Comments on: Reducing Headphone Noise from the HyperMac Battery

By: tlberglund

tlberglund — Wed, 17 Feb 2010 01:13:09 +0000

Heh. Well, thanks, Brian, but when it comes to actual hardware design, it’s best done by people who give their full time to that profession. I can hack a bit and interact with hardware guys, but ultimately I trust HyperMac to fix this properly in the next rev.

One caution about putting the filter where you’ve got it: you’re killing the hiss, but you’re also filtering out valuable audio signal. I’m sure it still sounds better with the toroid in place, but it will be knocking down high-frequency audio energy that should be allowed to make it all the way to your headphones. My post was definitely not clear enough, but the part you want is DigiKey 732-1534-ND. That guy is big enough to fit the MagSafe connector through with six windings of the cord like I show in the picture.

Regardless, I’m glad this helped! Thanks for contributing to the post.

By: Brian

Brian — Wed, 17 Feb 2010 01:04:45 +0000

My also makes a whine with headphones on and using hypermac. I wasn’t able to fit the power cord into toroid, I guess I bought a smaller size, so what I ended up doing was put the headphones cord through toroid instead. With music on the background static hiss noise wasn’t noticeable. Thanks for this solution, works for the moment. Hypermac should really address this issue or maybe hire the person who came up with this temporary fix, since their engineers can’t figure it out.

By: tlberglund

tlberglund — Tue, 16 Feb 2010 18:43:20 +0000

Yes, my battery squeals also. This is another dead giveaway that there is a switching power converter in there. It’s not unusual for switchers to whine occasionally (especially under conditions of very low or very high load), but I can’t comment on whether it’s indicative of any kind of problem. As it stands, I think of it as giving my HyperMac some personality.

If somebody who actually knows switchmode power conversion happens upon this post, your comments are welcome.

By: Ben

Ben — Tue, 16 Feb 2010 18:32:40 +0000

As a new owner to a Hypermac Battery (150) and apple power books in general I thought I was going crazy or my battery was just a dud. This at least makes some kind of sense as to what could be causing the issue. With my Bose QC2 the noise is like a hairdryer being plugged into a wall socket and the TV going fuzzy.

I will buy the toroid and let yall know if it makes using the battery on the plane is bearable. It is rather unfortunate that we have to do this with something that costs soo much to begin with…

Thanks for the idea

Also, my battery makes noises. This is the first I have ever experienced this phenomenon. The hypermac staff mentioned that this way natural. I was wondering if anyone else was experiencing this as well?

-Ben

By: Scott Davis

Scott Davis — Mon, 08 Feb 2010 16:02:33 +0000

Hey Everyone, look at the brain on Tim! Strong work, Friend. Strong work.

By: Matthew McCullough

Matthew McCullough — Mon, 08 Feb 2010 14:53:34 +0000

As a new owner of a HyperMac, I salute you. You are like a liason from a foreign society (hardware) bringing hand waving and words of harmony to the noise-suffering masses in the software community. Thanks. A toroid it shall be.