The Nuvistor circuit | Next Electronics

Recently, a music synthesizer has been constructed using vacuum tubes. Although designed primarily as a percussion synthesizer, it can also be controlled via a keyboard or a MIDI to CV converter. The initial module developed is a dual voltage-controlled oscillator...

Simple Cable TV Amplifier Circuit

This cable TV amplifier circuit is an RF amplifier designed for quick installation between two coaxial cables. Both the input and output impedances are compatible with 75-ohm cables. The main amplifier is the T1 transistor, while T2 functions as an...

Three ECC83-Based Tube Phono Preamplifier Circuits

The three circuits were based on the vacuum tube ECC83, designed to produce phono preamplifiers in compliance with RIAA standards. The described circuits utilize the ECC83 vacuum tube, a dual-triode component known for its low noise and high gain characteristics, making...

Miniature MW Transmitter

Here is a very simple, inexpensive and interesting project which provides lot of fun to a home experimenter or hobbyist. This simple transmitter can transmit speeches or songs within a short range. The circuit uses only one transistor. The entire...

Altec 1566 vacuum tube mic preamp and direct box

V1 and V2 are 12AX7 dual triodes. Each half of V1 is configured as a Class A voltage amplifier in a Common Cathode arrangement. In contrast, both halves of V2 are connected in a Cathode Follower configuration to provide current...

Receiver If Amplifier

Tl is tuned to the converter output frequency Ul to provide a gain of 45 to 50 dB, depending on the design of Tl and T2. C2, C3, C4, C5, and C6 function as bypass capacitors. R5 serves as a...

QSK 2KW

The QSK-2KW is an external RF T/R interface device that connects to any RF vacuum tube amplifier. It provides full high-speed RF amplifier T/R switching for CW or digital break-in operation. The QSK-2KW requires a low current keying input, allowing...

Interfacing MaxTrac Mobile Radios to Repeater Controllers

This article outlines a reliable, straightforward, and universal method for interfacing Motorola mobile radios from the MaxTrac, Radius, and GM300 series with common repeater controllers. The information provided is also relevant for radio interfaces used in IRLP or EchoLink applications....

1W-cwtransmitter

This is a small transmitter designed to fit inside a plastic Easter egg. It delivers approximately 1 W of measured RF output into a 50-ohm dummy load and does not generate any heating issues within the circuit. The crystal used...