So, Long story short I posted to someone's thread years ago (2012) about an Olson AM-221. It masqueraded as many different brands including Lafayette, Olson, Cal-Rad and more. These were intended to provide a MM and Tape Head preamp for inexpensive stereos that had a Ceramic cartridge input. It sounded terrible and recapping it made no difference. As a result I have rendered it into an empty shell, and removed everything except the little transformer, the tube sockets and the tape/phono switch. It looks pretty sharp, and cleans up nicely, so I don't want to toss it. My goal now is to turn it into an actual working Pre-Amp. We have a PA system at work that has standard line inputs, but an iPod/Phone does not give enough "Oomph" to make the system sound good. After hooking it up to a preamp it sounds fantastic, surprisingly so, and I am going to wire the line input to the shop 25 feet away. I have now been browsing the internet for possible 12AX7/12AU7/????? preamp schematics. There are literally dozens if not hundreds to choose from. Making a simple Diode bridge, the transformer makes about 132V. This is before any capacitors or any load. 6V is also provided for the heaters of the 2 12AX7's. So the first question is Voltage doubler or stick with the 130V? If I use a voltage doubler what is the proper way to incorporate it? Pro's / Cons??