Pros: Warm rich tone, great soundstage, musical purity
Cons: Lacks USB inputs, no balanced outs, no DSD support
The Tri-Vista 21 was a limited edition DAC sold in late 2004, early 2005. It was massively overbuilt - great power supply and output stage, and ran extremely long life 5703 milspec tubes, which are good for 100,000 hours. The unit is hefty, 20 lbs, and it has toslink and SPDIF inputs, and RCA outputs. The power supply is heavily regulated and has great chokes - Musical Fidelity built this unit to a spectacular degree. The feet of the unit feature LEDs that light up first orange then blue to signal when the unit has reached ideal warmup.
Compared to DACs of the day, the Tri-Vista outpunched its rather modest price - you had to spend about $5k to get DACs that bettered its sonic quality. The DAC upsampled redbook to 192k, and it dramatically improved redbook sources. If used with a CD transport, it favored high quality transports. Like all DACs of that era, it had no DSD support, nor could it take a USB input.
I recently brought my sparingly used Tri-Vista out of storage to use with Tidal high res streaming - thinking I would use it for a short while as I shopped for a more "suitable modern" DAC. But research demonstrated that for Tidal, which is limited to redbook quality, the Tri-Vista was ideal, and none of the modern DACs could significantly improve on the sound quality. I was bowled over by how much the Tri-Vista sounded on Redbook compared to contemporary DACs, so much so that I rethought my strategy of upgrading the DAC.
I'd still like a one-box solution which could handle multiple modern digital inputs, tidal and music streaming/network support. But those are either crazy priced ($5k and higher) or require multiple units specialized for either DAC and streaming.
The Tri-Vista therefore chugs along quite well. It easily surpasses my A&K 120 DAC for redbook, and it performs as well as (and sometimes better than) my Sony HAPZ1ES on redbook sources.
So it will stick around for a while, until I can find something that is sonically superior and more full-featured. If you can locate a clean used one (I see them for around $800-1k), don't think twice - it's alright.