Pre-Amp Power Supply Upgrade ????

I would like to get a clarification from you: do you really mean 50,000 mfd of storage capacitance for a PRE-AMP, or do you mean a POWER AMP? There are many power amps that have less than 50,000 mfd of storage capacitance, and pre-amps have considerably less than a power amp because they are only increasing the signal strength enough to cleanly drive the power amp. Having said that, and based solely on your question, I can see no logical reason to need 50,000 mfd of storage capacitance in a pre-amp (several thousand mfd ought to be plenty). A preamp does not have to produce the large voltage swings necessary to drive a speaker, and therefore does not need high storage capacitance.

(Without getting overly technical, my comments above are somewhat incomplete, since power supply filtration / storage capacitance is determined, in part, by the voltage level. Storage capacitors that are rated for higher voltages will store more energy.)
If you will provide a bit more information about the reason behind your question, and whether you are really asking about PRE-AMP storage capacitance, perhaps the "regulars" on this forum can give you more definitive advice.

Dnlyko- Increasing the storage capacitance can have a very positive effect. However, quality is of more importance than quantity once you've reached a design minimum of storage. Also, simply increasing the quantity without considering the rest of the power supply circuit and physical layout, may yield no benefits, or worse, damage the rectifier from overcurrent at turn-on.

Also, the greater gains will likely come from improved caps after the regulators which are closer to the audio circuits. The main a/c filter bank is important, but doubling, tripling, or quadrupling the size of the main bank alone may not bring about the improvements you desire. The power supply needs to be examined as a whole.

I'm not trying to impede your interest in DIY projects. In fact, I wish more enthusiasts would consider 'getting into' their components. But look into some of the more DIY websites and pick up a good source book on power supply design. They usually offer a relatively simple explanation to understanding the basics as well as getting into the math behind the scenes, and may help you avoid a 'magic smoke' experience. Follow your curiousity and interest. Enjoy the electronics that best serve the music.

Talk to Bill Thallman at Music Technology
http://www.musictechnology.com/
bill@musictechnology.com

Bill if a former Conrad Johnson engineer and knows preamps. He also
does power supply upgrades. He upgraded the power supply on my
CJ/Motif preamp with good results.