TG-16 Sound boost (or, how to get better sound from the EXP)...

[goombakid]

So, I got bored wait for a response (on various forums) for boosting audio from the TG-16's EXP. I looked online for a simple amp, when this came up (multiple times) in my search.

Hack A Week - Single NPN preamp

I had parts laying around, so when I had time, I built this thing.

After several minutes of prep and rewiring I got this. (Pardon outside link and shaky cam)
(after uploading the video, I didn't realize how soft the audio on the video was, so you may need to turn up the speakers to hear the difference. No scary things popping out, I promise)

I used two .1µF caps for the video's test. I'm gonna try a 1µF for C1 to see if I get a better bass response.

You'll have to build two of the circuits for both left and right audio channels.

Also, you do not need R1 from the above circuit. It's not needed in this case.

So, for those who ever seeked it, here you go.

[Drakon]

Awesome.  Mind posting an exact schematic of what you built?  My modding friends recommended that I use opamps so I bought some and I'm waiting for them to show up.

[goombakid]

I used the schematic that is on the page I linked. I'm sure an opamp would be better, but this worked out for me since I had the parts readily available. Quick and simple.

EDIT: I switched from using a .1µF cap for C1 in that schematic to using a 1µF cap. It gave too much of a bass response that it made everything sound static-y when played. In Street Fighter II', when the character gets hit or falls to the ground, you get the bump, but it's kinda scratchy. I'm gonna switch back to the .1µF cap again to see if there's a major difference.

[Drakon]

I built this circuit because I also had the parts laying around, crackle city with 1uf and with 0.1 uf zero bass.  I took a suggestion from a good modding friend tiido and added a 10k ohm resistor on the input and it's all fixed and perfect now.

[goombakid]

 Yeah, even after I switched back to using .1µF caps, I was getting crackles. Thanks for the tip about the 10K Ω resistor. Mine sounds great now. I'm not cringing now when the title screen for Keith Courage is on with all the distortion.

[Drakon]

Yeah, even after I switched back to using .1µF caps, I was getting crackles. Thanks for the tip about the 10K Ω resistor. Mine sounds great now. I'm not cringing now when the title screen for Keith Courage is on with all the distortion.

I found with that amp it wasn't powerful enough for me to filter the bass how I like.  Having a 12k ohm resistor on the input certainly didn't help with that but it was either that or crackling.  I'll wait for the op amps to show up they should do a much better job at this.  The problem with this 1 transistor amp is it's meant for a microphone:

http://circuitdiagram.net/simple-audio-pre-amplifier.html

[thesteve]

a properly working express is quite loud

[goombakid]

Like I said, I just went with simple and easy with stuff I already have. Dino at hackaweek.com uses it as an audio output preamp. Figure I could just use it in this case just for a quick and easy audio boost.

If your opamp gives more bass, put that schematic up. I may, in the future, do that for sound boost.

But for now, I'm fine with what I made.

[thesteve]

if your modifying and express that has all new cap in it, have fun.
im just saying try the repair before the mod

[HercTNT]

would replacing the internal speaker with something higher quality (not sure if such a thing exists) give a similar boost without building a circuit? As it is, steve recapped my gt and its very clear and loud. Maybe a better speaker would provide better bass. Hell, a internal stereo speaker mod would be better would it not?  I know squat about this stuff, but i do wonder if deeper bass on a gt is doable.

[thesteve]

simply putting a cup behind the speaker would increase the bass

[goombakid]

I'm talking about a standard Turbofrafx 16 console, not a Turbo Express. This was just a quick and easy way to boost the audio when tapping it from the expansion port. It was something I just played around with since I couldn't find a solution anywhere for amping the audio from the EXP.

[thesteve]

ahh thats completely different

[HercTNT]

my fault, i mentioned the gt and got this topic off track. I was just thinking about how his mod, might apply to a portable, or other possible solutions.

[SignOfZeta]

I don't understand the need for this. When I want louder sound I just...turn up the stereo.