System 9098 EQ 12/1/19
On the way to Analog Classics:
Rupert Neve on the Amek System 9098 Mic Amp
In keeping with the pedigree, I use a switch which accurately sets and resets the gain.
This enables optimum circuit configuration for the best performance at any position. There is a massive headroom at all settings and at 0 gain this ‘Microphone” input will accept + 25dBu without overload. This is achieved by a “T.L.A.” circuit which gives the advantages of a transformer without the penalties. A common mode inductive filter protects
against RF interference.
The double-balanced microphone amplifier output is available on XLR Male connector at the rear. This output is balanced but not ground—free.
On the Amek System 9098 Filters:
The lowest frequency on the High Pass Filter is 20Hz. Below this there is virtually
nothing musical but the filter does let you remove may very low-frequency rumbles or other unwanted low frequencies while or the high and it is possible to remove a great deal of the “spill” from adjacent low-frequency instruments in multi-track work.
The Low Pass filter extends its high as 3.9th in order to remove inaudible distortion and Processing product: which can, nevertheless, affect the way we hear music within the conventional audio band.
On the Amek System 9098 Mid Range Equalization:
The overlapping mid-range sections of the SYSTEM 9098 EQ are very powerful and much more flexible than found in earlier generations. This enables the
frequencies specific to a musical instrument to be raised or lowered; or, on the other hand, a broad bandwidth may be selected to adjust the tonal balance.
On the Amek System 9098 Low-Frequency Equalization:
The Low-Frequency section is one of the most important tools in the equalization tool chest. In the more extreme settings, dramatic effects can he imparted to the kick
drum, for example, and many famous recordings hear testimony to its effectiveness. At the other extreme, it is possible to provide the most subtle warming of the signal without otherwise affecting its naturalness. The circuitry has a very low basic phase shift imparting a very “solid” quality to the sound making a relatively small amount of equalization very effective.
On the Amek System 9098 Bandwidth:
Professional audio engineers have known for many years that the sonic quality of audio equipment does not relate fully to the technical specifications. Human hearing demonstrably ”cuts oﬁ” somewhere below 20kHz for most of us and it seemed to make sense that our equipment should cut of there too.
More recently research has shown that the experienced listener is right. It has now
been positively established that equipment which can handle signals well above 20kHz
faithfully gives a greater sense of enjoyment and fullness. These are qualities that we
would have associated with mid and lower frequencies. It seems that the presence of
these super-high frequencies – provided that they actually occur in the original acoustic
sound — can influence the way we hear sound within the traditional hearing hand.
Even if the out-of-band frequencies are severely attenuated the effect is noted.
The HIGH-FREQUENCY control is designed to peak above 20kHz and can give scintillating quality to the sound.
Needless to say, the out-of-band response must be free of self—generated noise and distortion. If the original signal contains unwanted noise, typically produced by digital processing, the LOW PASS filter is likely to he the preferred tool!
On the Amek System 9098 Shelf/Peak Curves:
If the PEAK function is selected, the fairly steep slopes of the equalization curve can alter the nature of an instrument by changing the relationship of harmonics to the fundamental.
The SHELF function raises or lowers the whole range of frequencies beyond the turnover frequency and can allow subtle modification of the tonal balance without altering higher harmonics.