My normal EPROM programmer won't do bipolars, but is convenient - it'll run on my netbook as it just plugs into a USB port. I have one and I have to drag out an old '386 PC to run it.
The ROMs in an H949 need to be read (and programmed) using a programmer that supports bipolar PROMs. The timing of one of the sample-and-holds was changed slightly. There are also two versions of ROM 7, but I can't find any difference in how they actually work. Just jotting down the differences in my service packet was enough.Īs for the PROMs, there was nothing wrong with the actual chips - only two chips appear to be different when equipped with the deglitching board. In that case, the RAMP bit is now toggled in hardware (divide-by-two flip-flop) and not firmware (as in the rev-C version), and some condition code bits were reassigned. The most important differences are in the control store (PROM) wiring, where a few of the microcode bits are rearranged, and the conditional instruction section. They are marked by the omission of 'Rev C+D' at the bottom of the page.
Rev D of the board is not in the Eventide service manual - there are about three pages with differences. The other two algorithms provide either simple ramped taps (ramping is continuous), or the normal crossfade.Īnyways, I think I have the schematic issues resolved. It appears to analyze the pitch of the signal and adjust the frequency or phase of the splices to better match the input signal. The third algorithm is implemented on a rather large analogue autocorrelator board (essentially a pitch detector made with shift registers).
What are the serial numbers of the two units?Īs for a rom image, you might contact THESE GUYS:īy 'non-deglitched' I mean with algorithms 1+2, not algorithm 3. If the ROMS are the same, then the hardware must be the only diference, and the discrepancy between the schematic and the unit may bear this out. I have never seen a non-deglitched 949, and until now didn't know that Eventide released one (since their marketing behind the 949 promoted the deglitched pitch change). Also, the schematic in the service manual seems to be slightly different than the PC board.
If the ROMs are indeed supposed to be different, I'm not sure how I'm going to get new binary images - nobody seems to have the ROMs any more.
I can program and copy the ROMs if I need to, and I also have a bunch of blank ones, but I only have a working deglitched 949, and a nonworking nondeglitched one - after replacing three DAC's, audio sounds great in delay and algorithm 2. Dale Ulan wrote on Sat, 19 December 2009 19:47ĭoes anybody know if the ROMs are different between deglitched and nondeglitched H949s? I have an nondeglitched H949 here that seems to have a mix of ROMs.