@tedsmith
Would it be possible to just replace the 8132 with the 8139 and replace the Q700 mosfet with a higher current part. This would be a good solution if using the current VOCM. With an external power supply I don’t think it would rail unless there is something up stream that couldn’t handle the extra current.
Thanks.
Part of the power supply filtering are RLC’s upstream. The R will drop twice the voltage with twice the current thru it and that will put the regulator out of regulation (more than one of them infact.) The DS wasn’t built with modifying it in mind. (Tho it was built to accept the XS4400.)
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I was afraid something upstream would prevent this. I guess the only way is to also redesign the RLC’s.
Thanks Ted.
It was interesting to observe how much better a component like the Mk I got with just a little bigger investment in some better HW, while the engineering work for those improvements was already known/done at the time of the initial design.
So for a factory parts value of let’s assume 500-1000$ for all the mods we speak of here, a DAC could have been released 8 years ago, which is quite competitive today.
I just say because I think as a designer who knows what he could do with just some $ more (exponentially calculating into MSRP), it must be hard to limit oneself to a budget. I couldn’t resist to make a pimped sample for my own at the time 
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Sorry I am crazy late to the game here… Is there a consensus on which mods are best?
Thanks so much!
This forum really needs pinned comments.
The best mods are, in order of increasing cost:
USB and I2S shorting plugs
Adding 47uF of capacitance across the eight resistors “R6” in order to stabilise the Vocm reference
Replacing the output transformers with the purpose-built ones made by APS @jkrichards
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What about external power supply board and external power supply. I have found a good custom DC cable between board and supply make for a nice improvement.
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The most efficient are:
VOCM (with or without resistor change)
Transformers
Ext. PSU for analog board
In anticipation of the arrival of my Mk2 (probably today, but it’s been delayed 3 times–I have doubts–I moved my modded Mk1 from the main system and replaced the OG stock MK1 I have in my headphone system with it.
This was a clear and decisive way to hear the differences that the Edcor transformer and analog power board with Farad Super3 brought to the table: a denser and more clear sound. The OG had an endearing mellowness that will be missed. . . but not for long. . .the modded Mk1 is certainly a better DAC.
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You should hear it with the VOCM mod and better transformers.
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Maybe I should but my audio budget is blown for the next few years.
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where do you obtain the external power supply?
I have a Farad Super 3
This one works very well.
Linear Power Supply Amplifier | Hifi Linear Power Supply Dc 12v - New 50w Hifi - Aliexpress
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A post was merged into an existing topic: Fore Sale: Directstream DAC sr. with nickel transformers and VOCM mod with USB shorting plug. Black
I will always keep one of my modified MK1 as it sounds awesome. Just a little different from the new MK2. Both sound awesome with the big nickel core transformers.
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My DAC has gone away for surgery. Reduced to running an analog headphone cable from my TV to my preamp. It sounds so bad even the picture looks fuzzy. I’m not even going to attempt to listen to any music this way.
Upgrading from Edcor 4400s to APS transformers as well as the R5/R6 replacements and Vocm capacitance. Can’t wait!
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You will be incredibly happy with the end result! I had @jkrichards modify my DSS with the XS4400’s and I thought the result was spectacular. Sent it back and had him upgrade it with his APS transformers and do the vcom mod and I’m blown away how big of a difference that made! I can’t see any reason to upgrade to the DSS2 any time soon
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Are the APS transformers still availble for order?
I currently have the XS4400 freshly installed.
Its a love/hate thing for me right now: big plus in soundstage but feel like the bass lost some attack/punch.
So maybe the APS transformers offer both for me
I think this strongly depends on the personal bass dips and bumps of the room, which transformer seems to provide more or less bass. In my case the XS 4400, although better, rather sounded a bit fatter than the original one and the big step in necessary bass control for the better transformers came by the VOCM mod.
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