Deep bass response of Audio Note 2.1x Balanced DAC

I've had this DAC for the past month and have been very impressed with it overall except for its seeming (in)ability to reproduce very deep reverberent bass, mostly from an acoustic bass. I hear--oddly not all the time--distortion and smearing from standup bass, in mostly jazz combos. I've changed the stock tubes,and reverse phasing it, but I'm finding it more and more musically unsatisfying when the sonic picture is marred by tubby or smearing of deep bass notes. Since my preamp allows me to switch inputs to hear the output of the CD player near-simultaneously, it is clear the roll-off is pretty pronounced from the AN. A significant flaw (?) in an otherwise fine DAC. I hear it when the transport is either my Sony XA777ES or my cheapo Pioneer DVD player, so don't think it's transport related. By the way, the dealer says this is the trade-off for a tube-based DAC. Is this common with others? Curious as to others experience with AN DACs, especially with deep bass output.
What tubes does this use? I ask because tubes have a distinct personality and I might be able to suggest a substitute.

Isolation is a big deal on the Audio Note DAC. Have you tried Still Points or Symposium Roller Blocks under it?

I also suggest putting some weight on top of the Audio Note. Begin with a large book, if that helps you can make a permanent load from a flat plastic container with tight lid (like you see for fish lures) and fill it with sand or lead shot, depending on the amount of weight needed.

Only other issue, you mention comparing sound between Audio Note and your Sony by switching your preamp. Unless the interconnect cable in these two positions is identical, you may be auditioning interconnect as well as DAC performance.
DH cones (large) w/ squares work really well for me. 2 in the rear and 1 in the front. I have the front about 1.5" to the left of the center. When centered, bass is a bit "sloppy", also less airy. Go figure.......
I'm not sure the problem has been successfully isolated to the DAC, but if truly has, there is something wrong. That is NOT the sound of a properly functioning Audio Note DAC at any level, most assuredly not from a transformer-coupled model.

Please contact me off-line. I may be able to help.
Its always amusing to read this type optimistic responses, it seems that some people are willing to go to any lenghts before accepting the obvious, which is a famous brand product has limitations.

I've owned several AN DACs in the past, none of them had true deep bass and the DACs had two distinct characters. Some like the 3 warm, slightly wooly and homogenized sound, soft bass and top end but musical in nature. Others like the 5 were apparently more detailed but had a hard midrange, rendering it a lot less musical than the warmer, woolier sound of their other DACs. Yes the bass was louder but not necessarily more detailed.

Sure, a good rack helps any equipment but footers are a different story. I've found every footer that I tried to add a distinct character to the over sound which in time becomes boring and montonous. All metal footers, whether, roller ball, points, cones, etc., impart the same sonic signature to equipment. Its a harder thinner sound with a more hifi bass, ie; no detail, warmth or girth like the real instrument, and harder top end. The mids suffer the most. From this point on every piece of music that you'd play will sound almost exactly the same. The DH cones have a different character but its of the additive nature also.

I know my opinion will be unpopular with many people here, but this is my experience, take it or reject it for its worth.

rgds, Mama
Mama, I don’t necessarily disagree with your assessment of DAC’s in general. All are compromised due to the limitations of the format.

However, the gentleman ask for solutions for a problem with HIS particular Audio Note, for which I assume he paid good money. I am an analog guy with a stock Sony for digital. However, I respect those looking for better digital and make suggestions based on experience.

Unless you have an unlimited budget, experimentation is often the only option available to move the sound where you want it. The tweaks suggested here are fairly powerful in relation to their cost.
If what you say has any foundation in reality, then there's something seriously awry with your system. The nature of your response suggests to me that you've never heard an Audio Note DAC 5, let alone owned one.
Thanks for all your comments. The dealer has contacted me and it will be arranged so that the DAC is checked out by Audio Note in Canada. By the way, use of points and mass loading the unit did not fundamentally change the problem with the deep bass.
I don't think your dealer can do anything about that.
The 2.1 balanced reproduce a lot less bass than I was used to get from my previous gear.
Its inability to reproduce bass is within its design, especially those small (weak ?) transformer outputs . You must live with it if you want to keep that liquid medium and sweet trebble.