Question Audio Jacks and Cooling

[Saix]

So I have two unrelated questions.

1. I'd like to add 4 3.5mm jacks to a cube. I have 5v amp. Wiring I assume is easy enough, just 4 pots and jacks in parallel but I'm a bit hung up on what jacks and pots to use. I'm pretty confident I can just use standard 3 pin headphone jacks just fine, but what kind of potentiometers should I be using (preferably wheel type)? I don't really know a ton about audio stuff, but I imagine that a big pair of headphones and a tiny pair of earbuds would have different power needs which I'm guessing would affect potentiometer choice but I need to be able to use both. Obviously I'm taking audio from the cube, but I need to be able to have audio play through the TV's speakers and any/all of the jacks at the same time, would that change or affect anything?

2. So I'm pretty tight for space and need some help on cooling. I'm pulling air from the heatsink and exhausting it but my fan is pretty close to the heatsink and cant breathe and its performance is suffering. What are you guys doing for getting rid of heat? I'm not super familiar with blower style fans, but would one of those work better for being super close to a heatsink?

 

[cheese]

As long as you have an amp between the audio out of the cube and the headphones, you will have no problems. Just get some kind of stereo potentiometer for each jack and put it between the audio amp and the jack itself. They look like this:

Spoiler

As for cooling, I actually took the cube fan and broke off the plastic shroud, cut down some of the fins in the heatsink, and glued it directly onto the heatsink (I believe this idea was first done by Ashen). Alternatively, you could get a blower style to suck air in the top and blow through the fins, if that works better for you.

As always on here, gotta plug wii portables since they put out less heat, use less power, and can be cut smaller. If you haven't gotten too far in your (what sounds to be) portable, you may want to look at the Wii

 

[Luke]

I might offer a suggestion here:

I don't know if you will be mainly playing this with 3 other people crowded around, and the 4 of you each using seperate headphones at all different volumes (Seems pretty overkill to me, and seems like a situation that will hardly ever happen. For me, I'd play a portable by myself 95% of the time, and for the times I played with other people it would be only with one other person, we wouldn't use headphones, and even if we did we would have used headphone splitters which would have been just fine.). So I would just advise that you make sure this is something you absolutely need before you devote so much surface area of your portable to 4x headphone jacks and 4x volume knobs (and again, idk if you've ever used headphone splitters but it doesn't really make a difference that the headphones are different sizes - seriously though, just get something like this and call it done).

Also, I don't know if other people put potentiometers in between their audio amp and speakers vs. in between the portable and the audio amp, but I have been told in the past not to put a pot in between the audio amp and speakers because it could damage the audio amp (because normally speakers are only 8ohms and by putting the pot in series you're adding more resistance which could cause strain to the output of the audio amp). Not sure though. Assuming you want to do this the "correct way", seems like you would need 4 audio amps, along with your 4 pots and 4 jacks

 

[Saix]

As long as you have an amp between the audio out of the cube and the headphones, you will have no problems. Just get some kind of stereo potentiometer for each jack and put it between the audio amp and the jack itself. They look like this:

Spoiler

As for cooling, I actually took the cube fan and broke off the plastic shroud, cut down some of the fins in the heatsink, and glued it directly onto the heatsink (I believe this idea was first done by Ashen). Alternatively, you could get a blower style to suck air in the top and blow through the fins, if that works better for you.

As always on here, gotta plug wii portables since they put out less heat, use less power, and can be cut smaller. If you haven't gotten too far in your (what sounds to be) portable, you may want to look at the Wii

Welp, switched over to a Wii, can't really argue with all the benefits. Okay so while I was writing this I think I may have realized my problem. I wired everything up, but all I was getting was crackling. I was using wheel pot I had lying around, and something didn't make sense to me because I was wondering where to wire the left and right negative connections from the amp but I've realized that problem should disappear if I use one of those dual channel pots like you pictured, I'm a dummy. Hopefully I can pick one up tomorrow and get it to work!

 

[Luke]

but what kind of potentiometers should I be using (preferably wheel type)?

Just so you know, if you still want a volume wheel (dial) instead of a volume knob, they have the double ones (for stereo) in wheel form as well.

 

[Aurelio]

Just so you know, if you still want a volume wheel (dial) instead of a volume knob, they have the double ones (for stereo) in wheel form as well.

Also make sure to get logarithmic ones

 

[Saix]

Just so you know, if you still want a volume wheel (dial) instead of a volume knob, they have the double ones (for stereo) in wheel form as well.

I have one, but I couldn't seem to get it to work

 

[Luke]

How many pins did it have? If it only had 3, it's not going to work, but if it had 5, it should.
Did you know the pinout? Here's one I found.

 

[Saix]

How many pins did it have? If it only had 3, it's not going to work, but if it had 5, it should.
Did you know the pinout? Here's one I found.

Yup, using a five pin. It definitely works, but I'm just getting crackling still.

 

[Luke]

I was wondering where to wire the left and right negative connections from the amp but I've realized that problem should disappear if I use one of those dual channel pots like you pictured

Did you end up grounding these terminals?

They should both be grounded; doesn't matter which pot you use, they're both dual channel.

There's 5 pins on the dial one instead of 6 on the knob one that cheese mentioned because on the dial one they have combined the 2 ground pins to 1.

 

[Saix]

Did you end up grounding these terminals?

They should both be grounded; doesn't matter which pot you use, they're both dual channel.

There's 5 pins on the dial one instead of 6 on the knob one that cheese mentioned because on the dial one they have combined the 2 ground pins to 1.

Yep, I realized that after I remembered that that's how it is for the jack. So I'm not quite sure what's going on. I'll post a picture when I get home, maybe that'll help

 

[Saix]

Did you end up grounding these terminals?

They should both be grounded; doesn't matter which pot you use, they're both dual channel.

There's 5 pins on the dial one instead of 6 on the knob one that cheese mentioned because on the dial one they have combined the 2 ground pins to 1.

I definitely have to be wiring something up wrong. I'm getting crackling no matter what I do with the amp, but I know the amp works. As soon as I solder the jack straight to the board without the amp there's no crackling.

I've gotta be overlooking something, right?

 

[cheese]

When you said you hooked it up directly, how did you have it wired?

 

[Saix]

When you said you hooked it up directly, how did you have it wired?

Just without the amp. Left and right audio from the board straight to the jack and then just grounded it. It works with the pot too, but as soon as I add the amp it goes to poop

 

[cheese]

Well, try wiring just the amp and no pot? The amp may be bad

 

[Saix]

Well, try wiring just the amp and no pot? The amp may be bad

Huh, weird. I had used the amp with some speakers yesterday and it was working just fine, but I guess it might be bad now? Skipped the potentiometer and still got the crackle. I'll order another amp and see if it works.

 

[Saix]

Well, try wiring just the amp and no pot? The amp may be bad

So I got a new amp, which works. I wired everything up, and it kinda works? Its definitely way louder, and no longer makes the speakers in the tv super quiet when you plug a pair of headphones into the jack. The sound comes in loud and clear in one ear, but crackles in the other. And if I turn the pot down to low volume it sounds like the crackling goes away? And then sometimes when I turn it all the way down and back up again the crackling will switch to the other ear? Not really sure what's going on here