I finally got my hands on the new Headstreamer DAC headphone amplifier. I’ve been looking for a while for a DAC/headphone amplifier that works with both my Mac and iPad. The CEntrance DACport, but it’s a bit too expensive. So the Headstreamer DAC looked like a good compromise.
I first connected the Headstreamer DAC to my MacBook Pro “15 i7. The Headstreamer doesn’t need a driver on Mac OS X or Windows, just plug it in and it’s up and running. It uses the USB bus for power, making it very convenient to use. I first tried to play lossless songs ripped from CDs with Max and imported to iTunes. To compare I listened to two well-recorded songs and set the audio to 16-bit 44khz via the Audio MIDI Setup application. A problem with iTunes is that it doesn’t switch the bitrate or sample rate to keep it bit correct. You have to quit iTunes, change the settings to coincide with the source material and then restart iTunes. But there are solutions available to solve this problem.
- Sennheiser HD 25–1 II
- Sennheiser HD–600
- To external headphone amplifier X-Can V2 with Sennheiser HD–600
Sennheiser HD 25–1 II
My travel and commute headphone of choice is the Sennheiser HD 25 II, designed initially to be used in the broadcast industry. The HD 25 II is well sealed, so it doesn’t leak much sound out or in, making them perfect for cameramen and recordists when filming. They are very linear, without the usual bass boost and other gimmicks you find on many headphones. I like the rugged design, after giving up on in-ear headphones because I have to remove and insert them too often when commuting, so the on-ear type is my new preference. The sound quality of these cans is outstanding, provided that the playback equipment can drive them. They are rated at 70 ohms, making them a little bit harder to drive than your regular headphones, but you can still use them from an iPhone or iPad loud enough to rock out.
I first listened to the headphones through the Headstreamer DAC. They managed to them without problem to deafening sound levels. But that also got me wondering, will they be able to drive more demanding headphones like the Sennheiser HD 600? The Headstreamer DAC features built-in volume control, controllable from your standard playback device over 50 dB in 1 db increments using your regular volume control on the playback device. There is no volume controller on the device itself.
After I started to listen to the Headstreamer DAC, I must say that I was impressed! The top end was much cleaner than from the built-in headphone amp of my MacBook. This is to be expected, considering the amount of money Apple would spend on the components to make the headphone output sound good. Not much money at all. The bass quality also increased notably, finally being able to drive my headphones with some momentum. Something that the build in headphone amp hasn’t been able to. Just to compare, I switched back to the internal amp with the same settings and the difference was pronounced. The Headstreamer DAC delivered a much better audio experience over the entire audio spectrum. So with these cans, it was an absolute improvement of sound quality. Because these headphones are a bit harder to drive than your normal middle-class ones, there should be no problem running most headphones to insane levels of sound pressure.
I also tried some 24-bit 96khz music from HDTracks, and the quality difference was still pronounced. But how about some more difficult headphones? Will it be able to drive the Sennheiser HD–600?
The Sennheiser HD–600 needs more power from the amplifier to be able to drive them. The Headstreamer DAC managed to push them to normal listening levels, but not much more. The bass was also lacking. These cans need more power than the Headstreamer DAC can deliver. But in a pinch they’ll do, the output level was much better than from the built-in output of the MacBook Pro. So overall, this amplifier/headphone combination is not a perfect match.
To external headphone amplifier X-Can V2
You have the option of connecting the Headstreamer DAC to an external amplifier, so I attached it to my modified X-Can V2 headphone tube amplifier.
Now we’re talking! It sounds great! I usually have the X-Can connected to a Squeezebox V3, but this plays much better! So if you have headphones that need more amp power, this is an option. The only problem is, there goes the portability. But for a home setup, it works perfectly. But by spending a bit more money, you could get a dedicated DAC with a headphone amplifier for home use with a lot more power available. Some examples are NuForce HDP or Beyer Dynamic A1 Headphone Amplifier
Using an iPad 3 with the HRT Headstreamer DAC
One of the likable things about this unit is that it’s compatible (kind of) for use with an iPad. You need an iPad Camera Connection Kit or similar to get USB input on the iPad connector. When connecting to an iPad, you get a warning message telling you that this unit is not compatible, but it works anyway. I don’t have any lossless or uncompressed music on my iPad because I need all the space for other things, but there is a way around that. By connecting your iPad with iTunes Home Sharing to your Mac where you have all your lossless music, you can stream in full quality directly to your iPad, utilizing the better DAC. This goes for high res music in 24-bit 88.2Khz and 96Khz as well.This makes your iPad a high end playback device!
You can’t upload high res files to your iPad using the built-in player, but you have alternatives like FLAC Player, which enables you to upload lossless FLAC files to the iPad and play them back correctly through the Headstreamer.
I bought a USB connector for iPad from eBay but had a lot of problems, so if your going this route, do some research to get one that works.
Inside the HRT Headstreamer DAC
The unit is using a Texas Instrument TAS1020B USB Streaming Controller, a chip that is now recommended by Texas Instrument to be replaced in new designs with the TMS320C5533 Fixed-Point Digital Signal Processor. The I2S signal is then routed to the DAC, a PCM1793 DAC IC, a quite capable cheap DAC from Texas Instruments. The analog stages are made up of two Texas Instruments OPA2132 Opamps (the recommended opamp by Texas instrument to use with the PCM1793). I’ve had good luck when opamp rolling with the OPA2132 on other equipment. But there are better opamps. Unfortunately, the opamps are surface mount, so to change takes a little soldering skill is needed. But I will try to replace them with LM4562, just for the fun of it. Hopefully, I’ll be able to do a measurement of the before/after performance and post it here.
|Full Scale Output:||1.40 Volts RMS|
|Output Impedance:||<1 Ohm|
|Output Power:||up to 130 mW|
|Frequency Response (20 Hz / 20 kHz):||+0db / -.4dB|
|Noise Floor (DC to 30 kHz):||18 µV RMS 100 dB|
|S/N Ratio (DC to 30 kHz):||100 dB|
|S/N Ratio (A-weighted):||103 dB|
|THD+N (1 kHz Full Scale):||.008%|
|THD+N (1kHz –20 dB):||.0006%|
|Jitter contribution (DC to 30 kHz):||130 dB below full scale|
|Attenuator range:||50, 1 dB steps|
|Sample Rate:||up to 96 kHz|
|Bit Depth:||up to 24 bit|
|USB transfer protocol:||asynchronous|
|Power Requirements (USB Buss):||200 mA|
Dimensions: 2.9“ x 2.4” x 1.0″ – 7.4cm x 6.1cm x 2.54cm
- USB Camera Kit
- iTunes home sharing
- FLAC Player
- USB Camera Kit
- Lots of audio quality for the price
- Rugged designed case
- No drivers needed, it works on
- Mac OS X
- iPad (with Camera Connection Kit)
- Micro-USB connector. I know not all will agree with me, but the connector makes them prone to disconnect or break.
You get a good portable DAC/headphone amplifier for a very reasonable price, that doesn’t need a driver, just plug it in, and uses the operating system to control the volume, which I find very handy (others might disagree). The case seems very rugged and able to stand up to the abuse associated with traveling. A good buy.