No one actually knows how to lculate what speaker cable they need

b4icu,
thank you so much Michael. If the 4 or 6 awg can be somehow attached to this coaxial connection of the amp, it will be wonderful. 

Dear b4icu,

I purchased 25 feet of 0 AWG form a supplier on eBay for $45 ($12 shipping) and four brass (supposedly gold plated) battery connectors ($7.49).

I constructed four five foot cables in just over one hour.  Battery connectors were converted to spades with a cold chisel and wire cutters, cable was cut with a hacksaw and insulation stripped with the hacksaw.  Spades were connected to Pass Labs 250.5 terminals (PL does not supply banana plug receptacles).  I attached banana plugs to a two inch piece of silver plated 8 AWG wire.  I hollowed out a holle in 0 AWG wire with a punch and did not remove insulation.  I then inserted the stripped 8 AWG wire in hole and secured the assembly with a hose clamp around the insulation at the cable’s end.

The cables were attached to my thirty year old modified MG IIIa’s.  The results are stunning.  The amount of undistorted energy filling the room, is jaw dropping.  I keep turning up the volume to levels that previously irritated my ears, and experience no irritation.  In the modified lyrics of B.B. King, “The shrill is gone.”  My wife is hearing new detail in cuts she has listened to many times before.

In my case, b4icu, you were absolutely correct, thank you (except for the part of you doubting ribbon speakers would be improved with installation of your design).  I can’t wait to try the cables in one of my other systems that employs cone speakers.

I am am sure every case is different.  Nevertheless, I encourage other hobbiest to test your theories.

Thank you for your generosity and patience.

All good wishes

Mr. keppertup

Thanks you. Thanks you again.

Could you please help me out with some supporting information? I posted just above this:

When the time will come, to share your impression here, please do it in some ordinary way:

> Specify your Amp and speakers: Pass Lab 250.5 with Magnepan III's.

> Specify the previous cable that was replaced: just gauge and length. (?)

Please avoid brand and model. Thanks.

You may add how much that cable cost… (?)

> Specify your new cable: gauge and length. If other than was: 0 AWG, 5 feet long

recommended, please notice what was recommended too. (if different from  0 AWG, 5 feet long)

Would you please be kind to do that for me? Thanks.

I’m really happy that it worked for you. I didn’t say it won’t work for none coil loaded speakers, I just claimed it is different. On the theory and the drowing board, it is.
Some pictures of your cables would be more than welcome. Thanks.

For the record:
> The same results would apply if you turn the cables direction! :-)
> The same results would apply if you say they were cryogenic treated! :-)
> If you make another set, at the time this set "goes through" a so called burn in, and then after some time you will connect the new cable, it will sound exactly the same. No "burn-in" excuse is required when the results are: 

jaw dropping. 

It sounds good from the first moment. Trust me on that.

Wish you lots of hours playing your music and discover tones of new sound bit’s you never know it’s there.

As I said, you were listening to only some of your system potential before. Now you are listening to ALL of it.

It is not only your ears that approve it, but some engineering calculations, I stand behind it. Something that never been done before with most systems. Welcome to the club. Thanks you again.

For all other, who are yet in the process getting there, it might be a nice clue of what is comming at you, when you are ready. God bless you.

"I’ll do say, that there is a no much sense in matching a Thiel CS2.4 to a Manley NEO 250!  
https://www.stereophile.com/content/thiel-cs24-loudspeaker-measurements
https://www.manley.com/hifi/n250/
That is a 4 ohms speaker and goes down to 2.73 ohms at 600Hz ! with 88dB/w/m SPL. one of the most difficult to drive.
I hope you enjoy the Manley NEO 250 1.5% THD and its 14.8 DF vs. 2.73 ohms...
In your case the cables are the last to worry about."

This simply proves my point. You know NOTHING about anything with regard to HiFi. But keep on plugging your 0 AWG battery cables, which also proves my point.

Don't worry Mr. stevecham. It's all good.

There is a say in Russia, that the local made shoes are very good.
Until you buy an imported brand...(I'm not from Russia!)