The new GlowMaster GM-70 is a large format monophonic power amplifier employing parallel vacuum tubes on its output stage running in pure Class-A to deliver the best quality of 70 watt/RMS of pure Directly Heated Triode characteristic power.
The output section: Each monoblock is equipped with two Russian NOS GM-70 vacuum tubes working in parallel SE Class-A. This vacuum tube is originally designed to be used in military environment thus having extremely linear and durability characteristics when used in audio amplifier. Its massive anode structure with heavy glass envolop reduce unwanted vibration or microphonic usually associated with other type of vacuum tube. By successfully buidling several custom made GM-70 SE amplifiers with one tube, we decided to reach further and higher for the completion and the perfection in the design of cost no object apparatus to withstand the test of any other challengers. The parallel configuration of GM-70 tubes appeared to be the best answer and to outperform one tube, works need to be done from all aspects of the design and implementation. Starting from newly development of SILK Super Output Transformer (SILK model S-3000GM70) to allow the two tubes configuration to work in ideal condition without degradation in harmonic or frequency characteristic over smaller output transformer. This task require the unique winding technique and winding arrangement evolve from several trial and error in the developing process. Although the transformer must withstand the voltage swing close to thousand volts and heavy current generated by two tubes, the outcome is amazing giant output transformer with 1,000watt power reserve that have bandwidth close to 80KHz with very low distortion and constant impedance throughout its working range allowing two tubes configuration to work successfully.
The power supply section: By having the solution with the best output transformer, next development is to design and build the best power supply section to feed both power hungry tubes with lowest impedance. Eight 1.5KVA Super Diodes work together with massive 1.3KVA handwound power transformer with special electro-magnetic shield to help ensure sufficient current supply when the load is at its most severe. The supply filter section comprises of audio grade large type filter capacitors and DC choke filter that block all noises from the rectifiers to get into main audio circuit. Additional low voltage separate power supply section is built around a naturally soft start vacuum tube rectifier (5Y3) with classic Capacitor-Choke-Capacitor configuration. This power supply section feeds the input and driving circuit directly thus completely eliminate any power drop off during maximum peak current drawing from the output tubes. These two power supply sections improve the sounding performance of the amplifier to the next level.
The input and driving section: Only the best vacuum tube and circuit are selected to work in this section as it is one of the most critical element to determine the sound of the amplifier. GlowMaster GM-70 has special NOS 6N1P dual triode vacuum tube to work as input tube generating precise and natural sonic signature with unparalleled clarity and dynamic range extending beyond ordinary tube amplifier. The driving section forms a solid backbone of the amplifier since it needs not only to supply pure signal, but also very high driving force to meet GM-70 extreme requirement. Only NOS 6BL7 large size medium mu twin triode in special anode choke loaded circuit can meet such demand of GM-70 to produce the extraordinary sounding amplifier.