Sound Performance Lab 2595 - Manual (Page 8)

8
Passeq
120 Volt Makeup Amplifiers
With passive filtering comes an unavoidable drop in signal level that requires makeup ampli-
fication, and with the Passeq, here SPL’s extraordinary Supra-OPs, with their unique analog
120-volt technology, come into play. With a 116 dB signal-to-noise ratio and +34 dB of head-
room, the SUPRA-OPs offer a stunning 150 dB dynamic range, placing them in an unsurpassed
leadership position in either analog or digital signal processing.
The tremendously fast SUPRA slew rate of 200V/ms allows for a highest possible precision
in filter output signals, particularly in the all-important arena of transient response. These
amplifiers effortlessly and without coloration or degradation, transmit all the desired filter
characteristics and sonic results an engineer has sought out and in the process, pushing
beyond the limits of what has been technically possible to now.
SPL SUPRA Op-Amps
The specially designed and for-audio optimized SUPRA-OPs are constructed in three stages
with high performance, extremely low noise transistors from the HF technology sector.
Input Stages of the SUPRA Components
The development of the SUPRA components focused on high loop amplification, extremely
low phase shifting and THD, combined with maximum amplification and a frequency response
up to 100 kHz.
A main and obvious advantage of the discrete SUPRA components is the exclusion of parts
often found in industrially manufactured standard components that are not necessary for
audio processing.
The SUPRA input stages are designed as balanced differential stages and comprise six
matched high voltage transistors switched in parallel.The concept of the input stage is based
on the established principle that currents of not correlated noise sources in shunt circuits
add up—which decreases the overall noise of the input circuitry. The input stages are free of
coupling capacitors to exclude additional capacitor noise. The balanced operational voltage
of +/-60V is delivered from a linear -80 dB high voltage power supply.
Intermediate Stages of the SUPRA Components
The audio signal is further routed to a differential stage and from there through further
processing stages to the Class-A output stage. All passive components have been tested to
yield the highest possible fidelity.
Output Stages of the SUPRA Components
Extremely low noise, high voltage output transistors are set up with a high quiescent current
and excess heat is dissipated via special cooling plates.
Introduction