I found one here:
Runway audio....
Kellerblues the One Spot may be shy of the 24 watts the KPP is rated for (at the Truetone’s 9v that’s a bit under 2700mA).
Some have reported that KPP’s work with less than 24 watts, and others have said they endlessly power cycle when under powered.
The Truetone seems to be suited for most standard guitar pedals that aren’t power hungry like our KPP’s or a Quad Cortex (will I be hit by Internet lightning for saying that product name here?
).
The 1-Spot works perfectly with the Kemper Player. I've been using them for several months now with no issues.
TrueTone has only 1.700mA, Roland only 2.000mA, recommended are 2.500mA
Both don't have ground.
Try the player with headphones only, it's a mess how it crackles and hisses without ground
The strange thing is that my powersupllies for labtop/usb audio interface/kemper player all have no ground and all is fine. By exchanging all powersupplies for groundless power supplies removed all my hiss issues. Even a groundloop breaker is being used for my USB connection from kemper player to Labtop.
So if i had to recommend anything it would be to take away all grounds.
The most troublesome powersupply in my chain was that of my original Lennovo labtop with ground connection. I bought an Asus (groundless) one and things improved enormous say all hiss went down to 0. After that i wanted to synchronize my tempo based kemper stomp boxes (delays etc) with my DAW and had to connect the USB cable to my labtop and again i had hiss. By inserting a USB groundloop breaker things solved the Hiss again, and have 0 hiss from this point. Really happy with my groundless setup now.
Ground loop (electricity) - Wikipedia
Taken from the wikipedia:
The solution to ground loop noise is to break the ground loop, or otherwise prevent the current from flowing. Several approaches are available.
And the use of balanced cables where ever you can to reduce the noise even more.
Display MoreThe strange thing is that my powersupllies for labtop/usb audio interface/kemper player all have no ground and all is fine. By exchanging all powersupplies for groundless power supplies removed all my hiss issues. Even a groundloop breaker is being used for my USB connection from kemper player to Labtop.
So if i had to recommend anything it would be to take away all grounds.
The most troublesome powersupply in my chain was that of my original Lennovo labtop with ground connection. I bought an Asus (groundless) one and things improved enormous say all hiss went down to 0. After that i wanted to synchronize my tempo based kemper stomp boxes (delays etc) with my DAW and had to connect the USB cable to my labtop and again i had hiss. By inserting a USB groundloop breaker things solved the Hiss again, and have 0 hiss from this point. Really happy with my groundless setup now.
https://en.wikipedia.org/wiki/Ground_loop_(electricity)
Taken from the wikipedia:
The solution to ground loop noise is to break the ground loop, or otherwise prevent the current from flowing. Several approaches are available.
And the use of balanced cables where ever you can to reduce the noise even more.
If you only use the Kemper with headphones, on any power socket (not a multiple socket), then you'll have a big problem with the hum. How are you going to interrupt a ground loop? The solution is a power supply with ground, and the fact that Kemper saves a few euros here is a joke and undermines the otherwise fussy, professional impression of the Kemper brand in terms of sound quality - in my opinion.
This one is available in Germany and has the negative pole inside. Unfortunately it's not cheap. But it works perfectly. You get what you pay for 
