If you’ve ever owned, regularly used or just love tube amps, then you’re probably familiar with the bias setting. It impacts the tone, proper operation and lifespan of a tube amp’s output section. An engineer will manually set the bias voltage when replacing the power tubes. Regular checkups in between swaps are strongly advised to avoid various issues and maintain a consistent sound. What if the amplifier itself would automatically take care of setting the optimum bias and keep it that way no matter what? A deBont bass amp will do just that. No more manual adjustments… ever!
Looking at tube amps from the past 60 years or so, either for guitar or bass, you’ll see a standby switch most of the time. Think of an Ampeg SVT or Fender Bassman for example. Where’s the standby switch on a deBont tube amps? Well, there isn’t one, because they’re not really necessary. At least not anymore. There are a LOT of persistent myths surrounding the standby switch. Why do amps even have them, how and why do people (still) use them and why can we do without just fine?
Every musician is faced with some sort of gain or attenuation control when connecting the bass to a (pre)amp. The deBont bass pre-amps will take a slightly different approach to the typical gain/pad control arrangement found on most amps. Given the low-noise and ease-of-use design aspects, the arrangement explained below is much better suited for the job. It will accommodate for the huge variety of basses out there while keeping everything simple and still give the user more than enough control over the input-signal, with of course the maximum quality of sound.
One major design aspect of every deBont bass amp is the absence of noise, humm, hiss or other unwanted artifacts. Silence until the bass tells it otherwise. The signal-path is the obvious candidate, but it goes for any mechanical noise as well. Unfortunately, where power tubes and high wattage power-supplies meet, fan cooling is a required. But there are ways to still make it virtually silent. Here’s my quest for cool quietness.
With the guts of the amplifiers almost completed, the enclosure and all that comes with it is up next. And that’s a lot! Knobs, front-panels, materials, silkscreen, colors, designs and structural strength to name but a few. Since my amplifiers are completely ‘from the ground up’, there’s no off the shelf solution. And a simple black box with plain text just won’t cut it. I want the amp to look as good as it sounds.
This article follows my experiences during the process of finally turning my cut-up, dented and abused prototype box into a professional and truly awesome looking bass amplifier. Part 1 focused on the why’s and how’s I got to the form factor I decided to go with. The post ended in sending the CAD files over to the enclosure fabricator. Guess what, Christmas came early…