Getting the best out of Allo.com's new Katana DAC...

Greg, You do a good job of describing the conventional thinking about power supplies for top notch audio. However, things are starting to change, although most audio product designers haven't figured it out yet. For example, Benchmark DAC-3 uses a SMPS, followed by what look like some LDOs, lots of SMD ceramic caps, and quite a few small electrolytics.

The SMPS can be seen in the upper right corner in the pic attached below.

DAC-3 is on the Stereophile A+ recommended equipment list. It sounds better than Katana ever could, as it uses external interpolation filtering and also some techniques to keep jitter very low while maintaining the benefits of ASRC. Just goes to show there are other ways to do such things, and although DAC-3 is not cheap, it is the least expensive on the Stereophile A+ list.

Another thing to possibly consider is that a lot of power supply problems come from the line rather than the load. For that reason I use a (discontinued) Monster HTPS 7000 Mk II power conditioner. That works for everything in the audio rack, and considerably reduces the requirements for power supplies in individual pieces of equipment. Although the power conditioner is no longer made they can still be found on ebay, and are extremely worthwhile. Most stereo systems sound much better immediately when plugged into one. The sudden improvement in sound is a dramatic effect.

When I do listening tests here, including for Katana, all devices are powered through the conditioner. It helps a lot.
 

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@Markw4,

First, thanks. AND welcome, @Bigun.

Mark, please don't take my comments as being a blanket condemnation of SMPSs. I know some highly-regarded gear, such as the DAC3, the Mytek Brooklyn, the iFi Pro iDSD, Emperical Audio, Devalet, Berning, Bruno Putzeys work, and many others use them to very good effect. Of the amps I've used in the last 12 years, 4 had SMPSs and only 1 had linear supplies. 2 of the SMPS-powered ones were my best amps for their time and one has a good chance of being my best amps in the future. AND my personal experience with SMPSs powering source components and some reviews I've read have suggested that for some of those units they can be improved with very good linear supplies... at a price. Both ideas co-exist for me... that SMPSs can be good and compete with and better linear supplies... and that in some situations SMPSs can be bettered by linear supplies. I'm just pointing out my experiences and some that I've seen that are similar.

Thanks for the interior pix of the DAC3. My unprofessional assessment is that they have implemented a more extensive than typical power filtering regime with a number of inductors in addition to the LDOs and MLCC. Allo does similar, but generally has less real-estate available, so less-extensive. I'm sure what Benchmark did there is a key element of the SQ of the DAC. And the internal pix of the Mytek Brooklyn seen in the 6Moons Audio review (here: http://www.6moons.com/audioreviews2/mytek4/4_big.jpg), seem to show less extensive filtering than the Benchmark unit. It was one of the DACs that was improved by using an external linear supply. Draw what conclusions one may from that.

Still, finding a good set of SMPSs for the Katana may be a lift with the current offerings. That's why I'm watching the Nirvana closely. BUT as Allo has indicated, getting the quality they want from a unit able of a 5V/3A output has been challenging. That's why I have latched onto Allo's suggestion that adding a +-15V supply as part of the base 'getting the best quality' configuration, along adding an isolator which requires a third 5V supply for the RPi. This all lowers the current requirements for the 2 supplies powering the DAC / isolator and the Microprocessor board and broaden the good choices out there.

Back to the DAC3, I do like that Benchmark implemented their own filter regime. While the current generation of ESS DAC chips have significantly improved filters than the previous generations, they still are limited by the DAC chip real-estate AND the need to push specs as far as they reasonably can. Many suggest that much of the sonic signature of the Ayre DACs is also due to their proprietary filtering. AND companies like Chord are deeply wedded to their digital filtering techniques. Hopefully Allo can move that direction with a future incarnation of the Kali and/or Katana.

Finally, I don't know if you saw my comments about my AC filtering regime over in the main Allo thread. If not, go check them out. We are in violent agreement on the need for significant AC line filtering. I have an extensive 'defense in depth' approach with distributed parallel passive filters around our entire house, passive filtering and active regeneration on my main audio gear, and I though I didn't mention these there, auxilary linear power supplies (for things like switches, music server, FMC's, etc) with some tweaks to lower the measurable noise fed back into the AC lines and optical networking links between the digital source gear and the final playback gear along with local isolation at the DAC input. All worthwhile.

Finally, I have another comment to add to my previous post on whether the Katana is a well-engineered product. In another realm from power supplies, I suspect a large portion of what people hear from the unit is due to the 6 Sparkos Lab discrete opamps in the output stages. At $80 for a dual version of that device, Allo has packed in the equivalent of $240 of output stage components into their $260 DAC. That makes it an even more incredible bargain!

Not that I'm trying to sell them (nope, no financial interest in Allo here!). BUT that thought just blew my mind.

Later!

Greg in Mississippi
 
... please don't take my comments as being a blanket condemnation of SMPSs...

Of course not! Just didn't want people who don't know as much about it as you who might be reading along to get the idea extensive linear supplies are the only way to go to get good results. However, designing good SMPS still remains more of a specialist activity. Anyway, probably enough has been said about it by now to last the whole thread. :)
 
@Markw4,


Finally, I have another comment to add to my previous post on whether the Katana is a well-engineered product. In another realm from power supplies, I suspect a large portion of what people hear from the unit is due to the 6 Sparkos Lab discrete opamps in the output stages.



@ Greg Stewart
The Sparkos Labs discrete opamps have made a positive difference in my modified Quad 44 preamp. I made the changes while I was waiting for Katana Ver1.2 to arrive in October. Consistent with the changes I had to adjust for the increase in load current to my shunt regulated power supply and resizing the heat sinks. Sometimes being the minimalist has its downfall! But then, isn't that what a DIY'er does which is to look for any excuse to tweak, experiment, build and enjoy the music?
Using the discrete Sparkos op amps I hear the darkness between tracks which is quite pronounced at normal listening levels. Hopefully this week I will get to hear the new Katana with this setup once the external +/- 15V supplies have been assembled and tested.
 
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@Markw4,

I would say the PCB of DAC-3 has an interesting structure which most tens of dollars DACs can't have. There are few traces on the component side in spite of several QFPs. This is because it has internal layers for routing traces, power plane, and a ground plane. A ground plane with no split line is mandatory for a DA converter to guarantee excellent SNR. Cheap DACs don't and can't use multi-layer PCB. I don't think high-speed DAC like ESS can do the job without an inner ground plane. This is not personal likeness but physical low in electronics.

DAC-3 probably avoids laying traces on the component side not only to prevent from reverse engineering but also to have good noise immunity. If their target is RF, this is not a good idea. It may result in many vias and impedance mismatching. But this is the best layer structure for an audio DAC, IMHO. I also prefer to use the same one as DAC-3. The component side is parts and ground plane for shielding, where there are no high-speed traces. I guess the 1st inner layer has necessary signal traces and the 2nd is a ground plane. The solder side is power rail. I'm sure their PCB is more critical than DAC chip itself for good SQ though I haven't listened DAC-3 so far.:)
 
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To keep the conversation going, here's some details of the Katana end of my +-15V supply that anyone with moderate DIY experience can to use to duplicate (or better!). ALSO, be kind, this was a 1-evening Q&D build... it is not pretty nor was it intended to be!

1. To compliment the Sparkos Opamps used in the output stage, I used +-15V Sparkos regulators (that have served me well in other builds/mods).

2. To keep the paths short, I cut a piece of perf-board to match the RPi DAC HAT outline and built the reg point-to-point on top.

3. To minimize the contacts, I fed the outputs directly into the +-15V input on the Opamp board via a pair of 3-position sockets (with only one contact used on each). I used another 3-position socket to engage the ground connection. I used those sockets to match the pins on the Opamps stage board and make it easy to mate correctly.

4. Raw DC was +-23V from the supply I described earlier in this thread. That's higher than needed. With a good stiff supply feeding the Sparkos +-18V should suffice, +-19V gives a bit of margin.

5. I used a pair of 3900uF/25V United ChemiCon KYB series caps as local filter caps on the inputs. A pair of 680uF/16V KYB are on the outputs.

6. I added small-ish heatsinks. Even with the current draw and the overly-high input voltage, they don't feel over-hot. I'll measure at some point.

7. It's all connected to the raw +-23V DC supply via 18G wire. The output of the raw DC terminates in a 7-pin Hirose connector (7-pin so that I can someday go to dual-mono raw DC supplies). There's also a pair of 2-pin high-current Deans Connectors (from the model airplane/model car world) to allow me to try different output regulator setups. Better to have just 1 connector, but those Hirose are expensive (and EOL now, so harder to get).

I've been prodding Allo to consider producing a generic +-15V regulator stage printed circuit board that would mount on top of the Katana stack the same as mine and have pads to support 7815/7915 pinout regulators (Sparkos or others). It would be cool if they could configure it for LM317/LM337 and LT1963/LT3015 regs, but that would likely lead to wiring mistakes and burnt regulators and/or Katanas. Better to do 2-3 different board versions... might be a good community project here for a group buy? I don't have board design chops, but I bet some reading this do.

Alternative higher-end regulators to consider are Belleson and the new Dexa discrete regulators. I have used both of these before in other projects with similar good results. But input and output filter cap requirements may be different... read and follow the datasheets.

AND of course, Salas might be some of the best you can use here, but they won't fit on top of the Katana as these series regulators do.

Other alternatives?

Greg in Mississippi
 

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I think all this here goes way over the top for most of the people.

I'd say. First things first. Or better the easy wins first.

1. I'd start with what RPI and what OS and what OS setup to use
2. I'd discuss how to get rid of this awful USB-C powering scheme
3. I'd discuss removing these cheap RCA sockets
4. I'd discuss what grounding scheme to apply

And there's more.

For sure I consider a $1000 power approach as one of the 1st things to do nonsene.

My 2 cents.
 
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Yepp, this easily goes the wrong direction. BUT the thread title gives us an idea of that direction. I'd rather be happy about an effective way of powering the Katana in order to get 92.5 percent out of it using a decent, medium priced, rather simple PSU. Just my 2 cents.

Thank you for all your efforts and entertainment.
 
@Greg, Since people want to know, how would you compare Katana at its best with the sound if you only use 5v power supplies, any number of them? How about if adding an okay but not great +-15v supply? What about without the isolator?

Probably these are the kinds of questions readers are interested in. I will try to address as many of them as I can over in the 'ES9038Q2M board' thread. ES9038Q2M Board

However, I don't think my best power supplies are probably as good as your best supplies. The best I could probably muster here would be the supplies I use for my modded ES9038Q2M dac.

The main problem with trying to do it that way is that I'm not sure how fast I could switch between the modded ES9038Q2M dac and Katana in order to compare them. I may be limited to comparing them one at a time to the DAC-3 if direct comparison isn't possible. I'll have to see what I can figure out for that.
 
I'd rather be happy about an effective way of powering the Katana

Until now Allo did just half the job. Katana is just half a product/solution without PS.
A pity they didn't manage to get Nirvana ready on time.
That would have made at least a complete Allo "solution" and live for a lot
of people much easier. Something people could have taken as reference to get started.

Of course you can buy these $11 Allo SMPS!?!? That's what Allo seems
to be using all along.
Then why people start building their very own solutions all over the place.
Let see where all this ends. This thread shows quite well how things
are developing.

As soon as I get the DAC in my hands, I'll attach my to me well proven
and reasonable iFiiP+capbuffer solution with heavily shortened cable to it.
What I need to find out first though are the best spots to solder the power wires to
the boards (nope no USB-C!). If anybody has done it already - let me know.
 
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Been work-busy, will have some responses in the next day or so.

In the meantime, Mark, can you list the post numbers of the relevant posts that describe your power supply setups in your 'ES9038Q2M Board' thread. I'm trying to avoid reading 3000+ posts to find those posts.

THANKS!

Greg in Mississippi
 
@Greg,
The general purpose 5v supply is an LT3042 board with pass transistor. It has a 22uf Cset, and fast start up option.

For +-15 volt power I use a dual stage regulator that is LM317/337 followed by LT1963/LT3015 regs for the 2nd stage. I also have a relocatable bank of Wima film caps I can put anywhere. Right now it is on the +-15v supply output with about 110uf on each rail.

On my dac board I use some LT1763 regulators to drop the externally supplied 5v to 3.3 for things like clock, VCCA, and DVCC. I also have some .053ohm ESR, 10,000uf caps on the +-15v rails. Since that stuff is all the my dac board it is not available for Katana. However, I could probably rig something equivalent. AVCC is treated very special, but of no use to help with Katana.

Also have on hand a couple of low ESR 5v super caps, ~330mf. Not currently in use though.

The basic supplies I would try with Katana to start with include some 5v wall wart types, one of them IFI. Also have one linear 5v supply with some basic regulator like 7805, don't remember. Also have a linear variable output dual rail supply, the + rail used to be LM317 and I upgraded it slightly, but don't recall the part number off hand. The negative regulator is an LM337. Those kinds of things would be what I would tend to play around with for Katana unless somebody told be I needed to use better. I kind of figured most people would probably not go to much more in the way of custom supplies that these, since I think most people are probably interested in Katana to get a better DAC, yet somehow keep costs reasonably contained.

Pretty modest, I imagine, compared to what you have been using.
 
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@Markw4,

Thanks for the power details. I think you have some fine starting points for powering your Katana when you get it. My 'gut feel' minimum for the 'best' sound would be at least a 3-supply minimum (5V RPi, 5V DAC / Isolator / Microprocessor boards, +-15V Op Amp board). It sounds like you can do that setup easily with what you have. One key thing that works for me... keep the final output of each supply as close as you can manage to the driven board, like I did with the +-15V regulators mounted right on top of the Katana. IMHO, that is always a good practice, especially for digital circuits.

You asked about 'the sound if you only use 5v power supplies, any number of them?'. I hadn't sat down and seriously listened to my current 3-5V supply setup with/without my separate +-15V supplies yet (I did do that comparison quite a bit in the previous supply tests AND with the various iterations of Katana as Allo developed the 1.2 upgrades), so I did last night. The result was interesting. First, using the on-board +-15V DC-DC supplies, the basic character of the Katana is preserved. It still sounds like the same DAC, though with some downgrades. BUT those downgrades to my ears and in my setup were significant AND very similar to what I'd heard before. Compared to the separate +-15V supply setup, the backgrounds became less black and transparent with subtle details obscured or missed altogether. Bass extension, impact and definition was also diminished. Micro and macro dynamics were both diminished.

Hearing it in the DC-DC converter mode I would say that it is a good DAC. Hearing it with my +-15V setup, I'd say it was a great DAC.

With the separate +-15 supplies, I was hearing some things that I'd rarely heard before...

- The super-low rumble of bass synths mimicking thunder at the beginning of Gino Vannelli's "Storm at Sunup".

- The sense of multiple overlapping recording spaces of the instruments in the intro to Michael Franks' "Popsicle Toes" with that sense of space changing when the vocals start.

- The delicacy yet threatening urgency of the guitar in David Sylvian's "When Poets Dreamed of Angels" along with the reverberation tails of the bass whacks during the instrumental 2nd half.

- Being able to hear and distinguish the different horns in each section on Maria Schneider's Evanescence.

Instruments and voices were all clearly delineated and I could focus on any one or just listen to and enjoy the interplay between them and the whole.

Listening to it in the DC-DC converter configuration, knowing what I was missing, I just wanted to make the comparisons I needed to confirm the differences and get back to the separate +-15V supply configuration. In that latter configuration, I just wanted to keep listening.

Yup, powered well, it is REALLY, REALLY GOOD! To me, surprisingly good! That doesn't invalidate how good it is with more common supply setups and all of the comments published so far. BUT it can get VERY GOOD!

On isolators, I had done some comparisons when I first received a Katana with the new Isolator. AND I also did an extensive set of comparisons right after both Ian's and Allo's isolator boards first came out over a year ago. I found adding the isolators IN ALL CASES quieted/blackened the background and allowed me to both hear the subtlties that were available from the subject DAC and get a much better sense of the music. That was true in all of my earlier comparisons and was true for the Katana too. IF one wants to hear the 'best' from the Katana (or from any RPi setup), you want to use an isolator. That is even true feeding something like my Soekris' that already have a level of isolation and reclocking built into the base board. Of course, that means a separate supply for the RPi. AND note that in all of my isolator comparisons, I already had a separate RPi supply in the non-isolator mode. So it was not adding another supply that caused the improvements.

BUT your other question stands Mark. What we don't know at this point is what level of +-15V supplies (and 5V ones) are needed to produce a good fraction or all the 'best' sound from the unit. Allo has done a lot to filter the raw DC coming into each regulator stage, so lesser supplies may sound better than they would without that level of care. My personal experience is that the better the supply, the better the sound. AND that one could get better sound from the Katana than I'm currently hearing. BUT to help understand that answer somewhat, I'm considering a set of down-scale power supply trials (over the next few months) based on what I have here, can easily make, and/or beg-borrow. Note that all of these will be in what I consider the minimum 'best' configuration... 3 5V supplies for the RPi, DAC / Isolator boards, and Microprocessor boards and a separate +-15V supply... and I plan to use my modified K&K supply for the RPi in all cases. My current thinking is:


- Basic supplies... 2 5V iFi iPower (if I can borrow a 2nd from someone, I'm not going to buy another!) OR 2 modified Jameco 5V/1A linear regulated wall warts OR 2 basic Allo 5V supplies (if I can borrow those).


- Good supplies... my raw DC supplies as outlined in an early post, but using 2 more basic (LT3080/3083) 5V regulators instead of the paralleled LT304x setups.


- Great supplies... my full supplies as outlined above OR 2-4 Uptone Audio LPS-1.2 for the raw DC.


- Alternative supplies... 2 5V direct Ultracap supplies float-charged from the modified Jameco 5V/1A linear regulated wall warts OR Uptone Audio LPS-1s/1.2s.


- TBD supplies... Nirvana and/or whatever Allo ultimately releases for the Katana, assuming I can borrow one.


- Downgrade potential... all of the above using 1 instead of 2 5V supplies for the Katana DAC / Isolator / Microprocessor boards.


To be clear, I don't intend to buy any or build much for these... got other projects to do too! BUT using some of the other supplies I have here or can likely get, I hope I can provide some sense of the differences one will get from various levels of supply setups. AND do remember, I had done ALL of my listening to the Katana during Allo's 1.2 development period using what I thought would be the best supplies... 3 Uptone Audio LPS-1.2s with post-regulation plus the +-15V supply outlined above. That configuration is very good and I expected it to be the best... yet my current one beats it. Always something to learn!

Greg in Mississippi
 
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@Soundcheck and @ernesternest, thanks for your replies. AND Soundcheck, you've reached a milestone... only 3 degrading / denegrating / demeaning put-down words/phrases, a new low-record for you. I applaud you! Even ErnestErnest only used 2. Be better, do better!

I DO have to ask, why do you feel what I've done and shared is nonsense? Oh, that's right, you spent the time & money to build up a set of supplies similar to mine and have compared them to bypassing the RCA jacks and found the RCA jacks were a MUCH larger upgrade than really good supplies... or not, right?

Uh, I started this thread with the title 'Getting the best out of Allo.com's new Katana DAC...' for a reason. It's not about 'getting a minimal acceptable SQ out of the Katana' or 'what's the cheapest I can power the Katana and still get acceptable sound for me' thread. Based on what I hear, the Katana will respond well to the best power one can give it. In my setup and to my ears, it seriously rivals and in some areas beats the best setups I have here, most of which are powered by the exact same raw DC supplies.

YMMV. You may have a different opinion. Ok then, start your own thread. AND I promise I won't come in and troll your thread with put-downs.

Also, do I need to point out to you Klaus that you are an expert in computer audio, especially Linux-based? SO the 'what RPI and what OS and what OS setup' is right in your area of expertise!

AND I would guess I'm pretty good with power supplies (though I'd never consider myself an expert there... just a talented and lucky amateur). SO the supplies I used were an 'easy win' for me... I have them here, they have served me well for many other setups, and it was just a matter of making an adapter or 2.

BUT let's talk about what are easy wins for you, as they still fall in the realm of 'Getting the best out of Allo.com's new Katana DAC...'.


<SNIP OUT THE PUT-DOWNS>
1. I'd start with what RPI and what OS and what OS setup to use
2. I'd discuss how to get rid of this awful USB-C powering scheme
3. I'd discuss removing these cheap RCA sockets
4. I'd discuss what grounding scheme to apply
<SNIP THE REST OF THE PUT-DOWNS>


Klaus, what DO you recommend for an OS / Player setup? Details we can all reproduce, please?

AND for those of us who can't easily hard-wire our Katana to our amp inputs, which do you suggest?

Then you posted this:

<SNIP>
What I need to find out first though are the best spots to solder the power wires to
the boards (nope no USB-C!). If anybody has done it already - let me know.

I haven't done that yet. Based on my past experience, those should both make worthy upgrades, as bypassing the USB-C on the Boss 1.2 did, though not huge ones.

I can help here. On the Katana, for the DAC / Isolator boards, I would solder underneath the DAC board to the protruding pins of the separate power socket.

On the Microprocessor board, I'd solder onto the + & - pins of the Supercap... the polarity is labeled on the board AND the top strap of the Supercap has a '-' on it, if you look closely. Do be aware that this bypasses the protection diode that ensures reverse polarity does not destroy the unit... you do this at your own risk.

I hope that helps. Please let us know the results.

Greg in Mississippi

P.S. Klaus, your comments on 'half a product/solution' are more generic to the Katana, I'll respond in the larger Katana thread.

P.P.S. I haven't tried the Katana's balanced outputs yet, but suspect they MIGHT provide a slight improvement. 'MIGHT' because the extra stage to sum the balanced DAC output is another of those apparently great Sparkos OpAmps AND as @Markw4 said in the main Katana thread (as I remember), the balanced out might not be as balanced as desired. I do need to try this, all of my current top amps are native balanced and I have 2 balanced attenuator setups.
 
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@Markw4, sure. BUT I'll want to take some time to reacquaint myself with the sound of some of these others... and give them time to fully warm up, several of my builds (Soekris, 2 of 3 of my Twisted Pear setups) have Black Gates and they take a few days to re-stabilize.

I've got the prototype ES9028Q2M DAC from Ian using a float-charged direct Ultracap supply warming up now.

Greg in Mississippi
 
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Nope.

This one:

DDU050100H4660: Jameco Reliapro : AC to DC Power Supply Wall Adapter Transformer Single Output 5 Volt 1 Amp 5 Watt : Power Supplies & Wall Adapters

I have also modified the 12V/1A version.

Nothing too exotic... Better diodes & filter caps before & after the regulator, add an AC filter cap & transformer ringing snubber, & shortened output wires with my standard plug on the end. I also build a simple C-L AC filter that I use with up to 3 of the units to give them a full C-L-C AC filter when I use them with digital networking gear. No magic, very low tech mods, the hardest things are opening the case & Dremeling the inside of the case so the AC filter C & snubber fits.

Greg in Mississippi