Owner's manual

Hedd upgrades

There are two parts to this

First, the D/A and the A/D converter; this requires some modification to the main pcb. How much depends on the

version of the pcb and when it was built. The best way to find out is to open the cover and look for the revision

number. It is possible to change only the D/A portion. The new D/A is a major improvement in sound qualitily.

However depending on some unpredictable things it may be necessary to do some of the pcb modifications. A

good tech can do all of it in an hour. A not so good tech will create much damage.

The new converters will run at 192K however the firmware to run the HEDD box at 192K is still being worked on.

If you are only looking for the converter upgrade it is fine to do this at this time

If you are wanting to run at 192K then it is best to wait until the 192K firmware is ready. There will be some other

hardware changes to run at 192K, such as the digital interface. Some of this is the result of bringing all older units

up to the same hardware and firmware as the newest rev pcb. This will result in better performance in the older

units and it also makes it much easier. We do not have to figure out and maintain several different versions of

firmware

Original HEDDs, the 48k units will not upgrade

LOCATION OF REV NUMBERS