Balanced Iso Trannies all around

drumminman
drumminman Posts: 3,396
edited March 2014 in DIY, Mods & Tweaks
With the build and installation of the new 2.5 kva tranny (Signal DU-5 found here: http://www.polkaudio.com/forums/showthread.php?158746-Heavy-Metal-my-new-Signal-DU-Balanced-Iso-Transfomer) I was able to reconfigure what I have equipment plugged into. The power amp and sub woofer are now plugged into the DU-5, the linestage is plugged into the DU-3 (1.5 kva) and the Oppo is plugged into a DU-0.5 which is in turn plugged into the DU-3.

The reason for getting the DU-5 is when I had the system cranked I felt like the sound was slightly constricted. The rig sounded good with plenty of power and great clarity, but over time I noticed that some female voices and some passages sounded slightly "thick" for want of a better term. The DU-3 the amp was plugged into is rated at 3 kva when wired as a simple isolation tranny, and 1.5 kva when wired for balanced power. The amp is around 200-250 wpc, high current so I thought it might be getting a little starved during transients and loud passages.

First listen was Thur night. The DU-5 is a brand new unit never having been powered up before. Lots of copper in there. I'm thinking it'll probably relax a bit with current passing through it over the next few weeks/months. Some of what I heard should be attributed to now plugging the line stage and sub into balanced power as the former was going into a simple isolation transformer and the latter into a power strip.

First up was my go to disc, "Silver Linings" by Bonnie Raitt. When she hit the high notes I heard occasional harshness in her vocals. Other than that they sounded the same. What stood out is a smoother, slightly punchier bass, more air around the instruments, better decay on the trailing edge of notes, and punchier brass. There was an improved front to back depth in the sound stage with background instruments having a slightly better presence. The width of the sound stage was as good as before, maybe a little better.

Next up was Joan Baez "Diamonds & Rust", a remarkably well recorded album especially given it's age. The strong suit here is definitely her vocals. Never heard the harshness I heard on initial power up with Bonnie. Her voice sounded absolutely stunning, perhaps slightly thinner than before, but clear and relaxed. Instruments, as before, had a more "right" quality to their tone and transients such as a drum stick on a cymbal, the leading and trailing edge of plucked or picked notes, punchy, tuneful bass. Busy passages had an improved clarity in that individual instruments had better tone and more air around them.

My sense of this is that the DU-5 is contributing 65-70% of the improvement, with the reconfiguration of where the other stuff is plugged into accounting for the rest. A definite keeper that I'm pleased with, especially since I bought the DU-5 for a steal. Overall improvement in sound quality is 6-8%, not mind blowing but easy to hear.
"Science is suppose to explain observations not dismiss them as impossible" - Norm on AA; 2.3TL's w/sonicaps/mills/jantzen inductors, Gimpod's boards, Lg Solen SDA inductors, RD-0198's, MW's dynamatted, Armaflex speaker gaskets, H-nuts, brass spikes, Cardas CCGR BP's, upgraded IC Cable, Black Hole Damping Sheet strips, interior of cabinets sealed with Loctite Power Grab, AI-1 interface with 1000VA A-L transformer
Post edited by drumminman on

Comments

  • drumminman
    drumminman Posts: 3,396
    edited March 2014
    Having around 20 hours on the the DU-5 I'm hearing significant improvement with familiar CD's. This am I played Madeline Peyroux "Dreamland". During one song I heard a muted trumpet way in the background. I hadn't noticed it before, and it was so low I wasn't sure what it was at first. The Lumineers playing presently, and this recording sounds much better. More slam, greater clarity, more air around instruments, better tone to each instrument.

    Wasn't sure what effect the increased head room from the DU-5 would provide, and what effect plugging everything into balanced iso trannies would be, but it's substantial and I like it! This system sounded very good before the upgrade in AC power filtering, and now it's been taken to a new level. I recommend this to anyone thinking about upgrades. You can buy these Signal DU trannies direct, brand new or on ebay at very good prices if you're patient.
    "Science is suppose to explain observations not dismiss them as impossible" - Norm on AA; 2.3TL's w/sonicaps/mills/jantzen inductors, Gimpod's boards, Lg Solen SDA inductors, RD-0198's, MW's dynamatted, Armaflex speaker gaskets, H-nuts, brass spikes, Cardas CCGR BP's, upgraded IC Cable, Black Hole Damping Sheet strips, interior of cabinets sealed with Loctite Power Grab, AI-1 interface with 1000VA A-L transformer
  • drumminman
    drumminman Posts: 3,396
    edited March 2014
    After about 60 hours on the new tranny I put on Revelator/Tedeschi-Trucks Band last night. Very familiar with this CD and while I like the music my impression has always been that the recording is a little lifeless. Imaging not spectacular front to back, side to side OK. Tone of instruments (not pitch) kind of flat sounding.

    I was quite surprised when the first song started. There seemed be more slam, more high frequencies, better tone of both instruments and vocals. The cymbals sounded more like cymbals, more like they do if you're in the room with them. They had less of the hissy wash sound they previously had. The snare had more pop. Imaging improved to the point where it's closer to other good recordings. Also, it was louder, which kind of puzzles me. Not sure why this would be.

    The change is dramatic and I'm guessing it's due to the tranny starting to relax with having current run through it. Burn in on the Oppo could also be contributing as I have around 150-175 hours on it.

    Very pleased here!
    "Science is suppose to explain observations not dismiss them as impossible" - Norm on AA; 2.3TL's w/sonicaps/mills/jantzen inductors, Gimpod's boards, Lg Solen SDA inductors, RD-0198's, MW's dynamatted, Armaflex speaker gaskets, H-nuts, brass spikes, Cardas CCGR BP's, upgraded IC Cable, Black Hole Damping Sheet strips, interior of cabinets sealed with Loctite Power Grab, AI-1 interface with 1000VA A-L transformer