Apparently not all GS-only sc-55s are the same, some are GM

[keropi]

Hiya!!!

today I received a 2nd GS-only SC-55 for my builds. Naturally I tested it and found that the 2nd unit is a GM-compliant one, with Breath Noise and all

On the following pics:
the upper unit is the "real?" GS-only unit with a serial of AC93519
the lower unit is the the one I just got, with a serial of DD61319

Here is a pic of Duke Nukem 3D level 1-06:


and here is tilakat's Descent2 mid (d2b.mid , stock game midi AFAIK)


and here is the same midi patched to play the Fl. Key Click instrument on GM units - the upper unit plays nothing on channel11:


I have tested Capital Tone Fallback feature in both units with unpatced/unmodded World of Xeen installation, arrow sounds play fine after you shoot - start walking - shoot again when you first load a game.
In DN3D and in tilakat's Descent 2 midis, the lower unit behaves like a GM-compliant one as you can see from the pics.

Anyone here has more info on this? Maybe some other test , something to show the version of the units? Or maybe this is just a GS-GM mobo in a GS-only case... (although it really seemed unopened, the roland tier ups etc, where unharmed)
As always, any extra info/thoughts would be appreciated

[Mau1wurf1977]

Wow that's interesting...

So for these two games to sound correct you need a very very old Sound Canvas? Is that the gist of it?

[keropi]

the 1st sc-55 has some subtle differences and omissions that makes it special IMHO... for example there is no Breath Noise or Sine Wave (IIRC) but there is Fl. Key Click sound instead of Breath Noise... so it's a little different than GM and IMHO that makes it special

[keropi]

more details:

following Roland's instructions to find the rom version:

SC-55/55MKII : Press the POWER button to make the STANDBY light come on. While holding both
INSTRUMENT buttons, press both MIDI CH buttons

I get these results:

[keropi]

OK, more findings... I have opened both units to inspect them.
As expected the control rom is different , R15209275 9126D (1.10) vs. R15209363 9152D (v1.21)
Also IC30 is different: R15199736 (old) vs. R15199778 (new)
The 3 ICs that hold the samples (AFAIK) are the same part numbers: R15209276 , R15209277 and R15209281

old v1.10


new v1.21


I have tried swapping the control roms, it did not work. Both units just power on with the screen completely OFF and both ALL+MUTE buttons lighted.
Maybe the newer IC30 has the ability to load the extra samples from the Control ROM, assuming that the 3 sample roms are indeed the same.
Ofcourse all that is pure speculation from my side, I thought it worth the shot to swap control roms and see what happens

[Mau1wurf1977]

Good work for looking into all of this!

I'm still amazed that TO THIS DAY new discoveries are still being made. Absolutely beautiful.

[Stefan_L]

Keropi have you tried holding down both instrument buttons when powering up the sc-55 with new program rom?

[Great Hierophant]

I did the test with my GM/GS SC-55, and I got a Ver 2.00 ROM with a '92 date. I checked inside and the three sample ROMs match Keropi's, but IC30 on mine is R15199799 and the control ROM is marked R15209387, 9224D.

I wonder if Keropi's 1.21 unit will respond to a GM System ON command, or if it just has the instruments of the later GM/GS units.

If you want an truly early SC-55, you probably will need to purchase a GS STANDARD marked unit.

[keropi]

Keropi have you tried holding down both instrument buttons when powering up the sc-55 with new program rom?

for a reset? is it supposed to do something else as well? both units don't have a battery btw so they don't store any settings.

@Great Hierophant

Any way I can check the GM_System_ON command?
I always thought the revisions went like this: GS -> GS Standard -> GS/GM -> MKII or at least that GS/GS-Standard were the same thing, that was the general consensus in previous threads.

also back to this, if the sample roms are indeed the same in all 3 units, where does the Breath Noise sample comes from ? Could it be the case that the 1.10 sc-55 has it already but due to a bug/error it does not get mapped? or is it loaded from the control rom?

edit: I also cross-checked with a friend, his GS-only SC-55 is also v1.21 , there is nothing funny (like mobo swap, aftermarket mods etc) going on with my 2nd unit

[Stefan_L]

My version is also 1.21.

So IC30 is some sort of MCU then? I wonder why Roland put the program rom in a socket since it would mean it should be possible to easily update the SC-55 with a new rom... but now it is proved it is not possible? So now you have to replace the IC30 (soldered) also.

Keropi, I was thinking maybe the new program rom needed to be initialized or something... but i see now you have no battery plugged in

[voodoo5_6k]

Hello,

I've been reading along the forums for years but a recent "discovery" made me join to ask about it and share the information. So apologies for reviving this kind of old thread but after browsing through the forum's search results this seemed to be the best spot for it.

Just yesterday I received an additional Roland SC-55, this time with GS logo (I already have a SC-55mkII unit). Because the seller wasn't able to tell me the ROM version I bought it "on risk". I was looking for a first generation unit without GM logo, but with the GM compatible instruments. That would give me capital tone fallback, a certain GM-reset behavior & correct instrument assignments for e.g. Duke Nukem 3D (according to recent insights).

Reference:
viewtopic.php?f=7&t=35933&start=62
http://nerdlypleasures.blogspot.de/2013 ... vices.html
http://nerdlypleasures.blogspot.de/2012 ... pport.html

Because of the information regarding ROM versions I was expecting either 1.21 or 1.10. But surprisingly (at least for me) this unit has a version 1.20. I searched the internet for a while but didn't find anything about it. This particular ROM version has the GM compatible instrument assignments (#122 Breath Noise and Fl.Key Click variation, as well as Sine Wave variation on #81).

ROM version

#122 capital

#122 variation

#81 capital

#81 variation

Does anyone know anything about this specific version and what has changed for 1.21? It would be a good thing if Roland had issued some sort release notes for all those ROM versions...

[James-F]

I think some of you will be surprised but because i was not convinced by the "Fl. Key Click / Breath noise" issue i asked directly Mr. Prince (via his website) and the answer is : ...... for Doom / DN3D he used a GM compatible SC-55 ("v2"), and he confirmed "Breath noise" was indeed the instrument intended.

So basically the "Fl. Key Click / Breath Noise" issue is debunked, no game intended to use Fl. Key Click @ #122.
That leaves us with the CTF issue with only 3 games because of lazy programming.
Is the CTF fuss that important? Only for these 3 games...

Games that use Capital Tone Fallback:

Lands of Lore
Worlds of Xeen
Space Quest V: The Next Mutation

[Cloudschatze]

That leaves us with the CTF issue with only 3 games because of lazy programming.
Is the CTF fuss that important? Only for these 3 games...

Games that use Capital Tone Fallback:

Lands of Lore
Worlds of Xeen
Space Quest V: The Next Mutation

Lands of Lore can probably be stricken from the list. First, the MT-32 was the favored compositional synth for this game (this is straight from Frank Klepacki), making it or an LAPC or CM-variant the ideal playback device (and for which the capital-tone fallback issue doesn't apply). Second, there is a patch (applicable to the disk version) that allows separate sound-effect and music devices to be selected, meaning the arguably superior PCM sound-effects can be heard in lieu of the Sound Canvas counterpart tones entirely.

The capital-tone fallback problem never really applied to Space Quest V.

NewRisingSun had discovered that SQ5's MIDI data includes drumset program changes. Since these messages are not passed by the General MIDI driver that shipped with the game, he created a custom driver that would do so, and that was provided privately to a few individuals. With this driver, it was subsequently discovered that illegal drum map numbers were used in the MIDI data, causing improper playback on the SC-55mkII and later. To address this, he created a second driver that sends proper drum change messages, and made it publicly available. In short, unless you're using that first custom driver, you'll never experience the problem.

[James-F]

So all the fuss is about ONE badly programmed RGP (blah) game?
Might as well forget all about "Capital Tone Fallback" and never mention it again.
Thanks Cloudschatze.

Hope the previous owner of my soon to be SC-55 MKII did not neglect the battery and periodically checked it.
I'll post some pics when it's here.

[Great Hierophant]

I had a somewhat longer list :

Blackthorne
Blood
Duke Nukem 3D
Lands of Lore
Hocus Pocus
Magic Carpet
Might and Magic : Clouds of Xeen
Might and Magic : Darkside of Xeen (combine with Clouds for World of Xeen)
Prince of Persia 2
Quarky & Quaysoo's Turbo Science
Quest for Glory III
Space Quest V

However, all of those games, except as described above and Duke Nukem 3D, only use capital tone fallback for the drum part. This is different I believe from the regular instrument banks I believe and should be supported on every module that supports multiple drum banks.

More info here : viewtopic.php?f=7&t=35811&p=308610&hilit=capital+tone+fallback#p308610

[Cloudschatze]

I had a somewhat longer list :

None of the Sierra titles are relevant. As with Space Quest V, the retail drivers don't pass the drumset program change messages, and the problem is fixed with the custom drivers.

In the end, it's still a short list, and patched drivers were made available besides.

However, all of those games, except as described above and Duke Nukem 3D, only use capital tone fallback for the drum part. This is different I believe from the regular instrument banks I believe and should be supported on every module that supports multiple drum banks.

The difference is that selecting a non-existent tone on the SC-55mkII and later results in a "NO INSTRUMENT" message, and silence for that part, whereas selecting a non-existent drum set results in a "NO DRUM SET" message, but leaves the part at the last correctly-set drum selection.

[James-F]

The difference is that selecting a non-existent tone on the SC-55mkII and later results in a "NO INSTRUMENT" message, and silence for that part, whereas selecting a non-existent drum set results in a "NO DRUM SET" message, but leaves the part at the last correctly-set drum selection.

The silence part is not true.
For now I can tell that SC-VA plays the previous instrument if changed to non-existent tone, instrument or drums.

Actually, it is impossible to select non existent drum-sets in GM, there is only one official standard drum-kit.
But GM supports 8 other drum-kits from GS unofficially (not in the standard), by changing patch number:
1 Standard
9 Room
17 Power
25 Electronic
26 TR808
33 Jazz
41 Brush
49 Orchestra
57 SFX

There is no BANK to be selected here, only Patch, so there is no way to select a non-existent tone on channel 10.
The game either uses a certain drum-kit or not, no room for mistakes.


To me, it seems that the first units of SC-55 are a mix up of unfinished GS and GM standards.
SC-55 in GM mode ignores the CC0 BANK number and obeys PC (patch change) no matter what.
Obviously, there is no Bank number besides 0 (capital) in GM.

When a new GS device receives a PC message:
The device first checks the the CC#0 in memory at that channel and only then triggers the PC command.
Each of the 16 channels have a memory for CC#0 and CC#32 (SC-88 and up), so you can send a CC0 and CC32 to any channel independently from the PC command.
If the combination of CC#0 and PC does not have a match, the bank+patch request is ignored, and the tones doesn't change.
The CC#0 for that channel remains in memory till a different CC#0 is requested, independently from PC.

Manual: "Bank Select" is suspended until receiving a "Program Change".
Therefor CC#0 is in memory (per channel) for SC-55 or SC-55 MKII.

The old SC-55 (with CTF) is different:
If there is no match, it will ignore the CC#0 stored in memory and obey the PC request, just like GM would.
It's not actually a "Fallback", rather a Patch has priority over a Variation (Bank+Patch) mismatch.

This happens only in GS mode, most games use GM mode, so switch to GM mode before playing games to ignore CC#0 (if there is even a chance it exists in a GM game).

[Cloudschatze]

The silence part is not true.
For now I can tell that SC-VA plays the previous instrument if changed to non-existent tone, instrument or drums.

I wasn't aware that this behavior had changed, but it looks like it did with the SC-88Pro and above. The silence statement absolutely applies to the SC-55mkII and SC-88 though, as you'll soon discover with your own SC-55mkII. (You can read about it in the manual in the meantime even.)

SC-55 in GM mode ignores the CC0 BANK number and obeys PC (patch change) no matter what.

When an SC-55 receives a GM System On message, it either:
1. Treats it exactly the same as a GS Reset (ver. 1.xx SC-55), or
2. Treats it as a GS Reset, but also sets Rx.NRPN to "Off." (ver. 2.xx SC-55)

That's it.

No SC-55 ever disables reception of the Bank Select when receiving a GM System On. That behavior was first implemented with the SC-55mkII.

[James-F]

When an SC-55 receives a GM System On message, it either:
Treats it as a GS Reset, but also sets Rx.NRPN to "Off." (ver. 2.xx SC-55)

You forgot Rx.Bank "Off for MKII...wait a minute... V2.xx is not MKII?

The silence statement absolutely applies to the SC-55mkII and SC-88 though

Is that a fact?
Do you experience this kind of behavior with your unit?
I don't see anything about silence if the bank is wrong anywhere in the manual.

[Cloudschatze]

...wait a minute... V2.xx is not MKII?

That's correct.

Is that a fact?
Do you experience this kind of behavior with your unit?

Yes, I've tested and experienced the behavior on my own unit.

I don't see anything about silence if the bank is wrong anywhere in the manual.

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