davidjt
pfm Member
The ISO-DAC is packed up and will be on its way to Divedeepdog tomorrow - it should arrive by the end of the week.
The current set-up here is an HP Laptop running Fidelizer Pro & JRiver Media Player, playing WAV files and a couple of videos. A Jitterbug feeds into an Uptone Audio Regen plugged into the MDAC. MDAC (pre-amp off) feeds a Myryad Pre-, Linn Klout, OTA Quad ESL57s, Townshend Super-Tweeters and a single REL sub. Clearly, I already knew the USB signal from the laptop needed cleaning up and that the MDAC pre-amp could be improved upon.
The room is rectangular, stone walls 1/2 to 1 metre thick, beamed ceiling, marble floor, soft furnishings, curtains, books etc., two solid doors and two glazed. Not ideal but it works remarkably well. My ears are seventy, so in decline.)
First, I simply removed the MDAC, Jitterbug and Regen from the system and substituted the ISO-DAC. There was an immediate all-round improvement, detailed later.
Then I re-inserted the MDAC, feeding it via the ISO- section of the box. The result was in general more detailed than (MDAC + Jitterbug + Regen) but without the depth and presence of the ISO-DAC. Occasionally a track such as the Pretenders' 'Back On The Chain Gang' would sound unpleasantly tinny.
But the preferred option was unquestionably the ISO-DAC.
I concentrated on (mainly live) Jazz and R&B recordings because a tight, driving rhythm and crisp percussion are (to me) the most obvious (or least subtle) improvements. Also, John refers on his website to Auditory Scene Analysis, and 'where the performers are on stage', and in my room this would be far easier to judge for small groups than a full orchestra. (Symphonies were equally enjoyable, just harder to analyse!)
Playing the better-known 'test' files - 'Famous Blue Raincoat', 'Live at Blues Alley', 'Jazz At The Pawnshop', and also Richard Thompson: 'Austin City Limits', Jo Harman: 'Dirt On My Tongue', Charles Fambrough: 'Blues At Bradleys', my notes are very similar: more drive, snap, crisper, focused, presence, 'in the audience' 'foot-tapping, again'.
Interestingly, there were other tracks - by Gwyneth Herbert and John Mellencamp among others, where there wasn't just 'detail I hadn't heard before' if you'll pardon the cliche, but a faint background beat, a keyboard line or some other element which pulled the whole song together, a missing link.
I also found 'Greatest Hits' albums useful for judging background atmosphere, since they switch from different studios to live performance and back again. Against Bob Marley's 'No Woman, No Cry' I've written 'That's how keyboards sound in the open air!' (Someone will now show me up by proving that all the recording 'feeds' were direct, but until then.....) When all the elements in a song are sharply in focus you become aware of just how good some productions are. I now regret that some Status Quo has found its way onto the drive, but Bohemian Rhapsody hasn't.
I have no doubt that the ISO-DAC would be a significant upgrade in my system.
(Having ten minutes to spare, and being an inveterate fiddler, I put the Jitterbug back (in between laptop and ISO-DAC) and fancied I was hearing a more solid bass 'platform', outweighed (for want of a better word) by less life at the top. Curious, as I'd associate that effect with extra capacitance, not jitter removal)
The current set-up here is an HP Laptop running Fidelizer Pro & JRiver Media Player, playing WAV files and a couple of videos. A Jitterbug feeds into an Uptone Audio Regen plugged into the MDAC. MDAC (pre-amp off) feeds a Myryad Pre-, Linn Klout, OTA Quad ESL57s, Townshend Super-Tweeters and a single REL sub. Clearly, I already knew the USB signal from the laptop needed cleaning up and that the MDAC pre-amp could be improved upon.
The room is rectangular, stone walls 1/2 to 1 metre thick, beamed ceiling, marble floor, soft furnishings, curtains, books etc., two solid doors and two glazed. Not ideal but it works remarkably well. My ears are seventy, so in decline.)
First, I simply removed the MDAC, Jitterbug and Regen from the system and substituted the ISO-DAC. There was an immediate all-round improvement, detailed later.
Then I re-inserted the MDAC, feeding it via the ISO- section of the box. The result was in general more detailed than (MDAC + Jitterbug + Regen) but without the depth and presence of the ISO-DAC. Occasionally a track such as the Pretenders' 'Back On The Chain Gang' would sound unpleasantly tinny.
But the preferred option was unquestionably the ISO-DAC.
I concentrated on (mainly live) Jazz and R&B recordings because a tight, driving rhythm and crisp percussion are (to me) the most obvious (or least subtle) improvements. Also, John refers on his website to Auditory Scene Analysis, and 'where the performers are on stage', and in my room this would be far easier to judge for small groups than a full orchestra. (Symphonies were equally enjoyable, just harder to analyse!)
Playing the better-known 'test' files - 'Famous Blue Raincoat', 'Live at Blues Alley', 'Jazz At The Pawnshop', and also Richard Thompson: 'Austin City Limits', Jo Harman: 'Dirt On My Tongue', Charles Fambrough: 'Blues At Bradleys', my notes are very similar: more drive, snap, crisper, focused, presence, 'in the audience' 'foot-tapping, again'.
Interestingly, there were other tracks - by Gwyneth Herbert and John Mellencamp among others, where there wasn't just 'detail I hadn't heard before' if you'll pardon the cliche, but a faint background beat, a keyboard line or some other element which pulled the whole song together, a missing link.
I also found 'Greatest Hits' albums useful for judging background atmosphere, since they switch from different studios to live performance and back again. Against Bob Marley's 'No Woman, No Cry' I've written 'That's how keyboards sound in the open air!' (Someone will now show me up by proving that all the recording 'feeds' were direct, but until then.....) When all the elements in a song are sharply in focus you become aware of just how good some productions are. I now regret that some Status Quo has found its way onto the drive, but Bohemian Rhapsody hasn't.
I have no doubt that the ISO-DAC would be a significant upgrade in my system.
(Having ten minutes to spare, and being an inveterate fiddler, I put the Jitterbug back (in between laptop and ISO-DAC) and fancied I was hearing a more solid bass 'platform', outweighed (for want of a better word) by less life at the top. Curious, as I'd associate that effect with extra capacitance, not jitter removal)
