Modding the DirectStream DAC


#1

The Lampis got them, the Yggys are getting them; in fact a lot of great designs yield a smoother, more detailed sound with mods.

Apart from SW updates maybe there are parts up to some tweaking.

Most obvious and super easy to implement are things like upgrading the power cord, shorting unused inputs or putting caps over them, using different footers, upgrading to audio grade fuses but about hardware mods?

IME bypassing caps, adding dampening material, disabling LEDs, adding WA Quantum Chips (they are still available) , upgrading connectors, etc are a good foundation. I wish we could roll some tubes but the DSD has no tube buffer stage (hint to the design team).

Anyone?


#2

There are some threads talking about DS mods - people have reported good effects from footers, better fuses (tho the stock fuses aren’t crap), SR ECT thingies (I have a post suggesting some positions for them and people have posted their experiences.)

There are no LEDs on the digital or analog cards, the analog and digital cards have gobs of caps (bulk, filtering, bypass, etc.) with carefully selected SRF’s which would function worse with any additional bypassing (you can’t get the parasitic inductance low enough to keep the HF performance.) Also, for example the resistors in the audio supplies and audio circuitry (and other critical places) are all thin film and are already better quality than many substitutes people use in mods. (Tho in one place good quality thick film resistors sounded better!?!) We’ve already removed caps that were just there for FCC, etc. (we didn’t need them and they degraded the sound.)

Tho most DACs which are based on chips at times need to do significant amplification of small signals and can use a tube buffer to an advantage, that’s just the opposite than what the DS needs - the DS has no need for voltage or current amplification - it has a passive output that only attenuates/filters the 5.6448MHz digital signal - even if the tube were linear to 200Mhz, what would the it do? If you like tubes you can use a tube preamp or tube amp.

Tho I wouldn’t swear that dampening material won’t make a difference, the DS avoids microphonic parts in the audio circuitry and the audio power supplies (like MLCCs, etc.) and since it’s a surface mount design there aren’t components waving around in the air on thin legs that can easily vibrate. Also there are no aluminum electrolytics beyond the top level power supplies on each card: SP-CAPs, film caps, etc. are liberally used downstream.

There are no wires in the analog path so the only wires that can be upgraded to silver are those from the power supply. The ribbon cable between the cards are purely digital signals and have controlled impedances to cut down transmission line reflections. Tho one could get some transformers with silver wire you’d have to be careful to match the leakage inductance of the transformers that are there so you’ll match the filtering that the current transformers provide. Ironically transformers that are too “good” will pass too much HF noise downstream to the preamp/amps.

The opamps are carefully selected (and are not cheap) and any deviations from the selected bandwidth (up or down), FR, input offset, output drive, PSRR, output noise, etc. will cause problems.

If you are careful and don’t mind voiding your warrantee, you might consider some hexfred’s (or other soft recovery diodes) for the main supply board’s power rectification. There’s plenty of bulk capacitance on the main power supply, but perhaps some careful bypassing of them there could be useful (really, the analog board has quite a bit of power supply design work already.)

My only point with this long winded post is that the DS is different than other DACs so many mods that we are familiar with aren’t necessarily a slam dunk, and many will cause degraded performance if all of the parasitics and other data sheet guarantees aren’t matched, in particular if it’s not surface mount it’s a bad idea almost everywhere on the digital and analog cards.


#3

Polyglot, as Ted has alluded to, there have been a few folks here who have made simple modifications with what they claim are good results. I believe Ted when he says there isn’t much room for improvement. Doing mods that are 100% reversible (footers, fuses) is a no-brainer if you are so inclined. More elaborate modifcations however, are done so at your own risk as I am sure you understand. There was a member here (Shilohdog) who (allegedly) made an all out assault on modifying the DS, sadly he never reported back his results nor did any other members admit to hearing the modified unit. One could make an assumption it was a failure, but it would be only an assumption. For details see the thread DirectStream Modifications (under DirectStream DAC), but as a teaser here is what he said he was going to do.

We are considering offering modifications to the DirectStream that would include:

  1. Custom transformers in 2 versions: Silver Clad Copper or Crystal Silver windings

  2. Jupiter Capacitors (complete or key areas)

  3. Cardas RCA & XLR inputs

  4. FuruTech IEC connector

  5. Viishay Resistors

  6. Silver wire in key areas

  7. Sorbothane Sheetiing

  8. All joints are WBT Ag + Resistance Soldering.

No changes in circuity - just increased values & quality.


#4
pmotz said There was a member here (Shilohdog) who (allegedly) made an all out assault on modifying the DS, sadly he never reported back his results nor did any other members admit to hearing the modified unit. One could make an assumption it was a failure . . .
A fair assumption.

Chris was noisy about his “accomplishments” and, if he had any success whatsoever, we would have riotously proclaimed he birthed a revolution in sound. Instead, only crickets.

Frankly, I am always amused by the blanket assumption that any untrained audiophilic monkey making random changes with a soldering gun can make a piece of kit sound better. If only these brilliant designers would turn their immense gifts to creating a new piece from the ground up. Imagine the breath-taking wonderfulness!


#5

Wow. Why so snide?

– (A different) Chris


#6

My former Wadia 861se was modded by Steve Huntley of GNSC fame, to the Statement Level,many years ago. Steve did great work [former Wadia employee] and I was pleased as punch in the improvement of sound quality. That being said, the DS/PWT combo, in stock form, killed the Wadia …across the board…hands down…and at a lower price point than the mighty Wadia.

I believe that any audio device can be improved upon if done in/with capable hands. But,as Ted mentioned,there is more to the process than meets the eye. I believe if the person doing the mods does not have a hand in the design process of the product, then problems can arise, as Ted stated. If mods are done on the fly,you might just g-e-t what you pay for. happy-082_giftoilet-2_gif

#7

flenser55, Christopher was a frequent contributor who at one time was listed in the “Top Posters” list (at the bottom of every page). He also was a vocal proponent of his own work. It was such that some thought it hubris. Personally I didn’t take offense at it and had a couple of transactions with him that went well. He kind of disappeared from here after the above pronouncement, though I still see him selling on Audiogon. Just another character on the internet highway …


#8

Would a separate power supply be possible and if so worthwhile?


#9

There’s the tautological response - since power cords make a difference, power supplies will as well. I already mentioned some ways to improve the supply that’s there. Yes, a competent engineer could probably splice in better supplies more easily than he could design other more intrusive mods.

Everything can make a difference but whether you get more bang for the buck working on the inside of a component compared to working elsewhere in your system is quite system dependent. “Simpler” things like room treatment, dressing of cables, speaker positioning, etc. may make more of a difference (or not.)


#10
flenser55 said Wow. Why so snide?
Which part? laugh

Short version: I have no patience with charlatans, professional or amateur.

Long opinionated version:

Chris is all hat, no cattle when it comes to his claimed expertise in improving components, designing cables, releasing miracle products, etc. Some had positive dealings in purchasing items from him, which is great. Others, dreadful experiences in which he sold improperly modded or non-functioning products, claimed he was a lawyer (he is not) and threatened to sue at least one purchaser for pointing out clear deficiencies in what he sold, etc. I doubt anyone was surprised when his claimed revolutionary improvements to the DS never materialized. I am not impressed with such people. Of course, YMMV.

As to modding in general, I find most to be random at best, installed by the great unwashed while second-guessing skilled designers. The automobile enthusiast community has many of these self-proclaimed experts as well, insisting that randomly drilling holes in an airbox will improve induction efficiency, clipping coils off progressive-rate springs enhances handling, etc. Complete nonsense in both camps. And both often do harm.

On the other hand, a skilled engineer can improve certain products and to a remarkable degree. As mentioned about, Steve Huntly did great work on Wadia products knowing what compromises were made in the original design. (As an aside, Steve very competently drives a Porsche and we have enjoyed numerous spirited drives chasing each other through the twisties.) Rick Cullen did great work on earlier PS Audio products. Steve McCormack offered wonderful, cost effective mods to his products. There are others, of course.

Note, however, none of these guys are random guys on the Internet proclaiming you should substitute random caps, incorporate silver wire, replacing transistors with boutique offerings, plaster the inside with shielding du jour, etc. Instead, their work is precise, well-reasoned, specific and effective.

My opinion only. All are very welcome to disagree.


#11

I do not see why opening up the dac is needed to mod or improve the sound.

Unless one has done everything else and at that point where is the value coming into this now.

A simple regen works wonders far more than any fuse or power cord I ever heard and actually I do not hear any changes from such devices.

Next would be a good tube preamp

if I use one it absolutely improves what’s missing for me.

The new firmware is best yet weather it’s beta or final. Tubes do add something my brain likes for sure. And of course there are servers but be careful some do not do well with the ds

my Krell connect is one for sure although it’s not USB. It’s sound is lacking real quality or realness. If I use one of custom servers it’s really good. Just lacks some weight for me.


#12

Yeah, I wouldn’t mess with this (Unless Ted specifically says change out this part…)… especially with how they tune the firmware.

I understand modifying hardware that’s built to a price point, where components were compromised on purpose.


#13

The DirectStream DAC most certainly was built to a price point, just a moderately generous one. In that though, the component compromises made were extremely carefully considered and the design was optimized around the specific compromises. This was done well enough that substituting “better” components in most places will actually compromise the sound quality of the total package. Kudos to Ted for doing such an excellent job of design, compromise and optimization within the given limits.

J.P.


#14

I believe that Ted said that the output transformers were one of the only spots of compromise and this would have made a big difference in the cost. Not worth it as I recall.


#15

I suspect that the next incremental improvement will be a different FGPA, bigger and with more/different capabilities - able to at least contain a bit more of Ted’s imagination and creativity.


#16

Ted: kudos to you and the design team, coming from analogue and dabbing around with digital for a few years, a.o. having (had) a Lampi L4, means that I indeed appreciate the PSA DS, esp. with the current Yale SW that I got and is currently being burnt in.

The hint with the tube buffer is, as you know, to yield a more euphonic result. Though I have an all tube system, I think others may benefit in a possible future tub insert.

I started this thread NOT to utter my critique but hoping to gain MORE OUT the DS.

As for those few replies with a somewhat defensive attitude:

-First of all, forums are intended to exchange ideas and the manufacturer may benefit from a closer relationship with their customers.

  • Secondly, I am no spring chicken, having modded most of my gear for a simple reason: affordability and the law of diminishing returns. PSA to my understanding has designed, manufactured and marketed to a broad segment. If PSA would make a super-duper DAC with high end components (again, I am not criticizing the DS) it would retail north of $10k, not their target audience.

A good example what I mean is the Oppo BDP-105, already an excellent blu ray player, mods by Dan and Ric (Modwright, Tweakaudio) takes the 105 to a higher level, indeed at a cost. Great designs in the commodity space like the Logitech Squeezebox are the foundations of other great things like the Lampi.

I agree that most consumers will just deploy the gear out of the box, some upgrade the obvious (power cords, fuse, footers, etc), few grab their soldering iron in the hope of reaching higher level.

Some designers (again, PSA folks not targetted) did not even know e.g. that caps are directional, some speaker manufacturers in the past have claimed that (speaker) cables can not make any difference. Still at least one DAC manufacturer (again, not PSA) claims that none of the USB cables can make a difference. Who is right? The more adventurous owner, seeking the “more” of his cherished unit, may benefit.

pmotz, thanks for the info!

P.S. Elk, what gives you the assumption that I am monkeying around? Even if you have an electrical degree, it is not appropriate to welcome a fellow IEEE engineer which I am. This thread was not started to solicit users to swap out ad hoc components. It is NOT about the a different value but a higher QUALITY of the component. If you have ever upgraded simple components to start with, like IEC and plugs with higher end components, maybe an isolation trafo, you would have known better than to put on your condescending hat.


#17

I for one feel tubes add something good as well if chosen well matched for what is needed.

I Have a few really good dacs and the ds is pretty good but adding a tube stage does work magic for what it’s worth


#18

In the end you never know until you try. The voltage stage in the BHK is a good example. I’ll bet some bold person out there will give a go at firebottles in the output of the DS (then again, it could be an expensive failure).


#19
1234 said I for one feel tubes add something good as well if chosen well matched for what is needed.

I Have a few really good dacs and the ds is pretty good but adding a tube stage does work magic for what it’s worth


Indeed it would. One can argue to put something like an iFi iTube but considering the cost of good interconnects and the fuzziness of another add on (I already have the must-have-Regen hanging out on the back), I would gladly pay a grand more (retail) for a version with tube buffer.

Looks like I may well end up with an iTube with +6db setting as I am driving my tube mono blocks directly and the Vout is too low from the DS.

The DS is a darn good product but I need to sort out the gain issue before deciding to keep it. After that, modding in some form will start.


#20

Let us know what you find!