Will the LPS make an impact on the HDP if it is only being used as a DAC? Also will this impact be worth the asking price of the LPS plus the selling price of the HDP? My current setup has the HDP outputting to a bottlehead Crack and I feel a new DAC is appropriate but I don't want to dump money into an LPS if it is a marginal upgrade, when I could take that money, sell the HDP and get something like the gungir for a little more money.
As I understand it the benefits brought by a linear power supply in a unit like the HDP is only to the solid state nature of the amplifier by giving the op amps a good, clean power input to help them reach their optimal voltage rails. So you probably wont notice any improvement if all youre using is the DAC from the HDP. That being said why are you unhappy with that setup? I was planning on using the HDP DAC to a Crack myself.
Oh yea, definitely get the Speedball first over a linear power supply.