You just need a ISO-PS with dual 5V outputs so choose 5V "The “dirty power” needs 5V /2-3A (RPI power). The “clean side” needs about 100mA and accepts from 5V to 6V."

It depends on what the PS is being used to drive in the audio chain. So for instance when I changed from battery power to supercapacitor power in my DAC with nothing else changed, the sound seemed faster, more precise, just that bit more focused - as a result the sound objects in the soundfield were perceived with more soldity, the soundstage more holographic with perhaps more snap to the sound. This is relative to battery power which itself produced these characteristics when compared to stock PS powering the DAC I'm pretty sure that these perceived audible characteristics have something to do with the dynamic noise floor which to me means that when an audio device is processing data, if the power supply is generating fluctuating electrical noise as it dynamically sources current to the devices being powered, then this results in a noise floor which is fluctuating. This is low level but form my research I believe our auditory perception is picking this up because it is changing. Here's a way to think of this & do an experiment which will illustrate - put a single hair under your finger - can you sense it is there? Now roll the hair with your finger & you can easily sense its presence. Similarly a steady state signal (or noise) at a low enough level is not perceived but when it fluctuates or forms a pattern, we are more sensitive to its presence This noise floor has much more possibility to be just static noise when a power supply is not based on active devices - it's the dynamic nature of the noise that is sensed by our auditory perception. The fact that we can "listen through" the relative static surface noise of vinyl/tape is testament to how our auditory perception can ignore such noise when it's constant. That's why some have discovered that a voltage regulator on the output of battery or supercapacitor power is detrimental - it introduces some dynamic noise because of the feedback nature of it's design. This also explains, for me, the reason such improved power supply can have an audible effect when powering digital only devices in the playback system - the dynamic noise is somehow getting through to the final D to A stage of the playback system - it may be on the ground connection between the devices, it may be through common mode noise on connections between devices, it may be through some other avenue? Now this is my conjecture & there will be some that say this is BS because measurements don't demonstrate this dynamic noise floor fluctuation. I agree that measuring this aspect is probably difficult but that isn't a reason to dismiss it completely as I'm sure measurements will eventually be done which will hopefully illustrate what I'm saying. Until then I'll use my ears & my logic to try to comprehend. I have written a bit about the difference on my webpage here " So any power supply being used in this situation needs to be immune to all these fluctuations in timing, current delivery. If not immune then the result is usually dynamic noise on the ground which has downstream effects on audio quality. ​ LiFePo4 batteries & supercapactitors are both capable of satisfying these requirements & the only difference between them appears to be the speed of the current delivery. High capacity supercapacitors often have a very low impedance (this value is a measure of the ability to deliver current quickly - the lower the impedance, the faster the current delivery). The LiFePO4 batteries have an internal impedance of <8mohm - the supercapacitors I use (Nesscap/Maxwell 350F ) have impedance <3.2mohm. This should mean that the supercapacitors can deliver current faster than the batteries. This seems to be borne out in the listening, supercapacitors appear to have slightly faster. However, pcb traces & wires will negate this impedance difference so perhaps the audible difference is due to some other factor? Both batteries & supercapacitors are still unfazed & stable when delivering the needed current. This means no dynamic noise is created in the ground plane which ultimately affects the audibility

Hi Huy A number of people have used the recent supercapacitor power supply to power their rPi with Allo. Both battery PS & supercapacitor PS will do the job fine.

@Robin Carmack - yes but this variable voltage design is on hold indefinitely - I'm focusing on fixed voltage designs at the moment & will get up to a 25V design soon

BTW, I have a supercapPS design in the works which will provide a settable voltage on one or two outputs. Each output can be individually set by the user to a voltage in the range 5V to 25V in steps of 2.5V - a voltmeter shows the voltage on each output

As you have identified, each supercapacitor is maintained at the voltage required to provide the set output voltage. This is achieved via double voltage regulators in series which together with the supercaps results in killing any noise coming from mains/charging PS but more importantly because there are no voltage regulators on the output (as most PSes use to maintain a stable voltage) the power delivered doesn't suffer from the dynamic noise of these PSes. In other words when there are fluctuating demands for current (as there are in all devices that involve processing of fluctuating signals) the direct supercap PS delivers this current without any electrical noise being generated by this demand. I have tested this & there is no audible difference (or difference on the scope) between running directly from powered supercaps or supercaps being trickle charged in the way I do it. How important this is for audio depends on what's being powered & where the device being powered is in the audio chain. The non-intuitive aspect to this is that digital devices have the most dynamic current demands & are also processing very low signal levels & prove to be the most sensitive to this power stability (or lack of). There is no significant impact to the lifespan of the supercaps which have a cycle life of about 1 million. Furthermore these supercapacitors are not going through discharge & recharge cycles - this is what the cycle life is a measure of - they are being constantly trickle charged. This trickle charging has been shown to have no detrimental effect on the batteries which I previously used in my devices. Thee Lithium Phosphate batteries have a cycle life of some 10,000 (very conservative estimate). I have devices in the field more than 7 years with no change of battery needed

Thanks, Franceso It's great to get feedback from customers. Yes, I found the overall improvement in the sound very worthwhile with the supercapacitors

Hi Ricardo There's a webpage about the difference here. If you have further questions, don't hesitate to ask

Thanks Bill Forgot to say - I believe you will find the ISO-SPDIF warrants a listen but I would say that, wouldn't I? Of course a home audition is the only way to evaluate & compare to other devices - a refund if you return it within 30 days.

Hi Bill I use NDK SD, not SDA clocks. Here's my take on clocks that I have gathered over time from RF experts & my own experience. These experts have said that clocks advertised as low jitter, such as NDK SD & even SDA are pot luck to a large extent. They say that the jitter graphs posted for these clocks are for selected best clocks from production runs. How many clocks come close to these jitter figures - it appears that it's a small percentage. Jocko Homo (Pat G) is an expert in clocks & RF - he has measured & graded NDK SD clocks from a large batch production run & the best ones were few. What you don't see on these jitter plots is the close-in phase noise or low frequency jitter which is said to be the most important sound-wise. He measured, plotted & graded this batch of SD clocks & sold the few that measured well for $25. I bought some to check how they improved the sound - there was some improvement in sound stage & realism but not as much as the improvements I got when other areas were addressed. The jitter at the DAC chip I2S input (where it matters) is not just from the inherent clock jitter, it comes from many other areas - stable power supply, noise on the ground, noise picked up by the I2S signal lines before the DAC. I believe these other areas are far more audibly important than the clock jitter itself. I have addressed all these areas to the best of my ability & each improved the sound noticeably. I firstly used battery power (just recently changed to supercapacitors) to provide as stable & low noise PS as possible. I then synchronously reclocked the I2S lines (i.e using the same two audio clocks that initially generated the I2S signals) just before they enter the DAC chip & finally I isolated & reclocked the USB signal before the USB Amanero receiver. These changes were made as a result of testing & experiments along with listening tests. Eliminating all these other sources that introduce jitter allowed me to evaluate just what audible improvements result from using a measured, low jitter clock (bought from Jocko) A small audible improvement improvement seems to be the result. BTW, the improvements from using better clocks are along the same lines as my other jitter reduction areas, just less so - more dynamic sound, more solid 3D sound stage, more realism to the sound.

@jerry Aha, great to hear from a dead head - I'm sure the ISO-DAC will improve your enjoyment of that wall of sound :)

@jerry Thank you - are you Pier?

Yes, a Paypal payment charges me ~5% fee unless you choose "Friend" option. If you do use that option I will refund you the 5% which has now been built into the introductory price (reduced from 10% discount to 5%). Unfortunately, I couldn't automate this in the payment logic If you use Transferwise you get the best exchange rate available & lower fees than Paypal. If that is chosen I will send you an email with the instructions & account to pay into

PCM5102A but looking at specs tell you nothing about the sound. For a start the specs represent the best possible laboratory conditions that the DAC can be used in - the manufacturers want to show the chip specs in the best light possible. Real world conditions seldom match the laboratory setup. My audio devices, now using supercapacitors, supply all the components, clock, DAC chip, surrounding circuitry with the best power available, IMO. This tends to minimise the sound differences between DAC chips. Apart from all that, the actual sound is the critical issues & the PCM5102A is a surprisingly good sounding DAC particularly when the low-latency filter is used.

BTW, just to update this - it has been resolved by John Zirkel himself - technician not need & now his ISO-DAC plays high-res files with no issues

Welcome Michael My USB audio devices address the issues that seem to plague most USB signals - noise & signal degradation. Computers (particularly Mac Minis) & USB cables are the two main culprits for these issues. I deal with these at the receiving end of the USB cable by isolating & reformatting the USB signals coming into the ISO-SPDIF. I also reclock the I2S signal just before it enters the SPDIF chip. All of this is powered by the very low noise, highly stable power of supercapacitors The result of all this is that the output SPDIF signal is optimal & results in an audibly better sound. But I would say that, wouldn't I? Or I could just say that people seem to like the sound :) There is a 30 day trial period for people to make up their own mind in their own audio system. PS. I'm just finalising new pricing on the supercapacitor versions of all my audio devices

@jerry Great to see your Ciunas shortlist :) Yes, supercaps seem to bring an added small but noticeable 'bite' to the sound - it's always difficult to describe. Durability of these batteries is exemplary, if treated as per the guidelines 5-10 years; supercaps 10 years & longer

Initially it will be in the format where the HUB ports aren't exposed i.e no 4 USB port openings. This seems to be the more popular option.

Hi John No dealers - mine is a direct business model to keep prices down. Any technician will be able to update the firmware with the instructions & pics I gave - just PM me if you need more info

Good question, Jerry Yes, 1. is the original Ciunas DAC which is battery powered & has reclocking of I2S signals before DAC chip 2. Is the above + isolation & reformatting of USB input signal but no external 4 USB ports of cleansed & isolated USB signals 3. Is the same as 2 but the 4 ports are exposed for use You will certainly get an uplift in SQ with the Intona in front of the Ciunas DAC When the prototype of 3 was auditioned in Tony's Vs the Intona + Regen in series, people preferred the prototype