Krell

So your amp meets factory specs. Quit you whining and enjoy it!

What do you care what color the caps are??

It would matter if the quality of the two different cap had different sounds, matched Cap specs don't always predict matched sound. I read of people using "better" sounding caps to modify their amps while adhering closely to the original specs. I have even heard of Capacitor comparison shootouts.
In this case if you couldn't hear a difference, then the two cap types have comparably close sonics by definition (to your ears anyway). Thus they are nothing to worry about. If you have an open or see through cover then aesthetically it may matter to you, and many of us want gear that looks good and sounds good too.

Sounds like a electrolytic power supply capacitor - sincerely doubt if you have anything to worry about, if installed originally by Krell I'm sure they meet spec. most of these come in standard values and sizes from many different manufactures.

Mechans the capacitor shootouts you are referring too are about capacitors for speaker crossovers and maybe coupling capacitors etc for tube amps and the best of them can be found here.

capacitortest

As always

Good Listening

Peter

As long as the power supply caps meet Krell design specs, you shouldn't have any reason to worry. These are power supply caps, not caps in the audio circuit chain. This is really not a big deal or problem. Power suppy caps can be very expensive, especially if the rail voltages are high. The higher the rail voltage, the more expensive the caps would be. So, they probably saw that one channel was damaged and the power supply caps on that side were questionable. So they replaced the caps on that side. If the other side's caps were okay, then why spend the money to replace them? I would have asked the customer if they wanted me to replace them all, which is probably what Krell's Technician did. The customer may have said no due to the costs. If they are quality caps, you would be hard pressed to hear any difference. Same capacitance rating, same or higher voltage rating and you are good to go. Take a quick look to see how much those suckers costs. Say a 33,000 micro farad cap rated at 100VDC. Go ahead and check.

Enjoy

Opening (just curiosity) recently a fellow's Parasound Halo JC-1s (purchased brand new, factory sealed, from authorised dealer), we both were surprised seeing all four power supply main caps (4x33000 mfarads) altogether different, named Rubicon CE LSQ, instead of original Nichicon Gold Tune…

On another forum we've been told that at a time Parasound factory was short of original caps, so they implemented the closest match.

To be honest, amps work flawlessly more than two years, for now..