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W4-AM Single-Chassis 20-Watt Amplifier


  • True Williamson-type high fidelity circuit
  • Special-design Chicago standard output transformer
  • Transformer taps provide output impedance of 4, 8, or 16 ohms
  • Rugged, heavy duty single chassis construction

Why only dream about high fidelity and the pleasure it affords—why not act! Get the model W4-AM Williamson-type amplifier which continues to amaze audio-wise people with its outstanding performance. The Williamson-type circuit features extended frequency response, low distortion and low hum levels. This amplifier can provide you with many hours of listening enjoyment with only a minimum investment compared to other units on the market. It employs 5881 push-pull output tubes and a special Chicago Standard output transformer, designed to Heath Company specifications to give you full fidelity at minimum cost. The use of this transformer makes it possible to sell the amplifier at a bargain price, even though its performance equals that of much more expensive units. Too, some savings were realized by incorporating the power supply and the main amplifier in a single chassis.

Just read over the specifications for this fine high fidelity unit and compare them to those for amplifiers costing many dollars more. High fidelity is emphasized even though the price is unbelievably low.

Building a hi-fi system with Heathkit components is a lot of fun in itself. In fact you may get so absorbed in the construction that you lost track of time and find yourself working into the wee hours of the morning. But, it's worth it when you listen to the results of your efforts after construction is completed. The construction manual is complete in all respects, making the amplifier suitable for construction by the beginner in electronics. The only prerequisite is ability to solder, and this can be taken care of with a little practice before assembly is started. Complete step-by-step instructions combined with pictorial diagrams insure your success.

Another point worth considering is that Heathkit equipment is compatible with most hi-fi accessory equipment on the market, such as turntables and various pickup cartridges, speakers, tuners, etc. You can select exactly whatever components fit your budget. Some of this equipment you may already have available, requiring only a good basic amplifier to give your system that quality touch. Frequency response extending from 10 CPS to 100,000 CPS within ± 1 db at 1 watt assures you of full coverage of the entire audible range, and clean clear sound amplification takes place in circuits that hold harmonic distortion at 1.5% and IM distortion below 2.7% at full 20 watt output. Hum and noise are 95 db below full output. Taps on the output transformer are at 4, 8, or 16 ohms to match the speakers system of your choice. Used with the Heathkit WA-P2 preamplifier, the W4-AM can be installed in an equipment cabinet or other suitable location and be controlled remotely. All accessory equipment is connected to the preamp which provides compensation, volume, and tone controls for reproduction as you like it.

A high fidelity system in your home will provide you and your family with a great deal of enjoyment and also a form of relaxation after a day at work or play. Don't deny yourself high fidelity because you feel you can't afford it. Assemble the W4-AM in just a few hours and use it with the Heathkit model WA-P2 preamplifier for many pleasant listening hours.

Specifications—Power Output: 20 watts. Frequency Response: ± 1 db from 10 to 100,000 cps at 1 watt. Harmonic Distortion: 1.5% at 20 watts. Intermodulation Distortion: 2.7% at 20 watts (60 and 3,000 cps, 4:1). Hum: 95 db below 20 watts. Damping Factor: 28.5:1. Input voltage for 30 watts output: 2 volts. Tube complement: 2-6SN7GT, 2-5881, 1-5V4G. Output Transformer: Chicaco Standard, Special Design. Power requirements: 105-125 volts, 50/60 cycles, 115 watts. Dimensions: 15¼" by 8½" shelf space, 7" high (allow 1½" by 15¼" additional shelf space for cables and connections). Shipping Weight: 28 lbs.

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