Meridian M2 upgrade (PS capacitor and other things)

I need help since i am a complete debutant in DIY audio.
I wish to upgrade the capacitor in a pair of Meridian M2 active louspeaker, the speakers are pretty old now, but still sounding awesome thanks to the active crossover and biamp. They are IFF 6800µF 36V 10a. I wish to put the highest quality possible in order to have an efficient sound upgrade. After some search i found these "THEL-Elkos "
they are 22000µF 63V. As I am completly debutant in DIY, i wonder if its ok since i know that higher capacitance means faster signal. At first I wanted to put 47000µF but none of the model i found would fit the rear of the Meridians. The original size of the IFF 6800µF are 4cm diameter and 7.5 cm long so the THEL Elkos will fit in. In the other hand some 5cm diam. caps are simply too big to fit in. thanks for any advice.
Also i wish to upgrade other parts like transistor or any other efficient part in the soundwise quality. But since I know very few I dont know what to ask. Thanks.


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2009-07-15 9:35 am
Hi Edodo,
I too own a pair of M2's and I've done this modification of bigger capacitors already. It gives the speakers more definition and they sound definitely stronger. I think that is because they can go somewhat lower now, but I've not checked this. The bigger capacitors will improve the dynamic power of the amplifiers used, especially the woofer-amplifier.
- You must not forget to put some small capacitors (say, 1 - 10 uF of non-electrolytes) parallel to the big electrolytes because that will improve the mid- and high frequencies.
- You can also put the bias-current of the high-amplifier somewhat higher. This gives the amplifier a bigger headroom in class-A amplification and so it will sound even less distort and more natural (as a minus this amplifier will consume more power and the rear of the speakerbox will become warmer). If you don't know how to do this I would not advise you to do this.


2009-07-15 9:35 am
Magura said:
If you really want to make a serious upgrade, put some 150uF PP film caps (or more if your wallet feels like it) in, that will give you much more than any electrolytic cap can.
Magura :)

I THINK this is overkill. A few uF's may give your PS somewhat lower impedance in the higher frequencies, resulting in somewhat more transparant and easier high frequencies, but 150 uF will extent this to the low-mid's and that is the area where the standard electrolytes work fine. Okay, it wouldn't harm to do so but it will not result in an audible improvement, IMHO.
- In case of the Meridian M2, one can also think of a bass-extender. Where the M2's start working at 38 Hz, the lowest octave (20 - 40 Hz) can benefit from a well-defined bassboost filter around 30 Hz. That would consume a lot of power but the box will sound more solid and mature (although with less well-defined midtones because the woofer works harder). A separate subwoofer for the lowest frequencies of max. 100 Hz, would give the M2's better bass AND better midtones, resulting in much cleaner and better sound.
Oh well,