Thursday, June 11, 2009

Sega Game Gear VS Master System

Here is a little recording. I thought it was very interesting when I compared the output of my Sega Game Gear (heard from 0:00 to 1:23) to the output of my Sega Master System II (from 1:24 to 2:47). The exact same data was used to generate these two recordings. Both have been normalised, however the GG was about 30 dB quieter than the SMS.

The output from the GG was via the headphone jack - I'm guessing it has some broken caps that need replacing, hence the lack of volume and the very dull nature of the sound. The output from the SMS was directly from the VDP chip via a line out I added (since the SMS2 only has an RF modulator for output).

Of course, this is only my SMS and GG, so please keep that in mind when listening.

Download here (1.9 MB)


Norock said...

interesting comparison! the GG's output, besides being quieter, sounds like a low bitrate mp3. any idea why that is? maybe you'll have to "prosound" your GG ;)

Sebastian Tomczak said...

Yes - the Game Gear has faulty capacitors as part of the headphone amp / audio amp circuits that need replacing (I think there are five caps that generally need replacing for the GG sound mod).

Maxim said...

Most GGs need pretty much all their caps replacing - the screen gets unreadable and they eventually get finicky about powering on. I'd highly recommend it.

In my experience, the GG headphone output is a lot less filtered than the SMS and does a much better job of maintaining the square wave under load (i.e. maintaining the DC offset) which helps make the sound more bassy.

Sebastian Tomczak said...

Hi Maxim,
Thanks for your comment!

I took the SMS audio from the chip directly, so do you think that a modded GG would yield a bassier sound?

Also, I was wondering if there is a guide on how to replace the caps and which caps to buy?

Thanks heaps for all of your information as always, Maxim, much appreciated! :D

Maxim said...

eviltim's got you covered on the cap repair.

If you look at a square wave sample in a waveform view, the curvature of the "flat" parts show you how well it can maintain the voltage away from zero, and the bass clarity is affected by this. At least, I see audio geeks saying things like that. I haven't exactly done a lot of trials but the cleanest waves I saw were from a GG and from wires soldered onto an SN76489 in an SC-3000.

Maxim said...

Hmm, eviltim didn't specify the sound board parts... there's a little info here but I don't know of any better guide.