Posted on Tuesday, May 8, 2012 • Category: Amplifiers
I'm not sure what motivated me to decide on building a high-gain tube preamp of this sort. Maybe it was the tube computer sound card idea I have seen, or the fact that I have enough junk to fill a dump truck. What ever it was, it all started with a cute little plastic Hammond enclosure that had been on my shelf for a couple of years. I originally thought I might use it for a tube headphone amp, but in the end realized there would not be enough space for the three tubes needed to make a head amp. This is a high gain preamplifier that is suitable for use where a lot of gain is required - to drive a power amplifier that needs plenty of gain or perhaps for use with instruments, like a guitar or microphone. If you need less gain, take a look at the RCA 12AU7 / ECC82 Cathode Follower Tube Preamp Schematic which has a gain of about 8.
Build Accurate LC Meter and start making your own coils and inductors. This LC Meter allows to measure incredibly small inductances making it perfect tool for making all types of RF coils. LC Meter can measure inductances starting from 10nH - 1000nH, 1uH - 1000uH, 1mH - 100mH and capacitances from 0.1pF up to 900nF. The circuit includes an auto ranging and reset function to make sure the readings are as accurate as possible ... [more]