rate, both set of specs show that there shouldn't be any problem driving any set of headphones and therefore go by listening.

Personally, I would go by cost!

Bob P.
Ok, well these two amps that I have posted are revisions of the same model! Amp one is the Pro-Ject Headbox SE and Amp two is the Project Headbox SE 2.

Both currently seem to be part of the project headbox line. The Headbox SE has more features in that it has multiple inputs and a switch to change inputs. The headbox ii has a redesigned chasis.

I just got a brand new pair of HD600s and I have the headbox se here. But the headbox se 2 is the same price and I am trying to figure out what the purpose of having an se 2 is.
Styling is mostly it. Pro-ject changed the look of most of their electronics over the last year. There were small technical changes at the same time, but no big substantive change.

Well, I finally got my hands on amp 2, which is the Pro-Ject Headbox SEII with the revised circuit board, and it sounds completely different from the original model. A lot more bass, punchier, quiter, and more pleasant. Also it is a capable of producing more clean volume on my HD600s.

Also build quality seems much better.

So amp two turned out to be a much better amp.