mac mc2200

need advice on modify to this pre, thanks in advance
There are some DYI things you can do for little to moderate cost that may eliminate the need for any professional modifications.

Start with tube upgrades. They can make a phenomenal difference on this preamp for a moderate cost - start with the line section first if cost is an issue. Amperex Bugle Boys are fantastic and will transform the C2200 making it clearer and more dynamic with better imaging and articulation. You'll think that you have a different preamp. Mullard and Telefunken are also excellent choices. But even with average tubes - General Electric, Phillips, etc. you'll notice a BIG difference. Once you've rolled your 12AT7 and 12AX7 tubes to these upgraded tubes you'll wonder how Mac could be rated so highly with the stock tubes. I have my stock tubes on a shelf and can't imagine ever using them again.

Next, use tube dampers. Herbies Audio Lab sells excellent dampers for about $12@ and you only need one per tube.

Next, put Marigo 3mm Green tuning dots on all the capacitors.

Also, apply Walker SST or Extreme SST to the tube pins (also include the internal fuses as well). It is an electrical contact enhancer and yields remarkable results.

Finally, don't use the stock feet on the C2200. Use Black Diamond Racing Cones or brass spikes. Although, I've found the most improvement with using small blocks of zebrawood directly under the chassis (not under the feet) in place of the feet. Different wood will give you different frequency emphases, so experiment with maple, oak, teak, mahagony, zebrawood.

Most of these tweaks have been discussed extensively on AudioGon or elsewhere on the web. The use of wood tuning blocks are discussed in detail at Stereo Times online under 'the art of audio system tuning.'

I've tried all of these on my C2200 and have found them to be well worth the effort. I would not part with any of them

Hope this helps.
Jgiacalo is correct on wood tuning feet and tubes. I own a MA2275 ( c2200 pre section in my integrated ) and have already rolled 3 sets of tubes. Yesterday I received a pair of Telefunken ecc 801s and heard the most dramtic change yet to my mac. Felt like the highs came alive with beautiful seperation and tighter. longer lasting decays. I have my system on sistrum sp004's, cutting out rosewood cups and resting the points on the cups also seemed to cut some glare and made my digital sound a little warmer. Tweak is in my virtual systems thread. Experiment and have fun, get those stock tubes out of your c2200.
One more tweak I forgot to mention that yields improvements far beyond their cost. Insert shorting RCA plugs into all unused input jacks. You can either make them yourself (if you can solder)with parts avaliable from Radio Shack @ 3 pair for $4.00. Or, you can order some ready made from The Tweak Shop @ $6.00/pair.

Velo62: I'll have to give rosewood a try...