I don’t have mkII. I can see very little from the pictures. The board looks like a multi-layer PCB, even in the power supply area. So there’s not much you can do, especially without schematics.
A lot of mods for mkI started with TedSmith’s explanations of how something was designed to work. He shared some schematics, and he himself suggested some improvements. Then, people were able to come up with their ideas.
MkII, obviously, is not as suitable for DIY projects as MkI is. That’s why, in my initial post (sorry for the bad joke), I said that, to me, mkI remains the best DAC because it has the potential to become something way better. I don’t see this potential in mkII…
Just a lyrical digression. What are we even talking about?? How to improve this extremely sophisticated device that TedSmith worked on for years! from scratch! He might have taken some ideas from mkI, but he didn’t use any parts from old generations. As opposite to the DirectStream DAC, where he designed only half of the device. This is where the potential for improvements came from.
Anyway, I’m the one who believes in good power cords and even more in good power supplies. From my experience with mkI, digital board as well as processor board turned out to be pretty sensitive to the main power supply mods even though there are multiple local regulators on each board. I see that in MkII, Ted implemented multi-stage power regulations, too, but I don’t see a substantial primary power supply. So here we go
I can only suggest theoretically. Only because you asked for it. Try it at one’s own risk. I haven’t tried anything of that on mk2 (but did all of that for mk1)
You could install two SHIELDED transformers to feed the boards separately (I’m taking about input high-voltage transformers)
Swap inlet for a Furutech one, and wire up the transformers straight from it (don’t forget the capacitor after the inlet)
I see the rectifying bridges, but I don’t know whether these are Schottky diodes or not (most likely not). Swap them. Swapping these diodes in mkI gave very noticeable improvement even with primitive LM317 remaining in place.
If I’d be able to figure out where the voltage from these bridges goes, I’d try to add a big capacitor after the bridge before the next regulators. 10,000uF with 1-1.5uF Wima MKP would be very helpful here.
I’m not sure if I’d go that far, but someone might try. I don’t know what the regulators are there after the rectifying bridges, but definitely, they are SMD. Some people installed microassembly regulators instead of SMD ones on the analog board in mkI. So there still might be room for improvement here for mkII. This mod could be the most destructive.
Vince, I’m sure the Rossini sounds great, but I’ve recently implemented the ultimate MK2 DAC mod. You might call it the “contentment mod” because it didn’t involve spending thousands of dollars on upgraded components and required only a few inexpensive mental adjustments. Not only does it sound awesome, but it also creates a zen-like calmness that has to be experienced to be appreciated.
I am eager to try out the Rossini mod, How does $300 down and $30 a month sound?
Just think you could become the Rent-A-Center of hi end audio. a market segment that has been severely neglected!
Lee
They are Schottky, Chosen for low reverse recovery…
Adding more capacitance there would cause much more noise. This isn’t a traditional PS.
There are no SMD regulators on the Mk I analog board, they are all discrete implementations.
I doubt you can find better regulators for this application in the Mk II:
“RMS Noise: 0.8µVRMS (10Hz to 100kHz)
Low Spot Noise: 2nV/√Hz at 10kHz
High/wide bandwidth PSRR: e.g. 76dB at 1MHz…”
And there are plenty of them.
The cost of more than one transformer was better spent lowering more noise at other points in the circuit. The regulation between the digital and analog boards is significant. The analog board regulators are prepared for any high frequency coupling in the AC transformers.
I must apologize for my categorical attitude. In the light of the new information I must addmit the simple look confused me, but turned out that the power supply part of the mkII was designed to perfection. You were right for the mkII part and I was wrong.
Now you know why nobody came up with any mods for the mkII other than APS transformers.
So, you have been deprived of the joy of soldering this time
Enjoy this perfect DAC!
It responds well to power cords, fuse, digital cords, analog ICs, digital usb and HDMI shorting plugs and limited RF absorber tweaks without opening it.
Nice to have Ted back and straightening out any misconceptions. Though I don’t understand it all, I’ve watched his and Paul’s video about the changes to the MKII 3 or 4 times.
Skipped this intermediate step by upgrading my MK1 straight with the Apex Vivaldi mod. Only problem arised was the end of added quality of music played through my beloved Audio Research Ref 6SE, so I had to sell that one…
You’re a good man, Anton. Acknowledging an error in assumption on your part with Ted’s information. Bravo. I’ll admit I kind of threw that suggestion out to you to see if Ted would respond. I know with the MkII he tried very hard to keep from having to make compromises similar to those made in the MkI.
I know with the MkII he tried very hard to keep from having to make compromises similar to those made in the MkI.