I'm not sure if this topic has been covered. But I'm new to this MSB unit as it replaced a very nice sounding Parasound D/AC-1100HD (don't ask why) ... Anyway I acquired this unit recently from a gentleman on the Audiogon site. It came with the upsampling board ... otherwise it's stock.
When I first got it, I noticed that it sounded OK, but was missing some of the low end that the Parasound unit had ... a lot of it. Also I noticed that the upper registers were somewhat harsh ...
In searching through the net, I found the site for mods; written by Dan Wright (
http://www.themorgue.org/audio/msb-link/) ... I've heard of Dan on the web, but have never dealt with him before. I sent him an email asking a few questions and he recocmmended that I change three things. The power supply bridge rectifier diodes for FRED's, the voltage regulator to +/-15V and upgrade the opamps to the BB OPA-627's.
Being one that knows how to solder a little (yeah, I once upon a time went to solder school!!) ... I acquire the requisite items from Dan directly as he had a module that would make a pair of OPA-627's (single opamps per package) fit into the existing dual package.
Overall, I would say the modifications DID EXACTLY what I wanted. That is to smooth out the upper registers and to put more punch in to the bass section. It was money well worth spending!!
Below are my notes during the modification process:
2Sept03
Mod:
• Replace U16 & U17 w/ AD827CN8 opamps
Sonic Observations:
>>> Not sure if there’s more bass there … if so, it may not be a real controlled extra bass … maybe a little boomy????? Too early to tell.
4Sept03
Mod:
• Replace U16 & U17 w/ OPA-627 opamps modules bought from Dan Wright.
Sonic Observations:
>>> Bass seems to be less boomy and faster … otherwise, the highs seem slightly clearer …
5Sept03
Mod:
• Replace 1N4002 diodes (two diode bridges) in power supply with FRED’s (Fairchild RHRD440) provided by Dan Wright.
Sonic Observations:
>>> Seems to be more and faster bass?? Is it my imagination?? Bass volume is certainly more, seems pretty fast too ... need more time to evaluate and compare to the Parasound. It’s only been about an hour.
6Sept03
Mod:
• Replace L7808 & L7908 (+/-8V) regulators with LM7815 & LM7915 (+/-15V) regulators provided by Dan Wright.
• Removed C40 & C56 from the analog section.
Sonic Observations:
>>> Most definitely more and faster bass! It is not my imagination. I can now feel the sub, whereas before I just hear it. Lower registers are more pronounced and more bass, seems pretty fast too ... Now I feel it’s more comparable to the Parasound D/AC-1100HD … still need to plug in the Parasound and compare.
