Gyro Gearloose wrote:If you're going to make an improved board, why copy 40 year old packages? Put all the digital crap in a FPGA,..
That's pretty much the direction I wanted to take but use 1 or more CPLD(s) instead of FPGA. I'm getting to love those Xilinx XC95xxXL chips; low power, 5V input tolerant and very flexible with slew rate limiters and low power mode.
Since there are purists out there, I wanted to offer the option of using a CMOS 65C02 or an original MOS 6502 by having a 40 pin DIP socket. Also since WDC offers 100% compatible VIAs now ( W65C22N series ), why bother integrate ones that don't meet the purist's criterias so... a pair of DIP sockets for these too and leave the choice to the customer wether to use MOS chips or new CMOS chips.
People want to use various different firmwares so the ROM will also have to be on socket.
Bottom line is CPU,VIAs and ROMs on DIP sockets, everything else surface mounted on the underside of the PCB for minimal footprint. I estimate the new PCB is barely going to make it to the screw holes for the heat sink of the legacy voltage regulators.
... and it's not like a head amplifier is magical anymore. For extra surrealness, I'd design one with a Nuvistor.
Watch out for that super tricky TTL/CMOS level thing. It's very hard to understand and easy to make mistakes.
I considered designing a new head amplifier but if you consider all the components for the legacy design are still available, AFAIK, all in surface mount too, I'm not 100% sure its worth it. I would be very happy if you were to come up with a more efficient design that keeps the same transfer function; there's a lot of filtering in there.
Wealth, like happiness, is never attained directly. It comes as a by-product of providing a useful service. -Harland D. Sanders