Headphones are easily one of the most straightforward pieces of audio equipment today. Plug them in, put them on, play your audio and you’re set. However, when it comes to professional headphones, such as the HD650, a truly immersive experience is incomplete without a decent amplifier.
Professional headphones are designed to produce the slightest of details in an audio file. They, however, rely on the quality of input they get. An amplifier works to enhance the audio quality of any device by improving its volume and detail.
How We Choose
The world of headphone Amps is quite vast, one gets easily drowned in technical jargon and fast. We wanted to have a descriptive and informative guide to buying the Amps that could get the job done and done well. Here is what we used as our guide:
When buying anything, this probably one of the most important things to look out for. Is it going to serve the purpose for which we are buying it for? Compatibility also played a big role when we were evaluating the functionality of any Amp. Would it actually work with the HD650?
The HD650 are largely used for professional purposes. This means they are used in a formal arrangement where there is a desk. However, we wanted our list to incorporate those people who wanted to use the headphones with an iPod, a phone or a laptop. For this, the Amps we chose had to be portable or at least to a reasonable standard.
On this basis, we wanted to choose an Amp that was easy to find and purchase. We valued Amps that we could buy on the fly highly and was well stocked. We also argued that being available was a sign that the Amp was good. “What good is anything if it isn’t available?”
We were also choosing Amps that did well with online rating systems especially where the rating was from customers like on Amazon. It is often difficult to match this satisfaction level with HD650 owners but an overall satisfaction was key nonetheless.
The Sennheiser HD650 Professional Headphones are not exactly cheap. With such an investment, it is always a good idea to follow up with high-quality accessories and add-ons. As far as price goes, quality is not cheap. This is an unfortunate reality in any buying journey today. In our case, we wanted to ensure we eliminated poor quality Amps but still chose Amps that were great value for money.
Aside from these guiding factors we also wanted the Amps we choose to produce really good quality sound and be easy to use. We did extensive testing on the ones we were considering for this list and here is what we came up with:
This is actually a preamplifier which has a built-in headphone amplifier as well as a digital to analog converter. Primarily, it is designed to handle computer-based media and this makes it ideal for home media servers, workstations, audio editing applications, and radio broadcasting systems. It is very versatile and can be used for conversion of Direct Stream Digital (DSD) signals along with Pulse Code Modulation (PCM) files up to 24-bit/192 kHz. Some other great features include; its asynchronous USB 2.0, 32-bit internal processing, and more I/O options.
Summary of Features
The DAC2-HGC tracks change in audio layers prompted by your audio source and then uses its asynchronous USB system for data transfer.
The unit acts as the clock master, minimizing jitter by transferring audio data to an internal buffer then to its DAC subsystem. The data transfer utilizes Benchmark’s jitter attenuation system which reduces jitter noise and distortion to at least 140dB below the level of the audio.
The 32-bit internal Processing (DSP) works with the active analog gain control and passive low-impedance attenuators. This results in a Hybrid Gain Control (HGC) which provides a dynamic range of the analog system and improves the accuracy of the digital control.
The input and output options include:
2 stereo unbalanced analog RCA inputs
2 optical Toslink digital inputs
2 coaxial digital inputs
1 USB digital input
2 stereo analog unbalanced RCA outputs
1 stereo analog balanced XLR output.
This is an award-winning amplifier that offers great functionality and boasts of several great features. In our research, we found out that great sound usually comes from Amps with well designed DACs. In the NT-503, a pair of VERITA AK4490 DACs that were designed by the Asahi Kasei Microdevices Corporation do the job well.
According to the manufacturer, the human ear can not completely hear the velvet audio range that this Amp can produce. We can only tell that it’s a really good quality of HD sound.
The NT-503 supports a variety of HD Audio sources such as a 32-bit/384kHz PCM and 11.2MHz DSD Native playback.
Thanks to its low distortion technology, it can reduce jitter noise and distortion to at least 112dB of S/(N+D). This is the highest level in the industry for a 120dB-class DAC.
Summary of Features
The NT-503 includes a programmable IC with an exclusive Fluency up-conversion algorithm. DSD up-conversion along with PCM up-conversions are supported up to 12.2MHz. The NT-503 can up-convert 16-bit/44.1kHz audio data from a normal CD to 11.2MHz DSD.
PCM/DSD filters give a multifaceted personality from just a single unit. You can choose from either four types of PCM filters and two DSD filters or any arrangement of these filters to produce the sound you want from any audio file.
The NT-503 has a digital Isolator built to completely isolate each power supply path and the ground. Computers are especially great sources of interruption when plugged in through the USB input. This interruption is prevented from entering the analog section through a power supply path or the ground.
The NT-503 features an organic electroluminescent display (OELD) with a 4-level dimmer. Thanks to this and a large size font, it provides high contrast and excellent visibility for checking the volume level even from across the room.
Other key features include:
Hi-Res Audio Playback from PC via USB Cable
High-res Audio Streaming via Network
High-quality Wireless Streaming via Bluetooth®
Front USB port for Hi-Res Audio Playback
Music Streaming from your iOS/Android Devices
This headphone Amp is built with one philosophy in mind, “hear the real thing if you love music”. The Audeze Deckard is a hybrid of a headphone Amp and a high-performance DAC. It has a volume control panel on the front and switches to tune the level of gain and input. It is honestly one of the most refreshing Amps we have found in our research.
Thanks to its brushed aluminium finish, it is a great addition to your space. It is not all beauty either, it produces 4 Watts of incredibly low-distortion sound to about 106dB. Thanks to an incredible design, its cutting-edge exterior look matches the interior circuit technology.
Summary of Features
The DAC section handles 16 to 32-bits and 44.1kHz to 384kHz sampling rates.
The Deckard has a single-ended class-A output stage with great damping characteristics for controlling strong and tuneful bass.
Its power handling at lower impedances are great for planar magnetic headphones, however, It drives any headphone leaving some power to spare.
Cutting-edge industrial design. You get what you expect from BMW’s i8 design team, a functional and impressive piece of equipment. It features functional heatsinks on the side that add to its overall aesthetic. It is generally a neat looking aluminium slab with some well-placed controls sticking out at the front, just enough for a headphone Amp.
The HDVA 600 was honestly an afterthought but it had to feature in this list. If there is ever going to be a great Amp for the HD650, it’s going to be made by the same company. On this premise, we set out to find an Amp made by Sennheiser and that was compatible with the HD650. Most of them were but the HD650 had the highest compatibility and functionality.
Unfortunately, this is an analog Amp and this may have some limitations with certain sources of audio data. However, the HDVA 600 has a uniformly symmetrical signal processing capability and a low harmonic distortion ensures an entirely precise sound.
Pre-amp performance eases adjusting and connecting directly to your headphones for maximum audio amplification. In effect, the HDVA 600 provides an amazing and immersive listening experience especially when paired with a pair of Sennheiser’s audiophile headphones.
Summary of Features
Symmetrical processing of signals from input to output ensures great resolution, dynamics along with musicality.
Short signal paths with premium components connected onto a custom APLS 4-pole potentiometer for accurate volume control.
Tandem operation with 4 dynamic, high-impedance headphones. (2 from four-pin XLR input and 2 from high-quality 6.35 mm (1/4”) jacks)
Chassis is made from machined Aluminum to minimize vibrations to help ensure sonic integrity.
The high gain Amp drives low-impedance headphones easily
Here are some other really good Amps that we found but didn’t make the top 4 list:
1. Sony TA-ZH1ES
2. Sennheiser HDVD 800 Headphone Amp with DAC
3. Marantz HD- DAC1 Headphone Amp
4. FiiO E10K Headphone Amp
5. AudioQuest Dragonfly
Headphones are considered to be very personal items, you spend most of your time in close contact with them and using them means you get a really good feel for them. However, for this to even happen, you need a good and compatible headphone Amp. It is important to take your time to research and know what’s out there.
We have tried to narrow down what we think is the best 4 Amps and what would definitely work well for you. However, remember that choosing any Amp depends on personal preference.