Directstream Regulator question


#1

Hello,

Question for @adminpaul or @tedsmith

Paul/Ted,

Do you mind if I ask what kind of regulators the Directstream DAC Snr uses - fixed or adjustable? Are you able to share the model number of the regulators and number present?

Many Thanks,

Alan


#2

It’s not a secret to anyone who has opened their DS, so I’m assuming it’s OK if I reply: the 4 main regulators with heat sinks on the power supply board are adjustable LM317 types, three for 5v and one for 12v.


#3

Thanks Minimalist!

Regards,

Alan


#4

The original intent was that the power supply board would be the same power supply board as the PWD so that people could upgrade PWDs to DSs, but we did upgrade the transformer on it so that’s not really relevant.

I’m not sure why you are asking. If you intend to replace the regulators, the ones on the power supply board won’t make a lot of difference to the sound (tho I’m sure you can hear a small difference.)

There are varying single chip regulators on the digital board and the regulators on the analog board are all made from discrete parts along with a lot of filtering of the power entering the board.


#5

Thanks Ted,

I’m talking to a reputable firm in the UK that I’ve bought from before and trust about them doing some mods on my DS. They offer a few modded products but the DS isn’t one of their normal range.

Anyway it started with a discussion around the Bybee iQSE and the Audio Magic Fuse, along with a Furutech power inlet. I mentioned that I had heard of another well-known firm in these circles in the US offering mods on the DS that included swapping the regulators as part of the mods. That firm (understandably) said the regulators made a big difference.

So based on the above is it your opinion that upgrading the regulators isn’t really worthwhile?

Many Thanks,

Alan


#6
Minimalist said

It’s not a secret to anyone who has opened their DS, so I’m assuming it’s OK if I reply: the 4 main regulators with heat sinks on the power supply board are adjustable LM317 types, three for 5v and one for 12v.


You realize we now have to kill you, right?

#7
Elk said

You realize we now have to kill you, right?


Hehe giggle_gif

Sorry Minimalist - I appear to have thrown you under the bus!


#8

The regulators don’t really affect the analog at all - the analog is 12V and is filtered and regulated down with multiple layers of custom regulators. The regulators on the power supply board need to be able to deliver at least 0.5A each so don’t put in replacements if they can’t handle that.

On the power supply board I’d replace the bridge diodes with soft/fast recovery diodes (e.g. HEXFREDs), that will quiet up the noise out of the DS back down the power cord and perhaps make a difference in the rest of your system.

Some people offer things like silver wire, etc. That’s essentially a waste since no audio signal goes thru wire. The ribbon cable between the analog and digital boards needs to stay the same characteristic impedance to keep from causing reflections so be careful if you modify that. The power supply wires carry relatively constant current so many of the benefits of better wire won’t matter as much.

It’s not that nothing will make the DS sound better, but some of the “traditional” mods places aren’t really possible - on the DS they are carefully chosen surface mount parts or internal traces that can’t be replaced with something else. (For example the audio path resistors are already thin film naked Vishay resistor quality and aren’t cheap… The audio caps are already excellent quality 5% or 2% film caps, etc.) Even the physical size of the bypass caps was chosen to get the best balance between available capacitance and package inductance…

In general I used the best quality parts in the places that matter (with no push back from PS Audio.) In the less sensitive places (e.g. some stuff on the digital card) I used good quality parts, but still carefully chosen for the specific application.

I’ve seen some horrible mods (not to the DS) where someone in their infinite wisdom replaced a number of surface mount parts with “better quality” thru hole parts, you’d be lucky if the system still worked after that brain damage.


#9

Hi Ted,

Again thanks for the very detailed reply.

Just to be clear I love the DS and bought a pair of the new M700 monoblocks unheard / unreviewed and on spec based mostly on how impressed I am with both PS Audio and the Directstream. I’m offering this disclaimer because I truly appreciate the quality of the Directstream and understand that chasing “more” is greed. But hey, pushing the envelope is the essence of this game respect-010_gif

So the background is I was talking to a well known US firm about a different product and mentioned it was to pair with a Directstream. They said the DS was awesome but pitched the following mods they offer or offered at the time:

upgrade them (regulators) to the Belleson Regulators

upgrade the input fuse to a a Synergistic Black fuse.

A few capacitors along the way get upgraded

So I’m not for a second accusing you or PS Audio of skimping at any stage. But I am wondering ‘what if’ and given I have a highly skilled outfit willing to undertake the work I’m very tempted to roll those dice.

The work would be part of a bigger upgrade to also install a bybee iQSE, a Audio Magic fuse and a better power inlet. The first two of which I could probably manage myself. But for something as precious to me as the DS I’m happy to pay a bit of a premium to get an expert to do it. And regulators / capacitors are definitely out of my confort zone.

So any advice on what upgrades make sense and what should be avoided are all very gratefully received.

Many Thanks,

Alan


#10

I understand about modding - I’ve got plenty of modded equipment myself.

Just be careful to not upgrade caps on the digital or analog board (unless you match the ESR (up and down), AC amperage handling, at least as good ESL) Not every parameter is important on every cap, but things like the ESR and ESL will affect stability of control loops in some of the filters and other caps are intended to filter a specific range of frequencies, etc… Some caps that look like aluminum electrolytic are conductive polymer hybrid caps, those are very specifically matched to their application.


#11

Thanks Ted,

I’m the first to admit that most of this goes over my head. I’ll discuss with the firm potentially doing the mods and see from there.

Meantime I really appreciate the input.

Regards,

Alan


#12
Ted Smith said

The regulators don’t really affect the analog at all - the analog is 12V and is filtered and regulated down with multiple layers of custom regulators…On the power supply board I’d replace the bridge diodes with soft/fast recovery diodes (e.g. HEXFREDs)…
…Some people offer things like silver wire, etc. That’s essentially a waste since no audio signal goes thru wire. The ribbon cable between the analog and digital boards needs to stay the same characteristic impedance to keep from causing reflections so be careful if you modify that…It’s not that nothing will make the DS sound better, but some of the “traditional” mods places aren’t really possible - on the DS they are carefully chosen surface mount parts or internal traces that can’t be replaced with something else…I’ve seen some horrible mods (not to the DS) where someone in their infinite wisdom replaced a number of surface mount parts with “better quality” thru hole parts, you’d be lucky if the system still worked after that brain damage.


Ted:

All of the above is really going above and beyond…and unheard of in this “business” as far as I know.

KUDOS.


#13

Hi Ted,

I agree with Scotte1 above - as usual you are going above and beyond what most companies would offer.

As an update I discussed with the firm that was potentially doing the mods and based on your feedback above we agree that it’s not worth pursuing the regulator upgrades. Instead we’re going to scale it back and I’m going to buy Audio Magic fuses and a Bybee iQSE from them which I will install myself.

So thanks again as your feedback has saved me money and hassle pursuing a mod that might not have made much difference.

Regards,

Alan


#14

Please provide us with an update after you make your additions to your DAC.


#15
Elk said

You realize we now have to kill you, right?


Uh-oh! Should have kept my big mouth shut.

#16

Really cool and unique Ted!

I also have some simple mods on simpler equipment like the preamp and some which are different to semiconductor change, but I’d never do an irreversible parts change with a complex device like the DS by a firm I can’t trust for very sure.

However it should be very easy for BigAlMc to compare one of their modified units to the original DS. I’d do this very carefully.

Basically I understand BigAlMc, but it’s important to be aware of the relation of risk and benefit of such actions. Good chance that there are many related to the whole setup with lower risk and much bigger benefit.


#17

Hi Jazznut,

Sorry there’s a little confusion here.

Months ago I approached a well-known firm that I won’t name here about a different product and mentioned it was to pair with my Directstream. This firm - let’s call them Firm-A pitched me some mods to my DS that included changing the regulators and capacitors. However I’m in the UK and they are in the US so it was a non starter due to logistics.

A few days ago I approached a UK based firm (that I’ve bought from before and trust) because they stock the Bybee iQSE and some audiophile fuses. Intention was to fit them myself. This firm - let’s call them Firm-B offered to fit the Bybee and fuses. I upped the ante and told them about the mods Firm-A had proposed and asked if they would consider doing these as well.

Firm-B to their credit said they would investigate it but would only do the work if it made sense and would definitely improve my SQ.

Based on Teds (amazingly candid & detailed) feedback Firm-B has declined to do the regulator and capacitor changes because they would take me out of warranty for little discernable benefit.

This is to Firm-Bs credit in my books.

I am left with a lingering bad taste in my mouth about what and why Firm-A were proposing (unsolicited remember). However as it was part of a private conversation I guess I’ll keep it private.

So comparing a modded and un-modded unit is not an option.

But Firm-B and I are following Teds advice and ditching those upgrades. I’m going to proceed with fitting the Bybee and some Audio Magic fuses which Firm-B will source for me.

Regards,

Alan


#18

Thanks for the update, I think this was a good decision!


#19

This story makes me wonder whether some firms who offer ‘upgrade’ modifications are up to the job. What Ted has described is a level of detailed design that indicates that it’s probably better not to mess with the art of an audio electronics engineer whose designs are inside products that have been widely praised by reviewers.

Peter


#20

On different matter, but related to a remark above about an aftermarket power inlet, I wonder what difference the short electrical path in a power inlet can make when the mains electricity inside the box either goes directly to PCB tracks—presumably not cryogenically treated (or quantum snake oiled)—or to short lengths of wire—presumably chosen for their known rather then unknown electrical properties. (I don’t know which of those options applies inside DS and DSjnr.) This is not to say that I don’t believe that there are better and worse power inlets. Features such as durability of metal, low electrical resistance and oxidation resistance of plating will differ from one make to another. But what are the chances that PS Audio has chosen one made with soft, cheap metal and thin plating easily oxidised? My DSjnr is fed from a dedicated mains spur and a PS power conditioner via a PS mains cable. If I thought the power inlet on the DSjnr would benefit from replacement by better(?) then I’d have to change the outlet on my conditioner too.

Peter