Ribbon cable inside amplifiers

@donavabdear  not true even my 30 year old krell amp has beryllium copper buss bars for the output stage.

The fact that high quality manufacturers don’t use "audiophile grade" cabling internally is not a definitive answer. I once got involved in a "speaker geek" conversation with the owner of one of the most successful speaker companies in recent decades. After a nice exchange of thoughts on speaker design he said (referring to cabling, connection methods, etc): "I get all of that. I just don’t want to argue with my engineers over it."

There are legit SQ design elements that go into equipment that may align with production efficiencies. Most often, they do not. There are also considerations service. In-field service board swap via detaching ribbon cables beats desoldering or sending a beefy chassis in 2 directions (including the risk of freight damage).

As others have stated, ribbon cables are often used for sending data, control, and lighting up the front panel. Sometimes low current power is sent to energize circuit boards. In the case of a streamer we "hacked" a while back, we eliminated the ribbon cable and direct silver soldered good cabling directly to the circuit board. Not an easy task. It got a little crowed in there. The SQ improvement was significant.

So, it depends on the use of the ribbon. Power delivery matters. Even if current demands are small.

I think A tube preamp does not go through tubes like an amp.  

There are lots of nice tube preamps.  The Pass would be nice.

I am using a passive so the idea is no change to the signal.

@invalid Yes bars for the output stage just like a real power plant. Just before WW2 the big power plant at Hermosa Beach Ca had the main output bars replaced with pure silver bars so if the Japanese did capture California they wouldn't get so much silver, just a note that one of the managers told me while we were filming in the building. 

I'm talking about the wiring inside your amp or control amp or DAC that has a several thousand dollar cable plugged into it from the power conditioner or the wall, In the metal box the power goes to a fuse and a switch which then probably to a transformer but isn't made with nearly the same cable material or scientific geometry as your power cables. Inside the equipment box is very high current sections very close to very low current sections, DACs have RF hell all over the place thus separate sometimes 4x boxes for the equipment. Why don't eqipement companies use even ¼ as expensive of internal cabling as the normal hi end audiophile people do?

@donavabdea you have posed this same question on the why cables matter thread and I think in few other places as well. You’re beating a dead horse. The discussion here is ribbon cables. Those are used for non-audio-essential tasks such as control boards and meters. 
What matters is that good designers use good parts in critical places where they matter the most. They also take great care to voice their components to sound their best. I had Rogue preamps and ST100 tube amp that were wired with Cardas wire. That didn’t make Rogue sound better than Audio Research or Pass. It’s a moot point. You’re stuck on something insignificant and…probably time to move on.