A good power cord has measurable effects on the equipment to which its connected. This can result in more power (less voltage drop across the cord), lower distortion and lower output impedance if a power amp is using the power cord. So it should be no surprise that its effects can be heard.
I have found that most power conditioners are a disappointment. But not all- the best I've seen so far was not even offered to high end audio (its industrial/commercial), made by Elgar. Otherwise we recommend that our amps be plugged directly into the wall.
The Elgar conditioners outperform every other conditioner we've seen (Furman, PS Audio, etc.). It employs a massive isolation transformer with a feedback winding. A low distortion oscillator is synced to the AC line frequency and the output of the oscillator is compared to that of the conditioner. A feedback signal is thus generated and applied to the feedback winding. In this way the conditioner can keep the output sine wave very pure with a THD of less than 0.5% and it can also regulate line voltage without limiting current within its capacity. The two most common models do either 1000VA or 28 Amps continuous(!). The are also older as Elgar got out of the market a long time ago, but for the most part they can be refurbished.
I have found that most power conditioners are a disappointment. But not all- the best I've seen so far was not even offered to high end audio (its industrial/commercial), made by Elgar. Otherwise we recommend that our amps be plugged directly into the wall.
The Elgar conditioners outperform every other conditioner we've seen (Furman, PS Audio, etc.). It employs a massive isolation transformer with a feedback winding. A low distortion oscillator is synced to the AC line frequency and the output of the oscillator is compared to that of the conditioner. A feedback signal is thus generated and applied to the feedback winding. In this way the conditioner can keep the output sine wave very pure with a THD of less than 0.5% and it can also regulate line voltage without limiting current within its capacity. The two most common models do either 1000VA or 28 Amps continuous(!). The are also older as Elgar got out of the market a long time ago, but for the most part they can be refurbished.