This is a mod to isolate the Zero's Headphone amp from the stock power supply and transformer (allowing use of HDAM modules in the H/Amp opamp sockets)
It's a wee bit expensive and not very practical for the average Zero owner but it certainly does allow for the full use of the 3 HDAM config with great results.
Personally I opted for this mod because I felt the H/Amp section could be improved by giving it it's own highly regulated power supply (plus 50VA transformer)
The PS1 kit is DIY from Welborne labs. All specs and such are located at the web site. I'm running the reg board at -15 0 +15V DC as per the spec for the Zero's head amp requirements. Current is limited to 1.5 amps at this time but the board can easily scale to 3amps with a transformer swap.
Here are some pics of it's construction and it's use with the FrankenZERO.
The Head amp has considerable balls now......the whole mod is still in burn in from extra modifications I added ( 8 bypass caps on the reg board) and 4 more bypass caps on the Head amp's beefed up electrolytic caps. Power supply caps were swapped from 330uf 16V to 1500uf 25V Nichicon PW's. The 47uf 10V Silmic caps were swapped for 47uf 35V Elna Silmic II's (both sets of these bypassed with .047uf 160V PIO) The same PIO's were used to bypass the 8 reg board caps.
I would say for 95 % of the Zero owners this mod is for the die hard cost no object type of person and I don't recommend anyone doing this mod unless they can source far cheaper options than the PS1 kit. It certainly was fun doing this modification. The whole Headphone amp has to be relocated into another chassis which adds even more cost to this mod...all told it makes little sense cost wise.
Peete.