This odd little amp was something I designed and built for a shootout at the European Triode Festival in 2007. The topic was `White Light` - amplifiers that use thoriated tungsten tubes. Some great photos of the event can be found here and here. Since it`s impractical to tote an enormous tube amp from the US to Europe, I decided on an approach th
Click here to download the full size of the above Circuit.
at uses a solid-state power output stage and a small thoriated tube as a voltage amp. I tried out just about all the small tubes of this type that I could find, and wound up using the 703A. The 703A is a small UFO-shaped triode designed for radar jammer service. I found that it made a pretty decent low-level amp when run with a B+ of 48V and a ~1mA CCS plate load (!), so that`s what you find in this circuit. It is coupled to TI (Burr-Brown) OPA548 power op-amps, which drive the speakers. Power is +/-24V, generated from some Vicor DC/DC converter modules. The 1. 15V filament is supplied by another pair of isolated DC/DC converters, running form the +/-24V (48V) DC supply, with significant common mode filtering. I set the amplifier up to sound somewhat like a single-ended 300B amp. It puts out about 20 watts into 8 ohms, and has an artificially high (for a solid-state output stage) output source impedance of 1 ohm, to emulate a tube amp output. It has about 0. 3% - 0. 5% THD at 1 watt output, dominated by 2nd harmonic, as a single-ended tube amp should be. And finally an FFT of the output. Dominated by 2nd harmonic, like a SE tube amp. but there are crossover distortion products from the solid-state output stage that extend all the way to 20kHz, albeit 90dB down. Note the measurement floor is -135dB! The power supply uses Vicor modules: An IAM AC input module (filter and rectifier with some supervisory functions) and two...
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.....
characters left: