- Written by Jim Milton
- Published on 26 October 2009
- McCormack LD-2 Preamplifier and DNA-250 Stereo Power Amplifier
- Page 2: Design of the McCormack LD-2 Preamplifier and DNA-250 Power Amplifier
- Page 3: Setup of the McCormack LD-2 Preamplifier and DNA-250 Power Amplifier
- Page 4: The McCormack LD-2 Preamplifier and DNA-250 Power Amplifier In Use
- Page 5: Conclusions About the McCormack LD-2 Preamplifier and DNA-250 Power Amplifier
- All Pages
When plugging in components, the connectors gave a solid "click" when the interconnects were snapped into place.These RCA connectors were the most solid and secure connectors I have had the pleasure to use in my experience. I hate plugging into connectors that wobble and "give" when you push an interconnect onto them. The front panel controls consist of "tactile" buttons that operate by touching and releasing. All functions can be operated by the remote as well. The display is large and can be seen easily from across the room. When muted, the display shows dash marks.
My overall impression of the LD-2 was that it is very well built and exudes quality and simplicity in design. The face plate is milled 0.25 inch aluminum. Believe me, neither of these units will flex when you lift them. The 3 prong power cord is removable on both units, should you chose to upgrade them later.
The DNA-250 is a 250 watt/channel amplifier that is based on the Distribution Node Architecture that contributes to the lighting fast dynamics the McCormack amps are known for. McCormack has over 30 years of solid state circuitry design in this amp. Rather than have a few very large reservoir capacitors next to each other, the DNA technique distributes many smaller reservoir capacitors among the output stage. This arrangement delivers a high degree of speaker control. The amp is heavy and the heat sinks make it somewhat challenging to grab and lift while holding it on the sides.
The main power toggle is located on the front. There is no trigger on the unit, so the pre-amp will not operate the amplifier. The amp is either ON or OFF as there is no standby.
The DNA-250 retains much of the signature McCormack "Distributed-Node" architecture, which puts individual capacitors right next to the output transistors for better performance. In the DNA-250, these capacitors are upgraded to conrad-johnson film-caps which deliver greater resolution and increased dynamic range. The DNA-250 incorporates completely re-engineered voltage gain and driver circuits well as a redesigned JFET input stage.
Judging from the heat radiating from the DNA, it must be sucking some wattage even in standby. A red light indicates that the unit is on, but does not change color to express a fault mode. Same aluminum faceplate and removable power cord as found on the preamp. Again, you can see and feel the quality.
The DNA-250 retains much of the signature McCormack "Distributed-Node" architecture, which puts individual capacitors right next to the output transistors for better performance. In the DNA-250, these capacitors are upgraded to conrad-johnson film-caps which deliver greater resolution and increased dynamic range and incorporates completely re-engineered voltage gain and driver circuits well as a redesigned JFET input stage.
I do not normally look inside my review products (a mortal fear of voiding the factory warranty!), but this is where the interesting part of this review kicks in. After setting up this system and test driving it with my Oppo 980H (analog outs, of course) for a few hours, I suddenly lost the sound. The LD-2 was on and not muted. The amplifier showed a red light, so it was on…but no sound. I did what any astute audiophile would do and shut it all down and "re-booted". Still no sound. I reconnected everything in a methodical fashion to no avail. Finally, I looked in the amps manual (why do we always do that last?) and read a blurb about blown fuses being a possible reason for loss of audio.
There are four +/- power rail fuses found on the underside of the amplifier. I opened the amp and replaced the 4 fuses ($1.99 for a bag of four at Radio Shack). Three of the four were definitely fried. Problem resolved. I had no further trouble with the amp for the duration of my review period. In all fairness, the blown fuses were most likely caused by something I did and was not poor workmanship on the part of McCormack Audio.
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