New Power Cable on a 1990 Hafler DH120?

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!

                        Be careful with your acceptance of advice!

     When choosing the values of a power supply's filter caps, it's important to understand how the supply/circuitry functions.

     ie: When a DH-120 is switched on: the capacitors initially present (what appears to be) a dead short to the amp's 8A (OEM) rectifier bridge.   The greater the filter capacitance: the higher the current necessary to charge the caps.

     Increasing the capacitance beyond a certain point, in most amps; it's easy to end up with blown rectifiers (possibly: a burnt transformer).

     Of course: much of the above depends on how well the amp is protected, but: too much capacitance is simply asking for trouble. 

     It's always been my practice, when addressing power amp improvements (50+ years now), to first upgrade the rectifiers/rectifier tube/bridge, as that's always made the most marked/audible uptick in presentation.    WHY?   Because, in most cases: manufacturers don't use the best/most expensive parts they can find.

     An increase in filter capacitance can reduce ripple in a power supply, but: going too far can change (decrease) conduction angles, increase peak currents and result in EMI/noise generation, in/from SS rectifiers.     The harmonics of that EMI/noise can easily defeat any performance gains, gleaned from ripple reduction.

https://electronics.stackexchange.com/questions/217212/how-can-i-observe-rectifier-switching-noise

'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). "

                                             +1 for the rest of that post, of course.