Overall Isolation - network, USB, and power

[jabbr]

Curious if you had a chance to experiment with the ClearFog? I totally missed this item being mentioned, but this would seem to be an awesome product for an NAA!

 

I'm running fiber from switch to media converter then eth to mini. Would be cool to go direct sfp w/o media converter.

 

What are the issues/limitations as of right now (does there have to be a new image created as opposed to using the cubox naa image)

 

Ordered the ClearFog base version and waiting for it to arrive -- need to be sure a version of Linux runs on it that supports NAA/networkaudiod.

 

It is different than the CuBox. Uses a Marvell Armada A388 SoC chip.

[tboooe]

First of all, I want to say a big thank you to @austinpop for allowing me to borrow his TeckNet battery for my tests. Over the last few weeks I have been testing using the Tecknet battery and the 5VDC from my HDPlex 400W ATX lps to power my TPLink MC220L FMC. Here is my audio network:

 

NAS --- Asus Nighthawk R7000 wireless router >>> Dlink DAP 1650 wireless bridge --Blue Jeans CAT6a-- Cisco SG300 router --multimode fiber (x2)-- TPLink MC220L (x2)-- Blue Jean CAT6a (x2)-- HQP PC, NAA PC

 

For this test, I was focused on the FMC wired to my NAA PC via a 1ft Blue Jeans CAT6a cable.

 

Without getting too long winded, I will say the difference between the battery and lps is apparent, even for someone like me who doesnt possess golden ears. Compared to the Tecknet battery, the HDPlex lps sounded more congested and veiled. With the battery power, everything sounded more clear and open. For example, when listening to Stacey Kent using my lps, it sounded like she had a slight cold, her voice sounding a bit more distant as well. With the Tecknet, she sounded vibrant. I want to be careful here and make it clear, the sounded wasnt more bright or edgy under battery power. In fact, I could actually listen to music at higher volumes using the battery. With the lps, my ears felt a bit of discomfort from what felt like a bit of bloom in the midrange pressurizing my ears at certain notes.

 

Based on this test, I am sold on battery power. In the short term I will be getting a battery to power my FMC. In the long term, I am going to look into also powering my NAA with something like the new Vinnie Rossie Pure 4EVR power supply.

 

QUESTION - is the Tecknet the best 5V battery for the FMC?

[scan80269]

First of all, I want to say a big thank you to @austinpop for allowing me to borrow his TeckNet battery for my tests. Over the last few weeks I have been testing using the Tecknet battery and the 5VDC from my HDPlex 400W ATX lps to power my TPLink MC220L FMC. Here is my audio network:

 

NAS --- Asus Nighthawk R7000 wireless router >>> Dlink DAP 1650 wireless bridge --Blue Jeans CAT6a-- Cisco SG300 router --multimode fiber (x2)-- TPLink MC220L (x2)-- Blue Jean CAT6a (x2)-- HQP PC, NAA PC

 

For this test, I was focused on the FMC wired to my NAA PC via a 1ft Blue Jeans CAT6a cable.

 

Without getting too long winded, I will say the difference between the battery and lps is apparent, even for someone like me who doesnt possess golden ears. Compared to the Tecknet battery, the HDPlex lps sounded more congested and veiled. With the battery power, everything sounded more clear and open. For example, when listening to Stacey Kent using my lps, it sounded like she had a slight cold, her voice sounding a bit more distant as well. With the Tecknet, she sounded vibrant. I want to be careful here and make it clear, the sounded wasnt more bright or edgy under battery power. In fact, I could actually listen to music at higher volumes using the battery. With the lps, my ears felt a bit of discomfort from what felt like a bit of bloom in the midrange pressurizing my ears at certain notes.

 

Based on this test, I am sold on battery power. In the short term I will be getting a battery to power my FMC. In the long term, I am going to look into also powering my NAA with something like the new Vinnie Rossie Pure 4EVR power supply.

 

QUESTION - is the Tecknet the best 5V battery for the FMC?

@tboooe, in your audio setup, the music stream gets pulled from NAS over wireless into the HQP PC, then out to NAA PC. Do you have two NICs in the HQP PC? If just one NIC, it seems that NIC has to work with network traffic in both directions concurrently during music streaming. I have a similar setup and I wonder if the SQ is in any way affected by the heavier NIC traffic.

 

I suppose I should do an experiment for the HQP/NAA setup, to compare music being pulled from a NAS vs. from local storage. My NAS serves my Aries streamers and the whole setup predates my interest in HQP/NAA, so I've been struggling a bit on how to best integrate HQP/NAA into the system as another streaming option. In other words, the question is whether it is best to have HQP and NAS as separate boxes or a single box to consolidate networking traffic associated with music streaming.

[tboooe]

@tboooe, in your audio setup, the music stream gets pulled from NAS over wireless into the HQP PC, then out to NAA PC. Do you have two NICs in the HQP PC? If just one NIC, it seems that NIC has to work with network traffic in both directions concurrently during music streaming. I have a similar setup and I wonder if the SQ is in any way affected by the heavier NIC traffic.

 

I suppose I should do an experiment for the HQP/NAA setup, to compare music being pulled from a NAS vs. from local storage. My NAS serves my Aries streamers and the whole setup predates my interest in HQP/NAA, so I've been struggling a bit on how to best integrate HQP/NAA into the system as another streaming option. In other words, the question is whether it is best to have HQP and NAS as separate boxes or a single box to consolidate networking traffic associated with music streaming.

@scan80269, you are correct I have just one NIC in the HQP PC. When I used to use Jplay I used a USB Ethernet adapter to essentially have another NIC. When I switched to HQP and NAA I didnt try to use the USB Ethernet adapter because I have read some people having issues with a direct connection between HQP and NAA. I just dropped the idea though now that you remind me I do want to try this. Ideally I would add a fiber NIC to my HQP PC but those are expensive.

 

Regarding local storage versus NAS I know some people use SSD or even multiple USB sticks. For me, the NAS is required as I have movies and documents on there that I need access to from other PCs. One thing I want to eventually look into is optimizing my NAS for noise, maybe with a better power supply or with some ethernet isolator between it and my wireless router.

[jabbr]

Fiber NICs need not be expensive -- that said our bandwidth usage is so low there is no need for two NICs. Really.

 

 

Sent from my iPhone using Tapatalk

[austinpop]

@scan80269, you are correct I have just one NIC in the HQP PC. When I used to use Jplay I used a USB Ethernet adapter to essentially have another NIC. When I switched to HQP and NAA I didnt try to use the USB Ethernet adapter because I have read some people having issues with a direct connection between HQP and NAA. I just dropped the idea though now that you remind me I do want to try this. Ideally I would add a fiber NIC to my HQP PC but those are expensive.

 

Regarding local storage versus NAS I know some people use SSD or even multiple USB sticks. For me, the NAS is required as I have movies and documents on there that I need access to from other PCs. One thing I want to eventually look into is optimizing my NAS for noise, maybe with a better power supply or with some ethernet isolator between it and my wireless router.

 

The data rate required to be streamed for even the highest resolutions is only 10-20Mbps. That is a very small fraction of the capacity that modern NICs and indeed computers can handle. If anything, one could argue that the high CPU utilization due to HQP's algorithms are more likely to add noise.

 

I would rather advocate placing the HQP box on the other side of the wireless bridge, maybe closer to the NAS. I don't use HQPlayer, but I gather you can control it remotely from a phone or tablet?

 

I recommend that the remaining gear starting with the wireless bridge, the switch, the FMCs, etc should be on ultra cap, battery, or linear PSes, where possible.

[gstew]

Greg,

 

Some of your points may be a bit too conservative, but in general I agree.

 

Again, it is not the digital transmission function that is the issue, but rather it is the good old fashioned analog noise that rides along that impacts SQ.

 

Unlike USB, data reclocking or regeneration is not an issue on Ethernet.

 

Sent from my iPhone using Computer Audiophile

 

Rajiv,

 

First I hope you've been having a very fun and informative weekend. I'm very curious if you'll have anything to report.

 

Second, I'm very curious to hear more on what points of mine might be a bit too conservative. I was basing my analysis on the thought that the ethernet protocol had some similarities to USB and that some of the same thoughts and ideas used to maximize SQ out of USB connections could be applied (with appropriate adaptations) to ethernet:

 

<SNIP>

I know that the Ethernet protocol does not function the same way as USB. There are of course similarities (both are transmitting/receiving an electromagnetic signal, in the case of USB always over a wire, in the case of Ethernet sometimes, both have PHY layers at the receiving end to best extract the data from the received signal, etc). But they do function in VERY different ways… and I am not much more than a slightly-educated layman on both.

 

But re-reading John’s comments, I suspect that approaching it the way he did that resulted in a whole new class of audio products, the USB signal regenerator (starting with the Regen, but moving on from there) MIGHT be the way that would produce the better solutions.

 

Sadly, I’m not sure any of us here are the ones to do that and John is otherwise occupied at the moment. But I suggest keeping John’s USB transmission issues and resolution analysis in the back of our minds (as Barrows appears to have) in looking at this.<SNIP>

 

Then John comes along and posts some very relevant information on how the Ethernet mechanism works at a physical level in this thread:

 

http://www.computeraudiophile.com/f22-networking-networked-audio-and-streaming/ethernet-cables-which-are-most-important-31052/index3.html

 

My read of his comments suggests there might be something to making some parallels between optimization of USB and of Ethernet:

 

<SNIP>

First off, Ethernet PHYs

I have worked in the semiconductor field for 33 years, during that time I have worked on over 50 PHYs for many different standards including many Ethernet PHYs. As a matter of fact there is a good probability that your computer has a PHY I worked on. I know a little bit about the subject.

 

Ethernet PHYs DO draw different amounts of current depending on the signal integrity of the signal being fed into the receiver. There is a LOT of both analog and digital circuitry trying to extract the bits out of that noisy piece of wire. When these circuits are running full bore (to extract bits from very noisy wires) they use a LOT of power. Part of my job has been to design power networks in the chip that can try and deliver clean power to those analog circuits. The advent of battery powered devices has put a premium on low power consumption of every chip in a device, so the PHYs are very carefully designed to use just the bare minimum of circuitry necessary to extract the bits. The result is the power varies radically with the signal integrity of the received signal.

 

When testing these PHYs we actually use a $700 cable to give the PHY the best signal integrity possible in order to find the baseline low power usage. These $700 cables use very expensive materials and extremely high precision geometry to have the least possible degradation on the signal. We then test with all kinds of more "normal" cables and lengths to see what happens in the real world.

 

What happens is that the BER stays almost the same, the chip is doing its job right and adjusting its internal circuitry to handle increasing signal degradation, which causes increased power draw and noise on power supplies and ground planes. At some point the BER skyrockets, it is interesting that what usually causes this is the PLLs that generate the timing for the PHY start outputing too much jitter as the noise on the PS and planes increases. One solution is to include an internal linear regulator on chip for the PLLs, which works, but increases the power dissipation of the chip. The customers don't like this.

 

The result of this modern heavy focus on power consumption HAS produced Ethernet PHYs which produce significantly varying power consumption depending on small changes in signal integrity.

 

On the issue of EMI coming from the cable to other parts of the system.

It is not so much the 125MHz symbol rate, but the PACKET rate that matters. In audio over Ethernet the packet rate frequently winds up right smack dab in the middle of the audio band where the human ear is quite sensitive. It is possible for the 125MHz to wind up getting into analog systems and going through non-linear parts of the circuit which can lead to small amounts of the packet frequency winding up in the audio signal. It probably is pretty low intensity and systems will vary radically on how sensitive they are to this, but I don't think it is wise to completely discount it.

 

On leakage currents and Ethernet cabling, I have no idea what is going on there. I have had no time to do any testing and won't for a long time. My lab is going to be packed up and in storage for many months so I won't be able to do any testing on this subject. I don't know enough about this subject at this time to make any comment on it.

 

On expensive Ethernet cables from audio cable makers, I'm fairly skeptical that they know what they are doing. I DO know what it takes to make a REALLY good cable, and what I have seen from the audio cable companies does not even come close to this. If these cables wind up sounding better I think it is much more likely to be an accident than any form of exceptional cable construction. And BTW making a cable with VERY low signal degradation DOES cost a lot of money, maybe the companies that make these should look into the audiophile market!

<SNIP>

Well I guess that is about it for now.

 

John S.

 

After trying to digest this, I look again at my rules of thumb and don't see anything I'd pull... if anything I'd make a few stronger AND add some.

 

So again, I'm really curious to hear what struck you as too conservative.

 

THANKS!

 

Greg in Mississippi

[austinpop]

Rajiv,

 

First I hope you've been having a very fun and informative weekend. I'm very curious if you'll have anything to report.

 

Second, I'm very curious to hear more on what points of mine might be a bit too conservative. I was basing my analysis on the thought that the ethernet protocol had some similarities to USB and that some of the same thoughts and ideas used to maximize SQ out of USB connections could be applied (with appropriate adaptations) to ethernet

 

<snip>

Hi Greg,

 

Indeed I am! And I will - soon.

 

I went back and reread your guidelines, and I take that back. I believe this was the one that caught my eye:

 

• Having a setup where Ethernet packets not relevant to your music feed reach your endpoint will cause additional electrical noise and reduce sonics. NO HUBS!

 

But I see now you were on a different point. I agree with NO HUBS, although these days, who has hubs anymore! And we've already seen some endpoints can get swamped even by audio packet trains from the server, so isolating them from extraneous traffic is a good thing.

 

However, I've heard others espouse using a completely isolated subnet, which I am still skeptical about. In today's switched world, only traffic related to an endpoint (and of course broadcast and multicast) flows on the link from an endpoint to the switch.

 

Mainly, I believe we all agree strongly on minimizing noise - both generation, and propagation.

[gstew]

Really you aren't doing any different with your Auralic Aries Mini in place of a CAPS. Just a different type of low power computer built towards audio. You can still use the smart phone/tablet to operate the media player on a CAPS.

The real question is how much isolation downstream the streamer/CAPS can negate the effect on USB from streamer/CAPS? Enough to where it doesn't matter? as much?

 

Maybe a Rasberry like gstew is the way to go? or some other itx low power board that could be operated by a galvanically isolated power supply? Many different ways to go at this isolation.

 

ElviaCaprice,

 

I would argue that a purposed designed Ethernet to USB renderer like Austinpop's Aries Mini (or the rest of the Auralic line or the uRendu or the SMS200) SHOULD clearly outperform something like a CAPS which is made with carefully selected, but still general-purpose HW that has no intention or pretensions of being designed for audio playback like this other units. Having no un-needed HW on board, carefully designed power and signal paths, and adding things like the 'improved Regen' incorporated at the output of the uRendu (and I suspect similar care, if not identical circuits were used at the outputs of the other units I listed) will all tip the SQ needle in favor of the purpose-designed/build audio endpoint.

 

AND I don't expect that USB improvements can negate the need for any Ethernet input optimizations. If you read through the posts I referenced in my long note a few pages back and the recent one from John Swenson in my post just above, similar mechanisms are in play, which means (to me at least) that related mitigations are in order (but optimized for Ethernet instead of USB).

 

As far as the R-Pi being the way to go, as a generalized audio endpoint, it is not a good choice IMHO. This is largely because of the Ethernet AND USB processing both being handled by the same chip, so electrical noise produced by one protocol DIRECTLY impacts the quality of the processing of the other. Where the R-Pi works fairly well is when it is used with an I2S-connected DAC, but this limits one to fairly low-end DAC HATS that require a bit of DIY to make into really good-sounding units OR a concerned DIY effort to build a fairly good I2S input DAC (I use them in both ways). AND then only in concert with an I2S reclocker like Ian's FIFO (available via Group Buy on DIYAudio) or the newly released Allo Kali (which I expect is close to the quality of Ian's FIFO if powered well, but I've not compared them yet). This is due to limitations in the on-board clocking and GPIO of the Pi that result in a fairly jittery I2S output which these devices correct.

 

I will say that with good power supplies, a tweaked out low-end DAC HAT or a good high-ish-end one, and with appropriate network tweaks (all linear supplies, an FMC segment, and multiple Baaske filters), I've gotten the R-Pi as a player to sound very good in my systems, besting my also tweaked-out Sony HAP Z1-ES, not a shabby unit even in stock form (though far from SOTA even tweaked-out).

 

And it is worthwhile noting that the uRendu (the purpose-built audio endpoint for which the most details have been published, AFAIK) is not far from a more powerful R-Pi done right as an audio device... with a good USB output. (And I keep poking various manufacturers to do a purpose-built audio R-Pi... one with the exact same active HW complement as the Pi so that it will work with all the existing distros/players AND DAC HAT hardware, but done with audio quality in mind... I suspect that would be another good killer product!).

 

But no, IMHO, a CAPS of any sort nor an R-Pi or any of its relatives such as the BeagleBoneBlack or Cubox will beat a good purpose-built audio endpoint such as the various Aries, uRendu, or SMS200 as a generalized audio-quality USB out device.

 

Greg in Mississippi

[austinpop]

@tboooe and I have been having a PM chat about his findings with the Tecknet battery, which broadened into a discussion about his setup. I had some suggestions for him, so I asked him if I could post them here so that:

1. others might benefit, but more importantly,
   
2. other experts here could keep me honest!
   

He agreed.

 

Current Setup

 

Pardon the atrocious handwriting.

 

 

Thoughts

 

Looking at your current topology, here are some potential gotchas:

1. By connecting your Dlink wireless bridge to the same HDPlex as your FMCs, you're nullifying the isolation provided by the fiber.
   
2. Your HQPlayer PC is a potential noise injector
   
3. There are several potential leakage loops
   

Suggestions

1. Move the HQPlayer server to a remote location, perhaps next to the NAS, and control it remotely
   
2. Take HDPlex along with the server, and perhaps re-purpose it to power both the server and the NAS
   
3. Power the DLink wireless bridge with a cheap LPS (or continue using HDPlex, which is overkill)
   
4. Use short Cat 6a cables
   
5. Replace NAA PC with something like the mRendu or the SoTM SMS-200
   
6. Power the FMC and mR/SMS with an LPS1
   
7. Evaluate the above and compare
   
8. Further isolation mods to consider:
   
   • Intona (or future USB isolation products) from mR to SU-1
     
   • Jensen PI-2xx XLR isolators from DAC to amp (Scan's suggestion)
     
   • Ultracap supply for the wireless bridge - this seems excessively expensive!
     

Respectfully submitted.

[gstew]

I have observed that devices that feature internal switching regulators can have a wide DC input voltage range. When fed a higher DC voltage, the current consumption is lower than when fed a lower DC voltage. <SNIP>

 

I think I know why my MC110CS has a higher minimum DC input voltage than MC100CM, MC200CM & MC210CS. The MC110CS has an extra bridge rectifier (made with 4 discrete 1N4004 diodes) in line with DC input jack. This causes the input DC voltage to be lowered by more than 1V. With this bridge rectifier, it looks like this MC110CS can work with reversed polarity DC or even AC input! I'm not going to try though.

 

These TP-Link FMCs all appear to feature one internal switching regulator, plus one or two LDO linear regulators downstream from the switcher to generate lower voltage rails. The internal switcher explains the DC input voltage latitude.

 

And I think you are right! Thanks for catching that.

 

I'd assumed that most if not all of the various TP-Link FMCs had the same or at least very similar power setups... it looks as though that is a bad assumption on my part. Also notice that the versions of the MC200CM and MC210CS shown have provisions for those diodes, but they aren't populated.

 

Looks like we'll have to open up the units to tell what we can really do with them instead of assuming that anything with that initial switching regulator will take the same wide range of voltage inputs.

 

Greg in Mississipi

[tboooe]

@austinpop thank you for offering to help me. One correction, my wireless bridge is powered by a smps wall wart NOT by my HDplex linear. It's just plugged into the wall. The Cisco SG300 fiber switch is powered by the HDplex.

 

I've thought about moving my HQP PC out side the music room. I plan to do so once I get another lps to power my NAA and downstream FMC.

[austinpop]

@austinpop thank you for offering to help me. One correction, my wireless bridge is powered by a amps wall wart NOT by my HDplex linear. It's just plugged into the wall. The Cisco SG300 fiber switch is powered by the HDplex.

 

Oh OK, yeah I misread your note.

 

By "amps" do you mean SMPS?

 

Doesn't change my recommendation much - put both on LPS. And plug that into the P3. You may find it useful to hang a power distribution strip off of one plug on your P3 to accomodate all these warts, especially if you go with Jameco-like LPS warts. I just repurposed a PS Audio Dectet that my P5 had replaced, but really just a good strip should do.

[austinpop]

I've thought about moving my HQP PC out side the music room. I plan to do so once I get another lps to power my NAA and downstream FMC.

BTW - it's important to note that the LPS-1 (or other ultra-cap PS) suggested for the FMC and NAA is not just to provide a good LPS, but equally importantly provide isolation to break ground leakage loops immediately upstream of the DAC.

 

That's what I've found the LPS-1 does so very well.

[tboooe]

BTW - it's important to note that the LPS-1 (or other ultra-cap PS) suggested for the FMC and NAA is not just to provide a good LPS, but equally importantly provide isolation to break ground leakage loops immediately upstream of the DAC.

 

That's what I've found the LPS-1 does so very well.

I don't suppose the JS-2 provides the same isolation to break ground leakage loops as the LPS1???? I would prefer the JS-2 since it has more flexibility.

[austinpop]

I don't suppose the JS-2 provides the same isolation to break ground leakage loops as the LPS1???? I would prefer the JS-2 since it has more flexibility.

@Superdad can answer this better.

 

The JS-2 is a different design point. It's an outstanding LPS, with 2 separate rails, and can deliver far higher voltages and currents.

 

The unique advantage of the ultra cap PSes like the LPS-1 is their galvanic isolation from the AC supply, but this comes at a cost:

 

1. voltage only up to 7v, and

2. current limited to 1.1A

 

The FMC and mR combo fits within those parameters, which is what makes it so attractive.

 

The Vinnie Rossi PURE 4 EVER ultra cap supplies can go higher I believe.

[gstew]

I have observed that devices that feature internal switching regulators can have a wide DC input voltage range. When fed a higher DC voltage, the current consumption is lower than when fed a lower DC voltage.

 

An interesting question is given a specific device (e.g. microRendu), is the sound better with high V / low I or low V / high I? I can imagine the answer being on a device-by-device basis or perhaps even system-by-system basis, requiring listening to compare.

 

Until recently I also thought that lower input voltage should translate to better sound, but I got hit with a couple of counterexamples:

 

(1) replaced Auralic LPS 16V with Vinnie Rossi MINI LPS 12V for Aries Femto

 

(2) replaced stock Netgear FS105v3 switch powered by Teradak 12V LPS with modified FS105v3 (low-noise linear regulator inside) power by Teradak 5V LPS.

 

In each case there was an audible SQ degradation, and my friend and I went back and forth several times to ensure what we heard was not a fluke.

 

One hypothesis here is that higher input current level (w/ lower input voltage) may translate to more board-level electrical noise. Things may not be quite that simple, however.

 

This is consistent with my observations here, especially the FMCs.

 

I think this is an area worth more investigation.

 

When I started DIY'ing back in the early '80s, one hot tip was to power the then latest-and-greatest LM317/LM337 regulators with a pretty high input voltage as they were supposed to sound better with a lot of drop and running hot. With modern linear regulators and LDO regulators, I think this is less of an issue. BUT in my 'test-bed' setup, I have 2 6.5v DC rails and 2 13v DC rails. Devices I use in that setup (all with linear regulators) that require only 1 or 2 rails and regulate down to 5v generally sound better (and never any worse) with the 13v rail(s) than the 6.5v ones, LDO regulators or not.

 

OTOH, there are the devices like the FMCs with switching regulators. In general, I'd tend to power them with a higher rail to lower the current consumed (and the current pulse produced by the devices). OTOH, my TP-Link MC100CM produces better SQ with a 5v TeckNet battery alone than with either a good DIY 7.5v linear or a Jameco 7.5v linear adapter.

 

Then there were some tests by SCAN80269 comparing various power options on several different pieces of EQ:

 

http://www.computeraudiophile.com/f22-networking-networked-audio-and-streaming/auralic-aries-and-sonore-microrendu-listening-impressions-29351/index5.html#post613478

 

and

 

http://www.computeraudiophile.com/f22-networking-networked-audio-and-streaming/auralic-aries-and-sonore-microrendu-listening-impressions-29351/index5.html#post615876

 

His results suggest that units with switching regulators DO work better in audio with input voltages on the higher side of their allowable ranges.

 

AND I've seen other posts suggesting that similar devices sound better with higher input voltages, but did not spend time to hunt them all down... sorry!

 

I don't yet see a clear path forward here.

 

Then there is this:

 

This is something I noticed too when I first got my PS Audio P3 AC regenerator. I am not an electrical engineer so I am not sure if my experience is analogous to what @scan80269 posted but here goes. My P3 allows me to adjust the output voltage to any of the devices connected to it. A few years ago when I first got the P3 I messed around with the output voltage and found that the closer I was to 120VAC, the music sounded more clear and energetic. I am not saying it was a huge difference but I could definitely hear it. At the end, I settled on 116VAC out.

 

Does my experience make sense for AC versus DC?

 

Makes sense to me!

 

When I got my first P10, it was powering a system with a really tweaked-out cMP/cPlay setup... super-low underclocking/undervolting BIOS settings, a super-tweaked WinXP that with player was <15mB, full linear supplies including ATX-24 (13 linear supplies total!), SSD with minimized music file load, an ultra-modified Juli@ sound card digital section with an attached I2S input DAC card, basically the works for that setup. AND it sounded best with my P10 set to 115vAC.

 

Fast forward several years and I modified the heck out of a Sony HAP Z1-ES that was a definite, but not huge step up. That unit is basically an all-in-one player with a lower-power CPU (same line as used in the uRendu), a DSP for upsampling PCM to DSD (I prefer the unit with playback in native format), and a fairly sophisticated DAC/output stage setup all fed from 8 linear supplies. With it in the system replacing the cMP/cPlay setup, 120vAC sounded best.

 

This is with the same amps.

 

So a number of different data points with some seemingly conflicting results. I don't have an answer here yet, just looking for more data and patterns.

 

Greg in Mississippi

 

P.S. Note that the Sony HAP Z1-ES stock uses 3 switching regulators on the digital side powering the screen/processor/DSP, the harddrive (which I replaced with an SSD), and the cooling fan (which I promptly removed). Replacing these 3 regulators with good (but not great) linear regulators was the single largest improvement of any of the mods I did to that unit (and I did a LOT!). That makes me think our FMCs could be improved with a little DIY tweaking.

[tboooe]

Another question...doesnt each outlet on the PS Audio AC regenerators offer complete isolation from each other? If so, wouldnt that also break any loops? Pls excuse of this is a dumb question, there is a reason why I studied mechanical engineering and not electrical.

[austinpop]

Another question...doesnt each outlet on the PS Audio AC regenerators offer complete isolation from each other? If so, wouldnt that also break any loops? Pls excuse of this is a dumb question, there is a reason why I studied mechanical engineering and not electrical.

 

No it does not. Some filtering, yes, but not isolation.

 

I can't cite a source, but if you look on PS Audio forums, this has been asked and answered by Paul McGowan, founder and CEO.

 

He's an opinionated fellow, and has his own strong views on isolation. Not all here would agree.

 

All I can say is the P3/P5/P10 regenerators are da bomb! Whatever the secret sauce is, I'll take it!

[austinpop]

I can't cite a source, but if you look on PS Audio forums, this has been asked and answered by Paul McGowan, founder and CEO.

 

He's an opinionated fellow, and has his own strong views on isolation. Not all here would agree.

 

All I can say is the P3/P5/P10 regenerators are da bomb! Whatever the secret sauce is, I'll take it!

 

Here is the link about the outlets not being electrically isolated:

P5 Zone and Multiwave advice please | Power products | ForumsPS Audio

 

This is Paul's view about isolation transformers:

In Praise of Isolation Transformers | Power products | ForumsPS Audio

 

The context of the above is specific to power amps, or subs, where the power requirements are too high to be met with a regenerator.

 

Many here, with John Swenson's guidance, have gained a lot using isolation transformers like Topaz etc. So opinions definitely vary! I mention it here for completeness, but please, if you want to discuss, use the existing thread:

http://www.computeraudiophile.com/f27-uptone-audio-sponsored/discussion-ac-mains-isolation-transformers-started-w-posts-moved-linear-power-supply-1-troubleshooting-thread-30378/

[gstew]

Fair to say you're Baasking in the glow of great sound, Greg.

 

LOL!

 

I got 4 thinking I would use 2 in my main system and move 2 downstairs to my smaller system as I set it up to work in networked mode. BUT I still need to listen to the effect of all of them in the main system... I don't want to regret pulling 2 of them.

 

I did confirm that 1 between the downstream FMC and the R-Pi was a positive change. The rest just got slotted in when I received them with no comparisons. I DON"T think they are degrading the sound, but don't know if they are helping either.

 

Thanks for the laff.

 

Greg in Mississippi

[tboooe]

@austinpop curious if you use the Multiwave feature of your P5? I just tried it again with my P3 and the music sounded muffled and completely lifeless. I think the P5 and P10 have different MW settings while the P3 only has 1.

[austinpop]

I have it on my list to try MW.

 

Right now I am using Sine wave.

@gstew had some suggestions - did you see them up-thread?

 

 

Sent from my iPhone using Computer Audiophile

[ElviaCaprice]

ElviaCaprice,

 

I would argue that a purposed designed Ethernet to USB renderer like Austinpop's Aries Mini (or the rest of the Auralic line or the uRendu or the SMS200) SHOULD clearly outperform something like a CAPS which is made with carefully selected, but still general-purpose HW that has no intention or pretensions of being designed for audio playback like this other units. Having no un-needed HW on board, carefully designed power and signal paths, and adding things like the 'improved Regen' incorporated at the output of the uRendu (and I suspect similar care, if not identical circuits were used at the outputs of the other units I listed) will all tip the SQ needle in favor of the purpose-designed/build audio endpoint.

 

AND I don't expect that USB improvements can negate the need for any Ethernet input optimizations. If you read through the posts I referenced in my long note a few pages back and the recent one from John Swenson in my post just above, similar mechanisms are in play, which means (to me at least) that related mitigations are in order (but optimized for Ethernet instead of USB).

 

As far as the R-Pi being the way to go, as a generalized audio endpoint, it is not a good choice IMHO. This is largely because of the Ethernet AND USB processing both being handled by the same chip, so electrical noise produced by one protocol DIRECTLY impacts the quality of the processing of the other. Where the R-Pi works fairly well is when it is used with an I2S-connected DAC, but this limits one to fairly low-end DAC HATS that require a bit of DIY to make into really good-sounding units OR a concerned DIY effort to build a fairly good I2S input DAC (I use them in both ways). AND then only in concert with an I2S reclocker like Ian's FIFO (available via Group Buy on DIYAudio) or the newly released Allo Kali (which I expect is close to the quality of Ian's FIFO if powered well, but I've not compared them yet). This is due to limitations in the on-board clocking and GPIO of the Pi that result in a fairly jittery I2S output which these devices correct.

 

I will say that with good power supplies, a tweaked out low-end DAC HAT or a good high-ish-end one, and with appropriate network tweaks (all linear supplies, an FMC segment, and multiple Baaske filters), I've gotten the R-Pi as a player to sound very good in my systems, besting my also tweaked-out Sony HAP Z1-ES, not a shabby unit even in stock form (though far from SOTA even tweaked-out).

 

And it is worthwhile noting that the uRendu (the purpose-built audio endpoint for which the most details have been published, AFAIK) is not far from a more powerful R-Pi done right as an audio device... with a good USB output. (And I keep poking various manufacturers to do a purpose-built audio R-Pi... one with the exact same active HW complement as the Pi so that it will work with all the existing distros/players AND DAC HAT hardware, but done with audio quality in mind... I suspect that would be another good killer product!).

 

But no, IMHO, a CAPS of any sort nor an R-Pi or any of its relatives such as the BeagleBoneBlack or Cubox will beat a good purpose-built audio endpoint such as the various Aries, uRendu, or SMS200 as a generalized audio-quality USB out device.

 

Greg in Mississippi

 

Thanks Greg, makes sense what you say and for the most part I would agree, but I can't help think that there is not a way to isolate those 0's and 1's from the PC via USB to rid of all electrical issues. If so then it shouldn't matter what one does on the streamer side of the issue. But for now it would appear that the networking Ethernet option has a leg up, with it's own dirty issues. I'll wait and hold down the fort here for a USB only option. Till then, I am placing my future upgrade on an isolation transformer to see what it can bring to the table, especially for the amp side of the equation. Getting that heavy pig here to Costa Rica should be fun. You guys keep firing away on the testing mods.

 

Mark

[gstew]

I have it on my list to try MW.

 

Right now I am using Sine wave.

@gstew had some suggestions - did you see them up-thread?

 

LOL Rajiv, I think I sent those to you in an email and never posted them.

 

In any case, here they are... do get them as 'What I've tried that works'. This is definitely an area where YMMV... for example, for some people Multiwave is the cat's meow. It has always made things sound a bit thick and less tuneful in my setups.

 

My PS Audio P5/P10 setup tweaks... not sure how many of these are not available on the P3:

 

1. Feet. I use Herbies Iso-Cups with his SuperSonic Hardball. I am sure there are much better ones out there, but this is a good high bang-for-buck solution.

 

2. Voltage Selection. 115v worked best when I was running my super-tweaked out motherboard-based cMP/cPlay setup with all linear supplies. 120v works better now for my modified Sony HAP-Z1-ES setup. Go figure....

 

3. Phase Tune. I currently have +2 on mine. I adjust this to get the most even waveform on the 'Difference' display screen, with the least amount of difference from neutral, which seems to work best. I have done it by ear in the past, but realized that I ended up with the same setting as above, so I now stick with the easy-to-do adjust to the waveform.

 

4. High Regulation. The manual says to use the 'Low Distortion' setting for SS gear, I have always found the High Regulation to sound better for my setups.

 

5. SW version. See this thread from a few years back: Variable Multiwave Update For P5/P10 - Interesting Results | Power products | ForumsPS Audio Variable Multiwave Update For P5/P10 - Interesting Results | Power products | ForumsPS Audio . The OP, DarqueKnight, liked V37.. So do I.

 

6. Pre-filtering. The early manual I have suggests using PS's Soloist AC in-wall receptical/filter. I prefer it straight into the wall, but with 2 Hammond choke filters in parallel on the other outlet.

 

7. Aftermarket fuses. I use AMR fuses because they were a high bang-for-buck option, there are better ones, but it does make a difference.

 

No it does not. Some filtering, yes, but not isolation.

 

I can't cite a source, but if you look on PS Audio forums, this has been asked and answered by Paul McGowan, founder and CEO.

 

He's an opinionated fellow, and has his own strong views on isolation. Not all here would agree.

 

All I can say is the P3/P5/P10 regenerators are da bomb! Whatever the secret sauce is, I'll take it!

 

Rajiv, thanks for the great links. AND I totally agree! My first P10 made a very significant difference in my first system, so much that I stretched my budget and got another when I setup my 2nd (main) system. Basically it was the turning point in tuning a pair of DIY amps I was using such that I decided I could live with them... and still have them today!

 

The topic of isolation is a very interesting one... it really means a LOT of things. In the context of an LPS-1, what it means is that the actual circuit producing the output into the powered device IS NOT connected through to the AC line at the time it is powering. They do this with 2 alternating Ultracap banks where one is charged as the other is used... and the one being used is not connected to the charging circuit or anything else BUT the output to the powered device. Vinnie Rossi's supplies do the same.

 

There's a good background note from John on the problems solved by the LPS-1s on the Uptone Audio website:

 

John Swenson's Tech Corner – UpTone Audio

 

In the context of an 'isolation' transformer, the output is 'isolated' from the input in that the input (primary) and output (secondary) windings are not directly electrically connected. Put a DC voltage across the primary windings (small so you won't burn it up) and you won't read anything across the secondary windings. BUT put 60hz AC voltage across the primary and you do get a corresponding voltage on the secondary. AND the ones recommended by John & Alex don't conduct much at higher frequencies, so they act as a filter for a lot of the noise that's on our modern AC lines.

 

Then there are 2 types of isolation inherent in a PS Audio P3/P5/P10. One is that provided by the power transformer. Since the units are basically high-powered amplifiers putting out a clean 60hz AC sine wave, they start with a large (VERY LARGE in the case of a P10) power transformer the is part of the basic power supply. This transformer does exhibit some of the same aspects of isolation as the isolation transformers above, but likely does not do as good of a job of filtering out high frequency noise. Still, it is much better than none.

 

Then there is what one could call isolation in that each piece of equipment plugged into a P3/P5/P10 has a lower negative impact on the voltage seen by all of the other pieces of equipment sharing the unit than if they were plugged into the wall socket together. This is because just as a speaker-driving amplifier is designed to have a low output impedance to provide 'damping factor' or control over the drivers, the P3/P5/P10 outputs also have a low output impedance and within their current limits, will produce MUCH less voltage variation for all of the gear plugged into the outputs. The wall socket has a much higher output impedance, though still sufficiently low that there is not much sag for most of our systems and circumstances.

 

John Swenson made a post a few months back going over many of the different types of what is termed 'isolation' and comparing their pluses and minuses... it's worth search for if you've not seen it.

 

OTOH, I am very curious about the current recommendation from John Swenson/Alex Crespi to use isolation transformers AND closely-coupled AC plugs in coordination with at least one LPS-1. I DO wonder if a hybrid solution, an appropriately-sized isolation transformer ahead of a P3/P5/P10 and for the DIY'er with an expired warranty like myself, modifying the P3/P5/P10 by removing the AC input surge protection devices (whose function is now served by the isolation transformer) PLUS possibly bypassing the filtering on the AC outlets of the P3/P5/P10 (if it is in series with the output) MIGHT be a better solution than either by themselves.

 

Someday when I have another $1000 to spend on isolation transformers!

 

Greg in Mississippi