Vivid Audio Si66

Stereo Integrated Amplifier

The Vivid Audio Si66 is the first in an original range of visionary hi-fi amps to be designed and built under the Vivid Audio brand by resident designer Randy Cail. This amp is the culmination of 40+ years of hi-fi listening, electronic experimenting, and empirical development. It is, in every way, a truly musical amplifier, ready to fulfill your desire for something far, far beyond typical EL34 push-pull amplifiers or 300B SET. Vivid Si66- it's audio thinking- outside the box.

About the Si66

The Si66 is an original, 10+ w.p.c. direct-coupled, single-ended, Ultra Linear, tube rectified, two channel audio amp using 7044 as input and KT66 output tubes. It is conceptually very different from all other tube or solid state amp circuits that precede it. Specifically, it is a direct-coupled two-stage amp. That means there is no coupling cap, choke or interstage transformer between the voltage gain section and the power section. This has some significant implications. First, the selection of the input tube is critical. Most tube types simply will not work in the front-end of this circuit. Secondly, and most importantly, you no longer are listening to capacitors or Interstage transformers between stages. In our experience, no cap or IT sounds as good as no cap or IT!

The Si66 "sound" can be described as neither warm nor cool, but fast and real- with more realistic bass than any of the amps we've compared it to. It has a see-through realism that must be heard, and startling, life-like dynamics (assuming the recording has them to begin with).

If you subscribe to the simpler is better school of amplifier design, it can't get much better than this. With only three components in the signal circuit per channel (that's right, only an input tube, output tube and output transformer are in the signal circuit. No caps, no resistors, no transistors, no interstage transformers, no chips and no chokes), the Si66 achieves new heights of ultra-realism through ultra-minimalism. Nothing more is needed, nothing less will work.

Vivid Audio Design Guidelines

  • Elite, world-class sound quality, far beyond their price.
  • Innovative appearance and an honest use of materials.
  • Innovative circuits built around some of the best vacuum tubes ever made, optimized to extract the maximum sonic "juice" from your recordings.
  • Amps that can be built in house, by us for complete quality control.
  • Compactness, low parts count, hand wired for reliability and ease of use.

Vivid Audio amps are perfect for the music lover who has little need for high power. Our amps have been designed for use with medium to high-sensitivity loudspeakers- in particular single driver designs such as Omega and Cain and Cain (both of which are Fostex based designs) or with any other speaker in the 90 dB/W/m or greater range, such as our own forthcoming Vivid Audio T-line designs. Vivid Audio will introduce integrated and mono-bloc designs ranging from 6 to 60 watts per channel, which should be sufficient for nearly any home hi-fi system.

Circuits and more...

We have an underlying quest for simplicity, low parts count (which we feel leads to a purity of sound), and the amplifiers' ability to convey emotional content.

Finishes, tubes, power, etc.

All Vivid Audio amps are made one at a time, by hand, by us, in our shop in Atlanta, GA. This means we can accommodate your special requests. Please contact us if you are interested in a custom finish, or want to learn more about the tubes we use, or to discuss options such as: input selection, tube choices, or to explore the suitability of Vivid Audio amps for use with your existing equipment.


The Vivid Si66 is hand-built on round, maple wood shells (15" in diameter) with a laminated aluminum top plate and a solid wood base. Standard construction is point-to- point wiring, using premium silver-bearing solder throughout, with no p.c. boards in our amps- even our entry-level products. We do not cut corners on parts quality. Key to our amps sonic success are custom-wound, US-made transformers and chokes, proprietary Vivid Audio internal wire, some current-production but mostly NOS state-of-the-art vacuum tubes, and of course, Vivid Audio know-how.

Nothing more is needed, nothing less will work.