Don Sachs D2 Linestage Review

Note: While Don Sachs has recently retired, his legacy lives on in the Don Sachs D2 Linestage. While Don isn’t actively building new products, he has, to some extent, passed along the baton to the speaker builder Spaitial Audio, who are producing Don Sachs’ designs, presumably under some form of licensing agreement with Don, and Lynn Olson.

I own two Don Sachs products, the Kootenay KT66 stereo tube power amp, and the subject of this brief review here – the Don Sachs D2 preamp/linestage.

I haven’t done much reviewing lately, having been in a state of lethargic stupor for some months now, but since I’ve been using the D2 more frequently in the second system, than the Veloce Audio Ls-1 linestage in the main system, I thought I’d reach for the Macbook and roll out a few words.

If you’re reading this review, chances are you’ve already heard of Don Sachs and his highly regarded audio products. Perhaps you’re even considering purchasing a Don Sachs linestage on the used market or exploring your options for a high-quality preamp. With that in mind, I’ll gear this review toward those who are actively shopping for a linestage and want to know what sets Don Sachs’ designs apart.

The D2 is a highly regarded tube preamplifier known for its exceptional sound quality and meticulous craftsmanship. Hand-built by Don Sachs, each unit was customizable to suit the unique preferences and needs of its owner. When browsing used marketplaces like Audiogon or USAM, you’ll often notice pricing variations, which can typically be attributed to the specific features of each unit. For instance, not all D2 models include an XLR input, as this was an optional upgrade available for an additional cost. Most units feature remote control functionality, a digital display panel, and two RCA outputs—each equipped with different value capacitors to allow for personalized sound tailoring. Additionally, all D2 models I’ve encountered include three RCA inputs, providing ample flexibility for a range of source components.

Tip: Expect to pay between $2000 and $2500 used. The price range is driven by the actual spec of the unit, but also the value of the tubes included with the sale. It’s worth paying more if the seller is including his stash of tubes, as the D2 lends itself nicely to the art of tube rolling.

Technical Specifications

• Tubes: Utilizes 6SN7 tubes for amplification, renowned for their rich tonal characteristics.
• Inputs: Multiple single-ended (RCA) inputs; an optional XLR input is available, employing high-quality Cinemag line transformers for conversion. (Source)
• Outputs: Single-ended (RCA) outputs; balanced (XLR) outputs are not available. (Source)
• Volume Control: Features a 64-step Khozmo attenuator with input relay switching for precise volume adjustments. (Source)
• Power Supply: Incorporates an all-film capacitor power supply, enhancing sonic performance. (Source)
• Customization: Options for capacitor upgrades and tube selections are available to tailor the sound to individual preferences.

Noteworthy:

1. The preamp inverts phase, so you’ll need to reverse the speaker leads at either the amplifier or speaker connections—but not both.
2. The tubes on the far left side of the preamp have a greater impact on the sound compared to the right bank of 6SN7 tubes. The front two tubes handle the left channel, while the rear two tubes manage the right channel.
3. The rectifier tube required is a 6BY5GA or an equivalent. Do not use a 5-volt tube, as it is not compatible.
4. Power on the preamp and allow it to stabilize for about 45 seconds before turning on the amplifier. This step is particularly important when using a transistor amp.

Here are some specific points of interest that came directly from Don Sachs:

You can turn them [power amp and preamp] off at the same time, but the preamp needs about 20 secs or so for the rectifier to warm up before you turn on a solid state amp.
If you had a tube amp you could turn them all on with one switch at the same time because your power tubes need 20–30 seconds before they can pass a signal, but a solid state amp can pass a signal in a second or two.

Relating to this specific unit under review, and the dual outputs, Don said: The 1.5 oil caps are out1, the .68 caps are out2. The .68 will give you a little bass roll-off.

Don Sachs here…
Tube life… well it depends. All tubes in every piece I build are run very conservatively and not pushed at all.
You should easily get many thousands of hours out of the 6SN7 types. The KT88 in the power amp should go 2000+ hours easily.
The old American and Russian 6SN7 types will last a LONG time. The modern Russian and Chinese tubes… well it depends.
If you get a good pair, then they also go on forever, but some of the Chinese ones will get noisy.
If you get 100-200 hours on a modern CV181 and they remain quiet, then they should go many years.
Most problems seem to crop up in the first 100 hours. I play every tube set for 5-10 hours.
If you get a noisy tube in the first 90 days, then of course I will replace it. To my ears in my system with my gear, the best sounding tubes are the Shuguang Black Treasure series. Even better than my Tungsol round plates, Sylvania bad boys, National Union black glass, etc… They have about a 5-10% failure rate in that they are noisy. So you just have to weed out the noisy ones, then they seem to last as long as any other tubes. The Shuguang Black Treasure CV181-T is about as good as it gets in my preamp and amp.

One other point. If you spend big dollars chasing down NOS or lightly used old tubes, you will find that a high percentage of them are noisy as well unless you buy them from a vendor who tests for noise.
If you just get some off eBay that were tested on a regular tube tester they will work, but many will be noisy. Caveat emptor…

Handwritten Note:
Preamp Inverts Phase
Reverse Speaker Leads

Partnering Equipment for this Review:

While I’ve had the preamp for around six months, I haven’t schlepped it around between the two systems. Primarily I’ve been using the D2 with a pair of Audio Mirror Reflection 45 SET monoblocks, and this pairing is quite special. For partnering gear, I’ve used a Lumin U1 Mini with SBooster upgrade, and a few DACs, the Ayre Codex, Chord 2Qute, and the PS Audio Directstream Jr.

I haven’t rolled power cords in the Don Sachs D2, I started out with my trusted ESP Reference PC, and that’s remained consistent throughout. Mostly I’ve used the RCA inputs, and cables have been a mix, including Paul Speltz’s Anti-Cable S3, Harmonic Tech Pro-Silway II, and several Cardas cables that I have kicking around.

Sound Quality

The Don Sachs D2 linestage is a well-regarded tube preamp that offers an impressive blend of refinement and versatility. After spending significant time with it in my system, it’s clear that this preamp was thoughtfully designed to cater to both technical performance and musicality.

Starting with the midrange, the D2 offers just the right amount of tube bloom—enough to provide richness and texture, but without veering into syrupy or overly colored territory. Vocals and midrange instruments maintain a natural quality that feels balanced and engaging, making it a pleasure to listen to tracks with strong vocal performances or intricate midrange detail.

The top end of the D2 is another strong point. High frequencies are extended and airy, with just the right amount of sparkle to give recordings a sense of openness. Importantly, the treble never draws undue attention to itself, nor does it sound harsh or fatiguing, even on extended listening sessions. Whether I was listening to the shimmer of cymbals or the delicate overtones of string instruments, the high frequencies consistently felt effortless and well-integrated. Tracks with intricate cymbal work, like Dave Brubeck’s “Take Five” or the shimmering guitar tones in Pink Floyd’s “Comfortably Numb,” had a sparkle and a sense of space that felt endless. The D2 preamp opens a window to the upper frequencies, letting the light pour in.

Bass performance with the D2 is somewhat dependent on which output is used, which makes this preamp particularly versatile. Driving my Merlin speakers via output 2, I noticed the bass had a slight roll-off—a characteristic of both the speakers and the 0.68-microfarad capacitors used in that output path. Switching to output 1, which utilizes 1.5-microfarad oil caps, made a notable difference. The bass gained weight and extension, fleshing out the lower frequencies and adding a noticeable half-octave of depth. This flexibility allows you to fine-tune the preamp’s output to better match the characteristics of your system, which is a significant advantage for those with bass-sensitive setups. An important consideration when connecting a subwoofer or subwoofers directly to the preamp (instead of using high-level speaker inputs, as recommended with my REL Carbon Specials) is the optimal configuration. The best setup is to run the main speakers from Output 2, which has a slight bass roll-off, and the subwoofer(s) from Output 1, which offers full bass extension. From a technical standpoint, this arrangement benefits the main power amp, as it reduces the load by rolling off the bass earlier through Output 2, compared to the unrestricted signal from Output 1.

In terms of soundstaging, the D2 excels at creating a realistic and layered spatial presentation. Instruments are well-placed, and there’s a clear sense of depth and separation. This aspect of its performance adds to the overall musical engagement, especially on complex recordings with a lot of layered and overlapping elements. My little Audio Physics Yara Evo speakers are champs at spatial presentation, particularly depth. The Don Sachs pre opens them up dimensionally more than the Art Audio DM-VPS Linestage I had on hand and more so than driving the amps directly from the Leedh volume control inherent in the Lumin U1 Mini streamer/server.

Dynamics are another strong suit. The D2 captures microdynamics with a subtlety that pulls you into the music—tiny shifts in a vocalist’s inflection or the lightest touch of a piano key come through with startling clarity. At the same time, it handles macrodynamics with authority. Explosive crescendos in orchestral pieces like Stravinsky’s “The Firebird” or the raw energy of Led Zeppelin’s “When the Levee Breaks” were delivered unconstrained by the preamp.

While the D2 provides excellent tonal balance and musicality, it also offers some flexibility in tailoring the sound further through tube rolling. The 6SN7 tubes used in the D2 play a significant role in shaping its character. In my experience, premium tubes like the Shuguang Black Treasure CV181-Ts add an extra layer of richness and depth to the sound, while vintage Tung-Sols lean more toward clarity and openness.

Overall, the Don Sachs D2 is a standout preamp/linestage that manages to strike a fine balance between tube warmth and accuracy. It leans more tonally toward a classic CJ, like the LS16 MKI, more so than my Veloce LS-1, which is more neutral. It’s not overly colored, nor is it clinical; it simply delivers the music in an honest and engaging way. The ability to switch outputs to tailor the bass response and the option to experiment with different tubes make it a versatile and adaptable component that should work well in a variety of systems. Whether you’re pairing it with tube amps or solid-state gear, the D2 is a well-rounded performer that delivers high-quality sound reproduction. At $2250 plus or minus $200, this is an absolute gem and great value if you see one on the used markets.

CAH December 2024

For more information visit Don Sachs’ official website: Don Sachs Consulting

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