Linear Tube Audio Aero DAC by Terry London

At the 2023 Chicago Axpona show, I talked with Mark Schneider, Linear Tube Audio CEO, about his great excitement about his company’s first DAC called the Aero. The prototype was in their room. However, Mark and his team were fine-tuning its voicing and its final physical appearance. In the past, I have reviewed all tube-based LTA preamplifiers and power amplifiers. They are all fantastic pieces priced fairly based on performance and build quality. Linear Tube Audio historically emerged because of the friendship between Mark Schneider and the legendary designer David Berning. One of the most innovative circuit/topographies in the last twenty years is Berning’s ZOTL (Zero Hysteresis Output transformer-less).  When used in either preamplifiers or power amplifiers, it offers incredible lighting, quick dynamics, absolute transparency/micro-details, and a very high pristine tone and color. LTA brought Berning’s costly tube-based ZOTL designs to market at a much more reasonable cost but with excellent parts and build quality. I also know that Mark and his team will never rush a new product. Regardless of how long it takes to get exactly what they want, that’s how long it takes. For the Aero DAC, which retails for $3,950, it took almost another year and a half to get it right. As you will see in this review, they got it right!

There are so many innovative aspects of the LTA Aero DAC that I refer you to their website for the numerous details on these new developments. However, here are some of the significant/new advances for LTA compared to their other gear:

1. The first ZOTL circuit is not based on an existing Berning design.
2. The first output is a balanced design in an LTA product.
3. First LTA design without inter-stage coupling capacitors.
4. You can choose to use either a pair of 6SN7 or 12SN7 by using a switch on the back of the DAC.
5. There is over 300,000uF of storage capacitance in the power supply. More than many amplifiers!

The Aero DAC’s dimensions are 17″ W by 3″ H by 10″ D. Its weight is 15 pounds. The black chassis of the Aero DAC is simple but very robust, and I find it quite elegant. I was also glad that the vacuum tubes were not placed on the inside of the chassis for two reasons. First, tube rolling is accessible without removing the chassis’s top. Secondly, I liked the aesthetic of seeing the glow of these tubes. Two brass push buttons are located on the left front plate. One turns on the DAC, and the other selects the digital input (USB – S/PDIF – TosLink). Three small LEDs indicate the DAC is on, what the sampling rate is, and which digital input is in use. Around the back is where the IEC input/master on/off switch, the digital inputs, the switch for using either 6SN7 or 12SN7 output tubes, and finally, either RCA single-ended or XLR balanced analog outputs are located. Undoubtedly, the Aero performed on a higher level when using the XLR/balanced outputs. The LTA Aero DAC uses no filters, feedback, or oversampling. It will process up to 24/192 PCM. LTA ships the Aero DAC with an excellent pair of NOS 12SN7s. I will share all the details regarding the performance of the Aero DAC using these tubes. However, I also used my favorite 6SN7 tube, NOS 1943 TungSol black glass/round plates. Everything in my description of the Aero DAC’s performance with these tubes went even higher.

One more technical point, which is very important and salient, is regarding the voicing of the Aero DAC: Mark and his team decided on the highly regarded NOS ladder DAC chip, the AD1865, instead of a current Sigma-Delta chipset. For my taste, I find R2R ladder-based DACs to be much more musical and relaxing to listen to. One of the best DACs I have ever had in my system was the Audio Note (UK) 4.1 Balanced Signature, which retails for $37,700 and uses the same AD1865 chip.

When I installed the Linear Tube Audio Aero DAC in my reference system, instead of my Reimyo DAP-999EX Toku DAC, which is a ladder DAC based on the famous NOS Burr-Brown PCM-63 chip, which still sells for around $13,000 if you can find a NOS one from Japan, I was shocked at the performance of the Aero. It closely matched the performance of the Audio Note DAC 4.1 Signature and my Reimyo Toku DAC. Both were way more expensive than the LTA Aero DAC at exponentially more dollars.

In all types of genres of music (classical, jazz, rock, hip-hop, and blues), the LTA Aero DAC produced the following musical virtues.

1. It floated a vast, deep, wide, and high soundstage with very accurate instrument location on that soundstage. Yes, this was recording, depending on whether it was a studio or live classical symphonic performance recorded in a vast hall. Either way, with great precision, the Aero DAC created spatial dimensions rivaling the best DACs I have ever had in my system.
2. As my readers know, I’m a timbres and tonality listener first; if a piece of gear gets this wrong (washed out – lack of correct intensity of colors – too bright or light up), it does not matter if other sonic characteristics are in place. The Aero DAC renders a voluptuous natural tonality, ease, and liquidity, drawing you into the music. This is mainly because of the AD1865 chip, the ZOTL/tube-based analog conversion section, and the unbelievably robust power supply.
3. The Aero DAC retains what the ZOTL strategy does in the rest of Linear Tube Audio’s equipment. Blazing fast transients, extended accurate bass reproduction, and a sense of PRAT (pace-rhythm-and timing) that makes it difficult not to tap your toes to the music.
4. This tube-based DAC has a vanishing low-noise floor that creates a very high level of clarity/transparency. This allows minuscule details of decay trails to be easily heard without being etched or sounding analytical.
5. The LTA Aero DAC has an octave-to-octave seamlessness and an overall “ease” and “wholeness” that many listeners will experience as analog in nature.

I coined a term in a past review where I referred to a piece of gear as being a “disruptive product” because it insanely snapped the cost vs. performance ratio. The Linear Tube Audio Aero DAC is such a product. With the quality of internal parts, build quality, and reference-level performance I shared in the review, I need to find out how Linear Tube Audio can sell it for under $4000. I have had vast experience with many highly regarded DACs, reviewed many, and own three highly regarded ones. Two of them exceed the price of the Aero by at least $10,000 or more, yet the LTA Aero DAC easily hangs with them regarding performance and the amount of musical pleasure I derive in listening to it. You could spend a lot more money, but you might not get a better-performing DAC than the LTA Aero. What’s great is you get 14 14-day trial period to decide. So far, there have been no returns to LTA, and I totally understand!

Specifications

Linear Tube Audio Aero DAC
Price: $3,950

Inputs: USB, RCA Coax, Toslink / Optical
Outputs: RCA (70 ohm), XLR (140 ohm)
Formats: Up to 24-bit / 192 kHz PCM
DAC: Analog Devices AD1865 R2R
Output Voltage:
RCA: 2.2 Vrms
XLR: 4.4 Vrms
THD+N:
RCA: 0.54% at 1.1 Vpeak.
XLR: 0.061% at 2.2 Vpeak
Hum:
RCA: -110dB at 1.1 Vpeak
XLR: -116dB at 2.2 Vpeak
Frequency Response: -0.3dB at 20Hz and -0.8dB at 20kHz
Tube Complement: 2 x 12SN7 (6SN7 tubes can also be used)
Power Consumption: 32W (Standby: 7W)
Dimensions:
Width: 17in
Depth: 10in (10.5 in including connectors)
Height: 3in (not including tubes)
Weight: Approx 15 lbs

TJ’s Associated Equipment
Sources:
Pass Labs DAC-1
Audio Note (UK) DAC 4.1 Balanced Signature
Reimyo DAP-999EX Toku
Mark Levinson 31.5 reference transport
Pro-Ject reference CD transport & LTA power supply
CEC-3 belt-driven transport
Amplification:
Coda FET 07x preamplifier
Coda S5.5 amplifier
SPL Elector preamplifier
SPL S1200 amplifier
Threshold 550e amplifier
AricAudio Motherlode MKIII preamplifier
AricAudio Super SET 300B amplifier
Loudspeakers:
Tekton Design Ulfberth
NSMT System Two Design
Accessories:
Black Cat – 3202XLR ICs
Jena Labs reference AES/EBU digital cable
Kirmuss Audio Adrenaline speaker wire
Krolo Design reference rack & footers
Puritan Audio power conditioner & circuit grounding system Audio Archon power cords