Last year I built and reviewed the low cost Oatley Electronics K272 Tube Stereo Headphone Amplifier Kit. In conversation with Oatley Electronics (located in New South Wales Australia), they told me that the kit became very popular and sold pretty much all over the world. The little headphone amplifier kit was based around new old stock Raytheon J
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AN 6418 sub-miniature pentode valves (tubes). Using the same JAN 6418 valves Oatley Electronics has released an inexpensive ($47AU, May 2010) tube based stereo RIAA preamplifier kit for moving magnet (MM) cartridges, and they were kind enough to send me a couple of kits. The printed circuit board (PCB) is double sided, solder masked and silk screened. Almost the entire top layer of the PCB is grounded to provide shielding. To keep the kit price low, the passive components are very basic. A mix of metal film and carbon resistors, polyester, ceramic and electrolytic caps. Polyester caps are generally not used in audio circuits because some say they do not sound good. Of course one can choose to upgrade the passive parts. The contents of the phono RIAA preamp kit are shown below. A full parts list of the kit contents is included in the Oatley Electronics K282 Kit Instructions (PDF - 646kB). The external power supply is a small 5V switch-mode power supply (SMPS) with a universal outlet adapter that can be used with American, European, Australasian and UK power outlets (100 - 240VAC). The circuit uses a MC34063A switched mode power supply integrated circuit (IC) to convert the 5V external supply to 30V. The switching frequency is set at around 100kHz. The phono preamp circuit is a two stage affair with each valve stage buffered by a 2SK170 Field Effect Transistor (FET). The new old stock (NOS) JAN 6418 tubes are used in pentode...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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