In my initial setup, using the Monitor Audio speakers in a room on the large size for those 6” woofers, I found myself wishing for more bass (not surprising given a medium-sized room and small speakers). Switching to a NAD 320BEE integrated amp, I recovered some bass energy, while trading off some definition. Be careful what you wish for. To this point, I’d call this choice a tie—and if I were to use an amp like the 151 in this sized room I would either add a sub or search for an efficient speaker with more mid-bass output. More on this later, when I submit a complete test and can try another room. For now, I can say that the 151's bass character could be highly desirable in a small room (the kind of room that would suit its limited power well).
Note: Wadia advises that the 151 PowerDAC requires a minimum of three solid weeks of burn-in before its sound fully blooms and develops optimal richness. So, I plan to give the 151 quite a bit more run-in time before doing a final assessment of its bass capabilities and writing my formal Playback review.

My concerns about bass were nearly forgotten when I really got down to listening. There is a naturalness and coherence to the midrange of this DAC/amplifier that one doesn’t often hear. This is a hard aspect of audio to explain, and has been for some time. As an example, for decades (the 1970s and 80s) many audiophiles favored Audio Research preamps. They had a certain midrange “rightness” that you had to hear to understand. Another example might be the 2009 release of the Meridian 808.2 DAC/Player. When you hear the Meridian, you suddenly realize it has banished many of the digital distortions that you’ve (probably) been living with.
With components like the ARC preamps and the Meridian DAC it is as if frequency response within the midrange is smoother, overtones are present in the correct amounts, and dynamics are more naturally explosive. These items don’t appear to be lacking in conventional equipment, but you realize they are when you hear something better. At this early stage, I’d say the Wadia 151PowerDAC is in that “something better” category. Pretty rare stuff for a component in this price class.
As we continue our tour of the frequency range, the Wadia’s treble is a bit harder to characterize. Partly, I would guess, that is because DACs don’t always reveal their high frequency problems on every disc. I haven’t listened to enough discs to be able to aptly nail the sound of the 151. I would say a few things about what it is not. The 151 is not bright. And the 151 does not have the splashy treble that some inexpensive CD players exhibit. Whether the 151 has a dark treble will require more listening with more ancillary equipment.
Imaging strikes me as another strength of the 151. Central images are precisely rendered and the lateral spread of orchestral instruments sounds quite natural.
If you have the impression that I’ve enjoyed the Wadia 151PowerDAC, you would be correct. It has a definite character, but in the essential midrange it gives a taste of the essence of music that is seductive.
Comments
If you are worried about bass in a largish size room, why use a speaker with a six inch woofer? Aren't you supposed to match equipment to the room and each other? I really don't these kinds of comments as a criticisim of the equipment when it really comes to poor room matching.
I compared the 151 PowerDAC Mini to several other amps, using the Monitor Audio speakers, for the comment on bass power. I also used two other speakers to come to this observation. I think you will find that the 151 has tighter bass but less apparent mid-bass output than conventional amps. In some rooms this will be desirable, in others it will be a limitation.
CEO and Editorial Director, Nextscreen LLC
This sounds very similar in concept to the new Nad digital amp. How would you get SACD output into this device?
You really can't use SACD with the 151. Wadia informs me that they have the circuit concepts to decode SACD to PCM, but they felt the circuitry would raise the cost too much for the likely usage. Also to interconnect with general SACD devices an HDMI license is required which again adds to the cost.
CEO and Editorial Director, Nextscreen LLC
It looks great but I just don't get the need for two boxes! All the dock is doing, as far as I know, is stripping away the pure digital signal and sending the bitstream to the DAC. Does this really require a whole separate - and not inexpensive - piece of gear? I like the concept, but I would find it much more compelling as a one-box solution, and have a hard time seeing why it can't be just that.
You don't need two boxes. The 151 is a single box device that accepts a variety of digital inputs as described. But, if you want to use a iPod and you want the highest quality, you need something like the Wadia iTransport. That's because the iPod's output, even from the multi-pin connector, is analog unless you have special licenses and circuitry. The latter is what the second box provides. If your comment is really about why the iPod connector etc isn't in the 151, I think it is that the licenses and circuitry would drive the price up and not everyone uses the iPod as a source. That makes a modular solution preferable.
CEO and Editorial Director, Nextscreen LLC
I heard this little beast with Polk Audio boxes at the Montreal SSI and it does Sound Good, wow!
The reviewer should have suggested to mate 151 with high efficient speakers for optimal sound in large rooms.
I suggest exactly that: "if I were to use an amp like the 151 in this sized [medium] room I would either add a sub or search for an efficient speaker with more mid-bass output".
CEO and Editorial Director, Nextscreen LLC
Hello,
I wrote the following comment to the WADIA forum:
; I'm using the 151mini in two different environments.
First: living room of 6.5 x 8 m2 with Klipsch Belle attached to it
Second: living room of 4.5 x 5.5 m2 with N.E.A.R 15M2 plugged to it.
In both environments it sounds sweet tube-like, with a punch one cold hardly believe coming from such a small amp. ... . But, you will have to burn in the 151 for at least two weeks, before you really can realize its abilities. ;
Having Audio Research tubed equipment at home as well as PASS Labs amplifiers I agree to what the listening test says about the midrange. I was always impressed by the unbeatable richness of wood winds coming from ARC amps. The 151 is very similar to this. As I hear very different kind of music from baroque chamber music via classical orchestrational works to jazz and trip hop, I had no doubt in the past, that the ARC and PASS systems are a very good match for me. But, the more I hear the Wadia 151 i realize that this small and modern piece is worth more than it's tiny dimensions and more that fair price says. Matched with the right room-fitting speakers and high class program-sources this thing could help a lot of people to step forward into a listening pleasure for what you have payed ten thousend of bucks before. Second: As it ist very easy to transport ;-) I've taken it to a friend of mine usually listening to Westlakes HR-1VF loudspeakers usually fired by a Levinson pre/power amp combi. Well, he's got a very big living room of about 8.5 x 10 m2 and his stereo sounded ever very impressing. After living with the 151 for three days he sold his Levinsons last week, because the 151 outperformed them in terms of sound richness and staging. Any Questions?
thank you for the review.
you suggest adding a subwoofer, how is that possible?
Many subwoofers have high level inputs which are connected to the speaker output terminals of the amplifier. REL subs in particular strongly recommend the use of this connection (and in my experience REL subs give excellent results connected this way).
CEO and Editorial Director, Nextscreen LLC
Does that mean that the subwoofer is connected to the amplifier/151 and the main speakers is connected to the subwoofer? I've been looking at the 151, but need be sure that I can connect my Linn Katan's and Sizmik. Thank you.
Both the main speakers and the sub/subs are connected to the amplifier (in parallel). But the sub must have high level inputs, and the current Linn Majik sub does not. I don't know about the Sizmik.
CEO and Editorial Director, Nextscreen LLC
Thank you. According to the manual the Sizmik has the following connections:
Line level audio in and loop out RCA phono
Line level high pass output RCA phono
High level 4.0mm input connector
Will it do the job? Thanks again.
I would think the high level input would work. A quick check of the manual (Linn usually has hook-up diagrams) should confirm a scenario where the Sizmik is connected to the speaker terminals. If you see that, you're good to go. Your dealer will know as well, and often can confirm that this works well (or not).
CEO and Editorial Director, Nextscreen LLC
Wadia had a power DAC out before they went bust the last time. Furthermore, howcome there is no mention of Tact's all digital power DACs in this article? Their power DAC was launched 12 years ago, in 1998 with the Tact Millennium M1 unless I'm mistaken.
NICE one Tom! LONG time no speak! I'm lookin forward to hearing one of these at home myself, and I thought your piece was both informative, and NOT sleepy! I also dug your focus on the bass resolving capabilities! BRAVO SIR, BRAVO
Michael Mercer
The Daily Swarm
Positive Feedback
Just curious, will you be giving a final verdict of the 151?
Tom, how does the sound of the wadia compare to WFS2 given they utilize different chips
Would it be safe to assume that this low powered amp with tight bass but good midrange and treble, might well with a speaker such as the golden ear Triton Two, which has good bass power with its built in woofer amps, and midrange and treble with its ribbon tweeter, and hi sensitivity to work well with low powered amps? Seems like would be great match. anyone heard this combo yet?