Using step up / down transformers?

@sns, 
I agree any transformers on the main AC power lines feeding your audio equipment will degrade sound quality. That is the reason why I run all my audio gear on 240 volts. I have 4 dedicated audio circuits in my audio room. Two of those circuits are dual voltage plugs meaning the top of the plug is 120 volts and the bottom is 240 volts. The plug is a Leviton 5842-I. The other 2 circuits are a Leviton 5822-W plug. All 4 circuits are 20 amps. Removing the 240 volt step down transformer from the main AC power line and running everything on 240 volts direct was the biggest improvement in my audio system. Improvements heard in the system are the following; better low level detail, dynamics, transient response, lower noise floor, micro dynamics, and the hiss from the speakers was eradicated. Also, I plug all my audio equipment directly into the plug. Switching from 240 volts to 120 volts in my system is now as easy as changing a power cord. Every time I switch my gear from 120 volts to 240 volts the latter is best sound quality. And that is my story.

BTW, 240 volts, is more efficient then 120 volts, 240 volts, is half the amps as 120 volts, 240 volts is quasi balanced power.

https://www.amazon.com/NEMA-6-20P-C13-Power-
Cord/dp/B00H7JR636/ref=pd_sbs_23_5/147-1650051-9596235?


https://www.amazon.com/Leviton-5822-W-Receptacle-Commercial-Grounding/dp/B000U3I1S0/ref=asc_df_B000U...

https://www.gordonelectricsupply.com/p/Leviton-5842-I-Comb-Receptacle-Nma5-20R-6-20R/5653867?gclid=E...

@cleeds, 
Sorry I was not clear:
I know the power goes through multiple transformers as part of the electric grid's distribution system before it reaches the transformer in my neighborhood. I know my audio equipment has transformers. I meant by adding transformers to the main AC power lines/branch circuits, from the electrical panel in my house to the audio equipment in my room. would be sound degrading. i.e. step up / down transformers, bucking transformers, power conditioners, AC regenerators (none of the former are on my audio lines)
Yes, my audio equipment sounds better on 240 volts. I plug all my audio equipment directly into the plug. That has been my experience. Audio manufacturer, Emotiva thinks audio equipment sounds better on 240 volts. See the link below. Page 10 section 7 regarding IEC power cord.
BTW, 240 volts, double phase is more efficient then 120 volts, single phase. Maybe ask Jim jea48, about voltage and amperage. Maybe he can explain to you better then I or show me where I could be wrong. Mike

https://cdn.shopify.com/s/files/1/2572/6926/files/XPA_HC-1_User_Manual_v10.pdf?30550

@sns, 
''IMO, amps should be on their own dedicated 10 gauge ac line, nothing else on that line.''

I agree 1000%. 

@cleeds, 
Remember: Volts/amps.
Maybe this will help.

P = I x E
P = Watts, Volt-amps.
I = Current, Amps.
E = Voltage.

Will a 240V 1500 watt space heater connected to a 240V source produce more heat than a 120V 1500 watt space heater connected to a 120V source? No.....
Current, amps?
P / E = ?
1500W / 120V = 12.5 amps.
1500W / 240V = 6.25 amps.