Ribbon cable inside amplifiers

Those ribbon cables are most likely used for the front panel meter, That meter measures current at the output stage so it appears each wire in the ribbon picks up the voltage from a transistor (probably across the emitter resistor) to do the conversion. Since there are a lot of transistors, it is much neater (and cheaper) to run circuit traces to the transistors and then gather them at a connector for a ribbon cable. Or else there would be a bird's nest of conventional wires if they were soldered point to point..

I’ve never had anything negative to say about Nelson Pass, the quality of his equipment construction or his business practices. I appreciate how open Nelson has been about his thoughts in amplifier design, and amplifier / speaker integration via seminars and published writing and his willingness to share with the DIY community via FirstWatt.

He makes a number of aesthetic choices when it comes to the sound of his preamp and amps which simultaneously have gotten his gear a large following and which does not work for me. It isn’t tribal.

Emailed Nelson and we talked about ribbon cabling, very nice of him to get right back to me…all is good..the reason I was concerned is I have a Pass XA-25 coming today and the ribbon cabling jumped out at me when I looked under the hood…My Primaluna amp died and didn’t have a spare amp..didn’t know I was trolling…

‘thanks for the help

Look at the binding posts on a Pass.  That will tell you how they are built.  All pass amps are overbuilt.  Mine is rated at 25W Class A, and the output transistors are rated for 500 watts(approx).  Couple that with heavy construction and heat sinks.  Pass is not the only company that does this.  I have ribbon speakers and they sound pretty good by the way.

Ok. Not trolling. Nervous. I get it.
How does the XA25 sound?