Sonic Frontiers SFD-2 MKII - Vintage Tube DAC with HDCD - SkyFi Serviced


This collectible and desirable vintage Tube and Solid State DAC was serviced in house for preventative maintenance based on our Sonic Frontiers experience.

We've fully restored this same model in the past, so we know where to look to avoid known issues down the line in its new home.

This specific model suffers from leaking electrolytic caps, as the power supply is actually fully running whenever the unit is plugged in.

We replace all of the original Panasonic HFQ capacitors with long life 105C Nichicon electrolytics to ensure smooth operation.

It's also highly recommended to unplug this DAC when your system is going to be left unused for a long period of time.

It's now working absolutely perfectly and is likely to do so for a few more decades.

This is also the more desirable MKII version with the HDCD chip that improves non-HDCD source material, along with many more refinements.

Please click here to read the glowing Stereophile review for more details on its sound quality. AND it's featured on the fabulous The Vintage Knob website so you know it's truly something special.  

Original MSRP was a whopping $5300 in the 1990's. That works out to over $10k in todays dollars when adjusted for inflation (!!)

Sonic Frontiers SFD-2 MKII - Owner's Manual

More from the Manual:

The SFD-2 MKII comes with two 6922 (6DJ8-type) tubes, individually boxed and bagged along with a cotton glove, screw- driver, and screws for fastening the SFD-2 MKII cover.
If desired, replacement of these tubes may be done to suit the listener’s preference.

The following tube types will work under the same technical parameters as the 6922 and require no circuitry modification to function:
• 7308/E188CC • 6DJ8/ECC88 • E88CC

The SFD-2 MKII includes a free HDCD-encoded sampler CD to demonstrate the HDCD process. This process is a true advancement in digital audio reproduction, providing one of the single greatest improvements in digital audio since the introduction of the CD format more than a decade ago.

This sophisticated encoding/decoding system greatly reduces both additive and subtractive distortions in digital recordings, providing a resolution and freedom from distortion equal to that of analog recordings.

In addition, the HDCD decoder’s internal digital filter provides significant sonic improvements to non-HDCD source material as well.

Click below to add our recommended matching cables from Kimber Kable, all brand new as SkyFi is an official Kimber dealer.

Kimber Kable - RCA Interconnects

Kimber Kable - XLR Interconnects

Kimber Kable - Coaxial Digital Interconnect

Kimber Kable - Optical Digital Interconnect

Kimber Kable - Digital AES/EBU (XLR Connector) Interconnect

Kimber Kable - Power Cords

Click here for a list of HDCD-encoded Compact Discs

More on HDCD from Wikipedia:

"High Definition Compatible Digital (HDCD) is a proprietary audio encode-decode process that claims to provide increased dynamic range over that of standard Red Book audio CDs, while retaining backward compatibility with existing compact disc players.

Originally developed by Pacific Microsonics, the first HDCD-enabled CD was released in 1995. In 2000, the technology was purchased by Microsoft, and the following year, there were over 5,000 HDCD titles available. Microsoft's HDCD official website was discontinued in 2005; by 2008, the number of available titles had declined to around 4,000.

A number of CD and DVD players include HDCD decoding, and versions 9 and above of Microsoft's Windows Media Player on personal computers are capable of decoding HDCD.

HDCD was a favorite for several artists such as Joni Mitchell, Neil Young and the Beach Boys, all of whom have had many titles in their catalogs reissued in this format.

Technical overview
HDCD encodes the equivalent of 20 bits worth of data in a 16-bit digital audio signal by using custom dithering, audio filters, and some reversible amplitude and gain encoding: Peak Extend, which is a reversible soft limiter; and Low Level Range Extend, which is a reversible gain on low-level signals. There is thus a benefit at the expense of a very minor increase in noise.

The claim that the encoding process is compatible with ordinary CD players (without audible distortion) is disputed: not being able to decode the peak soft limiting, a normal CD player will output distorted peaks."



Original Box





Not Applicable


Yes - Power Only

Physical Condition


Working Condition


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