Bigger Ben

Input Transformer

The draw of single-ended amplifiers has always been a level of engagement that other amplifiers often fail to deliver. Well designed single-ended amplifiers are not only impressive in the midrange, but across all frequencies.

The Bigger Ben is designed to offer transparency, rich detail, and an incredibly low noise floor. Parts selection was crucial during the design process, and each was chosen not for the price, but for the level of synergy between parts. Rectification is solid state which permits cooler operation and reliable performance. The amp is configured for ultra-linear operation allowing greater power output and minimal use of feedback.

The amplifier features an extremely stiff power supply; significantly larger than needed for primary filtering. In the early days of tube amps, chokes were easier to come by than capacitors and more reliable. As such, large chokes were utilized for primary filtering. As capacitor production gained reliability and costs came down, cap filtering and smaller chokes became the norm. In a single-ended design, a regulated and extremely quiet power supply is very important. Using a large 5 Henry choke is expensive, but yields significant improvements in reduction of DC ripple.

The chosen output transformers are over-spec'd and the highest quality. We consider the output transformer as essential as any other design choice. When buying any tube amplifier, the weight of the output transformer can be directly proportional to the quality of sound. In general, larger outputs have more massive cores which are less prone to saturation and have higher inductance.

Larger cores and greater inductance allow the transformer to carry a low-end signal with minimal distortion. These transformers are bench tested to perform down to 20hz and up to 20khz. Even if your speakers only go to 50hz like a classic LS3/5 two-way, having an amplifier able to drive that low is pivotal in recreating the whole soundstage.

Choice of Loudspeaker?

The Bigger Ben pairs well with most speakers 94db and above. However, Bigger Ben is so quiet it will perform beautifully with full-range or horn-loaded speakers of efficiency above 100db, 700 microvolts RMS noise at idle. Speakers that can go down cleanly to 30hz really bring out the very best of the amp. 20z-20khz -1db at full power. The Bigger Ben (depending on the choice of output tubes) will output between 5-7 watts, but there’s a lot more in the tank than that when matched with appropriate loudspeakers.

We’ve tested the Bigger Ben power amplifier with a wide range of loudspeakers including our Hudson and Seneca horn-loaded models. Other good options would include DeVore Fidelity, Spendor, Harbeth, Wharfedale, Spatial, Omega, Tannoy, Klipsch, Living Voice, and others.

The amp is compatible with all 6l6 family tubes, including the 6l6GC, KT66, KT77, KT88, KT90, and EL34s. The driver tube is a 6SL7. My personal favorite currently is new EH6550 paired with new production Tungsol 6SL7 driver.