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Class A 2A3 audio Amplifier
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The input stage is comprised of a both halves of a 6SL7 octal dual hi-mu triode in a differential amp configuration with a 1ma constant current cathode load. I'm using field-effect (constant-current) diodes for simplicity. the diff amp approach was chosen for good power supply rejection, ease of balancing, good gain, and ease of application of *feedback*, if desired (hey, i like to keep an open mind...). It also takes care of phase-splitting right up front.
Note: I've returned the constant current diode cathode to -9V instead of ground in order to avoid the non-linearities about the pinch-off region (Vpo ~= 1.5V)...
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Push-Pull Class A Amplifier
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This stero amp will give you 4-8W/ch of zero feedback triode power for less than a pair of Chinese 300B's ...if you know where to shop. For those of you who are unfamiliar with this lil' tube here's the poop: The 5687 is a 9-pin miniature twin triode (a la 12ax7, 12au7, etc - but with different pin-out). Its specs are quite interesting: mu = 16, gm = 5400uS, rp = 3k, plate dissipation: 4.2W each unit or 7.5W total (3.75W x 2). After playing with the curves (so kindly reprinted in The Parts Connection Catalog) I realized that you could get some juice out of them (these tubes were apparently designed for high current pulse application - hence the high perveance).
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Audio Signal Testing amplifier
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This mini audio amplifier will test the audio stages in amplifiers such as the front end of FM bugs. You can also use it on lots of our other projects as well as the output stages of radios. It is a very handy piece of test equipment and will make a perfect addition to your collection. The LM 386 is a high power op-amp. It is used to drive a speaker. The inverting input has been connected to the negative rail and the non-inverting input has been connected to a capacitor. Resistors inside the chip bias this input so that it only requires about 7mV before the chip turns on. This voltage is called the off-set voltage. ..
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4 Watt audio Amplifier
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The circuit is very simple and incorporates darlington output transistors that will provide more than enough output current than is needed to drive a 3-ohm speaker. The gain may be pre-set for a variety of input levels, making it suitable for amplifying computer and cassette-deck Line-output levels. The input level is also suitable for use with the TDA7000 receiver. All components are easily available and I will shortly be making this project available as a kit. Naturally, the project will be built on a PCB which will also be available separately. Here is the first PCB, assembled and working...
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| Clicks: 5673 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
Headphone Buffer Amplifier
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This simple amplifier is ideal for adding a headphone jack to equipment that lacks this feature. The Headphone Buffer circuit board is small enough (1.2" X 1.4") to squeeze into even the smallest spaces and power requirements are so low that existing supplies in retrofitted gear can be used. It's a useful addition to many PAiA products such as the Submixer or Submix-Master. Adding a headphone output turns a Stack-In-a-Box it into an incredible practice amp. ..
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Crossed from: Vacuum Tubes - Valves | Clicks: 14826 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
Old Valve Amplifier
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The schematic shows a valve / tube audio power amplifier and a type 390 Rectron B eliminator...
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| Clicks: 1640 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
audio amplifier with NE592
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The broadband amplifier NE592 can be used also for building a simple selective audio amplifier. By means of the +6 V and +12 V supply voltages a DC coupling between the product detector and the AF amplifier is possible. The DC level at the differential inputs is about 4,5 V. The mixer drives the differential input of the NE592 - after suppression of the RF proportions by two 47 nF capacitors - with the remaining AF signal. RF blocking between the outputs is feasible with only one capacitor, but not between the single outputs and ground. But the latter is absolutly necessary due to the wide amplifier bandwidth. The AF stage offers a gain of 200 (46 dB) at 660 Hz center frequency...
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| Clicks: 5543 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
50 Watt power Amplifier
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This simple audio power amplifier was originally designed for a circuit board workshop, conducted by the OSU IEEE Student Group. At the workshop, 20 participants each constructed this amplifier, by etching and drilling the single sided circuit board, soldering all components, and attaching a pre-built heatsink assembly with the output transistors. Three workshops were held between 1995 to 1996. Though the design is simple, these amplifers have impressive preformance, with a frequency response to approx 40 kHz, very low noise, reasonably fast slew rate, and approx 50 watts (true "RMS" power) with the proper +/- 40 volt unregulated power supply. Someday, I'll do some substantial testing to determine exactly what the power output is, and create some more detailed pages about how to build this amplifier. ..
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Crossed from: Microphone Circuits | Clicks: 452 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
741 Microphone amplifier
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This preamplifier uses a type of IC 741, and can boost a microphone signal to line level.
The microphone signal is connected to the "input" put. Any power for the microphone jack of the "food" are met. Here half the supply voltage.
Using the gain potentiometer P1 can be adjusted from 10 to 101 times...
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| Clicks: 11838 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
Headphone Amplifier LM741
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Here you will find a design for a headphone amplifier. The supply voltage is 12 volts. I have the circuit taken as 5 watt amplifier, but after a test showed that with a little speaker to the amplifier power was provided. It is better to connect to a headset. If you want stereo, you need double the amp build. The circuit is constructed with a 741, behind a balanced stair comprising a BD 139 and BD 140. The voltage for the speaker in the middle of this balance tapped using a blocking capacitor, which filters the amplified signal from DC. This capacitor has a value of 1000 uF. This provides a lowest possible frequency of 40 Hz at 4 ?. For this example, the amplifier bass boost or bass control can be switched. The current consumption of the circuit is up to approximately 50 mA. The transistors do not need to be cooled when a headset is connected...
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Crossed from: Vacuum Tubes - Valves | Clicks: 6272 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
Tube Headphone Amplifier ECC86
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Because it seemed fun to me also try the so-called "high-end tube technique to highlight here, I agree with some parts from the stock went to work. A second point was that my family had enough of my taste in music that boomed through the speakers. Opted for a triode circuit, based on EarMax Pro, ECC86's. This is a tube that had been designed as a front-end car radios in the serve. With an anode voltage of 6V DC ECC86 still works fine. This design is chosen for an anode voltage of 48 to 60V. This is a safe voltage. Also for less experienced hobbyists. The setup is straightforward, without print, and everyone should be doing. L1 is a ferrietkraaltje connection to a leg of R1. This is necessary for the required RF suppression. The frequency range is ± 20Hz to well above 1MHz. Described only one channel. The other channel is identical and there is an extra ECC86 badly needed. Power for this amplifier is described separately under the heading power...
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| Clicks: 19793 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
Amplifiers connecting Bridge
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This is a circuit that ensures that you can connect two amplifiers together so you get more power. When called in bridge linking two amplifiers plus you can link the outputs of the amplifiers to the speaker (see block diagram). One of the amplifiers, or with a signal in opposite phase are controlled, because otherwise you do not get double output. For anti-phase signal makes this circuit. One has to be ensured that the two amplifiers are the same. One amplifier is then controlled by the signal output from the 0 °, and the other is driven by the 180 ° output. R5 should be adapted to supply voltage. The tension left of R5 should be 12 V.. The resistance has the following formula to calculate: R = (R - 12) / 0.0015. Here R is the resistance of R5 and R5 V power supply right. When building the power you need to take into account that of course the dual power amplifiers two questions...
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| Clicks: 14150 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
40W audio amplifier using TDA2030
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This amp delivers a lot of power and uses 1 IC and two power transistors.
The circuit consists of an amplifier IC (a TDA 2030A) and a power stage consists of two transistors.
The amplifier can be powered with an asymmetric voltage of 12-44 V...
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| Clicks: 18228 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
250mW audio Amplifier
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This design can be used as a small booster. The amplifier is built around a balance stage.
The quiescent current is set by diodes D1 and D2. The simplicity of the circuit, the quiescent current depends on the temperature of the diodes. When T2 and T3 have a much higher temperature than the diodes, can be annoying. The transistors is a cooling solution.
It is best the two transistors on a small aluminum plate with some super glue to glue. The supply voltage is 9 volts...
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| Clicks: 19003 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
20 Watt audio Amplifier
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This is a standard amplifier based on LM 1875. It can deliver 20 W, with an 8 ? speaker and 60V power supply even 30 W.
The capacitors C4 and C5 should preferably be as close to the IC down. ..
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