TL;DR - the iFi iPower 9v power supply does not work with my SMSL M8 DAC.
 
After extensive testing which I concluded the other day, and which involved purchasing an Enercell Adaptaplug (size 'O'), a female DC socket, and 9v battery plus connectors, all from Radio Shack, these were my results:
 
9v battery with Adaptaplug powered up the M8 until it ran low on voltage.
Original M8 power supply connected via the new DC socket and Adaptaplug worked fine.
The iFi power supply was never able to power the M8 using the original tip nor with my ad hoc solution with the new socket and Adaptaplug. I double checked that the voltage at the Adaptaplug was correct polarity and measured 9.4v.
 
All I can conclude is that the M8 DAC (or at least the one I own) does not like the iFi's extra voltage, which measured 9.4v vs the original power supply's 8.7v.
The iFi was able to power an LED light array I own that also takes a 9v power supply, but probably a lower current to run it and recharge the batteries.
It was recommended by iFi support (who were very helpful and responsive to my support ticket), that I contact Music Direct for a refund, which will be my next step.

I just bought the iPower to eliminate a slight mains hum in the audio signal of my video cam when it was plugged it into its proprietary adaptor. It has made absolutely no difference.

Any luck at all powering the M8 with iFi iPower ? (Or did you end up returning it?)

I am seeing the same symptoms

Thanks

I ended up returning it to Music Direct for a refund. Still waiting but it's only been a week.
To their credit, iFi said they would send me a complimentary "cherry picked" unit for my troubles i.e. it won't affect my refund from Music Direct. I haven't  received it yet and frankly I doubt if it will work where the other two did not, but at least they care about the customer.
The only other test I could see worth trying is putting a resistor in series with the output to drop the voltage to the same as the SMSL power adapter, just to see if the higher voltage was the issue, but I spent enough time with other workarounds that I finally gave up.

Thanks for reply, an odd incompatibility for sure. Guess I'll abandon this tweak as well.

Good to hear that iFi are being good sports about it. If the 'cherry picked' version magically helps appreciate if you could drop a quick update.

Will do...

Is the 5v power supply available now? or just the 9v?

eh-yeon said:

  Is the 5v power supply available now? or just the 9v?

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I've been waiting, as well. All I can see at Music Direct is the 9v version. iFi Audio, where's the 5v version?

krutsch said:

 
I've been waiting, as well. All I can see at Music Direct is the 9v version. iFi Audio, where's the 5v version?

Click to expand...

I just got a reply to my enquiry, the 5v will hit the store the first week of October. A little slow of update due to the over demand of 9v version. 

eh-yeon said:

  I just got a reply to my enquiry, the 5v will hit the store the first week of October. A little slow of update due to the over demand of 9v version. 

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Great news! Thanks for sharing.

I got my replacement 9v iPower direct from the manufacturer yesterday and it works with the SMSL M8! I don't know what's different as I haven't checked the voltage yet, but I'm glad the problem is fixed.
I also got my refund from Music Direct about a week after I sent the second faulty one back. All in all I came out even due to postage and purchase of Radio Shack products to try and fix the previous units.

Thanks for update, that is good news.
 
It would be good to know if voltage is different, or if it is some other change. Does it have a serial number / updated model number ?
 
And of course  the obvious question; Did it improve sound ?
 
Stu

Sounds like nobody's getting results :/

Model # is LN-9030. I have not tested the voltage yet. Preliminary listening test on a DSD file (David Elias - Morning Light Western Town, downloaded from a website that provides free samples), mostly acoustic, showed no discernible difference. Maybe because of the time taken to swap the power cables and audio memory is very short, but certainly no noticeable improvement. I'll have to take more time with other types of music, but if it was like night and day I would have heard it. Neither power supply had any noise during silent passages. I remember the standard one got warm after extended use, but the iFi stays cool to the touch.
At this point I am just happy it works after all the hassle I went through with the previous units.
If I do find anything useful later I will post here.
One thing I prefer about the original power adapter is that it plugs into the mains via its own separate power cable whereas the iFi is a large wall wart.
 
p.s. Testing was done using Foobar2000 on my mini-itx 1150 based PC, standard USB port and cable into the M8 USB port, connected to a Nakamichi SR4-A receiver and from its 1/4" headphone output to Sennheiser HD-600 (upgraded with HD-650 cables).
 
p.p.s. If I do more extensive testing I will use my gaming PC, as that has a motherboard (GA-Z97X-Gaming G1) with dedicated DAC USB ports on which you can switch off the power and just let them supply the data signal over the USB interface for self-powered DACs.

An update on my problem from post #38

I contacted iFi support about the issue on a couple days after that post. I'm happy to report that I (finally) received a 'cherry picked' iPower a few days ago to replace the noisy iPower. The new iPower came with an adapter that can switch the plug polarity.

The new iPower is much quieter than the noisy iPower. I could hear the bad one from at least 5 feet away, the new one I can only hear from less than 1 foot away. That's still not as quiet as the original ULNA that came with the iUSB which I could only hear if I put my ear on it.

I hear some overall subtle improvements in music with the iPower powering my iUSB (versus the original ULNA).