Power supplies and cables - observations, considerations & commentary

[MikeyFresh]

Just so you know I'm using 9VDC from the JS-2 and the µRendu is barely even warm to the touch.

 

 

I'm finding the same is true using the 9vcd iPower supply, running barely warm to the touch which sort of surprised me, I was expecting it to produce more heat than that.

[MikeyFresh]

Quick update - got a large power bank with 9v output over the weekend and was able to play couple of hours yesterday. The uRendu sounds fantastic over the iFi and only cost a little bit more. Will do more listening today evening but I am leaning towards not buying any more linear power supplies at the moment and continue to use the battery bank, unless someone compares and finds something better :-)

 

I too experimented this weekend using a 9v/2.1 amp battery, initially I thought it sounded worse than the iPower, but after the system had resettled over a period of hours it wasn't necessarily much worse, just different.

 

I thought the iPower clearly had more weight/authority in the bass region, while the battery was in some ways more transparent and "clean/clear" sounding with better stereo image/soundstaging. Oddly, the battery also seemed to impart just a smidge of hardness to the upper midrange/treble, so not completely clean n' clear.

 

I think in the end I might use that same battery to energize the forthcoming UpTone LPS-1 in search of the best of both worlds.

 

I also tried to use an EMO Systems EN-30 Ethernet isolation transformer, however it seemed to be incompatible with the Airport Express I use as a wireless bridge/Ethernet source. All attempts/permutations in connecting the data cables and power sources in various sequences failed with the EN-30 inline (maybe because the AE is not GigE capable?).

[MikeyFresh]

Don't think I hear the same in my system.

 

 

 

And what do you gain by energizing the LPS with the battery pack ?

 

Subtract one SMPS (either iPower or MeanWell) dirtying the AC mains, and lessen the potential for ground loops.

[MikeyFresh]

While I want a nice LPS like everyone else, I'm wondering if plugging the iFi iPower into a filter like the AC-7A would eliminate/mitigate the kick-back-into-the-AC/system noise issue?

 

This filter was recommended by Jim Smith, author of Good Sound:

AC-7A - AC line filter with 1 ft cord with 120 V AC NEMA standard plug and receptacle for Wall-Warts or other AC mains devices.

 

So in theory to stop the contaminating "backwash" noise you'd plug the iPower into this and plug this into AC.

 

Is this conceptually accurate/effective? Would it in theory help sound quality?

 

 

In my particular system, powering the mRendu with an iFi iPower, the AC-7A made a very positive improvement to the sound when added to filter any SMPS backwash into the AC mains.

[MikeyFresh]

If I use 6 Panasonic Eneloop Pro Ni-MH AA batteries wired in series for approximately 7.2 volt output, what kind of run time would I expect from the microRendu given this battery's 2550 mAh rating with 2450 mAh as the stated minimum?

 

I said approximately 7.2v output because these batteries are rated at 1.2v each, but when I put my voltmeter on the 6 pack it measures 8.48v, any ideas as to why?

[MikeyFresh]

The microRendu by itself (DAC does not draw power from the bus) uses about 200mA at 7V. That comes out to 12.5 hours at the rated capacity. The current draw will increase slightly as the voltage goes down. A safe conservative number is probably 10H.

 

If the DAC is pulling current from the bus, those numbers will go down.

 

John S.

 

Thank you very much John, I had forgotten to take into consideration the DAC's draw, spec'd at "<300mA".

 

So thats why last night I ran out of juice somewhere between the 5 and 6 hour mark.

 

When the UpTone LPS-1 becomes available, I could put 8 of these same batteries in series for about 11.2 volts (I tested them fully charged they are actually about 1.4v each not the 1.2v in their spec) and 19,600mAh.

 

But some of that added capacity would be offset by the LPS-1 having a 1.5 amp draw as opposed to 1 amp (+ the 300mA DAC draw) right now directly connected to the mRendu?

 

I am still a bit stumped as to why the battery quit when it did last night, the pack still measured 6.5v after I disconnected it, and each of the 6 cells were between 1.04 and 1.12v. At that voltage I guess the pack couldn't provide the needed current anymore?

[MikeyFresh]

... so the ability to have more come through better defined at a lesser volume without being overly "hifi"...

 

Everything seems to be in the right place. GUI is super easy and everything worked. Tried so far with Kazoo, Kinsky, and Lumin. Prefer simplicity of Kazoo layout and speed of Lumin. Any other open home control software I should consider?

 

 

Thats a very important point and a quality that is elusive in all but the best hifi products (but not necessarily only the most expensive ones).

 

I have the same experience with hearing more detail at a comparably lower volume setting. There probably isn't a better compliment to be paid.

 

Do you have an Android device to use as a control point? If so the BubbleUPnP app is quite good as a controller, and I believe it is OH compliant.

[MikeyFresh]

Seems quite similar to the company making mine:

https://www.xtpower.de/MP-32000-Ultra-High-Capacity-Power-Bank-with-32000mAh-Multi-Voltage-Charger-5-20V-60W

I have seen at least 3 different variations of the same unit.

Good to hear that you are happy with it

 

What kind of runtime are you guys getting with that battery?

[MikeyFresh]

I get >24h with mine when powering the uRendu alone.

 

 

Can you shut down that battery using it's on/off switch, or must you physically disconnect it from the load for it to turn off?

 

I ask because I have an older Anker Astro with a 9/12vdc output that refuses to shut down unless physically disconnected from the load, despite the manufacturer assuring me it will turn off using the switch. I find that annoying, I would prefer not to have to unplug the umbilical cable when I want to shut it down, but there is no way to do that.

[MikeyFresh]

I get >24h with mine when powering the uRendu alone.

 

 

Thanks guys, I might pick up that same battery to energize the forthcoming UpTone LPS-1, pretty impressive run time... especially compared to my DIY battery:

 

 

I cobbled together 6 Panasonic Eneloop Pro AA Ni-MH batteries in series after reading the Regen battery thread suggested by Jesus R.

 

The sound is absolutely outstanding and a clear leap up from the iPower I had been using, just a different league in terms of transparency and especially stereo soundstage size/depth.

 

However my $35 solution only has a 6 hour runtime. I had initially expected more but my calculations were off, JS set me straight there, I had neglected to take into account the 300mA drawn by my DAC.

 

But if nothing else this further opens my eyes as to how well the microRendu scales up with a power supply upgrade.

 

Bring on that UpTone LPS-1!

[MikeyFresh]

I built a couple of capacitor buffered Li-on battery packs early on to use with the Regen. Tried one with the mRendu and found it "soft" sounding compared with iFi and LPSUs. "Undynamic" may be a synonym.

 

 

My Anker Astro Li-ion battery also seems a bit soft dynamically, not a giant difference, but discernible nonetheless.

 

I don't hear that same thing from my newer DIY Ni-MH battery pack, probably because it is just the bare minimum batteries wired in series with no regulator board, no controller board, no display... so nothing there that can potentially cause parasitic loss.

 

Or, perhaps there is something inherently different about the way the chemistry in the Ni-MH batteries delivers the power as compared to Li-ion, or at least as compared to the one suitable Li-ion battery I have for direct comparison in powering the mRendu.

 

The Eneloop Pro Ni-MH batteries do claim ultra low internal resistance, so perhaps that also has something to do with the results I'm getting.

[MikeyFresh]

What Astro model do you have? Is it just a 5V out? If so I do not recommend using 5V with the microRendu. There are 5V regulators inside which will go out of regulation when fed by 5V.

 

Also all the ones I could find have not terribly good switching regulators feeding the output, these will NOT be good for feeding the microRendu. Their outputs are VERY different than having the battery directly connected to the output.

 

John S.

 

I have an Astro3 10,000 mAh unit bought way back in July 2012, it does have a DC output switchable between 9 and 12 volts.

 

Anker no longer sells that version, although the identical battery is still sold to this day under the XTPower brand on Amazon.

 

I originally bought the Astro3 to power a DSPeaker room correction unit at 12 volts until such time as I got a 12 volt LPS to replace it.

 

Since then it hasn't really been used for hifi purposes. Now I just use it to recharge my phone and iPad on the road, although I did try it at 9 volts with the microRendu and didn't love the sound. That prompted my purchase of the Eneloop Ni-MH pack which is really much better sounding, likely as you said due to the Astro3 having a very cheap lousy regulator, as well as high internal resistance.

 

These cheap Chinese made Li-ion batteries definitely scare me, I worry about my house burning down!

[MikeyFresh]

 

Also all the ones I could find have not terribly good switching regulators feeding the output, these will NOT be good for feeding the microRendu. Their outputs are VERY different than having the battery directly connected to the output.

 

John S.

 

The folks at DSPeaker said more or less the same thing, essentially the cheap noisy regulator found in the typical non-audio purposed battery is no better (and sometimes worse) than the SMPS they shipped their dual core room correction unit with in 2012.

 

It was their opinion that any improvement in sound quality when using their unit with such a battery was far and away more caused by a reduction in ground loop currents than anything else.

 

That said, they changed to shipping that room correction unit with a DC supply the very next year, ditching the previously included SMPS.