@dabassgoesboomboom
In order to utilize my studio monitors, I have to add a USB to EAS3 (also S/PDIF and TosLink) converter. In my case a breeze audio china stuff, quite heavily modified to shut-up. See, my monitors only accept AES3 (or coax S/PDIF) in. This adapter have been modified also in the psu section even though it is a linear psu, manufacturers simply cannot learn to add RC-zobelnets frequently enought to have both decoupling AND resonance levels in control. And, yes, they forgot to connect protective earth on the inside to chassis, not even legal to sell to me in Sweden, without also add marking of double insulation and add adequate of this inside.
So, having said this, I have tried some Roon endpoints before connecting the HQP computer. Allo Sparky + Allo USB signature HAT (double psu’s one for CPU and one for HAT). Was not silent enough, using the Ifi psu’s that Allo suggested. Tried an external linear DC supply, but could not make it play good enough. OK, tried the Raspberry RPi3b+ and a Allo HAT feeding out AES3. Also here the separate psu’s was of the non-ground type, Ifi and linear, which could not reach the silence I am seeking. Found out, the Roon ROCK NUC was better that most endpoints. When the USB to AES3 converter landed, and a couple of days later in the cave accompanied by my hot iron, the adapter made wonders, not to mention when I started to understand what settings to use in HQP.
The thing is, most of my friends says they are completely blown away by the sound, I still cannot rest, because I know there are things still subject for improvements. I know the digital circuitry is suffering from a lot of disturbance, I know there are benefits from galvanically disconnect and by precision clocks reclock frequently due to jitter issues. Further the power circuitry in digital circuits are substandard to analogue, because of balanced power in anlogue and positive relative zero in digital, making the purity so much more challanging in the digital domain. Not only the ripple, but the decoupling of the ripple, relative to ground which must not be contaminated or else the Vref ground will be wobbly giving small signal degradation.
A computer is far from an ideal place for pure music. but I am afraid, the more expensive DAC’s I try, I see that also they are not ideally built, meaning my JBL monitors are far from it. I cannot get hold of the JBL circuitry, when I asked I got the reply, this diagrams are part of JBL intellectual property. I replied and closed the door for ever by answering back, “the property part I understand, but intellectual? really?”
Well, the monitor’s digital input response on providing very best of input is super-clear. My dear friend and movie sound guru, having the very same jbl system for mix and master, say they sound so much better in my residence living room compared to his mix rooms. It also validates there is further to gain, by being very thorough in the digital chain.
So, this is the scope, I must stick to EAS3. I am not impressed by any single board computer solution I have tried as endpoints.They are poorly power suppied and sensitive to rfi entering with e.g. cable shields, because the are not adequately grounded.
Yes, I can hear this. Some have said psykodynamics, and that may have been true if my friend and studio rat 
did not clearly validate my efforts. Further it also means I can very easily distinguish my efforts at work designing HiFi products, the entire system balance is so fine tuned that any change counts, also the subtle differences in the various but very similar filters in HQP.
Since it is my profession also, I find it very rewarding to be able to find these small design changes, products and other refinements that opens yet another dorr to the next layer of tiny notes in the music arrangement. It is ok to call me crazy, I cannot even argue against, but right now, the challange is to see if there are further qualities to salvage from the HQP computer by adding these small (but off course expensive) devices inside. My experience however is that most products are highly over-rated (except perhaps HQP), so how over-rated is SOtM? Does the power filters do a substantial difference or is it like the emperor’s new clothes? Anyone experienced a clearly audible difference with SOtM?
