KNIF EKSA - Magic Mastering

Eksa is an exercise in ultimate purity of sound, and unlike all other Knif products, it is not tube based, but uses in-house designed and produced class A discrete OP amps. It is also the perfect companion to Soma, which excels in the beauty of sound and has an enhancing nature, whereas Eksa gives precision, wide Q value range and much more frequencies. 

The topology is derived from Sontec, but the Q circuit is heavily modified and much more complex to attain independent behavior of noise and whole range gain, not depending on Q setting. You can read more about this from the manual. 

There are 24 discrete operational amplifiers in Eksa. They use jfet inputs and outputs, and always work in class A. There are 2 op amps for the basic signal route, and 2 op amps for each band per channel. There are also DC servos for each band and the basic amps. The servos are tuned very low, so that their effect on audio range would be minimal. The time constants are more than one minute, and the servos use high quality OP amps and polypropylene caps to further improve the situation. And like always in Knif gear, there are no potentiometers, just Elma rotary switches. 

Power supply is external. 

The sound is very, very transparent. Like nothing else. Accurate but not harsh. That is why Eksa got its name from the word exact. 

We now offer Eksa in four different versions. Standard, Standard with gain+filter section (4 units high), Optionally ganged version, and Optionally ganged with filters (4 units high).

The optionally ganged versions use double amount of rotary switch wafers on left channel and relay boards to switch right channel to be controlled from left channel knobs.

Frequencies & Q values

Power consumption 30W

Maximum input and output level is 24 dBu.

MS codecs, which use IC op amps (very high quality ADA4627-1) reduce the headroom with 1.5 dB.

Since everything is DC coupled (except the servos, and they are slooooow) the frequency response is flat to sub sonic frequencies. Upper limit is -1dB @ 120kHz.

Basic distortion is too low to be measured with my Audio Precision portable system one, also into 600 Ohm load and up to the highest frequencies and highest levels.

Input impedance is 20kOhms. Since input topology is minimalistic, it does not offer stellar hum rejection. So, don't try to use Eksa with source 200 meters away in the next building.

Output impedance is 22+22 Ohms, quasi balanced. (meaning that signal is fed from pin 2 only, and pin 3 has the same impedance for proper hum rejection in balanced use, but no signal.)

Xtalk is -96dB at 1kHz and -90dB at 10kHz.