the 4.1x comes with a small toroidal as a separate supply for the digital board. But still there are only 2 regulated rails. The digital and +ve analog have shared regulators. Interesting though that since it uses the same main power transformer as the 2.1, the +/-9V taps are free. That can potentially be used to supply the analog (or digital) part of the digital board.
I added a dedicated transformer for the digital supply board in my 3.1 ANK DAC. also changed the diodes here to NOS ITT gold plated ones. this improved the performance of the DAC for peanuts.
this is it: 5x 1N4003 ITT USA RARE - GOLD PIN LEADS - Silicon Rectifier Diode 1A 200V DO-41 | eBay I still have 96 of them on stock
The DAC upgrade has been a bit aimless for a while now but today I received the I/V trannys from Sowter, so maybe I can force myself back on track. The transformers are quite a bit larger than the original used in the 2.1 and are also surprisingly heavy. Check out the size of the box compared to the contents! In a few days I should have some low voltage power supply PCBs delivered for the powering of the DAC board. They were designed by me and produced by JLCPCB like the output board shown earlier and so will undoubtedly need a bit of testing. For that power supply, the first of two Hammond transformers arrived recently and I have to admit being a bit disappointed to see that the 266 series looks to be made in China now. Hopefully there's no quality impact with this change, but the messy, sugar-candy texture of the exterior varnish doesn't make a particularly good first impression. Compare that to the Canada made transformer from the same series I used in my preamp. The chinese one looks like it was dragged out of a junk pile. Hopefully the difference is just cosmetic.
A few months later than expected, but today I finished enough of my rebuild to turn it on and try it out. Just running it through an old Sony mini-system at the moment. It produces sound and does seem to be quiet - at least, it is now. There was a lot of crackling through the speakers initially because the analog section of the DAC board was ungrounded. I had thought I could leave that part of the power supply floating, but it seems not. That's what the green wire poking out is - a temporary fix. In the end I couldn't help going all the way and changing out most all the parts from the original DAC. Only the DAC board itself, the main transformer, and choke now remain. There was one major hiccup late in the build when I wasn't able to get the new filament board I had designed operating consistently, so had to do a second version using different regulators. Once again, another awkward thread started by me on the diyaudio forum. Hopefully in the next couple of days I can get it into my main system to really assess it. Thanks for the inspiration fellows! Would anyone be interested in a build thread?
I haven't visited this thread in a while and ...MAN, I'm impressed. You are really taking this modular design forward and a great example of what DIY can accomplish. I was very happy with that Sowter I/V transformer- a real bargain me thinks.
Thank you @dogilv for your kind comment. I'm looking forward to seeing what difference those Sowters may have made. I've become a bit of a fan of the modular board approach that ANK/Audio Note implement, even though it might be less aesthetically pleasing than a monolithic PCB can be. It certainly helps when an entire section of the project needs replacing!
I actually asked Sowter if they would wind these I/V's in silver. I dint get a hard no and think they might do it for a group buy thing. I know people think AN's different "levels" is marketing BS but I think it has merit and a good strategy. Just doing one piece of the puzzle in silver is not the way to go about things. It was my conclusion to either go all silver or no silver. If you ever source a reasonable silver OPT (oxymoron alert) , I may revisit. BTW- Once you get all done, I recommend you revisit the coupling caps... I found that to be the most responsive to exploring sonic flavors, way more than rolling tubes.
There is a review of the ANK DAC 2.1 Signature in The Absolute Sound https://www.theabsolutesound.com/articles/ankits-dac-2-1-signature-dac
My digital board seems different from the one posted here. Any idea which value or resistor must be replaced? With the forum listed Digital PCB, R19 and R20 to 200R change out.
I am far from an expert, but it looks like R43/44 are the I/V resistors on that digital board, which is different from mine. On the analog board, at least on mine, the I/V resistors are in the middle.
hi folks! anyone updated the line stage board with AN silver tantalums? if yes with what results? cheers
