Vacuum Tubes - Valves

This power amplifier has a subsonic highpass filter in it, to make sure that too low frequencies will not damage subwoofers. This type of car amplifier must be installed by professional installer. This kind of amplifier needs well prepared car electricity, like good battery, and high-output alternator...

This is an image Schematic. No Description available...

The Pro has basically the same output tube complement as the EarMax, but can provide higher current output into low impedance headphones. The specifications suggested that the topology of the EarMax Pro was similar to the EarMax (both having White cathode follower output stages), but the mystery remained as to how two amplifiers with similar output stages (no output transformers) could have substantially different output characteristics...

Fred Forssell`s circuit (figure 3) has the differential input stage of a true opamp with a high common-mode rejection ratio (CMRR) and a mu follower output stage (biased at 12mA). The open loop gain is about 510 (30 from the first stage, 17 from the second). When configured for a closed loop gain of 18, the performance approaches that of solid state opamps: THD < 0.1%, Rout = 8 ohms, Fh > 400 kHz and s/n ratio = -86dB. Despite the low output impedance, the load impedance should be 3K ohms or greater to avoid increased distortion...

The circuit is simple, yet is capable of excellent performance. I designed it specifically for use as an amplifier for the digital sound card in my computer. Audio input can be from any two-channel line level device such as a television, CD player, or VCR. It is of the tube type, using only 5 tubes total with no more than about 45 Watts power consumption from the outlet. It uses 3 types of tube 1 5Y3 GT vacuum rectifier, 2 6SF5 GT high-mu triodes, and 2 6K6 power beam amplifiers. These are all full-size octal type tubes which are commonly available today for between $3-5 each...

I spent much of 1997 designing and building my ultimate dream amplifier, which I named "The Emperor`s New Amplifier"TM (TENA) for a quality it shares with the fabled emperor`s wardrobe-- transparency. It was also an oblique reference to the marketing hype that pollutes high-end audio. I thought about commercializing it, especially when the lab where I worked announced it was shutting down, but I soon realized that marketing high-end tube amplifiers is not a reliable way to make a living. (I`m paycheck-addicted.) Counterpoint Electronics, a high-end audio manufacturer located in a 45,000 square foot building five miles from where I lived at the time, vanished overnight. Then I thought I might write a magazine article, but the move to Colorado distracted me...

This product comes with quite a story. I remember many years ago, when I install audio system in my own car, I always look for a "black box" that I hope can me my system sounds great. I was hoping that this "black box" can change the whole sound of the system instantly. So I begin to try various IC preamp, like RockfordFosgate PA-1, Precision power PAR225, Zapco SX and PX, Nakamichi PA101, Audio control products, and almost all the signal processor available on the market. They are the best available. It turns out that my dream of such a "black box" is impossible...

The interest for circuits of tubes, remains big. Thus I will give completed in enough big degree, circuit of preamplifier. It is mainly constituted by the department of main preamplifier, the department of input selector, delay of application voltage and connection output of preamplifier with the final amplifiers and the department power supply. The department of mainly preamplifier appears in the Fig.1. Deliberately it does not have something revolutionary in the designing. In the entry exists a simple circuit constituted from relay that is drive from input selector [S2]. The signal afterwards drive to the next stage that is constituted by a circuit cascade S.R.P.P (shunt regulated pushpull) and a circuit cathode repeater, in the exit...

It is three circuits of RIAA, amplification of low signals of heads [MM], following different solution, each one, as long as it concerns the eq. In the circuit of PHONO 1, we have deephasis with pathetic filter placed between the two departments of tube V1. In PHONO 2, is followed the classic solution of energy deephasis. In PHONO 3, finally exists also a combination of also two above solutions, pathetic for the high frequencies, energy in the low frequencies. The capacity of capacitor C1, can change so that it suits with the technical characteristics of each head, which the signal of will be called to amplification the each preamplifier...

The transmitter was designed with redundancy and cutback (reduced power mode) in mind, giving the transmitter more continuity of service. The final amplifier was divided into 3 separate modules, each using four RCA type UV-898 tubes in push-pull parallel making up a total of 12 output tubes. The outputs of the three modules were combined in series in such a way, that if one of the 3 RF modules failed, the transmitter could continue to operate using the other modules. This idea was a very important step in transmitter design as modern solid-state transmitters are designed entirely in this a modular fashion as is described in my WABC Digital AM Transmitter Page Digital Modulation Section. Modern transmitter with modular design are composed, typically of 1KW modules with lower power modules used for shallow slopes of modulation...

Amateur Radio Transmitters using valves such as 807 or1625 works well with a plate voltage between 600V to 700 Volts.The circuit described here is a full wave voltage doubler. The output voltage is twice the input voltage. For 230V AC input the output will be nearly 600 Volts. Resister R1 is used to limit the initial high voltage and high currents. Capacitor C1, C2, C3 together with coils L1 and L2 form input line filter. The capacitors C4 and C5 protects diodes from high voltage transients on the AC line as well as reduces inter carrier hum modulation of the R.F picked up by the mains...