150$ is indeed on the high side, I'd say 80~100$ is a more realistic price. The remote is kind of useless for gaming reasons.
All you need to play GS/GM games like DOOM is a joyport->midi adapter cable, it connects to the joystick port of your soundcard and provides you with a midi connector for the SC-55 , there are plenty and cheap on eBay

ok so i just need a cheap cable from ebay to connect it to a retro pc with a sound blaster 16

but what about the specific model number

sc-55
or
sc-55mkii

which model is the good one and which is the crappy one?

there is no crappy SC-55 , some people like how MK1 sounds - some how the MK2 sounds... there is some difference in polyphony and sound output were MK2 is better (24 vs. 28 voices and 16 vs. 18bit output) and some things sound better on MK1 some on MK2. Just get either one reasonably priced and call it a day IMHO

What keropi said!
More then no crappy sc-55, its more like no correct version.
Certain games prefer certain version, I cant find the list but it was for a few less popular titles. The common games like Doom, Duke3d etc made no difference if you had a Mk1 or 2

I've got the MK1 and happy

So...

1. old version is fine
2. you dont need the remote at all for pc games
3. I need a cable that connects to my soundblaster and the SC-55 (joyport->midi adapter cable)
4. what about mpu 401 ? do i need that too? nobody mentioned it. Why people buy it, and there is even an isa pcb replacement for mpu 401

1. yes it is fine
2. nope, remote not needed at all
3. exactly, you need a joyport->midi cable
4. mpu-401 cards are needed for games that need the "roland intelligent mode" and these are MT-32 games ... ofcourse you can use a dedicated MPU401 card for all your midi connection needs and never have to worry about anything. There is also SoftMPU that emulates the intelligent mode functions at cost of some cpu time and it's a good workaround for fast systems (486+ builds)

Pabloz wrote:

1) should i avoid the SC-55 ? the SC-55mkii is better?

Absolutely do not avoid it, especially for a good price. I bought one from Japan and it sounds great. Based on the research I did:

- SC55M2 does general midi. But this is a subset of GS which SC55M1 does, so the SC55M1 technically does it as well.
- Like all midi devices, the instrument patches might be slightly different. It doesn't make them better or worse, just different. Even different batches of the 55M1 may sound different to each other. Some games sound better on different devices. There is no one "true" midi device that sounds best on all games. You would need a stack of them to achieve that, and it's probably just not worth it.
- The Roland MT32 emulation is no different on the 55M2 to the 55M1 - which is to say not great and try and avoid it. I connect my DOS computer to the 55M1 using a standard joystick-to-midi adapter, and then connect the THRU of the 55 to a modern computer using a Roland midi-to-USB adapter, then run Munt for real MT32 emulation. Works a treat and even better I get both the visual display of the 55 and the sound from Munt (I use a mixer to silence the audio out of the 55). You either need a special card or a bit of software that allows games to make use of MT32 mode though.
- there is a version I almost bought, the SC55ST - which does NOT have a screen! I almost could not tell from the photo, and only at the last second realized this so I could avoid it. It has a clean face, and probably sounds great, but I love seeing the 55's screen reflect the midi music being played.

Much simpler answer:

Get an SC-55 Mk.I with firmware 1.21 for best DOS games compatibility, or an SC-55 Mk.II for best sound quality (18-bit vs. 16-bit, 28 voices vs. 24 voices, better output stage). That's it.