Dodd Audio Battery Powered Tube Buffer Preamplifier Review

No Gain, No pain. And No AC!

Gary Dodd began, as have many audio designers, as a do-it-yourselfer (“DIYer”). As word of his products spread, he began commercializing them, though to this day the Texas-based Dodd Audio remains a small enterprise. Although he does have some pricey “statement” products, Gary prefers to focus his efforts on affordable gear. He recognized early on, as have many others, that the AC voltage powering our rigs is a major source of noise and grunge. Whereas many take the approach of massive and complex power supplies designed to clean up and regulate the noisy AC voltage, Gary decided to bypass it completely, relying instead on batteries. Circa 2007 Gary introduced a battery-powered preamplifier that met with rave reviews. But not willing to rest in his laurels, Gary put on his thinking cap. He knew the benefits of passive linestages, but recognized their weaknesses as well. But how about if one were to combine battery-power with a no-gain linestage, but add a buffer to circumvent impedance mismatches? Thus was born the Dodd Audio Battery Powered Tube Buffer, the subject of this review.

The Dodd Buffer is relatively compact, measuring only 9” wide x 8 ½” deep x 4 ½ tall. The unit is composed of heavy gauge steel with a wood front panel, a variety of which are available as options. In a world of ornate audio jewelry, I find the Dodd refreshingly simple and pleasing to the eye. On the rear panel are three RCA inputs, two RCA outputs (both volume controlled, thus useful for systems with subwoofers), and a connection for the battery. On the front panel are three large rotary dials. The leftmost is the INPUT SELECTOR; the rightmost controls VOLUME, while the middle dial has three positions: “OFF” (about which more in a moment), “MUTE,” and “ON.” The Dodd Buffer comes standard with a plain-Jane Universal remote for controlling volume only. It does not come with a battery, which must be purchased separately. Gary recommends the Power Sonic PS-1270-F1battery and CTEK Multi US 3300 Charger, which retail for about $20 $60, respectively. When the Dodd Buffer is switched to the “OFFf” position, the battery automatically begins recharging. I am told that a fully charged battery allows for about 10-12 hours of play.

The DABPTB is available either fully assembled for $1,595 or as a kit for less than $1,000. My review sample was assembled, and included the battery and charger. To set it up, I removed the screws allowing access to the interior, and installed the single, provided tube. I then connected the inputs from my digital and analogue sources, the outputs to my amp, and last the battery; I then allowed it to charge over night. Regarding the tube, one can use pretty much anything from the 6DJ8 family, including the Russian 6H30. My unit came with the 6H30DR, 1986 vintage which many feel is the best choice for the DABPTB. I did not do any tube-rolling. I used the DABPTB with my Hybrid Tube Distinction Soul monoblocks (30W/channel), and 104 dB-sensitive OMA horns.

Listening

Over the past few years I have owned and/or auditioned in my own system a number of very fine preamps, all but one of which, an autoformer, about which more later, are considerably more expensive than the DABPTB. I wasn’t sure what to expect from the DABPTB and truth be told, I didn’t have very high hopes for it. So let me jump to the punch line: The DABPTB far exceeded my expectations, proving itself to be an extraordinary piece of gear.

When I get a new preamp or amp, one of the first things I do is check its noise floor, especially with tube gear, which tends to be noisier than those based on silicon. To do so, I simply turn up the volume without a source playing, and listen. Most of the preamps I’ve owned or demo’ed over the past few years have had a very low noise floor – even with my 104 dB sensitivity speakers which leave no place to hide – which I attribute to their excellent design. When I tried this with the DABPTB, I heard – or more accurately, didn’t hear – anything that distinguished it from the other linestages. I was a bit disappointed but soon realized that this approach tells only half the story. Once I switched to music, the DABPTB was revelatory.

In my recent review of the TT Weights GEM turntable, I spoke about its reproduction of microdynamic shadings and low-level detail, which I attributed to its low noise floor. The DABPTB displayed the same behavior, but to an even more startling degree, which is not to imply that the DABPTB is “better” than the GEM but rather, that different components in the chain add different degrees of noise. Listening to music with the DABPTB, notes appeared from the blackest background I have heard in my system (with one exception). All the audio chestnuts came to the fore: veils lifted, windows cleaned and thrown open, newly revealed detail, hearing old standard discs as if for the first time, listening into the wee hours of the morning, and so on. Clichés ? Absolutely; but also absolutely, positively true. The DABPTB’s contribution to musical enjoyment is impressive. Irrespective of whether one is a “you are there” or a “they are here” type of listener, the DABPTB’s transparency to the source provides a level of sonic realism that truly must be heard to be appreciated.

I compared the DABPTB to three tube preamps, two from well-known companies, the last from a new company, each retailing for between $3,500 and $4,000. The DABPTB made clear how colored all three units are. To be sure, the colorations were often pleasant, but as colorations they masked musical detail, in some cases to a considerable degree.

Tonally, the DABPTB was much less colored than the other tube preamps. It has a bit of “tube warmth,” but is devoid of the glare and hardness that typifies many solid-state preamps. Instruments, including voices, were well separated from one another, both spatially and tonally, allowing the natural quality of the music to come through.

There are two areas in which one might find fault with the DABPTB. In my system, the volume control was typically between 12 and 1 o’clock, so there was always sufficient volume, though it should be noted that I never listen at particularly loud levels. But despite the adequate volumes, the overall sound lacked the last iota of energy of which I know my system to be capable. Are the slightly recessed dynamics the result of the DABPTB’s lack of gain? While I cannot know with certainty, it is worth noting that Gary recently released a battery-powered, active (i.e,. with gain) preamp which he claims has better dynamics than the DABPTB. I hope to review that new preamp soon. The other area of weakness (and I hesitate to use that term), was the bass. While the DABPTB’s bass was tight and tuneful, it seemed to not plummet the depths quite as well as the active linestages I’ve used, nor did it have quite as much slam. But lest I be misunderstood, these are minor quibbles.

As I mentioned earlier, there was one other linestage/attenuator that was sonically similar to the DABPTB: an autoformer-based unit from Dave Slagle. It’s transparency was in fact even greater than that of that of the DABPTB, and it too put to shame the three tube preamps to which it was compared. I did, however, encounter impedance mismatches between the autoformer and certain phonostages, which were not problematic with the DABPTB.

Summing Up

At this point in a review of great-sounding gear, one typically launches into a discussion of diminishing returns, and how we each must ascribe our own monetary valuation to sonic performance, etc. It is a delight to not have to do so for the Dodd Audio Battery Powered Tube Buffer. The Dodd Buffer is not just one of the better-sounding tube linestages I’ve had the pleasure to hear, and I’ve heard and owned some damn fine units; it is also one of the greatest bargains in high-end audio. I have purchased the review unit, which is now part of my reference system.