Altec Lansing MX5021 Modification


After making a CMoy and hotrodding my X-Fi, I needed a new project. I’ve had the Altec Lansing MX5021 speakers for a couple of years now and they’re the best ones I’ve owned so far. However there’s one nagging thing about them, speaker hiss. I searched around for modifications on this thing from Head-Fi with no results. Google however, gave me Jimmy’s Junkyard – Altec MX5021 Speaker Mod and Amplifier Mod.

I took after it and decided to first swap one of the op-amps from the stock ST 4558CN to a BurrBrown OPA2134 just as the guide recommended. I had an extra OPA2134 from my CMoy project and a bunch of extra sockets, so I figured what the hey! I’ll mod my speakers too.

The hardest part during the disassembly is unplugging the power supply and the subwoofer cables.


You can see here that I actually tore off the plastic connector. When I tried to push it back on, the traces at the back started to come off. With a few blobs of Loctite superglue, the piece was firmly affixed to the board.


The worst part, is that this glue is on the back side when you remove the panel to access the PCB. So you’ll be tugging away at the connectors and wondering why it’s so difficult to remove… They’re glued!

The BurrBrown OPA2134 in action! I put in a socket so I can later change it to an AD8620 for hopefully even better sound.

Next I will be sourcing some capacitors to replace the stock Samxon ones, and attempting the crossover modification.

11 Comments

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11 Responses to Altec Lansing MX5021 Modification

  1. Phil

    Hi, I have the same system mx5021 and it stop working today.my controller lights come on but no sound…can you help me?

  2. bz

    Sorry I’m not too familiar with testing for faulty components. The best advice I can give at this point is perform a visual inspection and a sniff test…

  3. Darren

    Hi, my MX5021 power transformer primary winding is open circuit, need to take it out for repair, unfortunately it was glued on the base panel. Anyone can give me a clue how to dismantle it ?

  4. Mircea

    Hello, Darren, I just finished repairing my MX5021. It had the same problem as yours. I had to replace the thermal fuse that is in series with the primary winding. It is buried beneath the side of the transformer that has the plastic protection.
    To remove the transformer I drilled some holes in the base of the cabinet after approximating the position of the screws.
    Good luck, hope my advice is not too late.

  5. Sloba

    Hey, do you remember if chnging op-amps did anything to the statis hiss from the speakers?

    Cheers 🙂

  6. bz

    Hi Sloba, this did nothing to stop the hiss. I’ve learned to live with it, and now put on headphones when I want to listen at very quiet volumes.

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