DogTag
Offline
Murcia, Spain
Timbob wrote:

Well, spend all day working on a schematic.
With a tl072 won't work. 10k resistors gives you a really low volume, almost can't hear it.
And diodes won't work as well, which is strange, and I can't figure out why. Maybe my plugs are just crap.

What's the average maximum voltage of a line-out on a Game Boy? That schematic is designed for 1V input signals. Maybe if the iput voltage is wrong, then the whole circuit is not working as it should.

Self response:
Line-Out-------------Vpp--------------Amplitude
Pro sound -----------1V------------------0.5V
Stock-----------------0.2V----------------0.1V

So the problem might be the resistors value.

Last edited by DogTag (May 8, 2013 7:51 pm)

SAMWAVE
Offline
United Kingdom

Wasn't Low-Gain building a chiptune mixer at some point?

Although that was a long time ago.

Timbob
Offline
DogTag wrote:
Timbob wrote:

Well, spend all day working on a schematic.
With a tl072 won't work. 10k resistors gives you a really low volume, almost can't hear it.
And diodes won't work as well, which is strange, and I can't figure out why. Maybe my plugs are just crap.

What's the average maximum voltage of a line-out on a Game Boy? That schematic is designed for 1V input signals. Maybe if the iput voltage is wrong, then the whole circuit is not working as it should.

Self response:
Line-Out-------------Vpp--------------Amplitude
Pro sound -----------1V------------------0.5V
Stock-----------------0.2V----------------0.1V

So the problem might be the resistors value.

Yeah, 10k might be a bit too much. smile
Changed it to 680 ohm, seems to work better. Loud enough for headphones.

Zef
Offline
thursdaycustoms wrote:
Zef wrote:

Yup, I've tried using a headphone splitter in reverse, it does weird things to your stereo and really just doesn't sound good.

That being said, if anyone gets a Stereo solution to this problem that's small and cheap, let me know and I'll pre-order one pronto. I don't have a mixer and I do a lot of 2xLSDJ work, so this would be a Godsend. THISMEANSYOUTHURSDAY (still using my Thursday-boy daily, VERY nice work smile)

Awesome!
Yeah I'll see what I can come up with tonight if possible. I'd like it to have two stereo inputs with panning and one head phone output.
Should I do all jacks 1/8"? 1/4" would be more my style but 1/8" would obviously save space.

I understand it's less rugged, but my whole set-up is rigged in 1/8" right now so that's my preference. It's easy enough to get an 1/8" to 1/4" converter cable for those who need it.

AuburnKitsune
Offline
California
Timbob wrote:


WIP.
Well, it's something tongue
I'm now using 1K resistors. Sound is still quite soft, so I might switch to 680Ohms.
To top one still needs to be connected, I want to do a mono / stereo switch on that one.

!!! this is rad smile throw the schematics on here when youre done. no lie ive been thinking on making something like this all week.

Zef
Offline
Timbob wrote:


WIP.
Well, it's something tongue
I'm now using 1K resistors. Sound is still quite soft, so I might switch to 680Ohms.
To top one still needs to be connected, I want to do a mono / stereo switch on that one.

Nice case choice! Haha, that's pretty cool.

Timbob
Offline
Zef wrote:
Timbob wrote:


WIP.
Well, it's something tongue
I'm now using 1K resistors. Sound is still quite soft, so I might switch to 680Ohms.
To top one still needs to be connected, I want to do a mono / stereo switch on that one.

Nice case choice! Haha, that's pretty cool.

And easy to carry with the rest of the gameboy stuff tongue

thursdaycustoms
Offline
Cleveland, OH

Cart cases are so useful! I had my USB to MIDI adapter board in one for awhile.

DogTag
Offline
Murcia, Spain

I thought it should be 1kOhms each... weird. Have you changed R4 and R5 as well?

Last edited by DogTag (May 9, 2013 4:18 pm)

Timbob
Offline
DogTag wrote:

I thought it should be 1kOhms each... weird. Have you changed R4 and R5 as well?

I just took out the whole Op-amp part. couldn't hear anything.
Now I've got 680Ohms. stil a bit soft, but acceptable i guess.

DogTag
Offline
Murcia, Spain
Timbob wrote:
DogTag wrote:

I thought it should be 1kOhms each... weird. Have you changed R4 and R5 as well?

I just took out the whole Op-amp part. couldn't hear anything.
Now I've got 680Ohms. stil a bit soft, but acceptable i guess.

If you took the amplifier thing out, then forget what I just said hahaha.Why don't you try with a lower value?

DogTag
Offline
Murcia, Spain
DogTag wrote:
Timbob wrote:

I just took out the whole Op-amp part. couldn't hear anything.
Now I've got 680Ohms. stil a bit soft, but acceptable i guess.

If you took the amplifier thing out, then forget what I just said hahaha.Why don't you try with an even lower value?

ForaBrokenEarth
Offline
Nottingham, UK

I've got this ultra simple amp design I use a lot. I was going to build an amp into a briefcase, but I thought it'd be cooler to add a passive mixer in as well so I can have multiple inputs, so this thread's really interesting. smile

iLKke
Offline
Psydney, Australia

I'd always rather make a massive pixer, but that's just me

Timbob
Offline
ForaBrokenEarth wrote:

I've got this ultra simple amp design I use a lot. I was going to build an amp into a briefcase, but I thought it'd be cooler to add a passive mixer in as well so I can have multiple inputs, so this thread's really interesting. smile

Do share. smile

SAMWAVE
Offline
United Kingdom

I know you want a DIY line mixer. However, just found this one on ebay:

http://www.ebay.co.uk/itm/Micro-Mixer-4 … 27a3f8ab40

Requires no battery. Haven't a clue what the sound quality is like.