This is a 7 tube 20 watt amplifier that must be used in conjunction with a pre amplifier having volume an tone controls. For this, I recommend this 6 tube pre-amp. With this amplifier you may use 6BQ5 output tubes. A 5U4-G rectifier is used so that the power supply will have plenty of pep to run the amp. This amplifier is basically a Magnovox amp
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lifier I bought on ebay years ago and rebuilt after building the 6 tube amp. It is really amazing how it sounds, and the circuit is very minimalist, as you can see. Because of the output setup, you must use a quartet of matched 6BQ5 tubes. You will notice in looking at the schematic my preference for the balance control. I find this a convenient way to compensate for less than optimal speaker placement in my living room Above, the amplifier`s schematic. In addition to the 6BQ5 output tubes, a 6EU7 dual-triode is used in each channel. This amplifier also uses a curious phase-inverter circuit I have heard described as a "paraphase" inverter. *Note R4 and R24, optional fixed balance control, omit 750 ohm 1/2 watt pot. The original balance control was mounted inside the tuner. When I began using this amplifier without the tuner, I had to add two resistors in place of the connections to the pots. For whatever reason, I installed two 330 ohm resistors and used the amp this way for years before the rebuilding when I added a balance control pot. I was lucky to find a pot with the same value as the original at a real electronics parts store. Many readers have emailed saying they are having difficulty finding a 750 ohm pot. If this is the case for you, just omit the pot and use the 330-ohm resistors as shown. You may want to install a 3-prong line cord and connect the chassis to ground. Make sure the fused and switched side of the...
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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