Reply 80 of 129, by maxtherabbit
Eep386 wrote on 2021-02-13, 16:23:
I think what fixes issues with OPL3, is to increase the number of 8-bit ISA wait states (sometimes called 'I/O Recovery Time') in BIOS. Some lame-ass BIOSes (typical of OEM systems) don't allow you to change the wait states, however. For those that do allow the option to be changed, I usually ramp em up all the way to 8 or so if the system's a 'fast' one (say, Pentium 200).
Also, I'm beginning to think that the DAC chip has less to do with self-noise, than whether or not the cards have floating op-amps. Creative's left a number of quad amps on their cards with one or more sections of certain amps floating, which is terrible for noise and power consumption. I have a first-revision CT2760 with a CT1701 DAC, that had *six* sections of op-amp floating. I tied the amps down and the hissing doesn't seem any worse than is typical for ISA sound cards, at least to me.
technically I/O recovery time isn't the same as wait states - wait states are inserted within an access cycle to allow for the target device to decode address or whatever, I/O recovery time is waits inserted between consecutive access cycles