I wonder if the effect is similar to the Sound Blaster Pro with its dual OPL chips synthesizers that could play in stereo.

Kahenraz wrote on 2023-08-02, 09:37:

I wonder if the effect is similar to the Sound Blaster Pro with its dual OPL chips synthesizers that could play in stereo.

No. AFAIK, SB Pro 1 plays only the left OPL2 when in AdLib compatibility mode. Same as with the Dual OPL2 Pro Audio Spectrum.

To play in stereo games need to specifically send data to the left OPL2 at 388h (220h also in SB Pro) and data to the right OPL2 at 38Ah (222h on a SB Pro).

Stereo on a OPL3 is programmed slightly differently.

2 OPL3’s playing at the same time gives kind of a “flanged” effect, specially when combining a YMF 262 + YMF 289 due to the latter slight oscillating frequency difference.

I present you the new version of the LT board (in black proto color, when this is made in bulk it will be again classic green color) - all changes made with the sole purpose of replacing the OPL3 chip:
from this point onwards on every orpheus flavor the YMF289 will be replaced with the classic YMF262 opl3 chip:

since the YMF262 cannot be interfaced digitally to the CS4237 chip it got it's own high quality analog section which meant there was no space for a shiny logo in front ..
but it was moved at back side and enlarged 😁
there is no quality drop from the OPL3 chip replacement, it's analog section is very thought out and undergo several revisions before settling on this one , meaning that the OPL tunes will still sound great and better than the vast majority of old cards out there IMHO
there will be one feature lost though: the orphinit "minimum digital mode" that only outputs YMF289+PCM from CS4237 via s/pdif: this is not possible to do with the YMF262 OPL3 but the CSFM+PCM combo will still work in this mode

just to make clear, this does not mean that all previous orpheus cards are "inferior" , this was another change needed because of price and availability issues.

Sweet.

Are there any functional differences between YMF289 and YMF262?

keropi wrote on 2023-08-09, 11:45:

I present you the new version of the LT board (in black proto color, when this is made in bulk it will be again classic green color) - all changes made with the sole purpose of replacing the OPL3 chip:
from this point onwards on every orpheus flavor the YMF289 will be replaced with the classic YMF262 opl3 chip:

Nice! I know at least a few people on this forum prefer the original YMF262 to the newer YMF289 version. Personally, I can't tell the difference between the two, but maybe my hearing isn't what it used to be. 😁

Out of curiosity, does the Orpheus (or I guess the CS4237) support low-pass filtering in SBPro mode? And I mean for PCM audio, not for FM synth.

@appiah4

Function wise 100% the same. YMF289 was for Low power applications and had a standardized digital interface output. YMF262 is not low power and needs a dedicated DAC. Both have same FM features 100%

@Joseph_Joestar

No LPF for SBPro mode. Crystal chip has an SBPro interpreter that goes to WSS, so audio output is resampled in 16bit DAC as datasheet says.

Marmes wrote on 2023-08-09, 12:49:

No LPF for SBPro mode. Crystal chip has an SBPro interpreter that goes to WSS, so audio output is resampled in 16bit DAC as datasheet says.

I see. Thanks for the clarification!

Marmes wrote on 2023-08-09, 12:49:

@appiah4

Function wise 100% the same. YMF289 was for Low power applications and had a standardized digital interface output. YMF262 is not low power and needs a dedicated DAC. Both have same FM features 100%

Ah, so that's why a YAC512 sneaked its way onto the board 😅

vswitchzero just posted a review on youtube about the LT board: https://www.youtube.com/watch?v=03xrEIiZZTk
😀

keropi wrote on 2023-08-10, 15:11:

vswitchzero just posted a review on youtube about the LT board: https://www.youtube.com/watch?v=03xrEIiZZTk
😀

Great review, as usual, from vswitchzero and great sound card.

640K!enough wrote on 2023-08-02, 03:41:

It has hardly been mentioned since the introduction of Orpheus II (LT), but the layered mode simply uses both FM chips at the same time to play back the same content.

I'm wondering if adding some kind of "detune" mode would make the OPL3 sound richer?

It would but it cannot really be done in any easy way as you kinda need to adjust the actual frequency writes and just the right way too and this is not so easy. Some sort of data filtering middleman needs to be there for it.

GL1zdA wrote on 2023-08-15, 08:38:

I'm wondering if adding some kind of "detune" mode would make the OPL3 sound richer?

It might, but, as Tiido said, it would not be an easy thing to do, and for questionable advantage. Here, you'd have to insert that middleman before the CS4237, which already handles almost all of the bus interfacing. Then you'd undoubtedly get people who want the option to turn it off, apply different parameters, etc. In short, it would be a significant effort for rather little return; it will not happen on this design.

This method was just an experiment, since it was basically "free". Nobody asked for it, and most people seem to have entirely ignored it. That tells me that anything that would need more than a few lines of code qualifies as too much effort.

OrpheusII rev1.1 is now on solder bench and shipping 😀

r1.1 changelog:
- we now use the classic YMF262 OPL3 chip instead of the YMF289 previous boards had
- extra IRQ options added for PCMIDI , you can now use IRQs 10,11 and 12
- SMD Nichicon audio capacitors used instead of hole-thru ones

all new Orpheus2 variants from now on will ship with these changes - all needed because of availability/manufacturing reasons

keropi wrote on 2023-08-09, 11:45:

just to make clear, this does not mean that all previous orpheus cards are "inferior" , this was another change needed because of price and availability issues.

Ah, I was wondering when that change was going to come through.
As I mentioned on the De-CQM'ing SB16/SB32/AWE32 thread a little while ago, OPL3-Ls skyrocketed in price due to presumably low stock, which is really sad in general 🙁

Plenty and plenty of YAC516s though, but I have no idea how useful those are for anything but replacement parts, as they don't seem to be able to work on other chips as far as I can tell.
(Late reply because I didn't check this thread for a while)

I don't think YMF289 has low stock, more likely it is greed behind it, just like what happened with the chip shortage where a simple FPGA chip was 1000e
Many old chips are now having prices between 20~30 eur, give it some time and after no sales prices will drop 😉

Hi Keropi.
I would like to have the Orpheus LT, especially now there is no more MK8330, but i am still annoyed that the board is longer than the ISA connector, because my specific usage would be to put it in my A4000TX where there is zorro slots inline with the ISA slots. Is it possibile to know the precise lenght after the edge of the ISA connector to be sure the board won't overlap with a zorro slot? If it does, i would have to limit myself to shorter boards such as OPLx or similar.

Xanxi wrote on 2023-09-06, 11:44:

Hi Keropi.
I would like to have the Orpheus LT, especially now there is no more MK8330, but i am still annoyed that the board is longer than the ISA connector, because my specific usage would be to put it in my A4000TX where there is zorro slots inline with the ISA slots. Is it possibile to know the precise lenght after the edge of the ISA connector to be sure the board won't overlap with a zorro slot? If it does, i would have to limit myself to shorter boards such as OPLx or similar.

the extra length is 7mm , not sure if it will conflict or not...

edit:
btw there are a few CMI chips left, maybe when things slow down a little we do a small final batch to use them

Limit seems to be at 3,5 mm unfortunately.
In case there would be more MK8330, would that include the PCMIDI addon?

Xanxi wrote on 2023-09-07, 13:46:

[...] In case there would be more MK8330, would that include the PCMIDI addon?

yep, it will be an option