[jkeny]

A 4.5” X 3” X 1.5” (about the same size as iPhone) polished plastic ABS box is provided that contains:
- a modified Hiface (see below)
- a Lithium NanoPhosphate (LiFePO4) 3.3V battery
- a 3.3V regulator
- a 5V regulator
- an internal battery charger
- Leds, switches & connectors

This is the same size as the MK1 box but it in addition it contains a battery charger & a 5V supply.
The device now draws no power from the USB connection. This has again improved the sound! A 9V to 12V DC supply is plugged into the 2.1mm socket. When the unit is switched on this acts as the power source for the 5V & 3.3V internal regs. When the unit is switched off, it powers the internal battery charger. Top-up charging takes place until the battery is again full & the charger turns off. This is a plug & forget arrangement.

Hiface Modifications
These Hiface modifications are performed on the important circuits normally supplied by the internal 3.3V regulator. This regulator is removed & the clocks powered from a 3.3V battery. A new low-noise internal 3.3V regulator powers the output stages of the Xilinx chip & the output stages of the SPDIF generating chip.

The external Power Supply
Some consideration should be given to the external 9V to 12V power supply. Yes the switched mode power supplies that come with most modern appliances  WILL PROBABLY DO - you know the light ones. But it is better to use a better quality PS i.e. probably one with a transformer in it (i.e heavier). Remember, this is the feed for the 5V & 3.3V regulators in the MK2 modified Hiface box so the cleanest possible power is advisable.

A suitable 9V DC supply is £14 here  but others may be available locally in your area. A 500mA or greater output with a 2.1mm plug with positive centre contact.

See Here https://sites.google.com/site/hifacemods/home

[Jon L]

Will a "12V" SLA battery that actually measures 12.8-12.9 V be OK for those regulators?

[jkeny]

Yes, JonL, no problem, I should have mentioned the battery option! You will need a 2.1 plug on the battery leads to plug into the 2.1mm socket on the Hiface box. You can get something like this http://www.maplin.co.uk/Module.aspx?ModuleNo=390561

[rklein]

I had the MK1 version of John's creation and liked it quite a bit.  I was waiting to get my new amp and pre from Blair at Nightshade before I gave an opinion. But heck, just running foobar2000 from a small fanless computer that Mike Galusha built for me into a modded Zhaolu 2.0 DAC, into an old Yamaha receiver, I could tell that John was on to something special.  Unfortunately (or fortunately, depending on your take...) I inadvertantly left the boxed HiFace on overnight.  Then went to work the next day to come home and find one of the batteriers drained.   I am shipping back the MK1 for a new MK2   Can't wait to try the new and improved version with my new gear.

Randy

[rklein]

A 9V to 12V DC supply is plugged into the 2.1mm socket

Hi John:

What do you think of this as a Power Supply?  Cost is + or - $75.00.

http://www.amb.org/audio/sigma11/

Any other ideas for a PS?

Thanks,

Randy

[jkeny]

I got your email too, Randy & this is what I said:

Yes, that should be good, Randy - it may not provide much more benefit than a $10 linear transformer though, I'm not sure, I don't yet know the full parameters of the MK2 ! It won't do any harm though.

Here's what I say on my website about this supply:

A word about the external Power Supply
Some consideration should be given to the external 9V to 12V power supply. Yes the switched mode power supplies that come with most modern appliances  WILL PROBABLY DO - you know the light ones. But it is better to use a better quality PS i.e. probably one with a transformer in it (i.e heavier). Remember, this is the feed for the 5V & 3.3V regulators in the MK2 modified Hiface box so the cleanest possible power is advisable.

A suitable 9V DC supply is £14 http://www.maplin.co.uk/Module.aspx?ModuleNo=46107&C=SO&U=strat15 but others may be available locally in your area. A 500mA or greater output with a 2.1mm plug with positive centre contact.

[rklein]

Thanks John

Randy

[Zander]

It was the highly recommendable for the power supply. In all appliances, it great to have some features of the power supply. Those features were for the safety and productivity of power supply.