Blog
Bruce Heran writes:
It has been a while since I did anything really crazy in DIY and had it work out far above my expectations. Such is the case for the Mini Blocks. I had a lot of extra parts lying around (really a huge amount of them) and tried to figure out what I could build. Two small chassis about 5 inches by 9 inches by 2 inches (12.5 X 22.5 X 5 cm) were just begging for a project. They are just the right size for lots of things. I first thought of a pair of SET amps. But since I didn’t have any suitable single ended output transformers I nixed that idea. A preamp perhaps could be built on one of the chassis. Since I have many preamps now that didn’t really get the nod either. A pair of small push-pull amplifiers was next on the list. Maybe, but I have so many amps now that it doesn’t make sense either. Since this hobby doesn’t always have to make sense, that is what I built. Clever observers will note that each of the mini blocks is a whole lot like half of a PoddWatt amplifier
Mini Block Push-Pull EL84 (6BQ5) Valve Amplifiers - [Link]
Plastic Water Solenoid Valve – 12V – 1/2 NPT. Control the flow of fluid using the flow of electrons! This liquid valve would make a great addition to your robotic gardening project. There are two 1/2″ (Nominal NPT) outlets. Normally, the valve is closed. When 12VDC is applied to the two terminals, the valve opens and water can push through. The valve has a gasket arrangement inside, so there is a minimum pressure requirement of 0.02 Mpa (3 PSI). Also, liquid can only flow one direction.
Plastic Water Solenoid Valve – 12V - [Link]
Bruce Heran writes:
This is a project that I always wanted to do, but managed to put off for a long time. It has been over a year in the doing. Partly because there are so many good phono preamps in existence and I was slightly concerned that it was beyond my design skills. It took over a year to get it up to my satisfaction. There were several iterations and lots of frustration along the way. My goal was to make a preamp that would not embarrass the builder with inferior performance. I used a number of commercial products for comparison. My thought was why bother to design and build something that was already available for a lower cost. As it turns out, it was not as inexpensive nor un-complicated as I first hoped.
The Groovewatt Tube (Valve) RIAA Phono Preamp Project - [Link]
Bruce Heran writes:
This is a project that I made to take care of an ever increasing need to prototype vacuum tube (valve) circuits. As you can see from the photos, it really is a test “board”. I do a lot of work with tubes and love to design and improve circuits. In the process I often use various CAD type programs to rough out the designs.
DIY vacuum tube prototyping board - [Link]
A small and simple tube amplifier project using one 6T9 vacuum tube per channel. A single PCB makes this a simple project even for beginners. The enclosure is a low cost baking pan.
If you are just getting into do-it-yourself (DIY) audio and have wondered about building a valve amplifier but been put off by the seeming complexity and high voltage, this 6T9 valve based amp may just be the answer. The high voltage concern is a real one and is no less important in this project than any other. But what does soften the build complexity is the entire amplifier is based on a single printed circuit board (PCB). The valve used in this project is the 6T9 compactron which is a triode and pentode in the one envelope. The 6T9 valves I used are new old stock (NOS) General Electric which are cheap (about $7) and available from several online sources such as Tube Depot.
DIY 6T9 Tube / Valve Amplifier Project – [Link]
