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Greg Stewart 13th November 2018 02:08 AM

Getting the best out of's new Katana DAC...
Allo's new Katana DAC joins other recent offerings such as the ApplePi DAC, Markw4's experiments with other ES9038Q2M boards, Ian's prototype ESS-based DACs, Abraxalito's LingDAC, and others in raising the bar for RPi I2S DAC Hats. I was one of the lucky ones who given the opportunity to hear this DAC as Allo refined it into the well-performing product it is today. I listened to the Katana with high-performing power supplies and was rewarded with sound in many ways as good as any I've had at home.

I posted some of my experiences with power options for the Katana, isolator, and RPi over in Allo's main vendor thread here:

New FIFO buffer for RPI/SBCs

I'm creating this thread to discuss getting the best from the Katana, including, but not exclusively power options. I'm hopeful Soundcheck and others will post some of their op system, player software, driver, and hardware tweaks. And I'm sure there are other areas to explore.

Based on Allo's recommendations AND my experience, you'll get the best performance from your Katana with 4 power supplies:

- 5V/1A-2A RPi / Isolator input (>1.2A or may not boot consistently in my experience)

- 5V/200mA Isolator output / DAC board (measured 100mA DAC board only)

- 5V/20mA Microprocessor board (with +-15V DC-DC converter disabled, 1A with them active)

- +-15V/100mA-150mA / rail Opamp board

I am focusing on variations on this configuration in this thread.

I outlined the components and configuration of the best supply setup I found in my testing so far in post #4 below. (NOTE that the cost I listed for the RPi and Katana package combined is about $120USD high, due to misunderstanding how Allo listed the components). I will focus on additional options for this configuration in this thread and where I can make comparisons, how they compare to what has been my best so far.

Below are some sources for appropriate completed supplies and kits, and components that will work for the various Katana rails. This is not an exhaustive list, feel free to post or PM me with additional sources and I'll add them here. AND as you have tried them with your Katana, please post your results:

Mamboberry HD DAC+ - - 5V Mambo power supply

Twisted Pear Audio - 5V Placid HD or Centaur, +-15V Placid HD Bipolar or LCBPS, and appropriate transformers - various DC input board sets for 5V & +-15V and DXP complete supplies for 5V

MPAudio | Home of the HPULN | LT3045 based Power Supplies - various DC and AC input board sets for 5V & +-15V and appropriate transformers - various DC and AC input board sets for 5V & +-15V and appropriate transformers - 5V/12watt AC input low voltage power supply kit is what I use for RPi / Isolator input power and would also work well for the other 5V supplies - several AC and DC input power supply kits for 5V & +-15V. - various DC and AC input regulator board sets and some parts... YOU will need to source transformers and the remaining parts - high-quality discrete regulators for building your own 5V & +-15V supplies - high-quality discrete regulators for building your own 5V & +-15V supplies & supply build articles - high-quality discrete regulators for building your own 5V & +-15V supplies - Salas shunt regulator boards and partial kits for 5V & +-15V... YOU will need to source transformers and the remaining parts... there are other products and group buys in the DIYAudio Vendor forums, please feel free to recommend additional products - low cost 5V/1A & 12V/1A linear regulated wall adapters that can be modified into credible low-cost alternative supplies for the Katana

One supply that has exhibited issues with the Katana is this one:

Based on several reports, these may require additional C on the output and possible connection to the load after they have fully powered up to function well on the Katana +-15V rails.

My tips on separating the Katana boards without breaking the inter-board connector pins in post 2574 of the main thread

AND here's the current state of my Katana:

- 2nd release Katana with firmware fixing the original issue, but not the latest firmware

- Isolator 1.2

- Developmental upgrades that were incorporated in lastest production including additional power lines filtering, updated I/V filtering, and SQ mod (but using an alternative pre-I/V filter not chosen for production)

- +-15V supply (post #28)

- Direct 5V bypassing included connectors on DAC and Microprocessor boards (post #217)

- +-15V on-board LDO bypassing & revised filter Cs (posts #299, #301, #311, #316)

- DAC and Isolator board jumpers bypassed with soldered jumpers

Greg in Mississippi

stellarelephant 13th November 2018 03:03 AM

Subscribed. I don't have a Katana, but I expect I'll learn something here that will apply to RPi-based systems using other DACs as well.

Puggie 13th November 2018 03:49 PM

Excellent, I'm a Boss 1.2 user (Rpi3 and picore player), but I've been keeping an eye on the Katana since inception to see what sort of upgrade it could give. I'm also looking here at what gems of knowledge could carry over to the Boss!

Greg Stewart 14th November 2018 02:48 AM

2 Attachment(s)
Markw4, you had asked what it would cost to duplicate my Katana setup in the main thread. Here's my quick tabulation (forgive me if I made mistakes adding):

$43 - Raspberry Pi 2B

$429 - Base Katana... Katana for DietPi, isolator, extra output stage, 16GB SD card, black case (for isolator)

~$80 - RPi Power... K&K 5V/12W Low Voltage Power Supply kit ($52), parts for John Swenson transformer ringing snubber, upgrade caps / C-L-C AC filter / power cord (~$28)

~$227 - DAC & isolator boards power... MPAudio (Stammheim on DIYAudio) SD-HPULN PS ($102, NOTE you only use 1/2 of the supply), 47,000/16V Jensen 4-pole cap 47,000uF/16V ($53 PC), 4 DSEP30-06A diodes ($18 DK), Hammond 229D16 transformer ($29 DK), parts for John Swenson transformer ringing snubber / misc wiring/mounting hardware / AC filter cap / fused AC IEC socket / cap discharge resistor (~$25)

~$293 - DAC & isolator boards power... MPAudio (Stammheim on DIYAudio) SD-HPULN PS ($102), 2 47,000/16V Jensen 4-pole cap 47,000uF/16V ($106 PC), 8 DSEP30-06A diodes ($36 DK), Hammond 229D16 transformer ($29 DK), parts for 2 John Swenson transformer ringing snubbers / misc wiring/mounting hardware / cap discharge resistors (~$20) (note, shares the same AC IEC socket as above)

~$363 - Output Stage power... Sparkos Labs + and - regulators ($94), 2 47,000/25V Jensen 4-pole cap 47,000uF/25V ($136 PC), 4 DSEP30-06A diodes ($18 DK), 65W R-Core transformer ($75? EBay), input/output caps for the regulators / parts for 2 John Swenson transformer ringing snubbers / misc wiring/mounting hardware / fused AC IEC socket / cap discharge resistors (~$40)

$1436 (GULP!)

Note that this does not include shipping (significant for the R-Core transformers from China) taxes and custom fees, a case for the power supplies (mine is just mounted free-air on a bamboo cutting board), 3 AC cords (the ones I use are not expensive or fancy), and any additional connectors between the power supplies and the DAC (I use fairly expensive Hirose connectors that are now end-of-life), I suggest hardwire for best sound and low cost.

Also note I indicated suppliers in many cases... if not obvious in the description, I followed the cost with PC for PartsConnexion and DK for Digikey.

I understand most wouldn't want to spend this much for supplies for their Katana (or Boss or other RPi DAC) setup. You can still put together a VERY good high-quality power setup (that MIGHT end up being better than what I created for likely less $) using modules and components from Twisted Pear Audio, AMB, MPAudio, and many others. The K&K Audio Low Voltage Supplies would also be a good bet not only for the RPi, but the DAC board and microprocessor board. Another direction would be to use supplies built using the Salas shunt regulators detailed here in DIYAudio and sold regularly in group buys (some would suggest these might be the best solution available... I would not argue with that, though I haven't tried them myself yet).

Another interesting option would be the C-L-C power supply John Swenson originally posted on the Audio Asylum that was the basis for the well-regarded Uptone AUdio JS-2 supply (see attached schematic & JS-2 picture). Based on what he wrote about it, you'd want to stick to the specified transformers, choke and raw DC caps, though I suspect you could use a different regulator and post-regulator cap without compromising performance. I'm not sure it if can source the current needed to power the output stage via the onboard DC-DC stages, but if you use a separate +-15V supply like I did, it should work very well too.

Any other options to add?

Greg in Mississippi

Markw4 14th November 2018 03:47 AM

Wow! That is very different to the simple idea that one can get a really good dac for $250 that rivals dacs costing $!,000 or more.

One can mod a cheap imported $39 dac (total cost maybe around $250 including power supplies) that may be very similar to Katana in terms of sound quality. Don't know yet, but that was the case for Katana 1.1, and the modded dacs have improved during the same time Katana was being improved. Unfortunately, it is a lot of work to do all the modding, and almost no one has the time and patience to do it all. However, $1,000 or so for one's labor might seem attractive to some.

As an existing Katana reviewer, I recently received an email saying that Katana 1.2 would be shipped to me soon in order to continue with the reviewing. As before, we are expecting to do listening comparisons between a highly modded $39 dac, Katana 1.2, and a Benchmark DAC-3. Should be interesting. We will be talking about it over in the 'ES9038Q2M board' thread.

cdsgames 14th November 2018 09:09 AM


we are also present here, shoot with any questions

cdsgames 14th November 2018 09:13 AM

I will go first.

I think that most people will use Katana with 2 PSUs , one for RPI/Isolator side and second for Katana. The best mod for sound quality will be to use a linear dual rail 15V to power the opamp stage. I will try to get the schematic of such power and post it.

Markw4 14th November 2018 01:27 PM

Just using an extra +-15v supply seems much more doable cost-wise. One has to wonder how much difference in sound quality can result from power supply substitutions.

randytsuch 14th November 2018 03:04 PM

I do agree with Greg that good power is a key component to good sound, but I'm unlikely to invest an additional $1000 in power supplies.
To me, it becomes the somewhat standard issue with audio, dollars and diminishing returns. I tend to not go for that last 5-10% to save the dollars.

For +3.3V, I really like to use the A123 lifepo4 batteries, and would do the same here, with a simple linear PS to keep them charged. You can also use them for 5V, but you need two in series, becomes more complicated, and running the cells at 2.5V each is not optimal.

Ian is working with big super caps instead of lifepo4 and reported positive results, but I already have the batteries but may try the super caps in the future. I would expect super caps to be a better solution especially for 5V, but it will more expensive than lifepo4 batteries. Looking at prices, depends how low ESR you want, less than 1 milliohm will cost up to $75 each. The one Ian had in a picture is less, $20 each, and you need two for 5V of either.

For the +/-15, seems like a good reason to finally build some salas shunts I bought the parts for be never used.


Greg Stewart 15th November 2018 04:10 AM

@Markw4, I think any expectation that one can get a $250 DAC that rivals ones costing $1000 and more is unrealistic. One gets what one pays for. Even just adding a couple of 5V iFi iPower adds another $100, so adding those to the base $260 Katana makes it a $450 DAC including an RPi 2B and shipping. A case, an isolator, and a 3rd iFi bring it to $550. I think it will sound pretty good at the no-isolator 2-supply level, but based on my limited down-quality supply experience with the Katana, a 4-supply setup even using the same supplies for the 3 5V ones will be a good step up.

Still, if you haven't read the review series I mentioned in a post on the main Katana thread, do so just to get the comments and test results of supply upgrades to those units. What they reported (and in my experience), better supplies produced better sonics. BUT as I found out, what is the better supply for a given setup may not be what one thinks.

OTOH, I don't believe one needs to duplicate my setup to get good performance out of the latest Katana. I haven't tried any lower cost supplies yet with the Katana and I can't comment on the SQ with them yet. I can say I got significant SQ differences between the 8 power configurations I've run so Katanas on far, confirming that power does matter with it. Of course only the full-monty gave what I considered 'break-through' sound. BUT it was not the most expensive of the options I tried by quite a bit!

I will agree with @cdsgames that one of two the largest bang for the buck upgrades from a 2 supplies/Katana only basic configuration will be adding a good +-15V supply for the output stages. I heard that back when I experimented with the Dial DAC. I first powered it using a Silent Switcher supply, another DC-DC converter producing +-15V from a 5V-9V input. That DAC showed some promise, but was nothing special in that configuration. Swapping in a +-15V set of shunt regulators (similar to simplified Salas) and fed from the same raw DC supply as I'm using for the Katana was a good upgrade and it became a very enjoyable DAC most of the time with that power. Of course, the stock Dial derives the 2 rails for the DAC chip (+3.3v/+5v in the version I had, +3.3V/+6V in the later version) from the +15V rail, so that supply likely has a larger effect on the sound. AND I heard the benefit of a separate +-15V supply very clearly with the Katana... half of those 8 setups were with the DC-DC converters, the other half were the same basic 3 supplies (RPi, isolator/DAC, microprocessor) and adding my +-15V supply.

I am curious how much simpler and less expensive you can go than my +-15V setup and still reap good benefits. The Katana already has 2 stages of regulation for the output stages. My +-15V supply may be significant overkill.

IMHO the other bang for the buck upgrade will be an isolator and an added supply for the RPi. As the isolators (first Ian's, then Allo's) became available, I tried them with all of the RPi-sourced setups I had at the time (modified HiFiBerry and Mamboberry, stock and hot-rod Dial DACs, Boss and Piano 2.1, and my modified Soekris setup) and even though I already had separate supplies for the RPi and the DAC, in every case the isolator lowered the apparent background noise and made it easier to hear subtle details when added.

One worthwhile reason to use a 4 supply setup on a Katana (RPi 5V, DAC/isolator 5V, microprocessor board 5V, and +-15V output stages) is that the current requirements becomes much more reasonable for each supply and MAY even allow 'budget' supplies to produce good results for the 5V supplies. The Jameco 5V/1A linear-regulated supply at under $25 each then may become a useful choice. AND if one is DIY-handy, the mods I've done to them (upgrading the rectifier diodes along with the filter caps before and after the regulator and adding a John Swenson transformer ringing snubber along with an AC filter cap) takes them up a level.

@Randytsuch, I agree that direct LiFePO4 batteries and Ultracaps beat traditional supplies when used correctly. One of the reasons I haven't pursued them on the Katana so far is an impression (from what I've read and from my experience in using a direct Ultracap setup with one DAC, Ian's ES9028Q2M prototype) is that they work best when used direct, bypassing on-board regulators. Looking at the Katana boards I think that will be a challenging modification because of the fairly sophisticated and more complex than average power supply network designed to provide the best from lower-cost supplies. Likely worth it, but until someone blazes that trail, one takes a chance of damaging the $260 unit. Still, depending on their cost, Ian's battery and Ultracap supplies should be VERY good alternatives to standard supplies for a non-modified Katana. And a 3-battery or 3-Ultracap float-charged supply setup coupled with a good supply behind those +-15V Salas you mentioned should kick butt!

I'll see if I can find some time over the next several days to price power setups from the other vendors I mentioned. AND there's the supplies Allo is developing, which if history is any indication, should be good performers at surprising prices

Any more suggestions on other kit, DIY, or ready-built supply options?

Greg in Mississippi

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