Pre-amps with seperate power supplies .....

I have a pre-amp with a seperate power supply that is connected by an umbilical cord. I am not an electrical engineer and I do not pretend to be one nor do I play one on TV.....I am pretty sure that there is DC current going from the power supply to the main pre-amp to power that component. Does it make any sonic sense to upgrade that umbilical cord seeing how that it is ''only'' carrying DC current ????? The pre-amp in question is a Classe' CP-700. I have asked this very same question to the fine people at Classe' and they said improving that cord would not make any difference.... So, I will ask that question here and also see if anybody has actually upgraded that power cord.
I bought my Cardas power cords at CES in 1990, about 5 years after we switched to IEC connections. By that time Cardas was already doing quite well for himself :)

I do remember thinking that I didn't want to deal with how people would cut up the wiring in our amps which I was hoping to eliminate by using IECs.

In 1990 we built the first MA-2s. That amp had (and still has) two IECs *per chassis*, and also different (larger) fuseholders, as we wanted to reduce the effects of the AC cable on the sound of the amp, and having two AC circuits was an easy way to do it.

That was also done to reduce the effect of the internal AC wiring; the special fuses were used because they sounded better- a good 18 years or so before upscale/aftermarket fuses became popular in the high end market. All I am saying here is that by 1990 we were very well aware of the effects of AC line and power cable issues- and had been aware of them for some years prior. So I am still thinking that '1985' is about right.
All parts make have a sonic impact (caps, wire, resistors, transformers, even chassis, etc.). Some more than others. Silver and copper wire will sound different. How much of an improvement can only determined when you swap them out. There are better ways to filter AC than most conventional manufacturers use that probably would improve the sound much more that the cable.

Happy Listening.
Atmasphere, Cardas may have been doing quite well in 1990, however, it was not with power cords. It was with speaker cables and interconnects. Power cords, to my recollection, did not even start to become popular until the late 1990s. The reason manufacturers were installing IEC sockets in the mid 1980s had more to do with shipping their products to other countries with different types of wall outlets. Even Tandberg had their own 2 prong socket for the purpose of being compatible in any country.

I'm not trying to beat this to death. I'm just trying to remember how it all happened.
To the OP. I previously owned a Classe CP60 and replaced the stock umbilical with one made be Revelation Audio Labs. It cost about $100 or so and made a very nice improvement in the sound. YMMV
Rrog, I appreciate that- but the reason we went to IECs in the mid-80s was because we already knew at that time that the power cords made a difference. At that time we didn't know if anyone overseas would even want our amps... It does seem to me though that when we bought our power cords from Cardas that they were a fairly new product.