@cudfoo - the conversation w/ Jeff is about weather I’d use the AQVOX USB LPS versus external PS, not weather their manual (external PS) is correct. Manual is fine and you can use the voltage they tell you. Jeff mentioned someone did a measurement of external to AQVOX powered and the external was noisier. I am merely postulating why the external could be more noisy. However, I don’t have schematics, just screen shots of the PWB and their website info… all of this conversation is VM at this point…
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This also seems funny to me :^ /
Then LDO route it is. I definitively would like to avoid the DC/DC switched convertion inside the Matrix.
That would explain why I prefer this method
@jaime - yes, I can see why. There are many approaches to the Matrix and this seems to be yet another. Jeff’s approach is yet another. I love AQVOX equipment, I have their AQVOX-SE and love it. In addition, I’m getting tired of not seeing double DSD so I’ve recently given some thought to skipping the PSA Bridge. The DSD I2S is the preferred SQ input; therefore, I might just give it a shot. All of my ramblings at this point are VM and just postulating on what I see in the Matrix website for PS and what @JeffofArabica said about the external being noisier. I like Sbooster LPS; however, they do not have a “data only” mechanization for the USB supply… This seems like a lot of fun so I got to thinking. The down side is that I just got (2) T5 (2TB each) SSDs w/ AQVOX 40cm cables that I had hooked to my Nucleus+. I just reconfigured them to hang off my wireless router and they seem to work… I don’t know, all these changes and I love my set up and it sounds better than my DMP… IDK… 
I think some of the confusion stemmed from a statement made by Arthur who is the US distributor of Matrix products. He stated that anything going into the external power port on the Matrix gets stepped down internally to 5V. It was Arthur who suggested running 5V as anything above gets stepped down anyway. Yes, it does draw slightly more current but he was not concerned about that as it is such a low current draw anyway. So @Cardri was correct in what he stated about the 5V. Not from the manual perspective, but from Arthur, the main distributor for Matrix.
So here we have the only distributor of Matrix products whom most of you have purchased from saying one thing, and the manual saying the other. Who is right? Who is wrong? Could it be both are right? Who knows. If it was me, I would run 5V in. But I am going the AQVOX LPS route so this doesn’t apply to me. All I know is there is a documented case that the external power chain on the matrix creates measurable noise above and beyond USB cable supplied power. That compels me to avoid that external power port at all costs unless there was a counter test done to prove that it was a fluke and not an inherent design flaw. We can guess, but I would rather mitigate the risk and stick with the USB power via the AQVOX and data only cable and use the power chain this Matrix was primarily designed around - the USB pathway, not the external port.
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Got ya - can’t hurt to check out the lower voltage to see how it sounds. Sonically the Matrix is dramatically better with the Upton LPS. If there’s also some measurable noise (I don’t hear it) don’t think it’s anything to be concerned about. I don’t think anyone that is using the Matrix with the LPS 1.2 has mentioned anything about it.
I don’t doubt that what you have communicated is true within your specific system. Worth noting, your (and all ofours as well) setup has attributes that most - if not all - other users here on this forum do not share.
That being said, not all USB power fed from the USB outputs of our source into the Matrix is created equally. Some audio equipment manufacturers pay far greater attention to the quality of power within their boxes and dedicate far more resources to ensure that noise and other pollutants are mitigated. For example, my music server uses two discrete SBooster external linear power supplies. One LPS is dedicated to the main server board and the second LPS is dedicated to nothing but the USB output card. Not many music server/streaming appliances assign such a high quality LPS to JUST the USB card. The model above mine, as well as Pink Faun uses no less than three discrete power supplies for each server! So, my Matrix is being fed some excellent power via USB.
If the power supplied by the music source to the Matrix via USB is really poor, an external LPS on the Matrix may in fact be an improvement, but this is entirely dependent on the quality of the source USB power and the specific LPS make/model. But is also does not mean it is void of noise that would not be audible based on how resolving one’s system is and their ability to detect such subtle anomalies. I feel that most on this forum have invested enough into their systems, especially if they own a DS DAC that they want to eliminate noise - just out of best practice - if it is a variable they can control. Noise is never a positive attribute. If a system is resolving enough, my guess is that even subtle noise will erode SQ to a degree, but it is all relative.
I think it is too early to say one way or the other whether a modified approach to USB power or an external LPS is the best solution for the Matrix. There is enough information to raise a doubt in my mind with regard to how the external power is implemented within the Matrix.
The good new is, I am setting up a test scenario that will pit what I consider the very best solution for USB delivered power against what I believe to be one of the best LPS power supplies on the market, the SBooster.
Let the games begin…
You guys made me nervous. When I hooked up my LPS1.2 I set it to 9V. All my gear is currently powered down so when I do power back up I’ll back it down to 7V.
(Unless someone says 5V makes an audible difference)
(9V sounded really good BTW)
I agree - the context for any of our observations is our listening environment. I wasn’t aware that there would be any significant difference between the 5V USB supply provided by the source and didn’t think the power supply the source was using would have all that much influence on the USB power it could provide. For me and my system the Uptone LPS is significantly better sounding then the USB power provided by my Aurender server. I suppose it’s possible but I really don’t think it has anything to do with my system not being able to resolve the noise.
Don’t get nervous the Matrix is rated for 6-9v so if you’re using an external PS which ever setting sounds best to you is the right setting. Try 5V -9V and let us know which you prefer.
Hi Cudfoo, when you were using the 5v from the Aurender, was it on the same USB port/cable as the data was been transmitted or was it on a dedicated 5v USB power port with a double ended cable?
I’m thinking of using the 5v USB power output on my Melco N1ZH via a double ended cable and I don’t want to go down that route if someone’s tried something similar and has found the LPS to be better. Alan Ainslie from Melco confirmed the 5V USB output on the Melco is very clean as it uses the same supply used for all other USB level processing in the Melco, so I’m hoping it could be a good solution.
Thanks, Mike.
There must be a good reason why the specs say the input power source should be 6v-9v rather than 5v-9V when the USB supplies 5v. Is it possible that the higher voltage of 6v is enough to switch the unit to use the 6v supply, whereas 5v might not be different enough to force the switch over to the power port? It would be hard to know which 5v supply is being used.
My view is if it says 6v min then that it what it needs to be
It’s been interesting reading everyone’s thoughts on the external power issue. I tried the iFi 9v power supply and definitely prefer not using it and going without external power. Not that the iFi was bad, its just that the music is a bit more palpable with better overall soundstage and presentation without it. The USB cable I am using does have a separate 5v power lead along with the data lead. I’m tempted to try the Uptone 1.2 but can’t really justify spending that money at this time.
I am back home now and I switched the LPS1.2 to 7 volts, down from 9. All the magic is gone.
(Kidding) I dont think there is a difference.
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I know @bootzilla was considering dropping his down as well.
Boot, did you ever get around to trying 5V?
I don’t think it’s that complicated. If you plug a DC barrel connector in with no power, it cuts the usb power. At least, that’s how mine behaved when I tried
Edit: this is wrong, see below
Hi - I’m using a curious usb cable. Curious uses a separate power line outside the their usb cable – so in that way I suppose it’s separate. Sounded good in this configuration. Adding the LPS 1.2 (7v) improved things considerably.
Hi Jeff, not yet. Will let you know if/when I do.
I don’t think it works like that, at least mine doesn’t - I’m using a battery power supply and when I disconnect the battery but leave the connector in the Matrix, it continues to work off the USB power.
Regards, Mike.