musical-fidelity-a3.24 mods

Digital Drive

Upsamplers, DACs, jitter, shakes and analogue withdrawals, this is it.

I have done some mods to the MF A3.24 which some of you with some electronic experience may wish to try. These mods greatly improve the transparency and bass tightness of the unit. Which truly makes it one of the best dac's around. The output stage of this dac is awesome, fully discrete and capable of driving a speaker direct, up to 6wrms!!!!!!!
1/ Direct coupling to the outside world, instead of going through a very average coupling electro. I tried a Blackgate instead of what they used, it was better but nowhere as good as direct coupling (removing the cap altogether). But you CANNOT just remove the cap as you'll get large amounts of DC offset at the output, and you will blow you pre or power amp.
This is how it's done
A/ Remove and short or just short out the output caps 470uf/63v C101 and C201.
B/ Find the 2X 2.2kohms resistors R108 and R208 (around 3inches from the back of the board) remove these resistors and replace them with 2x multiturn 5k cermet mini pots set at 2.2k to start with (Spectrol are good and avalible at most good electronic shops) You only need to use the centre and one of the outside legs the spare outside leg can be left in the air or attached to the center leg.
C/ put a digital multimeter on the output and earth and set the sensitivity to dcmv 200mv, powerup the unit and let it warm up and adjust the mulit turn pots for zero (0dcmv) offset. you can get it to stay at zero it will drift +1mv -1mv.
2/ For the very keen ones this will make it sound even better again.
A/ Find the i/o opamps 2x NE5532 after the dac and replace them with 4x AD825's these are smd singles and have to be mounted on 2x Brown dog boards. 2x ad825's for each Browndog board. They now replace the 2x NE5532's This jobs takes some patiences and care as the NE 5532's are through the hole plated on both sides.
Now you have a dac that is truly awesome to listen to.
Note: these mods will definatly void your warrenty
Cheers George

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Topic - musical-fidelity-a3.24 mods - georgehifi 19:34:48 05/24/05 (1)

Re: musical-fidelity-a3.24 mods - chijo 21:44:14 05/24/05 (0)

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