[mmerrill99]

Another test (I hope I'm not hogging this thread now?) I paralleled my Sony h/ps (70 ohm) with the HD650 (300ohm) for a load of 56ohm & there is the beginnings of some audible distortion being heard. So AKG701 (32ohm) would not be happy, I guess.

There is probably some distortion below 5K but I can't hear it. I guess putting a 27K LDR vol control before the h/p would solve this.

Quote:

Originally Posted by punk_guy182 /img/forum/go_quote.gif That's kind of weird! You should hear a difference between your DIY DAC and a your tube headphone amp. The sound signature shouldn't be the same.

Yep, but I can't hear any - I will be doing some more intensive tests with LDR vol control, AKG701s & an Aikido h/p amp sometime soon!

All I know at the moment is that this is an amazing sounding portable USB transport/DAC/headphone driver (all running on batteries)

 

[slim.a]

Quote:

Originally Posted by jkeny /img/forum/go_quote.gif I'm listening to this through HD650 headphones directly connected to the ESS DAC's outputs, no caps, etc needed (the ESS DAC outputs 2V rms with no voltage bias). Everything sounds wonderful right through the frequency range - very much like heard on the QUAD ESL 989 speakers last night. The datasheet recommends a load >5Kohm but is not complaining with the HD650's impedance of 300ohm. The vol in foobar cannot be turned up full as it's painful but as someone pointed out digital vol control is not the best idea in the world (it doesn't seem to have any detrimental effect here, maybe because the system operates in 24bit mode even on 16bit material?). But my idea to kill two birds is to put a nice LDR vol control (fixed 27kohm R + shunt LDR) on the Vouts of the DAC bringing the DAC within it's comfort zone & dispensing with digital vol control. A nice 24/192 USB transport + 24/192 DAC/headphone amplifier/LDR vol control? Whadya reckon?

Quote:

Originally Posted by jkeny /img/forum/go_quote.gif Another test (I hope I'm not hogging this thread now?) I paralleled my Sony h/ps (70 ohm) with the HD650 (300ohm) for a load of 56ohm & there is the beginnings of some audible distortion being heard. So AKG701 (32ohm) would not be happy, I guess. There is probably some distortion below 5K but I can't hear it. I guess putting a 27K LDR vol control before the h/p would solve this. Yep, but I can't hear any - I will be doing some more intensive tests with LDR vol control, AKG701s & an Aikido h/p amp sometime soon! All I know at the moment is that this is an amazing sounding portable USB transport/DAC/headphone driver (all running on batteries)

jkeny,

I could be wrong but I find it hard to believe that the Sennheiser hd-650 can be properly driven straight from a DAC without the help of any kind of beefy buffer/headphone amp. You are probably hearing only a fraction of what they can do with a proper headphone amp.

Here is an interesting read Sufficient volume vs. Sufficient headphone amping and critical listening - Head-Fi: Covering Headphones, Earphones and Portable Audio

By the way, if the ESS DAC data sheet is recommending loads over 5K ohms, it probably means that it doesn't have a super low output impedance. In that case, you will probably have a (measurable) roll off at the highs and lows and an increase in distortion and intermodulation. I am just bringing this up because the expected increase in distortion could yield unpredictable results (it could mask or overemphasize details).

 

[mmerrill99]

Quote:

Originally Posted by slim.a /img/forum/go_quote.gif jkeny, I could be wrong but I find it hard to believe that the Sennheiser hd-650 can be properly driven straight from a DAC without the help of any kind of beefy buffer/headphone amp. You are probably hearing only a fraction of what they can do with a proper headphone amp.

I know it's hard to believe but I did say that it sounds exactly the same as when I use a Millet Hybrid max tube based headphone amp. So I'm not basing it on sound memory but on direct A/B comparison - no change in reproduction of the frequency range - bass is as strong, highs are as crystalline!

Quote:

Here is an interesting read Sufficient volume vs. Sufficient headphone amping and critical listening - Head-Fi: Covering Headphones, Earphones and Portable Audio By the way, if the ESS DAC data sheet is recommending loads over 5K ohms, it probably means that it doesn't have a super low output impedance. In that case, you will probably have a (measurable) roll off at the highs and lows and an increase in distortion and intermodulation. I am just bringing this up because the expected increase in distortion could yield unpredictable results (it could mask or overemphasize details).

I already said that the ESS DAC has a recommended minimum of 5K & all along I've been saying that this shouldn't work BUT it does. We don't know the internal structure of the output stage of this DAC - it uses a charge pump to generate -3.3V & can swing it's output close to the rails - maybe this has a bearing?

I posted that I started to find the load impedance range at which distortion is starting to be audible & this was maybe at 56ohm. There may be some distortion on my cheap 70ohm Sony MDR-XD200 that I had put down to a vibration in one of the drivers but this only happens very seldom & only happens at very, very low powerful bass where I thought I heard a break-up in the right ear driver.

So, these my findings, so far - as I say more tests will be done on AKG701(35ohm?) & Aikido headphone amp

 

[slim.a]

Quote:

Originally Posted by jkeny /img/forum/go_quote.gif I know it's hard to believe but I did say that it sounds exactly the same as when I use a Millet Hybrid max tube based headphone amp. So I'm not basing it on sound memory but on direct A/B comparison - no change in reproduction of the frequency range - bass is as strong, highs are as crystalline! I already said that the ESS DAC has a recommended minimum of 5K & all along I've been saying that this shouldn't work BUT it does. We don't know the internal structure of the output stage of this DAC - it uses a charge pump to generate -3.3V & can swing it's output close to the rails - maybe this has a bearing? I posted that I started to find the load impedance range at which distortion is starting to be audible & this was maybe at 56ohm. There may be some distortion on my cheap 70ohm Sony MDR-XD200 that I had put down to a vibration in one of the drivers but this only happens very seldom & only happens at very, very low powerful bass where I thought I heard a break-up in the right ear driver. So, these my findings, so far - as I say more tests will be done on AKG701(35ohm?) & Aikido headphone amp

Those are interesting findings ... maybe its the battery power? Anyway, I am getting off topic. Let's go back to the hiface

 

[rosgr63]

Quote:

Originally Posted by jkeny /img/forum/go_quote.gif I'm listening to this through HD650 headphones directly connected to the ESS DAC's outputs, no caps, etc needed (the ESS DAC outputs 2V rms with no voltage bias). Everything sounds wonderful right through the frequency range - very much like heard on the QUAD ESL 989 speakers last night. The datasheet recommends a load >5Kohm but is not complaining with the HD650's impedance of 300ohm. The vol in foobar cannot be turned up full as it's painful but as someone pointed out digital vol control is not the best idea in the world (it doesn't seem to have any detrimental effect here, maybe because the system operates in 24bit mode even on 16bit material?). But my idea to kill two birds is to put a nice LDR vol control (fixed 27kohm R + shunt LDR) on the Vouts of the DAC bringing the DAC within it's comfort zone & dispensing with digital vol control. A nice 24/192 USB transport + 24/192 DAC/headphone amplifier/LDR vol control? Whadya reckon?

Transport+DAC would be a better product IMHO.
Leave the amp out and upgrade the Transport+DAC components as much as you can.
Whatever you decide count me in from now!

 

[regal]

Quote:

Originally Posted by hawkhead /img/forum/go_quote.gif Thinking out loud - what about this as an alternative to batteries ? Adjustable DC Regulated Power Supply (CSI 1802X) [CSI 1802X] - £34.77 : Circuit Specialists Europe, circuit boards, soldering, PCB equipment, power supplies, test equipment any comments on the specifications ?

No batteries are the ultimate solution to powering sensitive clocks. There are specialized powersupplies for driving clocks but they are expensive and hard to find.

 

[regal]

Quote:

Originally Posted by jkeny /img/forum/go_quote.gif Do you mean a holder into which the batteries are fitted which is connected to the HiFace? I don't have such - here's a photo of the batteries attached. If you mean where's the socket for the external 3.3V (batteries or whatever else you wish) to the HiFace - it's the white socket at the side that you see the battery connect to. ][/URL]

I meant a socket for the battery so you don't have to desolder everytime you want to recharge, or are you able to slide the battery into the charger with the wires attached?

Excellent work btw

 

[mmerrill99]

Quote:

Originally Posted by regal /img/forum/go_quote.gif I meant a socket for the battery so you don't have to desolder everytime you want to recharge, or are you able to slide the battery into the charger with the wires attached? Excellent work btw

I haven't decided on a battery charger yet so I don't know the ergonomics. Have you got a LiFePo4 battery charger?

 

[Emokid]

Hi guys, does M2Tech hiFace have working DS on Windows 7 x64? I know it's primary for music tru KS but i'd like to use it too with MPCHC or other media player for music DVD's, downmixed DTS audio and other stuff, thanks for replies.

 

[punk_guy182]

Quote:

Originally Posted by Emokid /img/forum/go_quote.gif Hi guys, does M2Tech hiFace have working DS on Windows 7 x64? I know it's primary for music tru KS but i'd like to use it too with MPCHC or other media player for music DVD's, downmixed DTS audio and other stuff, thanks for replies.

This has been answered a few times in the thread already.
They don't have a driver out for DS in Win 7. However, they are working on it.
Currently Hiface is optmimized to work with Foobar in KS mode.

 

[sniper0710]

1.02 version supports DS and works on win7 too

The followings are from the faq in M2tech website

5)Which drivers are available at the moment?
To date, the driver for Microsoft OSes is available. It’s compatible with XP, Vista and 7,
both 32 and 64 bits. Mac drivers will be released shortly; Linux drivers to follow.

13)How can I use hiFace in Direct Sound mode?
Just select it as system audio card: this way, every player will use it to play back music files and streams. Instead, Kernel Streaming mode is only used when explicitly chosen by the user, which select it for a specific player when configuring it (please check FooBar configuration procedure indicated in the installation manual provided in the installation CDROM
or zip file for driver release 1.00).



By the way,the freeze problem is handled?
I cant find any solution for this problem.
The following systems are tested by mt friend,and they can't work with M2tech even with the latest driver.

AMD AM2-5000 GA-78GM-S2H v2.0
AMD AM2-4200 GA-78GM-S2H v1.1
AMD AM2-5000 MSI-K9A2VM

 

[Andrew_WOT]

Quote:

Originally Posted by sniper0710 /img/forum/go_quote.gif 1.02 version supports DS and works on win7 too

It works on Win7 and Vista but not in DS mode, unfortunately. And you can't select it as a default card as it's not get registered in Control Panel as audio device, visible in Device Manager under "Sound, video and game controllers" though.

 

[doctorcilantro]

M2Tech hiFace 24-bit/192kHz USB Digital Audio Interface A journey into the world of PC audio. Review By Mike Galusha

 

[pompon]

Why not use USB extention with the hiface and bypass completely the need to use coax cable ?

Just plug the hiface directly on the dac with a simple gender changer (or bypass completely thoses connectors (but need to open the HiFace)).

Seem good or bad idea ?
I look for good coax and the price I see (StereoVox 1.5m it's 500$ ... and DB-510 is 215$ for 1.3m). For 1-2$ I have 1.5m USB extention!

 

[regal]

Quote:

Originally Posted by pompon /img/forum/go_quote.gif Why not use USB extention with the hiface and bypass completely the need to use coax cable ? Just plug the hiface directly on the dac with a simple gender changer (or bypass completely thoses connectors (but need to open the HiFace)). Seem good or bad idea ? I look for good coax and the price I see (StereoVox 1.5m it's 500$ ... and DB-510 is 215$ for 1.3m). For 1-2$ I have 1.5m USB extention!

Good idea, the SPDIF is the weaker link since Hiface is using a good protocol on USB. If you have a USB DAC, you can even put the Hiface inside and bypass USB entirely.