Tips & Advice

A Word About Output Tubes

Your VAC Amplifier can use 2 different output tube types: the KT88 Beam Power Kinkless Tetrode and the 6550A Beam Power Tetrode. We consider the sound of a good KT88 to be superior. Properly manufactured 6550/6550A will work, but may have a slightly higher incidence of failure in the PA100/100. Feel free to experiment with different brands and types to customize the sound to your tastes.

As with interconnects and speaker cables, each tube manufacturer's KT88 tends to have a distinct sound when used in VAC amplifiers, and of course the 6550As sound different as well. Here is a brief summary of our experiences with currently available tubes from different sources.

M-O Valve Company/Genalex/GEC KT88 (U.K.) PRE-1970:

An accurate and sweet tube with good bass quality. Quality is surprisingly variable for a premium tube. World wide supply is limited. Highly recommended.

M-O Valve Company/Genalex/GEC KT88 (U.K.) POST-1980:

Hard, glaring sound, only fair detail. Not recommended.

VAC Tested KT88-T:

The best of the versions from China, and our current first choice. Good combination of punch, air, sweetness, and detail. Reliability is very good.

Golden Dragon KT88-M:

No longer available from production, but an excellent tube. A bit more matter-of-fact than the KT88-T, having more of an NOS US tone, but still preserving the airiness of the KT88.

Golden Dragon KT88, KT88 Classic, KT88 Super:

Generally fairly good for sound; reliability somewhat inconsistent.

National NL-KT88-USA:

A version produced by the US arm of the Richardson's organization. Visually very similar to the original and sonically satisfying, slightly lightweight sound, but sweet. Very expensive.

Svetlana KT88:

Several versions have been made, so it is difficult to give a blanket comment. The newest version (as of summer 2000) shows promise, with a sound somewhat similar to the GE 6550A.

US made RCA and Tung-Sol 6550:

Early 6550 type in the "coke glass" bottle. Pretty good sound.

GE 6550A (applies to those manufactured in USA by MPD):

Somewhat soft and lean, with a slightly buzzy character, but fairly sweet.

Phillips/ECG/Sylvania 6550A:

Similar to the GE tube; later production samples may have a somewhat hard upper midrange.

Sovtek 6550:

Samples tested do not bias correctly, having insufficient current flow. Not recommended.

VAC PA100/100 specifications

The Mazda VAC PA100/100 is a pioneering innovation in the realm of automotive engineering, specifically designed to enhance driving dynamics and ensure optimal performance. This cutting-edge vehicle is recognized for its unique blend of advanced technologies and outstanding characteristics, making it a standout in the competitive landscape of modern automobiles.

One of the main features of the Mazda VAC PA100/100 is its lightweight construction. Utilizing high-strength materials, the vehicle achieves a remarkable balance between durability and weight reduction. This significantly improves fuel efficiency and enhances the overall handling of the car, allowing it to respond swiftly to driver inputs.

Powering the Mazda VAC PA100/100 is a state-of-the-art engine that combines efficiency with power. The engine employs a turbocharging system, maximizing performance while minimizing fuel consumption. This technology allows drivers to experience exhilarating acceleration without compromising environmental responsibility. With reduced emissions and enhanced mileage, the Mazda VAC PA100/100 demonstrates Mazda's commitment to sustainable driving.

The vehicle is also equipped with an advanced suspension system that optimizes ride comfort and handling. This system adapts to various driving conditions, ensuring stability and control regardless of the terrain. Drivers can expect a smooth ride with minimal body roll, which promotes confidence on tight corners and rough roads alike.

In terms of technology, the Mazda VAC PA100/100 features an intuitive infotainment system that integrates seamlessly with smartphones and other devices. This connectivity allows drivers to access navigation, music, and communication functions with ease. Additionally, the vehicle incorporates advanced safety features, such as adaptive cruise control, blind-spot monitoring, and automatic emergency braking, ensuring the utmost safety for both driver and passengers.

Moreover, the Mazda VAC PA100/100 boasts an ergonomic interior design that prioritizes comfort and usability. Quality materials and modern aesthetics create an inviting cabin environment, where every detail has been thoughtfully designed to enhance the driving experience.

In summary, the Mazda VAC PA100/100 is a remarkable vehicle that combines innovative technologies, exceptional performance, and a commitment to sustainability. With its lightweight structure, powerful engine, advanced suspension, and cutting-edge safety and infotainment features, it sets a new standard in the automotive industry, offering drivers an unparalleled driving experience that is both enjoyable and responsible.