Chassis

Unlike 3 Dimension Audio, few companies discuss their chassis design in detail. There are plenty of good looking chassis: powder coated, chromed, hand finished, exotic wood, and so on.

Why is the chassis design critical in a tube amplifier? Besides holding the various components (tubes, transformers, capacitors, wiring, chokes), a chassis has other tasks such as:

resonance control,
vibration absorption,
heat dissipation, and the
ability to withstand wide temperature variations with no change or damage to the chassis.

3 Dimension Audio has devoted a material amount of design and prototype testing to chassis design. The designs we selected specify .25”, 0.375” or 0.50” thick aluminum for the frame.

The entire chassis is professionally powder coated. Powder coating enhances the appearance while protecting the aluminum from scratches and oxidation.

Our chassis are as inert and solid as possible. You can whack it on the side and you just get a dull thunk; there is no “ringing” like when you whack a folded sheet metal chassis. Other materials, such as wood which is a popular choice with many builders, can be adversely affected by the large temperature range between when the unit is cold and fully operational. Wood always has the potential for cracking due to these temperature variations.

The chassis come in two basic types: a dual monaural or a mono block design. Use of a stereo or monaural chassis is determined by customer desire and the type of amplifier selected. Some of the designs must use a monaural design as they simply will not fit on a stereo chassis and be of a reasonable weight and size.

An example of an amplifier requiring a monaural design to keep the amps of a reasonable size/weight would be a 211 output tube based design. The transformers are of a size that makes it quite difficult to use a stereo chassis and keep the weight and dimensions to acceptable values. This also comes into play when shipping the items; a very large and heavy tube amplifier might be more easily damaged in transit simply because if it is heavy to lift it might get dropped or treated with less respect than a smaller box of lesser weight.

The stereo design consists of two chassis of the same dimensions. One chassis is the signal/amplifier chassis; the second is for the tube rectified power supply.

The mono chassis consists of two signal chassis and two power supply chassis.