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Heath W5M Amplifier Heathkit Peerless Output Transformer
Still a favorite in its power class, the W-5M represents one of the most outstanding high fidelity amplifiers available at any price. It employs a specially designed Peerless output transformer. The Peerless 16309 Output Transformer was originally designed in 1955 by Ercel B Harrison. Primary impedance is 10K CT with 50% screen taps; secondaries are 16, 9, & 4 ohms. In order to reduce harmonic distortion at low frequencies it is essential that the plate current of the output tubes be balanced. The exclusive balancing circuit in the W-5M makes this balancing operation easier and much more accurate. Precision balanced resistors are connected in the cathode circuits of the power output tubes. These amplifiers use a split load inverter direct coupled to the input stage, and have a driver stage before the cathode biased ultra-linear connected output tubes. B+ is 520 volts. The plates and screens of the output valves run at 500+ volts and this amp will destroy any valve not designed to take this kind of voltage. I have seen these amps use 5881s, Kt66s, 6550s, and 6L6GC output tubes. This pair uses RCA 6L6GC tubes and they sound very good; that warm tube sound that can’t be duplicated by solid state amps. Each amp also uses two 12au7 tubes and a 5R4 rectifier. The Williamson circuit design is a proven circuit that can still hold his own against competing designs. The circuit is rated at 25 watts and will follow instantaneous power peaks up to 42 watts. Both amplifiers work. They both have cages—not displayed. 35lb

You can pay with a US Post Office money order, US check (I hold the item for 2 weeks until it clears), Western Union Money Transfer (www.westernunion.com), or a credit card by using Paypal. If you are using Paypal click the BUY NOW button below.

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Copyright 2003-2004 Howard Stone PhD.
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