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Mac Mc225 amp.












This is the 4th Mc225 I got in, in the last 4 months and three were for McShane type rebuilds..The Panasonic 820s are for the doubler caps and then downstream is the dual 100@500v JJ.There is also a few Muse KZ caps in the cathode bypass of the input 12AX7 as well as the negative bias filtering which went from 10uf to 100uf.

Everything I did to these amps worked out well because I was able to keep the physical and sonic architecture intact,while at the same time enhancing everything about the amp that is good.

I did change the .047 bumblebee caps with .047 K40y at 1000v. The input caps were also bumblebee so I ended up putting in those wonderful Panasonic film and foil caps that Jim sold, and they work extremely well on the inputs.There is no reason to change out the rest of the Mallory film and foil mylar couplers as those don't really go bad and they sound incredibly good.

You can add extra decoupling capacitance if you choose and I usually do but this time, I went with a 35uf poly in place of the 15uf in the last section.I used Schottky-Cree diodes, but I shrink wrapped them..I used a UF4007 for the negative bias diode and you just put it right across the old selenium which makes a nice holder for the new diode..The Mcshane citation 2 and Citation 5 upgrades are really fit into the amps with doubler stacks like a glove..You don't have to cut up the chassis and it makes these amps go to town.




"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken


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Topic - Mac Mc225 amp. - Michael Samra 23:02:35 03/22/14 (5)

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