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Gieseler Audio

GIESELER Groß DAC official release

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Love the look of the Groß DAC Clay.  It would be great to try it out at some point.

 

Out of interest, what influenced the decision to use output transformers?

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I am still planning on sending one to Melbourne for demo purposes but I need to fill the current orders first.

It would certainly be good to see how it compares to the Mola Mola Makua.

 

Ouput transformers;

Actually there were several reasons but the first was sound quality. Ages ago and just on a gut feeling I ordered a pair of entry level Jensen’s line out transformers from Parts Express. I jerry rigged these up to a Klein II DAC & the result was a serious step up in sound quality. This was a big surprise as the Klein II has an excellent class A output stage & I really wasn’t expecting an improvement but there certainly was. Then after some research I discovered that the PS Audio Direct Stream & Linn Klimax both used line output transformers for the audio out. Now these are seriously good sounding units so that certainly helped confirm that line output transformers was a good way to go. Also the Direct Stream was actually using Jensen transformers.

I also wanted to a try a direct out approach from the DAC chip and a transformer is an ideal way to do this.

There were some hurdles on the way though as the transformer needs to be well matched to the DAC output & you also need a reasonable drive level. Fortunately the AK4497EQ chip has some special heavy load mode options that can be implemented from the registry. Anyway to cut a long story short I had some helpful suggestions from a AKM engineer & by experimenting with a range of Jensen transformers finally got a great result. I did need to move up to the top PC mount transformer to get two volts RMS out though & this bumped the cost up a bit.

The other bonus is by using a transformer output stage I can offer balanced or standard RCA out as well as full galvanic isolation if required.

Phew! A need another coffee after that explanation!

 

Edited by Gieseler Audio

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Very interesting Clay. The PS Audio Directstream is certainly a good example of a great sounding DAC using output transformers.  I can’t wait to hear how your implementation sounds.

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It certainly looks like a interesting device.

I will do some investigation.

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Update 

I’m happy to report the Groß DAC will now play native DSD 512 files from Windows or Linux based USB digital sources.

Typical  Linux based sources are  Auralic Aries, microRendu, SMS-200 ect. I need to re flash the Amanero board with special firmware & this enables up to DSD 512 playback. There is a downside in than once flashed with the new firmware Windows based USB sources will no longer work. The firmware change is reversible & relatively easy to do using a PC.

Now there are a few pop/click issues but Amanero are currently still working on the firmware & will hopefully have it perfect soon. With my Auralic Aries the pops were only minor but much more obvious on a SMS-200.

For testing purposes I converted a DSD 256 track to DSD 512 using software.54B6E734-F09B-4FED-8D4F-8F2AD75BD774.thumb.jpeg.744a41fc3c2c9468cb90d55c08cfe605.jpeg76345797-2BF5-4F27-A759-B9F180AD0FC5.thumb.jpeg.2dc20a31715a28d6af7a1f6fce9a337f.jpeg

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Hey Clay. Just a quick clarifying question, so is it possible to have DSD512 playback with Windows sources or does that not work?

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Yes - DSD 512 works perfectly with a Windows based USB music source.

I just use the standard default Amanero firmware. 

With the same standard Amanero firmware Linux units will work but are limited to DSD 128.

 

The Groß DAC which uses the AK4497 needed a small firmware update so the DSD sample rate would auto adjust to correctly work with DSD 512 material. 

We spend all day yesterday fine tuning the DAC firmware to further improve auto muting with mixed PCM/DSD playlists. The final result was even better than the earlier firmware so I’m happy now. It’s quite complex perfecting the auto mute system as there are so many options.

Part of the critical muting control information comes from the USB board so it’s very important that my OEM board works well in that area. Fortunately the Amanero support is excellent & he is always updating his firmware to improve things so that is a big plus. There are lots of impressive sounding Chinese USB boards out there but the support is poor with little or no firmware update options.

 

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Ah k, got it. So basically there will be firmware versions that will allow DSD512 for Windows (but not Linux) and for Linux (but not Windows). Great to hear that improvements are still being made.

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Spot on Jermain.

The DAC firmware is looking pretty good now but we will continue to look at ways of improving it.

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Guinea pig again!  :P

 

The latest DAC firmware is excellent, with almost no clicks/pops when skipping/pausing DSDs and switching between PCM/DSD.  Not concerned that I may get an occasional odd one here & there.  Please note that if all your material is PCM, there are no clicks/pops. 

 

In summary:

  • Using Linux box (eg. SoTM SMS-200, Auralic Aries, microRendu) and want DSD256, DSD512, use Amanero firmware 2003be_71. 
  • Using Windows box (eg. Jriver, Roon on laptop) and want DSD256, DSD512, use Amanero firmware 1096c3w2
  • Not using DSD256, DSD 512, can use either Amanero firmware

 

If he has not done so already, Clay should be sending out the updated Groß firmware soon and details on how to update the Amanero firmware.

Edited by Snoopy8
Typos

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Thanks Guinea Pig.

Mine should be at my home this week, so I will also be testing the Linux with my microRendu and Aries Mini.

By upsampling with Roon to 256 and HQPlayer to 512 I’m hoping to have no inter-track clicks.

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2 hours ago, Raffinator said:

Thanks Guinea Pig.

Mine should be at my home this week, so I will also be testing the Linux with my microRendu and Aries Mini.

By upsampling with Roon to 256 and HQPlayer to 512 I’m hoping to have no inter-track clicks.

I was trying hard to create the pops/clicks by skipping, pausing quickly, mix of DSD, PCM, different bit rates etc. But it is not something you would typically be doing when listening. Clay's latest firmware has largely eliminated the issue. 

 

One more thing, for others not interested in DSD 256, 512. Try both firmware and see if there is a difference...

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1 minute ago, Gieseler Audio said:

No unfortunately. 

What about @  casa joz's

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Now that sounds like a good plan - just got to find a spare Groß DAC.

I have even sold my personal unit to a local that kept hounding me.

Seriously though I will make a big effort to sneak one off the production line & get it to Melbourne in the not too distant future.

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Just some interesting Amanero firmware info.

 

The current default Amanero firmware 1.096c3w will do all DSD rates including DSD 512 on windows based music servers.

 

On Linux based servers (eg Auralic Aries, SOtM SMS-200, microRendu ect) the default firmware will only go to DSD 128. 

However there is a beta firmware 2003be_71A that will enable DSD 256 & DSD 512 on Linux servers but it still has a few pop/click beep issues.

More info here

 

https://github.com/lintweaker/xmos-native-dsd/issues/12

 

Once the Amanero is flashed with this firmware window based servers will no longer work. Apparently Amanero are about to release a new windows driver 

that will work with firmware_2003be_71A.

There is some good info on this thread.

 

https://www.computeraudiophile.com/forums/topic/37303-combo384-amanero-firmware-upgrade-for-dsd256-lampizator-lite-7/

 

The bottom line is once 2003be_71A is finalised & with the new windows driver is should be possible to use Windows or Linux based servers without custom changes.

I don't this is too far away as Lampizator & T+A both use the Amanero USB board so there should be pressure from them.

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Current version has a few small changes.

Smaller power switch.

Display moved up a bit 

Groß DAC now on the back

IMG_1440.thumb.JPG.4fd8d595d99f7690643777debe4734e4.JPG

IMG_1369.thumb.JPG.fd00aa2c31c8d471d4b646a1d5a97983.JPG

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Now where's the emoticon for fingers tapping on the desk?;)

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Any news on the demo unit for Melbourne?

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Getting close.

I just have a Konverter plus one Groß DAC to go & then I'm on to it.

It will probably be the USB only version as I feel it sounds a bit better.

The only tough decision is which Amanero firmware to  flash the USB board with.

Windows or Linux version?

Edited by Gieseler Audio

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Guest scumbag
12 minutes ago, Gieseler Audio said:

Getting close.

I just have a Konverter plus one Groß DAC to go & then I'm on to it.

It will probably be the USB only version as I feel it sounds a bit better.

The only tough decision is which Amanero firmware to I flash the USB board with.

Windows or Linux version?

 

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16 minutes ago, Gieseler Audio said:

Getting close.

I just have a Konverter plus one Groß DAC to go & then I'm on to it.

It will probably be the USB only version as I feel it sounds a bit better.

The only tough decision is which Amanero firmware to I flash the USB board with.

Windows or Linux version?

Suggest usb plus s/pdif for demo unit. This will maximise the number of people who can try it out.

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4 hours ago, Snoopy8 said:

Suggest usb plus s/pdif for demo unit. This will maximise the number of people who can try it out.

I understand the dilemma here - but my experience with the USB only version is it is the only way to really hear what it will do.  For example while still better than the PS Audio DS with Audirvana on an old mac-book. it really came alive, and the difference quite pronounced with HQPlayer which, of course requires USB.

 

I think it's best left up to Clay - my vote is of course the USB only version.

 

Thanks

Bill

 

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