Forum Comments

PS BYOB Dual voltage vs PS Dual Voltage
In Ciúnas Audio Devices
Admin
Nov 16, 2019
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
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ISO-PS - Battery/Supercapacitor power supply
In ISO-PS
Admin
Apr 25, 2019
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
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World first USB isolated USB-SPDIF
In ISO-SPDIF
Admin
Feb 13, 2019
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.
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World First USB isolated DAC
In ISO-DAC
Admin
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