Question about chip amp with different type of transformers???

[Leolabs]

Assume that the whole circuit is as same as the original Gaincard,just minus the input coupling cap,will there be any sound differences by using a normal square transformer vs a toroidal transformer???

[BWRX]

The input coupling cap shouldn't have any bearing on transformer choice or how the transformer affects the sound.

Assuming good quality transformers and good clean line voltage in both cases you shouldn't hear a difference.

[AndrewT]

Hi,
in general the EI and toroids available cheaply for the DIY market differ sigificantly in regulation.

The EI usually have a significantly higher regulation.
This may be audible.

[KSTR]

But EI and especially UI have less bandwidth and less capacitive coupling than a toroid, which is often a benefit (less mains noise coupling)

As usual, a trade-off and the net result will depend on your actual system in total.

-Klaus