Gieseler Audio Posted August 30, 2017 Share Posted August 30, 2017 (edited) Hi everyone I would like to present my new Groß DAC. It is based on the AKM4497EQ DAC chip running in software mode with a onboard micro controller.There are three digital inputs, Async USB using the Amanero Combo 384 USB board plus coax & optical. I have really gone overboard this time in terms of parts quality. The USB board & DAC chip run from four ultra low noise Analog Devices ADM7150 series regulators. The noise output level on these is only 0.9 u volts up to 100K. The critical DAC output stage is based on a zero feedback design using massive top quality Jensen line output transformers. The -3db bandwidth range is from 0.1Hz to 15MHz! No HF or LF roll off with these babies. Distortion 0.004% typ at 20 Hz and +4 dBu output level. These are the highest quality line output transformer Jensen make with PC mounting which I needed. It is a ultra simple output stage just using the transformers. Output level is 2v RMS. I have been in touch with AKM engineers & as a result changed a lot of the default AK4497EQ registry settings which now enables the chip to drive the transformers much better than normal. The other big bonus is the DAC output is fully variable (via remote) using the DAC chip internal 256 step attenuator. Bottom line is the DAC will drive a power amp perfectly with very smooth level control. You do throw away bits at lower levels but due to the DAC chips 32 bit architecture there does not seem to be much loss. There is a built in memory function so the DAC always remembers all setting including output level even after a full power off. Price - Unfortunately I did not have enough time today to do the full parts costing which I need to do to calculate the final price. I will definitely post that before the weekend. Build time is much quicker than the Konverter so that helps keep the final cost down too. OK the bottom line - how does it sound? As usual I am totally biased but this has to be the best sounding DAC only unit I have ever built by a country mile. I think the combination of ultra low noise power supplies, the AK4497EQ increased output drive & the excellent Jensen transformers is a match made in heaven. Price UPDATE! The first five at the introductory price of $2000 have now been sold. Current price will now go to approximately $2350 but I will confirm this shortly. Edited September 3, 2017 by Gieseler Audio Price update 17 2 Link to comment Share on other sites More sharing options...
Snoopy8 Posted August 30, 2017 Share Posted August 30, 2017 Nice looking unit. My only doubt is around the name ? Gross=very obvious and unacceptable. I can see many puns coming up e.g. It sounds gross, it looks gross etc... Did you compare the sound with the Konveter? And any other dacs? Link to comment Share on other sites More sharing options...
Ancientflatulence Posted August 30, 2017 Share Posted August 30, 2017 Another piece of inspired genius from the House Of Gieseler .............. Link to comment Share on other sites More sharing options...
Gieseler Audio Posted August 30, 2017 Author Share Posted August 30, 2017 (edited) All my DAC's are based on German names so compared to the Klein which means "small" in German this one is the bigger brother so "Groß" (in German means big ) was the obvious choice. However I must admit when it was first suggested to me my reaction was similar to yours. At least with a name like that you will have no problem remembering it. Also Schiit Audio has a pretty odd name but it certainly stands out. Edited August 31, 2017 by Gieseler Audio 2 1 Link to comment Share on other sites More sharing options...
joz Posted August 30, 2017 Share Posted August 30, 2017 Clay come to us for naming in the future. My German inspired name would be after the Band. Kraftwerk But I do get the Gross as in the old Mercedes Grosser Nah stick with Gross 1 Link to comment Share on other sites More sharing options...
betocool Posted August 30, 2017 Share Posted August 30, 2017 When I saw it was spelled "Groß", all doubts were dissipated. But yeah... reading it in English it was a bit of a shocker in an East End kind of accent... "Tha' is gross". As long as you're next product is not "Scheiße"! 2 Link to comment Share on other sites More sharing options...
Steven Hinchliffe Posted August 30, 2017 Share Posted August 30, 2017 Hey Klay (I feel I should keep with the Germanic theme), looks beautiful and no doubt sounds better! Can you give us case dimensions? Is it essentially the same as a Konvertor minus the preamp stage? Cheers, Steve :-) Link to comment Share on other sites More sharing options...
matth Posted August 30, 2017 Share Posted August 30, 2017 (edited) Hi Clay, the DAC looks nice, BUT I have a big problem with the scripture on it. On the left side you have GIESELER, so far so good. On the right side you have the name of the DAC, but written in an antique font which I absolutely dislike and which IMO in no way matches the font of GIESELER. This antique scripture on the right side is a NO GO for me. It does NOT suit this high-tech DAC. Sorry, but please have the name of the DAC in the same scripture (font) as GIESELER. Thank you. Matt Edited August 30, 2017 by matth 5 Link to comment Share on other sites More sharing options...
krappo Posted August 30, 2017 Share Posted August 30, 2017 46 minutes ago, matth said: Hi Clay, the DAC looks nice, BUT I have a big problem with the scripture on it. On the left side you have GIESELER, so far so good. On the right side you have the name of the DAC, but written in an antique font which I absolutely dislike and which IMO in no way matches the font of GIESELER. This antique scripture on the right side is a NO GO for me. It does NOT suit this high-tech DAC. Sorry, but please have the name of the DAC in the same scripture (font) as GIESELER. Thank you. Matt Yes to this very Much 2 Link to comment Share on other sites More sharing options...
naggots Posted August 30, 2017 Share Posted August 30, 2017 (edited) Looks like I might be selling my trusty Klein SE. Well done Clay Edited August 30, 2017 by naggots 1 Link to comment Share on other sites More sharing options...
bhobba Posted August 30, 2017 Share Posted August 30, 2017 Hi Guys Wow - nice piece of work. Have recently got myself a dedicated notebook to run HQ Player. I have found its up-sampling to be - well stunning - dead music simply comes alive with it. My Direct Stream just goes 384 but Clays DAC to 768 - cant wait to hear how it sounds with that. Will drop my PC fully loaded with music on its internal SSD and HQ Palayer to Clay in the next few days and see how it goes - should prove interesting. I have gone through my DAC buying Days but if this thing takes out my DS - anyone want a DS? Just kidding - mu DS has the inbuilt Bridge with MQA - but then again have this thing called an Auralic Aries - interesting listening ahead, Thanks Bill 1 Link to comment Share on other sites More sharing options...
Jventer Posted August 30, 2017 Share Posted August 30, 2017 Clay Based on the feedback - offer a custom front plate? e.g. just Gieseler, nothing, with the name Gross,Klein etc. The model number can be a plate/sticker or something at the back or inside. I actually like the idea of a model and date number signed by the manufacturer somewhere inside or on the back. At the end of the day the sound is what matters, but if bespoke or tailor made or special can sell more, why not. 2 Link to comment Share on other sites More sharing options...
Gieseler Audio Posted August 30, 2017 Author Share Posted August 30, 2017 (edited) Hi Guys, yes I suppose I should have used the correct German spelling in the title but I don't know how to to that funny B on my keypad. Just worked it out. Steve, Width is 300mm x 200mm deep & 50mm high. The front panel is five mm bigger all round. The design did start out as basically the Konverter less the preamp part but I ended changing quite a few parts. In the Konverter the output transformers are driven by a active stage so there is plenty of level but the Groß DAC is using a totally passive design so the smaller transformers didn't work there. With a totally passive output stage the transformer matching is more critical & the large Jensen's ended up being a perfect match. The control menu is the same as the Konverter less the analogue inputs. Matth & Krappo. Yes guys I totally agree. The front panel in the photos was cut out about six weeks ago & at time the different font for the name was just a impulse decision to try something diffent. The acrylic panels take ages to do so I was being lazy with this first unit & just used the panels I had. OK I will machine a new front panel with Groß in the same font ASAP & edit the lead photo. Some more info which may be of interest. During the R&D on the Groß DAC I spent ages looking at Galvanic isolation for the I2S lines, reclocking with a nice master clock ect. Unfortunately there are quite a few technical issues that prevented me from doing this. All AKM DAC's operate in "slave mode" so I can't just plonk a gun clock next to the AK4497EQ & run it from that. There are ways around this though like using a sample rate converter ahead of the dac but the sonic results aren't always they best & I feel it adds unnecessary complexity. At one stage I did have success by runing the Amanero in slave mode & then added the isolation/reclocking. Unfortunately when the Amanero is in slave mode I lose the DSD & mute flag lines which I need to operate the DAC correctly. HOWEVER there is a solution for for those who insist on isolation & better clocks. Singxer make a nice plug in USB board called the F1 https://www.shenzhenaudio.com/singxer-f-1-xmos-usb-digital-interface-board-xu208-chip-high-end-u8-upgraded-version.html Apparently it has the same pinout as the Amanero so in theory it should be a drop replacement option. I will order one & do some testing shortly. If this works out ok I can offer a choice of either Amanero or Singxer USB input when ordering. The Singxer option will cost about $165 more. At the moment the Groß DAC (to me anyway) sounds incredibly good & it's hard to imagine it getting much better but when I have a Singxer version I will do a side by side comparison & let you know the results. Edited August 31, 2017 by Gieseler Audio 6 Link to comment Share on other sites More sharing options...
matth Posted August 30, 2017 Share Posted August 30, 2017 33 minutes ago, Jventer said: Clay Based on the feedback - offer a custom front plate? e.g. just Gieseler, nothing, with the name Gross,Klein etc. The model number can be a plate/sticker or something at the back or inside. I actually like the idea of a model and date number signed by the manufacturer somewhere inside or on the back. At the end of the day the sound is what matters, but if bespoke or tailor made or special can sell more, why not. Very good idea. Two thumbs up! GIESELER only at front left, nothing else at the front, plate or sticker at the back. Perfect for ALL DACs, not for custom version only!!! Matt 4 Link to comment Share on other sites More sharing options...
matth Posted August 30, 2017 Share Posted August 30, 2017 27 minutes ago, Gieseler Audio said: Hi Guys, yes I suppose I should have used the correct German spelling in the title but I don't know how to to that funny B on my keypad. Steve, Width is 300mm x 200mm deep & 50mm high. The front panel is five mm bigger all round. The design did start out as basically the Konverter less the preamp part but I ended changing quite a few parts. In the Konverter the output transformers are driven by a active stage so there is plenty of level but the GroB DAC is using a totally passive design so the smaller transformers didn't work there. With a totally passive output stage the transformer matching is more critical & the large Jensen's ended up being a perfect match. The control menu is the same as the Konverter less the analogue inputs. Matth & Krappo. Yes guys I totally agree. The front panel in the photos was cut out about six weeks ago & at time the different font for the name was just a impulse decision to try something diffent. The acrylic panels take ages to do so I was being lazy with this first unit & just used the panels I had. OK I will machine a new front panel with GroB in the same font ASAP & edit the lead photo. Some more info which may be of interest. During the R&D on the GroB DAC I spent ages looking at Galvanic isolation for the I2S lines, reclocking with a nice master clock ect. Unfortunately there are quite a few technical issues that prevented me from doing this. All AKM DAC's operate in "slave mode" so I can't just plonk a gun clock next to the AK4497EQ & run it from that. There are ways around this though like using a sample rate converter ahead of the dac but the sonic results aren't always they best & I feel it adds unnecessary complexity. At one stage I did have success by runing the Amanero in slave mode & then added the isolation/reclocking. Unfortunately when the Amanero is in slave mode I lose the DSD & mute flag lines which I need to operate the DAC correctly. HOWEVER there is a solution for for those who insist on isolation & better clocks. Singxer make a nice plug in USB board called the F1 https://www.shenzhenaudio.com/singxer-f-1-xmos-usb-digital-interface-board-xu208-chip-high-end-u8-upgraded-version.html Apparently it has the same pinout as the Amanero so in theory it should be a drop replacement option. I will order one & do some testing shortly. If this works out ok I can offer a choice of either Amanero or Singxer USB input when ordering. The Singxer option will cost about $165 more. At the moment the GroB DAC (to me anyway) sounds incredibly good & it's hard to imagine it getting much better but when I have a Singxer version I will do a side by side comparison & let you know the results. Hi Clay, please do NOT offer a SRC, the experiences with the AK4137 in the Holo Spring DAC are not good. Very good idea to compare different USB interfaces. And please do not forget the USB only version to keep the price as low as possible. Thanks Matt 2 Link to comment Share on other sites More sharing options...
Volunteer sir sanders zingmore Posted August 31, 2017 Volunteer Share Posted August 31, 2017 3 hours ago, matth said: Hi Clay, please do NOT offer a SRC, the experiences with the AK4137 in the Holo Spring DAC are not good. Very good idea to compare different USB interfaces. And please do not forget the USB only version to keep the price as low as possible. Thanks Matt Whats an "SRC"? Link to comment Share on other sites More sharing options...
Gieseler Audio Posted August 31, 2017 Author Share Posted August 31, 2017 Hi Matt - definitely no SRC (Sample rate converter) & yes a USB only version will be available. 2 Link to comment Share on other sites More sharing options...
Raffinator Posted August 31, 2017 Share Posted August 31, 2017 Clay, is DSD512 over USB available? Windows and Linux (eg for microRendu or Antipodes servers)?Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Raffinator Posted August 31, 2017 Share Posted August 31, 2017 Clay, is DSD512 over USB available? Windows and Linux (eg for microRendu or Antipodes servers)?Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Gieseler Audio Posted August 31, 2017 Author Share Posted August 31, 2017 (edited) I have just been listening to DSD 256 over USB using a windows based server & that plays fine. I don't actually have any DSD 512 material so I can't test at that rate I will have to get back to regarding Linux based servers. Update - just tried some DSD using my little Celeron NUC running Daphile. The native DSD setting was greyed out in Daphile so I enabled DOP. DSD 128 played fine but DSD 256 was garbled so too much processing for the little NUC I think. Sorry for the edit but I just realised my highest rez DSD material is DSD256 Not DSD512. Edited August 31, 2017 by Gieseler Audio update Link to comment Share on other sites More sharing options...
Snoopy8 Posted August 31, 2017 Share Posted August 31, 2017 2 hours ago, Gieseler Audio said: I will have to get back to regarding Linux based server. Plus the Sotm SMS-200. It seems to able to recognise my current dac by its name, so I assume it reads the info from dac??? Link to comment Share on other sites More sharing options...
bhobba Posted August 31, 2017 Share Posted August 31, 2017 Hi Guys Sent Clay an email to order one. Just spoke to soimeone whose ears I trust, but cant name who was VERY impresssed - that good enough for me. Want the Singxer version. Will be giving Clay a special notebook I have purchased just for Music. It will run HQPlayer and upsample everything to 768K - which is getting close to DSD anyway. My current experimentation showed music was dull then up-sampled it to DXD (354k) and it came alive. Used the Direct Stream DAC which does massive up-sampling itself, so obviously HQPlayer up-sampling is better than what the DS does. But it really up-samples - to 10XDSDS- wow. Thanks Bill 2 Link to comment Share on other sites More sharing options...
jermaink Posted August 31, 2017 Share Posted August 31, 2017 Nice work Clay, I'm interested! With so many clever things going on inside I thought my suggested name, Klug DAC ('clever' DAC) would've been perfect! Is there any reason why the power button appears to be mounted sideways? Very keen to hear the final price. 1 Link to comment Share on other sites More sharing options...
matth Posted August 31, 2017 Share Posted August 31, 2017 Hi Clay, some info from kitsunehifi.com, the US Singxer distributor. The Singxer F-1 is under SALE, so maybe there is a new one upcoming. There is a second best Singxer C-1 in two versions with different clocks, less expensive than the F-1. All versions are Amanero compatible. I have read that the F-1 has DC-DC converters onboard, maybe not the best solution. Please be so kind to check this out. Thanks Matt 1 Link to comment Share on other sites More sharing options...
Gieseler Audio Posted August 31, 2017 Author Share Posted August 31, 2017 (edited) Whoops on the power switch orientation - I was looking at the back of it & kept the terminal text upright but obviously not correct. I should have done a quick Google on the symbol & the correct orientation comes up instantly. Name - it is a bit tricky but just think small DAC - Klein or big DAC - Groß Matt thanks for the info on the Singxer boards, I will look into it. Bill - thanks for the order - left work early so didn't see the email. Yes our mutual friend was most impressed. Guys sorry for few small glitches - my offsider who normal handles all this was away & my skills are in electronic area & not marketing. Edited August 31, 2017 by Gieseler Audio Link to comment Share on other sites More sharing options...
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