The FX-Audio L07 amplifier and DS07 DAC/Preamplifier by Greg Voth

Mark Schifter of Vera-Fi Audio, LLC has been on a mission to cap his multi-decade audio career in audio with special offerings. I began reviewing products from Schifter’s hands shortly after reviewing for this publication in 2014. At the time, I did not know the depth of his influence in my little corner of this wonderful hobby. I owned an Audio Alchemy Digital Decoder Engine V1.1 when Schifter was a partner with Peter Madnick, and a friend owned Genesis floor-standers when Schifter was a partner with Arnie Nudell and Paul McGowan—small world.

Shifter, above all, takes great pleasure in offering the audio enthusiast components of solid value at an affordable price, whether they be serious primary system components or discernible, dollar-saving tweaks. It’s been a pleasure to watch the birth and growth of a couple of his businesses during my time with Stereo Times.

Vera-Fi Audio, LLC., the most recent of Schifter’s ventures (as far as I’m aware), is his most interesting, at least to these eyes and ears. Over the years, I’ve reviewed many components and tweaks that fall under the Veri-Fi Audio banner and other companies utilizing Schifter’s skills. Emerald Physics and Core Power Technologies are only two of them. Mark Schifter likes to share things – I’m not the only person in this industry with whom he’s shared concepts, working drawings, or 3-D renders on Facebook and Instagram, oftentimes just before product release. Still, I’ve always approached every review of his products honestly, without favor, as I have all others.

Mark Schifter has posted on social media that this next period will be his “final semester” in the audio field, as retirement and health concerns are pressing him to commit to what will be his grand finale. He’s shared with many in the industry what some of the products will be. If it is his last, this next act promises to be a beauty! His cohorts and conspirators have produced many great things together over many years, so I have little doubt this next phase will be a fascinating trip for many of us!

The FX-Audio L07 power amplifier and DS07 DAC/Preamplifier

I’d come across the FS-Audio L07 amplifier and DS07 DAC in internet searches and was intrigued by them at the time. A few weeks ago, Schifter told me he considered adding these two components to his online store and asked if I would review them. I surmised this product addition had more to do with offering browsers more options, as it makes little sense to spend time developing comparable products when these two already exist in the wild. Our Mr. Schifter would rather concentrate on his pursuits.

The two FX-Audio components came well packed, and both included power cords. The DS07 DAC/Preamplifier has a remote, USB cable, and Bluetooth antenna. I had to provide both my Toslink and 75-ohm Coaxial cables, and had batteries for the remote in the pantry. The remote that comes with the DS07 DAC is comfortable in my large hand and features on/off, mute, Input, EQ buttons, as well as those for Amp, DAC, and Player. Also included on a ring push surrounding an OK button are Vol+, Vol-, and << and >>. The EQ button gives access to 3 on-the-fly filter presets.

Each of these components stands tall each being taller than tit is wide – the SL07 DAC/Preamp measures just 125 x 80 x 176mm. Its front panel features a 1.54″ full-color LCD screen and a sizable multifunction V/M (Volume / Menu) knob for fine tuning as a preamp. The rear panel offers optical, coaxial, and USB connections and balanced and unbalanced jacks. The power supply is inside the unit, so there’s just an IEC inlet for the included power cable and a power on/off switch.

The FX-Audio L07 amplifier measures 278 x 222 x 182mm, slightly deeper than the SD07 DAC. These units stack easily, with the SD07 placed atop the L07, taking minimal space beside my right Vanguard Scout loudspeaker. On the amp’s front panel, we find a large volume knob, that’s coarse for quick big jumps in volume, compared to the SD07’s fine knob, and a Select button, with which to select the unbalanced and balanced option and 3 small red LED lights that denote that choice as well as a Power On indicator. The L07’s rear panel has actual binding posts (!) for speaker connection and pairing balanced and unbalanced inputs. There’s a Stereo / BTL switch for stereo use or bridging the amp to mono (add another amp for stereo output), a power on/off switch, and an IEC inlet for the included power cable.

To run these components in fully balanced mode, first connect the two units with XLR interconnects and push the Select button to choose “balanced” on the amp’s front. Then, you press and hold the SD07 DAC’s multifunction volume to bring up the Menu, where you select the balanced output setting. I dove into setting this pair of mini components up with a pair of Vanguard Scout Bookshelf speakers (reviewed in these pages) in near-field on my computer desk. I also set up the amp and DAC with my floor-standing Double Impacts for feature tests. I ran through various scenarios, testing the various options each offered.

As I did my feature tests, I texted Schifter my findings. He, in turn, would reach out to the developers for guidance. We all know what happens when we assume, eh? On my recently acquired 2023 Mac mini Pro, I opened the Sound Panel and selected the “DS07” driver. Through trial and error, while the DAC’s front screen was obscured behind my monitor, I didn’t notice that the DAC’s other output options required a different driver to be selected. My bad. I needed to understand the included remote more fully. After successfully getting sound out of this gear, I sat back for a listen. Wow, this diminutive amplifier is powerful. I returned to Schifter with additional findings, which I shared the following day.

The FX-Audio L07 power amplifier

Schifter texted, “The amp is ridiculous, Greg. It is this new Infineon engine [doing] things I would not have thought possible. It’s nuanced and nuanced, [italics mine] in a way that Gan bridged the divide but didn’t do it at a workable cost for a new world.  “Can you imagine all the people we can bring [into] audio as youngsters if they have an amp for $199, a streaming engine for [$199] bucks, and a pair of speakers for a couple of hundred [?] Suddenly, this becomes attainable, and we could make it lovable simultaneously. That little amplifier is so lovable, every single person that has come into contact with it in my world loves it – they don’t know what to make of it.” Schifter gets a lot of joy from bringing audio to those new to the hobby.

Why the excitement, you ask? This stereo, Class-D amplifier provides 200 watts per side into 4 Ohms, and it’s bridgeable, providing 400 watts per amp in mono, using the BTL setting and required jacks (you’ll need a pair for stereo if using this BTL option). This amp can also run fully balanced, providing ample power to a pair of passive speakers. FX-Audio says the LO07 amp is “for bookshelf speakers,” but I put this setup on my Double Impacts and was duly impressed with the layers of soundstage produced. I also listened through 2 different pairs of bookshelf monitors. But wait, there’s more.

The FX-Audio DS07 DAC/Preamplifier

To test the functionality of the FX-Audio DS07 DAC, I downloaded a sample DSD FLAC track of David Elias’ “Crossing“ entitled Morning/Light Western Town (2005 Sketti Sandwich Productions), encoded as MQA. I then went to the Mac’s Audio MINI Setup in Utilities and changed the DS07 driver’s input setting to “1-ch 32-Bit Integer 176.4 kHz.” The track played flawlessly with no hiccups. The DAC’s front display currently displays the settings “USB / PCM”, “Filter 2”, “Output RCA“, and “176.4 kHz.“

While this DSD, FLAC track won’t import into the Apple Music interface under the Sequoia OS, it will import into the Decibel audio player (my Apple App Store purchased version is still 1.3.5). This older version added Mojave OS capability and DSD64 to PCM conversion a few years back. Over the years, I’ve used the Decibel app to hold and play the things that iTunes and Apple Music won’t – its refreshingly stripped-down interface is a breath of fresh air.

Playing from the Decibel app on my Mac, this DSD MQA-encoded track was unlocked. The front screen of the DS07 DAC highlighted “MQA” along with “352.8kHz.“ That’s good news for those on Tidal who use MQA! When I returned to the Mac mini to play CD-R rips, the 44.1 kHz parameters I had set for this Mac displayed correctly on the DS07.

While the DS07 is a DAC without a headphone amplifier *(see note at bottom), it provides impressive features under the hood, including an ES9068AS DAC chip that supports files up to DSD512 native and PCM 768kHz@32Bit audio. Its USB interface uses the XMOS XU216 chip with full MQA support. Other features include Bluetooth 5.1 connectivity (with a Qualcomm QCC5125 chip), support for the following protocols: SBC, AAC, aptX, aptX LL, aptX HD, and LDAC, and a group of OPA1612 op-amps for amplification (as do Topping and SMSL). The DS07 sports impressive measurements: 125dB SNR, 120dB DR, and 0.00015% THD+Noise.

A coaxial connection from the 32-bit Laufer Teknik Memory Player to the DS07 DAC resulted in 44.1 kHz, which was displayed on the DAC’s panel from a 32-bit processed CD-res rip. Playback of a few  24-96 rip files, as processed by the Memory Player’s software, was displayed as 96 kHz on the DAC’s screen. A Coaxial connection from the new SMSL PL100 CD player sounded great. It’s nice to have a CD player in-house again.

Optical files played CD-res rips beautifully in my near-field listening. When I switched to playing 24-96 rips, playback stuttered until I went into the Audio MIDI Setup and selected the 2 ch 24-bit Integer 88.2.0 kHz.  The relay appears to start at the beginning of every track and stop at the track’s end, so there may be an occasional slight stutter as the relay catches up, if the selected track has a different resolution. Once I had played a couple of tracks in a row, the transition to the following tracks played smoothly.

Next up, Bluetooth. I disconnected all other sources and selected the DS07 in the Mac mini’s Bluetooth preferences, and then went down to the Sound Preferences and selected DS07 as the source. All tracks played well at 44.1 kHz. To pair a device, note the following – the front-mounted volume knob on the DS07 DAC’s face is multifunction, it will allow you to mute with a quick push or, with a longer push, gives you access to the DAC’s Menu. There, the user can manually change the Input without the remote; you can access BT Rematch, Output (RCA or XLR), Filter Select (3 choices), screen Brightness, and Dimmer time. Select “BT Rematch“ to pair a device and look for the “SD07“ driver in your Bluetooth Device List.

Pairing my iPhone 16e with the DS07 DAC/Preamplifier was easy. Granted, I ended up staying in the interface, pressing and returning to the “BT Rematch“ window a number of times for the “SD07“ driver to finally load in my phone’s Device List. We live in an old converted warehouse with many Bluetooth devices coming up from other lofts; perhaps that contributed to this lag.

Once connected, things worked and sounded fine, so I played music for a while. At times, connecting my Mac mini via Bluetooth took some trial and error, as changing inputs didn’t always produce immediate sound. Necessary selections need to be made in multiple drop-down menus on more than one device or component that came into play.

Our loft is one big box, and the distance between my desk and any given audio setup can challenge some technology. In past reviews, Bluetooth connectivity between the Mac and the component has occasionally suffered from failing to properly see and transmit audio data over the 18-foot distance from the desk to the rig. As such, I’ll listen with my iPhone, my coaxially connected CD player, and a long optical cable from my Mac mini.

Listening to a Few Tunes

In a near-field setup with the Vanguard Scouts (reviewed in these pages) speakers on my desktop (with my passive sub under), the L07 amplifier and DS07 DAC/Preamplifier sounded great, with plenty of volume for this small rig in this big room, when kitchen duty called. Vera-fi Audio’s $299/pr. Vanguard Scouts are my daily drivers, and they, along with my passive sub, provide plenty of low-end and easy listening for hours with their treated paper cone woofer, silk dome tweeter, and superb construction.

I set up the FX-Audio L07 amplifier and DS07 DAC between my Double Impacts in a balanced configuration, connected to the $1095/pr, gloss-finished XSA Labs Vanguard Bookshelf Speakers (reviewed in these pages), with the SMSL P100 CD Player and a long optical cable running from my Mac as my sources. The Vanguards are 83dB @ 2.83V 1m sensitivity so the volume knob on the amp was promptly turned to the 2:30 position.

This review is already a bit long, so I’ll list my impressions and play a few tunes. First up, through Bluetooth on my iPhone 16e, the John McLaughlin Trio’s Josie, is a track from their 1990 release, “Live at the Royal Albert Hall, November 27, 1989“ (JMT Records). The percussion here defined the depth of the stage, as deep drum wallops punctuated the space and air between the artists. It’s a terrific recording with lots of nuance and dynamics, both very well presented through the Vanguard monitors.

On to coaxial, with a CD spin of Nik Bärtsch’s Ronin’s Modul 60, from 2018’s “Awase“ (ECM Records, GmbH). This DAC/Pre and amp combo had a great grip on the music; nuance and dynamics were presented well. Modul 58 built on those dynamics, adding warmth, depth, and width to the stage, as spatial cues entered, further delineating the space. Percussive work followed, crisp and full of energy. The piano work was dimensional as the bass clarinet and bass growled, adding aggression and drive to the performance.

I connected this balanced pair to the Double Impacts and switched to optical from my Mac. Chien Chien Lu’s cover of “Blue and Green“ from her album, The Path (2020 Chien Chien Lu), was quite spacious, and her vibraphone work is as thoughtful as it is beautiful, accompanied by both piano and organ, all well-presented in frequency range, dynamic content, and sound stage dimension. The bass work was warm and percussion crisp, yet subtle, as transients snap and the organ swells offered nice textures that complemented Lu’s mallet-driven melodic strikes in a drifting, ethereal interplay.

* For those of you bummed that the DS07 DAC/Preamplifier doesn’t include headphone functionality, the Vera-Fi Audio store now lists the FX-Audio R07 Plus Headphone Amplifier as available ($199.00US).

The Wrap

Could the FX-Audio L07 amplifier and DS07 DAC/Preamplifier be perfect for the desktop audiophile? That depends on one’s expectations and depth of pocket. Regarding affordability and performance, my answer is a resounding “Yes.“ I’m as excited about this FX-Audio pair as Mr. Schifter for their inclusion in his product line. They offer a good bit of, dare I say, musicality, at a “first system“ price point that I, too, got giddy when spending time with these products.

Schifter pointed out in his brief commentary that youngsters having access to such affordable, good sound would be attracted to our hobby. Cruise on by Vera-Fi Audio, LLC, and give them a try!

Products reviewed:

The FX-Audio L07 amplifier $199.00US

The FX-Audio DS07 DAC/Preamplifier $199.00US

Contact:
Mark Schifter
Vera-Fi Audio LLC
9025 Crestview Drive
Denton, Texas 76207
Website: verafiaudiollc.com
Phone: (818) 584-6870
Email: verafiaudio@gmail.com

The FX-AUDIO DS07 DAC / Preamplifier features:
• USB Optical Coaxial support MQA
• ES9068AS dac chip, three filter modes to choose from
• THD+N 0.00015%
• USB Chip XMOS XU216 Customized Driver
• DSD up to DSD 512, PCM up to 32Bit/768kHz Hi-Res
• Wireless
• IR remote control freely
• RCA & Balance output
• USB Optical Coaxial MQA Renderer

The FX-AUDIO L07Amplifier features:
• 200W + 200W HiFi Stereo AMP
• Bridged 400 watts power output impedance 8 ohms
• Class D Amplifier
• Fully balanced architecture
• Audiophile-Grade Components – MA5332MS chip and Built-in independent isolated dual power supply
• Balanced XLR/single-end RCA input supports multiple device connections
• What You Get: Class D amplifier x1, User Manual x1, Power Adapter x1, AC Cord x1