|Product code||LNC2 C|
|Category||MARK LEVINSON LNC2 CARDS|
When we fall in love with a product, the passion that we have drives us to study its electrical and sound characteristics thoroughly
The Mark Levinson LNC2 electronic crossover is one of those devices that it is impossible not to be passionate about.
An extraordinary object, with an incredibly neutral sound
An instrument of absolute precision
Used by Mark Levinson in the HQD system together with a battery of ML2 power amplifiers, it was developed by John Curl on Dick Burwen's original design (LNC1) of the early 70s
Even today it remains probably the most performing component of this type ever made.
For the goal that we will describe later, we have recovered four exemplar.
In reality at least three different LNC2 series were produced and for our purpose we had to be certain that what we would have gone to develop would have worked perfectly regardless of the series and the date of production.
But what does this project consist of?
It is the first in the world to develop a series of "cards" with whatever frequency cut is desired, with slopes up to 18dB per octave exactly identical to the original, plug and play.
In fact the biggest advantage in terms of sound of this device is due to the fact that the choices of the cuts are fixed, determined by a battery of four cards inside the device. In this way, a whole series of deleterious components which are normally present in the machines which allow the cutting frequency to be varied continuously is eliminated.
In this case we have only attenuators consisting of precision multiturn potentiometers for level adjustment.
Many LNC2s have been made and despite the quotation, centered around 2500 euros, it is still much sought after.
But generally there are two types of problems: the first due to a design error, that is the use in the first version of the infamous resinated modules. There is a very high probability that over the years, the overheating of some components, in particular the special low noise group transistors, will cause irreparable failures on these modules.
These special transistors were in fact more units inserted in a single container, the heat developed is already high in free air, embedded in resin becomes fatal over time.
We have dissected a faulty module and verified that the malfunction was due precisely to these elements.
In fact in the following series the resinated modules were replaced by "open" printed circuits and the transistors in question were brought into contact with the upper aluminum panel for better dissipation
The second problem that can incur paradoxically derives from the great sound advantage given by the pre-set boards, in practice it is difficult to find specimens with cuts suited to the needs of the purchaser
Therefore, as already mentioned, our project foresees the possibility of having the desired cuts in any part of the spectrum from 20 Hz to 20000 Hz with slopes up to 18 dB per octave, simply by specifying the desired frequency and slope during the order process.
Obviously redesigning from scratch the printed circuits (keeping unchanged the circuit topology) we took the opportunity to improve the components and update it to the higher quality standards available at 40 years from design.
The resistores are the PRP specifically for audio use. The transistors have lower noise and better thermal dissipation, so we decided to install a small heatsink on each group of transistors for pure precaution, not for actual necessity.
The welds are made with tin containing 4% silver.
The price refers to the set of four cards, a pair of low pass and one of high pass for each channel
Please specify in the notes the desired CUT frequency and the slope between 6-12-18 dB
The cards as mentioned are plug and play, just extract the ones that currently equip your LNC2, obviously with the device switched off and disconnected from the supply, and insert the new ones in this order, from left to right:
LOW PASS CHANNEL A
HIGH PASS CHANNEL A
LOW PASS CHANNEL B
HIGH PASS CHANNEL B
paying attention to the precise input pins on the motherboard
The set will in any case be accompanied by the users manual
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