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

[keropi]

oh wow I always thought that the synth parts of SCB-55/SCC-1A/SC-55mk2 were exactly the same... thanks for this clarification

[Cloudschatze]

https://youtube.com/watch?v=lr2Vm4EIe5s

I had another idea of what Roland might have changed to result in this dissimilar behavior, and just need to verify when I have a chance...

So, regarding the playback of that "Jhelom" piece...

v1.21 SC-55:
http://www.symphoniae.com/synth/Roland/ ... Jhelom.mp3

v1.01 SC-55mkII
http://www.symphoniae.com/synth/Roland/ ... Jhelom.mp3

v1.01 SC-55mkII with an "undocumented" SysEx parameter tweak:
http://www.symphoniae.com/synth/Roland/ ... elom_W.mp3

[James-F]

an "undocumented" SysEx parameter tweak:

Well... what is it?

SC-55 MKI v1.21 definitely performs better in this case.

Listen from 00:52 there is a Bell sound together with the "echoing flute".
Not even the sc-55 v.121 handles this.

Still, my custom Voice Reserve on the MKII handles JHELOM better then all of the examples you posted.

Code: Select all

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SC-55 MKII Custom Voice Reserve JHELOM.mp3

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As for the sc-55 combining, great info there but I'll cheat and use the 8820

The SC-VA is always just a cable (real/virtual) a way...

EDIT:
In the end it doesn't matter, Ultima Online was not meant to be played on the SC-55 but the Soundfonts that came with it or a more capable synth of that time.

[Cloudschatze]

an "undocumented" SysEx parameter tweak:

Well... what is it?

I want to do some more testing before attempting to describe the parameter and its presumed behavior, the problem being that it's yet conjectural, and presupposes a behavior of the SC-55 that has, heretofore, been described exactly nowhere.

In the end it doesn't matter, Ultima Online was not meant to be played on the SC-55...

This likewise applies to two additional cases that I'm aware of - Settlers 2, and Zone Raiders.

[James-F]

It's your job then as a learned person to figure its transfer function using nothing but input and output data.
All this SC-55 difference business becoming more academic than I thought..

[Cloudschatze]

Here's some version information that I'd been tracking for the SC-55 and its variants, inclusive of units belonging to myself, Keropi, and Great Hierophant. You'll notice that version 2.00 SC-55s exist with faceplates both lacking, and having, a General MIDI logo. The version dates for the 1.00 - 1.20 SC-55s are also something of an oddity, being both uncharacteristically close to each other, and (in some cases) unrealistically disparate from the dates-of-manufacture.



Fun fact: The SC-55 and JV-80 synthesizers both use the same custom PCM core IC, where it provides 24-voices of polyphony in the former, yet 28-voices in the latter.

[Jolaes76]

Sorry for my ignorance, I did my best to read through this excellent thread and at least 5 others here at Vogons concerning the most suitable SC-55 type for DOS gaming but the technical quirks and limitations are way too much for me to keep the whole picture in focus.
I would like to know that if I only have a pure DOS environment and want to skip routing MIDI to an anachronistic "Windows MIDI Correctional Facility" for fixing errors, which SC-55 model is more compatible with more DOS games "outta box" or at the most effort being pressing a few keys to init a gm or gs reset etc. I hope my question is comprehensible...
I do not mind if for post '93 games I need to use my SC8820 which will not sound 100 percent authentic but at least, hopefully, doesn't skip or hang notes (?) but for earlier titles, what is a better one, an SC-55 with GS LOGO which is internally GM compatible like keropi's second one, or a rare SC-55 mk1 with both GS and GM logos?
Buying dual modules is not in my means.
Thanks in advance for any guidance.

[PhilsComputerLab]

There are a ton of General MIDI supporting games, and the way I see it, it doesn't matter which sound canvas you get, 99% of the games will sound correct and great

The early unit is more compatible with a handful of games, the later units can play more instruments at the same time which also affects a handful of games.

So I wouldn't worry about it much

[Cloudschatze]

...which SC-55 model is more compatible with more DOS games "outta box"...

With that criterion, and given currently known information, an SC-55 with either ROM version 1.20 or 1.21 provides the greatest degree of "out-of-the-box" compatibility with DOS games. These units shipped with "GS" logo faceplates, and with serial numbers greater than AC94800.

[Jolaes76]

Thanks a lot!

[Jolaes76]

I have purchased an SC-55 that fits the description (matching looks and serial number in the Bxxxxxx range). Is it possible to upgrade to v1.21 - where can I find that ROM dump? Is it legally obtainable?

[keropi]

What rom version your SC-55 has Jolaes? is it 1.20 ?

I have tried exchanging the ROMS between my 1.10 and 1.21 units and neither worked. IIRC the control cpus are different between them so they cannot run each other's program rom... kinda sad if you ask me.

[Jolaes76]

I see. I couldn't check the version number because I did not ask the seller to power up the unit once again, but guess that it is either a v1.20 or v1.21. Maybe it is possible to upgrade from 1.20 to 1.21, although according to Cloudschatze, both are acceptable

[keropi]

1.20->1.21 seems possible - let's see what happens when you get it

[Cloudschatze]

1.20->1.21 seems possible - let's see what happens when you get it

This will absolutely work. Stefan_L dumped the v1.21 control ROM, which can be used for this purpose.


When upgrading the SC-55 control ROM, compatibility needs to be maintained between its major and minor version, and that of the CPU ROM.

In other words:

CPU ROM v1.00 is only compatible with a v1.0x control ROM (only 1.00 exists)
CPU ROM v1.10 is only compatible with a v1.1x control ROM (only 1.10 exists)
CPU ROM v1.20 is only compatible with a v1.2x control ROM
CPU ROM v2.00 is only compatible with a v2.0x control ROM

Roland used to provide an upgrade path that included replacement of the CPU, in conjunction with an associated control ROM, but alas, these parts are no longer available for them to do so.

[Jolaes76]

Many thanks for the details. This is, again, vogons' wiki class material

[keropi]

[...]
Roland used to provide an upgrade path that included replacement of the CPU, in conjunction with an associated control ROM, but alas, these parts are no longer available for them to do so.

interesting, I suppose you sent them the unit to perform the upgrade then? AFAIK the cpu is not socketed

[sprcorreia]

I don´t know if it's relevant but I have a SC155 with the GM logo and running version 1.01. 1992.

[Cloudschatze]

I don´t know if it's relevant but I have a SC155 with the GM logo and running version 1.01. 1992.

That's more of an overall "product version," specific to each model (in this case, the SC-155). What are the nine digits reported to the right of that? 201200119, presumably?

[sprcorreia]

I don´t know if it's relevant but I have a SC155 with the GM logo and running version 1.01. 1992.

That's more of an overall "product version," specific to each model (in this case, the SC-155). What are the nine digits reported to the right of that? 201200119, presumably?

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