Here is the assembly manual for S/N1400 to S/N3133.
Starting in April of 2022, all kits will have Rev H amp boards.
As of January 1, 2017 all QSK kits for the Hardrock-50 amplifier have surface mount PIN diodes and switching MOSFETs pre-installed on the PCB. The QSK inventory and assembly instructions have been updated to exclude these parts.
As of June 1, 2016 all Hardrock-50 amplifiers are shipping with a Rev H rear panel board. The differences between Rev G and Rev H rear panel boards are:
FTDI USB to TTL serial bridge instead of a Microchip to simplify driver installation
Isolated USB connection to prevent ground loops with some SDR's
No 12 MHz crystal
Different form factor for RCA jack
The only difference in assembly is to omit the installation of the 12 MHz crystal and make sure the USB jack doesn't touch the metal of the rear panel.
The Rev G rear panel is backward compatible with previous version of the Hardrock-50 so if you are interested in updating the panel in your amp contact us to see how you can get one of the new Rev G boards.
Starting in May 2019, T2 should be wound with #22 enameled wire, which is the same wire used to wind the toroids. This change makes it easier to wind T2 and #22 has ample current rating for 50W operation. Even if you kit has the #18 enameled wire, you can use #22 for T2.