kdoot

You could save a few bucks on the caps by buying direct, and the shorting plugs can be done for about a tenth of that price if you aren't looking for something "elegant". But the transformers are pretty magic and the external power option just dials in the focus that little bit extra (you need to buy your own 12V PSU to match... I got an INexpensive one from China and am happy with the difference it makes). Anybody with the skill to solder surface-mount components can safely do the transformer and Vocm mods. I used a reputable local hifi repair agent. The DC offset issue is something only APS have raised and I don't have a clue what they do to fix it. Can't help you with that one sorry.

No worries Nah APS (jkrichards) don't offer a 230V compatible version of their new internal power supply solution. Best you can do is their output transformers and possibly the analog board external PSU option if you aren't using a Bridge II card in your DAC. The Vocm tweaks are easy – just need to order some suitable caps from Mouser and get your tech to install them. I can help with those instructions if you need. The transformers, Vocm and shorting plugs get you into territory that's said to be competitive with a Mk2 for a lot less money... at least it was said to be that way prior to the recent Mk2 FPGA software update.

Frank, in my comment just above I said I've done exactly those things and that's why I was interested in doing a comparison with a Mk2. It's V, O, C, M in that order by the way. Voltage, output, common mode. Vocm. I initially did the XS4400s before the APS transformers came on the market. Later I went for the APS transformers and got the Vocm upgrade done at the same time. I also have the USB and I2S shorting plugs and an external linear PSU for the analog board. The improvements overall are not subtle. Still, the Mk2 design includes improvements on par or better than all of those except for the transformers. I'm very interested to see what Ted can do with the additional FPGA capacity and it sounds like the very recent release is the first time he's really gone much beyond what the Mk1 could do in that regard. That's what brought me back here to see if there was anybody in my neck of the woods with a Mk2.

I dunno, man, it's an interesting one. Ted did a lot of things in the circuit design of the Mk2 which are equivalent to what can be achieved with mods on Mk1, or which eliminate weaknesses which can simply be avoided on the Mk1 if you are careful. The FPGA power is an advantage, for sure. But PS Audio still kept the budgetary constraints on and you only get the XS4400 audio transformers – admittedly a big step up from the factory ones in the Mk1 but definitely not in the same league as the APS nickel ones which were specifically tailored for use in the Mk1 circuit. My Mk1 has APS transformers (much better than Mk2), an external linear DC supply for the analog board (almost as good as Mk2), the upgraded Vocm capacitors and resistors (roughly on par), and shorting plugs on USB and I2S inputs (par). It's come a long way in the almost-decade that I've had it. I'm curious to hear how it compares to a stock Mk2 with the newest firmware, which is well beyond the processing capacity of the FPGA that's in the Mk1.

I still haven't heard a Mk2. Anybody in SEQ interesting in doing a comparison of their Mk2 with my modified Mk1, just out of curiosity?

Original or 2nd gen?

You haven’t heard the mods. They are frankly astonishing and cover roughly the same ground as what the Mk2 changes were, give and take. But the extra FPGA power in the Mk2 could - and possibly just did - see that machine pull ahead. My question is by how much.

I think Paul exaggerates too much, but Ted’s track record of making music sound better with each release is impeccable. I still want to put my modded Mk1 alongside a Mk2 to get a sense for when I might justify an upgrade.

Hopefully you can spend the funds on a new camera But wow I haven't seen one of these in years – very cool. GLWS.

Sale pending

Further Information: Active bass trap, tuneable to two frequencies, works to suppress bass nodes in your room. Sort of an anti-subwoofer. Purchased from this forum some years ago. I made enough changes to my system and room that after moving it out of the way one day I never put it back. Original box and packaging, ready to ship. https://bagend.com/wp-content/uploads/2014/11/E-Trap.pdf

Sold pending payment

Further Information: Great bang-for-buck sonic upgrade for the original PS Audio Directstream DAC. Designer Ted Smith built the analog board to support either these or a cheaper alternative, PS Audio went with the cheaper one but these are a drop-in replacement easily performed by any competent electronic tech. Soldering is required. Less distortion, especially in the lower frequencies, delivers tighter focus and a more cohesive sound across the board. While your DAC is being worked on, get the Vocm capacitor mod also recommended by Ted Smith done at the same time to enjoy a substantial uplift in sound quality. These are the same transformers included with the new DS DAC MkII. https://edcorusa.com/products/xs4400-quadfiler-1-1-1-1-matching-transformer

Lots of excellent modding potential with this one. GLWS.

Hi all. I'm still rocking my DS DAC MkI but it's heavily modified now, with the APS nickel transformers, external 12V LPS for the analog board, R5/R6 replaced with thin film equivalents, Vocm mod with R6 bypassed using 47uF surface mount caps, and home-made shorting plugs in the USB and I2S inputs. It's pretty damn good Anybody in the Brisbane area got a MkII and interested in doing a side-by-side comparison?

PM sent with a couple of questions

Be careful. From my amp's manual: "This unit features a BRIDGED speaker output and should NOT be grounded on either speaker output terminal as both red and black speaker terminals are effectively “hot”, i.e. carry high current signals. Please check if using any active “sub”, electrostatic, or other non standard potentially grounded speaker types directly connected to the speaker outputs of the M8s 500s." In my case I'd definitely prefer to use the loop outputs from the back of the amp into any sub.

Can anybody recommend somebody who's expert with a soldering iron up in Qld? I'm thinking about ordering a set of upgraded transformers as per the PS Audio discussion linked below, but I have zero chance of installing them myself. Who can I hire with confidence to do a quality job with some delicate through-hole solder work? https://forum.psaudio.com/t/modding-the-directstream-dac/2680/381

@DrSK Sorry for the slow reply. I don’t come around here often any more. I only had a single set of XLRs to begin with, so my first experience of the EC was with one set of XLR and one set of older single-ended, both from Mike. I had to wait a few days to get the second pair of Lenehan XLRs which is what I was describing in my earlier post.

My first hifi amp was the C320BEE. I absolutely lusted over the Cyrus 8 gear, having been introduced to hifi proper by the nice bloke who happened to be a Cyrus dealer back when the 6's were current. Those little boxes can be magic and I've no doubt you'll enjoy this upgrade.

Hey folks. I have had a DS DAC for something like 4 years now, and for the first 3 and a bit I ran it direct to power amp. I'm a fan of transparent clean resolving but not harsh or edgy sound, and I am not a fan of valves in general. Despite the DS DAC's volume control being actually lossless (though as discussed by one poster earlier, the musical signal gets pushed down relative to the DAC's own noise floor) and the output stage being nothing but direct taps from the output transformer driven by reasonably high current switching devices on the input side, I have ended up with a pre-amp in the system. (Fully balanced, solid state, to match the DAC and power amp.) It's not better in every respect, but bass is better defined and the soundstage is bigger and more free from the speakers. There was noticeable colouration of the signal (not unpleasant, but not right) before I put the pre-amp on isolation springs. Some of the fun was dialled back by the springs but on balance I prefer this set of compromises to those I had without the pre-amp. It's a close-run thing and even for those prioritising transparency and accuracy in their gear choices, sometimes the more complicated system seems to take you a bit closer to where you want to be. PS Audio has a much more expensive unit based on the DS DAC architecture in the works, including a lot more current capability in the switches that drive the output transformer and a more flexible level matching system. That one might be the DAC that unequivocally sounds best without a pre-amp. The existing DS... close but maybe not quite.

What's the objection to using a transformer? Our entire AC power infrastructure is based on transformers stepping down from 250kV to a nominal 230V. Electrically speaking there's absolutely nothing wrong with adding another step to 110V, regardless of how expensive are the items you'll be powering. OT... my first ever pre-amp is the one I bought from the classifieds here:

Great write-up, thanks heaps. What’s the maximum rate supported by the Pi in this configuration? I’m currently limited to 192kHz PCM or DoP64 in my setup and accessing the higher speeds would be the main reason I’d consider switching to an I2S input.

New set of balanced interconnects now linking the EC4.7 to my power amp. Holy wow this sounds beautiful.

And it turns out... that’s because I only knew half the story! I got some foundational RF training as part of a Wi-Fi course and they never mentioned that their definition of decibel only applies to power, not to amplitude. You are correct. Thanks for prompting me to dig deeper. Wish I liked logarithms more.