I don’t have access to demo equipment so I troll the forums and look for some user feedback pattern that jives with my personal preference sound wise. Well my search for an entry level DAC, preferably tube based began Oct 2012. A couple of the DAC's I looked at began with Maverick, Matrix mini-i, Matrix Quattro and others but the term tube is used loosely in entry level equipment. I started focusing in on a true vaccum tube buffered DAC made by Grant Fidelity called Tube DAC-11 pretty early that had all my requirements for a modest $350. As I began cross-referencing reviews and forums it became obvious that for its price it could be a giant killer, giant killer in that it could compete with DAC’s in the $500-$750 range. Since I had already selected my active monitors Adam A7x’s I thought the tube buffer would warm the neutral Ax’s nicely. When I received the TD-11 I was impressed and thought it was a good match but since I don’t have a point of reference with other DAC’s I doubted giant killer status. Once I had everything dialed in I was a happy camper. Until I met a brother from another mother that convinced me that I had not scratched the surface of the TD-11’s capabilities until I begin tube rolling. He started the ball rolling by sending me several tubes to begin the exercise of dialing in the tube to match my monitors. The first tube I rolled was the Zaerix 7DJ8, which added clarity, controlled low end and airier sound over and above the very good Chinese tube, supplied by Grant. The next was a Russian tube Voskhod “rocket” which had all the Zaerix benefits but also included a perfect balance from revealing high resolution, punchy mids and tightness in the bass region that had my head bobbin. I was convinced this was the tube but my arm was twisted to continue the experiment and keep rolling. The next was the Amperex Bugle Boy, which warmed up the sound beyond what my system was capable of balancing out. I was not at all disappointed since I had the rocket waiting in the wings. Via special delivery, I also rolled the very popular Amperex PQ white label O getter and the sound was excellent on a higher-end level but the synergy with my monitors was off in comparison. The giant killer for my system was the combination of the Grant TD-11 with the rocket tube and even though I’m sure it gets better, but at what cost?
I am now at the halfway point on my digital rig and looking forward to the next chapter that brings me closer to audiophile bliss!
! I matched them with a tube-dac that added the perfect warmth/mid-bass extension to the technical (neutral) studio monitor sound. I just added the Adam Sub-8 (bass woofer more so than sub) to my setup equaling a classic 3-way sound. Playing high-res 24/96 flac files on my new digital rig is moving closer to my 80's vinyl reference rig (10in rosewood technic tt, nakamichi dragon, carver preamp & mono blocks, ads bi-amp 4-way towers). The sub is really not needed for 95% of my listening requirements but it does add that subtle growl that is present in most recordings from time to time and when your this close to digital mid-fi bliss (on a shoestring budget) with analog hi-fi memories, why stop short LOL!! I replaced the power cables on both monitors and sub with higher-end aftermarket power amp cables for additional dynamics and bass extension IMO! The cable upgrades and tube-dac are not needed for great sound though, I used the A7x with my MBP audio out via rca adapter for the first month and they sounded very very nice. 
yeaha! ---->$$$ Oh Oh
!!
!!!!!!!!!!!!!!!