1.5m for 75ohm digital coax?

I have read the same thing in many forums and magazines. If at all possible try to acquire two lengths of the identical coax one 1.5 meter the other not and see if there is any discernible difference.

How necessary it is will depend on the jitter reduction capabilities of the dac (if any), the risetime and falltime of the output signal from the upsampler or transport, the degree of impedance mismatch between cable, connectors, and interface circuits at both ends, and other factors. As Rcrerar suggested, the only way to tell for sure is to try it both ways.

BTW, it's not a matter of preventing signal reflections, it's a matter of affecting the timing of their propagation back and forth along the cable such that they don't arrive coincident with the critical parts of the original signal (the critical parts being their high-to-low or low-to high transitions).

Also, I would seriously question whether changing from copper to silver in the case of a short run of a digital signal will really accomplish anything.

Regards,
-- Al

There are quite a lot of very good digital cables that don't cost very much more in a 1.5m length than they do for a meter. Atlas Opus and Compass, VH Audio cryo Pulsar, Apogee Wyde Eye are examples. All these are at or near the top of their price class.

Mike, you are talking about digital cable here. For digital cable, impedance is important but length is not, unless you are talking about very long length in which signal degradation becomes a factor. Signal reflection is caused by impedance mismatch, not length. You shouldn't have to spend more than $30 to $40 for a good digital cable, silver or copper makes no difference. Don't spend too much on it.