This Project is done only as a Personal interest of mine, This Thread is a Blog of What I did with the MX5021 Rather than a Guide, By Posting this I only Intend to share Information, Any Damage done to your MX5021 Attempting any of the Mods Posted here Are not my Responsibility.
I'm sure many of you know of the Altec Lansing MX5021 Stereo Audio System, Its Without a Doubt the best Computer Speaker Altec Lansing made yet, and is among the Best 2.1 PC Audio Systems in the world, The Key to its Superior sound quality is a combination of careful craftsmanship of the Sub woofer and Satellite Compartments combined with High Quality Drivers, The Trade off for this is Sub Par Electronic Components inside, even though for you when you listen to the Stock MX5021 it might sound fantastic, but the truth is that its sound is far from being Hi-Fi, Through these Mods I was able to Improve the sound quality to a whole new level, I must tell you that not everyone can hear subtle differences in Audio Quality, for some these mods will not sound any better than the stock MX5021, Audio is very Subjective, Its a combination of Good Hearing + Good Audio Equipment.
MX5021 (Ver 1)
Throught the existence of this speaker system Altec has made two Revisions to its Components, the one on the Picture is a First Generation MX5021, Notice the Speaker Cones have a Flat Surface, newer Models have completely Curved Cones, Apart from this, Changes includes the Crossover network of Satellites, and the Main PCB.
MX5021 (Ver 2)
All the Mods I have done are on the newer version of the MX5021
Modding the Main PCB
Most Significant Mods are done to the Main PCB inside the MX5021 Sub Woofer, Im changing most of the poor quality Electrolytic capacitors (Samxon a Chinese brand) With High Quality ones, as of this Writing I have Changed All but three Electrolytics from the PCB, Im waiting for the parts for the other three.
Also All the Op Amps will be changed to High quality Audio Grade ones, the Stock ST4558 Op Amps are very old and has very poor Audio performance, I will be using Texas Instruments - Burr Brown Op Amps here, You are free to use Any compatible Op Amp, Make sure they can handle the Voltage.
Electrolytic Capacitors are a extremely Bad Choice in a Audio Signal Path, I Will Remove all the electrolytics from the signal Path and replace them with Film Caps
Also Changed is the poor quality Sub Woofer Cable, and a Mod to the Power Cables.
Heres the Stock PCB
After the Mods...
U6 = Effects the Sound stage Significantly, you can operate the sub without this but the sound will get concentrated on the center, this also effects the mid range quite a bit, very Important Op Amp in my opinion, Use a Op amp with a Wide sound stage here, Im currently using OPA2277 but I think OPA2111 will do better here.
U12 = This one is Tricky It Effects the Overall Gain of the system, its probably the Gain for the Tone Control Stage, OPA2277 fits Perfect for this application
U5 = This is the input Op Amp for the Sub, Use a Op Amp with tight and Accurate Bass here, like OPA2107
U7 = This Op slightly effects the Tonality and Clarity, Im not sure of its Purpose but Things work Fantastic when I use a High quality Op there, like OPA2111
U9 = This is the Input Op Amp for the Satellites, use a Quality op here also, OPA2111 is my Choice
Power Filter Caps are Changed to - 10000uf 63V, 3300uf, 2200uf from 4700uf, 2200uf, 1000uf. This mod will dramatically Improve the Bass Performance and make the Amplifier Stable at Very High Volumes, After these Mods you will be able to crank the volume to the Top without hearing a Hint of Distortion.
C61, C54 – 2.2 uF 50V to 1uf 250 Polyester Film
C50, C52 – 2.2uF 50V – 22uF/47uF 50v
C45, C34 – 22uF 50V – 22uF/47uF 50v
C41, C46 – 2.2uF 50V – 22uF/47uf 50v
Sockets for the Op Amps
Power Cables Mod
I have Modded the Power Cables for the MX5021 also, Since they are so short I have to remove the socket every time I Open the Sub, so I extended it by removing the Socket on the board and soldering it to some Wires, I have Soldered the extended wires directly to the board, I used heat Shrink Tubing to insulate the connections of the socket.
Quality Improvements from these Mods are Extreme, With these Mods the MX5021 can Easily Out perform some Book Shelf Speakers many times the price of this system. I will Update this thread with the Crossover Mod for the Satellites as soon as I get the Components, Stay Tuned.
I'm sure many of you know of the Altec Lansing MX5021 Stereo Audio System, Its Without a Doubt the best Computer Speaker Altec Lansing made yet, and is among the Best 2.1 PC Audio Systems in the world, The Key to its Superior sound quality is a combination of careful craftsmanship of the Sub woofer and Satellite Compartments combined with High Quality Drivers, The Trade off for this is Sub Par Electronic Components inside, even though for you when you listen to the Stock MX5021 it might sound fantastic, but the truth is that its sound is far from being Hi-Fi, Through these Mods I was able to Improve the sound quality to a whole new level, I must tell you that not everyone can hear subtle differences in Audio Quality, for some these mods will not sound any better than the stock MX5021, Audio is very Subjective, Its a combination of Good Hearing + Good Audio Equipment.
MX5021 (Ver 1)
Throught the existence of this speaker system Altec has made two Revisions to its Components, the one on the Picture is a First Generation MX5021, Notice the Speaker Cones have a Flat Surface, newer Models have completely Curved Cones, Apart from this, Changes includes the Crossover network of Satellites, and the Main PCB.
MX5021 (Ver 2)
All the Mods I have done are on the newer version of the MX5021
Modding the Main PCB
Most Significant Mods are done to the Main PCB inside the MX5021 Sub Woofer, Im changing most of the poor quality Electrolytic capacitors (Samxon a Chinese brand) With High Quality ones, as of this Writing I have Changed All but three Electrolytics from the PCB, Im waiting for the parts for the other three.
Also All the Op Amps will be changed to High quality Audio Grade ones, the Stock ST4558 Op Amps are very old and has very poor Audio performance, I will be using Texas Instruments - Burr Brown Op Amps here, You are free to use Any compatible Op Amp, Make sure they can handle the Voltage.
Electrolytic Capacitors are a extremely Bad Choice in a Audio Signal Path, I Will Remove all the electrolytics from the signal Path and replace them with Film Caps
Also Changed is the poor quality Sub Woofer Cable, and a Mod to the Power Cables.
Heres the Stock PCB
After the Mods...
U6 = Effects the Sound stage Significantly, you can operate the sub without this but the sound will get concentrated on the center, this also effects the mid range quite a bit, very Important Op Amp in my opinion, Use a Op amp with a Wide sound stage here, Im currently using OPA2277 but I think OPA2111 will do better here.
U12 = This one is Tricky It Effects the Overall Gain of the system, its probably the Gain for the Tone Control Stage, OPA2277 fits Perfect for this application
U5 = This is the input Op Amp for the Sub, Use a Op Amp with tight and Accurate Bass here, like OPA2107
U7 = This Op slightly effects the Tonality and Clarity, Im not sure of its Purpose but Things work Fantastic when I use a High quality Op there, like OPA2111
U9 = This is the Input Op Amp for the Satellites, use a Quality op here also, OPA2111 is my Choice
Power Filter Caps are Changed to - 10000uf 63V, 3300uf, 2200uf from 4700uf, 2200uf, 1000uf. This mod will dramatically Improve the Bass Performance and make the Amplifier Stable at Very High Volumes, After these Mods you will be able to crank the volume to the Top without hearing a Hint of Distortion.
C61, C54 – 2.2 uF 50V to 1uf 250 Polyester Film
C50, C52 – 2.2uF 50V – 22uF/47uF 50v
C45, C34 – 22uF 50V – 22uF/47uF 50v
C41, C46 – 2.2uF 50V – 22uF/47uf 50v
Sockets for the Op Amps
Power Cables Mod
I have Modded the Power Cables for the MX5021 also, Since they are so short I have to remove the socket every time I Open the Sub, so I extended it by removing the Socket on the board and soldering it to some Wires, I have Soldered the extended wires directly to the board, I used heat Shrink Tubing to insulate the connections of the socket.
Quality Improvements from these Mods are Extreme, With these Mods the MX5021 can Easily Out perform some Book Shelf Speakers many times the price of this system. I will Update this thread with the Crossover Mod for the Satellites as soon as I get the Components, Stay Tuned.
