New Power Cable on a 1990 Hafler DH120?

The Hafler DH 120, owned by the OP, has a " captive " cord, not an IEC connection. 

Without gtting into the flat earth debates, i think it is clear to say that before spending money on a power cord, one should address the extensive known areas for improvement in that excellent design with budget parts. search for an get a copy of "pooge" by walt jung from the audio amateur and follow his list of upgrades, starting with bypassing signal chain electrolytic caps with itsy bitsy films.  jack up the bias.  clean all the contacts. replce the stamped metal RCAs (unless they improved those on the -220 over the -200 on whcih they sucked, that's a thechnical term.

Have fun. Cord will certainly cost more and do less.

Some think zero, others disagree.

BTW Mr Decibel makes a reasonable point.  One area that, IMO, all components fall short is the quality of the connection to the wall AC.  This has two parts - the plug on your cord and the outlet in the wall. I routinely put in heavy duty outlets, and also replace the plugs with higher quality ones. You are looking for a tight connection and a large contact area.  The DH220 only draws about 1-1,5A most of the time and dynamics draw n the large filter caps, so the 14 agg cord diameter ought to be fine. On my much larger, vastly costlier amps i cannot really tell the difference between 14 and 12 guage. But i have good outlets, good plugs, power conditioning and massive power supplies int he amps. You can turn them off and they keep plying for a bit :-)

G

eric makes another solid point.  The two large power supply capacitors, being 30 years old and electrolytic, probably only have about 1/3-1/2 of their original capacity.  Buy new drop-in replacements - the largest that you can fit into the band-clamps (in other words same form factor, same or higher voltage, biggest capacitance possible).  That will produce a staggering difference. The power cord, well.....

Agree with the above comments, especially in terms of the priority/order in which things ought to be done.  Go ahead and replace that old power cord--but do the other stuff first.  Could be a very satisfying project!