Vivid Audio Si66t

Stereo Interstage-Transformer Coupled KT66 Integrated Amplifier

The Vivid Audio Si66T is the second 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 Si66T- it represents audio thinking- outside the box.

About the Si66t

The Si66t is an original, 6+ w.p.c. Interstage-Transformer-coupled, single-ended, Ultra Linear, tube rectified, two channel audio amp using 7119 input and KT66 output tubes, or almost any other octal output tube. This amp is intended to be a slightly more traditional design than the Si66 or Si74, allowing the use of readily available 6V6 and other lower voltage octal output tubes. Thousands of these NOS tubes are available at affordable prices allowing tube rolling on a budget.

The Si66t "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 four components in the signal circuit per channel (that's right, only an input tube, interstage transformer, output tube and output transformer are in the signal circuit. No caps, no resistors, no transistors, no chips and no chokes), the Si66T achieves new heights of ultra-realism through ultra-minimalism. Nothing more is needed, nothing less will work.

The Si66T power supply features custom wound, US made transformers and chokes and high quality film caps (no electrolytic caps) for decades of reliable service (see our warranty, below). The Si66T is tube rectified and can accept a wide range of rectifiers. The revealing nature of this circuit makes rectifier “rolling” rewarding. The Si66T is available as a stereo amp (no volume control) for use with your passive or active line stage (or, better yet, a Vivid T:dac), or with a volume control installed for direct connection to your CD player or phono preamp. It has one pair of input jacks and a pair of 8-ohm speaker outputs which can be wired to 4-ohm secondaries on request.

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 Si66T is hand-built on round, maple wood shells (15" in diameter) with an aluminum top plate and a solid wood base. Standard construction is point-to- point wiring, using premium Wonder-brand 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.