Suitable DAC and Amp for Sennheiser HD650

[mumer8637]

Hello,

I am looking to upgrade my current headphone setup to a Sennheiser HD650 and a DAC.

Currently, I am using Sennheiser HD 558 Open Headphones with my Alienware-18 on-board Realtek Chipset Realtek ALC3661. It is one the highest performing on-board sound card with a 600ohm headphones amp. The SNR of 90dB is also pretty darn good for an on-board solution.

My headphone will most probably be a Sennheiser HD650. It took me over a month to decide so please don't suggest anything else as it will make things more complex for me. For the soundcard, I need a AIO solution for Movies, Music and Gaming. My current on-board solution uses Dolby Home Theatre v4, something I love, and specially, the virtual surround mode which makes my stereo Senns sound better surround than any other gaming headsets (I own many of them and they all suck!).

I can either get the well rated Asus Essence One DAC and Headphone Amp but it’s only a stereo solution with no virtual surround software. Many people suggest that a high-end DAC like this with SNR of 120dB coupled with big soundstage of HD650 gives better surround effect that Dolby!? Another solution would be the Asus Xonar U7 which is a gaming oriented card but has a really high-end Cirrus Logic CS4398 DAC and Dolby Home Theatre V4 just like my current card except better in every way! The only trouble is that its Headphone amp is only 150ohms which is inadequate to drive the HD650. Of course I can add an amp like Objective2 to drive the HD650 and would still cost far less than the ASUS Xonar Essence One DAC.

So to sum up, would you recommend the Asus Essence One DAC and Headphone Amp at £349.97 or ASUS Xonar U7 + Objective 2 Amp with a total cost of £166.99 any why?
I don't mind paying the extra but given its worth it.

Thank you.

Best regards,
mumer8637

 

[BumbleBee]

The Aune T1 is on sale

http://www.techpowerup.com/forums/threads/aune-t1-integrated-headphone-amplifier.197069/

Massdrop.com ships to Europe but you should email them to make sure it comes with EU Plug.

Sennheiser headphones scale with better equipment. I would get something like a Schiit Bifrost and Schiit Valhalla. you can buy a USB microphone if needed.

not long ago I did an experiment with the Asus Xonar Essence ST that is collecting dust inside my computer. I played a couple rounds of Conquest Domination in Battlefield 3 with and without Dolby Headphone using my Sennheiser HD600 headphones. I went 104-33 and 99-38 on Ziba Tower and Operation 925. The only thing Dolby Headphone does is make everything sound artificial. it does not make you a better player.

 

[mumer8637]

The Aune T1 is on sale

http://www.techpowerup.com/forums/threads/aune-t1-integrated-headphone-amplifier.197069/

Massdrop.com ships to Europe but you should email them to make sure it comes with EU Plug.

Sennheiser headphones scale with better equipment. I would get something like a Schiit Bifrost and Schiit Valhalla. you can buy a USB microphone if needed.

not long ago I did an experiment with the Asus Xonar Essence ST that is collecting dust inside my computer. I played a couple rounds of Conquest Domination in Battlefield 3 with and without Dolby Headphone using my Sennheiser HD600 headphones. I went 104-33 and 99-38 on Ziba Tower and Operation 925. The only thing Dolby Headphone does is make everything sound artificial. it does not make you a better player.

That's a very good suggestion! I'll try the stereo with a high-end DAC and compare it with Dolby or THX Surround..

 

[BumbleBee]

if you can't afford the Schiit Bifrost the Schiit Modi will do.

 

[mumer8637]

if you can't afford the Schiit Bifrost the Schiit Modi will do.

Its my first high-end audio solution so I want to stick with a famous brand that mass-produces them.
In the future, I'll consider these custom ones..

 

[Frederik S]

A used ST or STX from ASUS or the new sound blaster Z from Creative . The TI amplification chip on those are ideally suited for the HD650s.

No reason to get a the O2 + DAC setup for the HD650s

 

[mumer8637]

A used ST or STX from ASUS or the new sound blaster Z from Creative . The TI amplification chip on those are ideally suited for the HD650s.

No reason to get a the O2 + DAC setup for the HD650s

I am using laptop so need to get the USB version. I am looking forward to the Creative Xi-Fi HD as the ASUS Xonar U7 won't be able to power the HD650 with its 150ohm output impedance.. The Xi-Fi HD on the other hand has a 330ohm impedance so it won't have trouble powering the 300ohm HD650.

 

[Frederik S]

Get the O2+ODAC http://www.techpowerup.com/reviews/JDSLabs/O2_ODAC/
Epiphany makes the same solution in the UK which should be roughly the same as the U7 + O2, but the ODAC is better than the U7.

 

[mumer8637]

Get the O2+ODAC http://www.techpowerup.com/reviews/JDSLabs/O2_ODAC/
Epiphany makes the same solution in the UK which should be roughly the same as the U7 + O2, but the ODAC is better than the U7.

Last question: Money no objection, ODAC or ASUS Xonar Essence One? And if possible, why?

 

[BumbleBee]

I don't like the Objective 2 Amplifier or ODAC. I don't like how it sounds, the front panel layout or the USB receiver. I like the Schiit Modi more.

when the Asus Essence One came out I read a couple reviews but didn't like some of the design choices. I don't know anybody in Canada that owns one so I never checked it out.

tubes are the way to go with the Sennheiser HD650. if you do some research you will come to the same conclusion. the Woo Audio WA6, Bottlehead Crack, Schiit Valhalla and La Figaro 336C/332C are the most popular headphone amplifiers.

 

[BumbleBee]

the Bottlehead Crack is really good value ($280) but it's a kit you have to assemble.

it's all point to point soldering like a traditional tube amplifier. you don't need to populate or work with a PCB.

 

[Frederik S]

Last question: Money no objection, ODAC or ASUS Xonar Essence One? And if possible, why?

Essence One if you need the extra connectivity (studio monitors and stuff), the O2 for everything else. The amplification stage on both is transparant with high impedance headphones, but the O2 can also be used with in-ears and highly efficient headphones since you can tweak the gain ratio.

 

[johnspack]

A bit pricey for me, but very nice! I wonder if a tube dac would work well with my ref AKGs....

 

[BumbleBee]

A bit pricey for me, but very nice! I wonder if a tube dac would work well with my ref AKGs....

the Aune T1?

I bought a MHDT Steeplechase ($399) recently. it's nicer than I expected. i'm going to upgrade it.

 

[johnspack]

Nah, looking at the Bottlehead.... I like to build things too, so I'd love to get my hands on the kit. Dam, that Steeplechase looks nice too.....

 

[BumbleBee]

Nah, looking at the Bottlehead.... I like to build things too, so I'd love to get my hands on the kit.

it's a Headphone Amplifier only.

http://www.bottlehead.com/store.php/products/crack-otl-headphone-amplifier-kit

 

[johnspack]

Well, it would be for my AKG Q701s.... think it would work pretty good!

 

[BumbleBee]

the MHDT Steeplechase is different than other MHDT D/A converters. it's not NOS (non oversampling) and it uses a AK4396 chip instead of Burr-Brown PCM56. it's more modern but only comes in silver. it's all steel, aluminum and acrylic.

 

[BumbleBee]

I started looking into Tube D/A converters after I came across this DIY Tube DAC on a russian website which linked me to the original engineer who sold the kit. he was trying to make something that could rival the Audio Note Tube DAC.

Tx

A tiny high-frequency input transformer makes the sp/diff receiver less sensitive for spurious common-mode currents which might run along the digital cable from your CD drive. This method of isolation is adopted from the aes/ebu professional version of the sp/diff interface. The transformer creates a nicely symmetrical and differential input signal to the receiver chip, which helps in minimizing the generation of jitter. .

Receiver

The Crystal CS-8412 chip is used as sp-diff receiver, since at the time of selection it was well-known for its good clock stability, and requires very few external components for proper operation. We have deviated from its standard external PLL filter to improve the clock stability. Nevertheless, we regard its 11.289MHz output clock as our 'dirty' clock signal. .

Dig.Filt

The SM5842AP from Nippon Precision Circuits inc is used as digital filter. We use it in a mode with 16-bit input, 8x oversampling, and 20-bit dithered output signals. The most important reason to select this chip was its dual-clock feature: It allows an input bit-clock which is independent from the the main operation and output bit-clock, with a word-level buffer in the clock-domain bridge.

PLL & VCXO

We found an extremely stable clock signal to be very important for good sonic performance of our DAC. This is achieved by generating a 'clean clock' with a high-quality VCXO (Voltage Controlled Crystal Oscillator). The voltage control allows a small adjustment of the clock frequency (+/- 0.01%) to match and follow the clock in the CD transport, which was re-generated by the sp-diff receiver as 'dirty clock'.
The voltage control is realised by a newly designed PLL (Phase Locked Loop) circuit, containing a 3rd-order low-pass filter at 2Hz, to ensure a smooth frequency adjustment (low jitter). The PLL design required a significant number of components, as no standard PLL chips could support our demands for higher-order analog filtering, and low control bandwidth at this clock rate.
As this 'clean clock' will react very slowly upon input clock variations, a buffer is required for temporal input signal data storage. In our design this is provided internally in the digital filter.

Reclock

To obtain full advantage of the stable clock in terms of a clean timing of the dac chips, al their input signals must obey a clean timing (have low jitter). We found (measured) that the standard output signals of the digital filter which normally control the dac chips, show a terrible amount of jitter even if the clock itself was clean. Therefor a separate 'reclock circuit' is introduced, which re-samples all signals between the digital filter and the dac chips. Take a further look at detailed information.

Dac

The digital-analog converter chips, are the (single channel) BurrBrown PCM-63 chips in their best (K-) selection. They provide a 20-bit conversion into a current-mode output.

Analog Filter

An analog filter is needed to get rid of the high-frequency components in the output signal, related with the 8x oversampled clock (around 353kHz) and multiples of that. We chose a passive 3rd order RLC filter, applied before any amplification. Due to the current-mode output of the DAC, a low-impedance filter is designed, which creates an output voltage by a small resistive load. The actual filter configuration is an RC-L-RC pi-filter, with a butterworth low-pass characteristic. The 2 resistances of 150 ohm are low enough to avoid significant distortion effects due to dac output voltage limitations.

Amplifier

The final amplifier is needed to bring the small voltage from the analog filter upto a level which is common for cinch outputs. A vacuum-tube amplifier stage is used, providing a voltage gain of about 20x. Initially a Golden Dragon E88CC tube was used, later most devices changed over to a Svetlana 6N1P. Upto now, we found this tube output stage to be more transparant in comparison with several attempts for bipolar transistor, field-effect transistor, or opamp-based amplifiers.

Supply Dig

To minimize cross-talk effects between the digital and the analog circuitry, the digital circuitry has its own power supply, including its own mains transformer. A clean power supply is required for low jitter, as gate delays strongly depend upon the supply voltage. Therefor 7 voltage regulator IC's are used, each responsible for a small section of the design. Furthermore a clean circuit operation is obtained by applying a small ferrite bead in series with the supply of each digital IC, a decoupling capacitor next to each IC, and series resistances in all digital signal lines. These measures are to improve the EMC behavior, by decreasing peak current values, and keeping such currents as local as possible. Listening tests were used for confirming good series resistance values.

Supply Analog LowV

A separate power supply and transformer is used for the 'analog' power supply pins of the BurrBrown DAC IC's. It provides four separate stabilized outputs: +5 and -5 volts for left and right. The voltage stabilization is done with a discrete transistor circuit, which operates without feedback to obtain good dynamic behaviour.

Supply Analog HighV

Finally, a third power supply is used for the vacuum tube output amplifier, operating at a DC voltage of about 250V, consuming about 10mA. This is made through a rectifier tube (type 6X4) and a CLC-RC filtering. Besides the high-voltage winding, this transformer also provides two low voltage outputs for the rectifier tube filament (directly connected) and the amplifier tube filament (after rectification and voltage stabilisation).

Layout

During designing the DAC, it became apparant that a good PCB design was crucial, to avoid RF, EMC and jitter effects.

MHDT D/A converters ($399-$1400) are much cheaper than Audio Note (2.1x kits start at $1500-$80,000) and a lot of people like to upgrade them so I bought one.

sorry to go off-topic