Introducing the rega IOS flagship coil amplifier
Designed as the ultimate MC phono stage and the perfect match for the RegaApheta MC cartridge Ios has made the transition in to the reference style case to match Isis and Osiris.The new Ios has the addition of balanced XLR connections mute and mono functions.
The PCB layout has been redesigned to improve the noise floor and the entire unithas been fully rewired with ultra low capacitance cabling.
The function of a phono pre amplifier is to match the output
from a pick up cartridge to the input of a line level amplifier.
It is required to amplify the very low signals produced by the cartridge and also to equalise the sound in accordance with RIAA record cutting standard.Rega believes that moving coil and moving magnet cartridgesrequire different types of phono pre amplifiers to achieve optimum performance.The IOS is therefore dedicated to moving coil cartridges and avoids compromises.We have avoided including any superfluous functions as they obstruct the signal path
and degrade the sound quality.
The Rega Ios is a four stage all symmetrical amplifier.
To provide optimum performance it is dedicated to amplifying
the very low level signals that are generated by moving coil cartridges.
The first stage uses a 1:10 step-up transformer, which can be optimised to the cartridge by the selection of the correct loading and zobel DC resistance correction network connected across the MC transformer secondary.
The second stage is a symmetrical compound pair class A amplifier,
using paralleled low noise Hitachi transistors in the input stage.
This drives the passive high frequency part of the RIAA equalisation stage.
The third stage is a symmetrical class A differential amplifier with a common base driver stage;this is also used as the active amplifier in the low frequency part of the RIAA equalisation stage.The fourth stage is the active filter, this configuration uses the same circuit as found in the second stage. The filter element uses a very high bandwidth operational amplifier.
The power supply is a symmetrical discrete tracking power supply
using fast diodes and a low noise voltage reference.Each stage has its own localised power supply, and LED referenced current generators.Very high quality, polypropylene capacitors have been used in the signal path. 1% tolerance polypropylene capacitors are used in the RIAA EQ stages and audio grade capacitors are used in the rest of the circuit.
* Width 434mm x Depth 350mm x Height 100mm
* Weight 18kgs
* Generator source resistance 15Ω
* Load set to 100Ω & DC resistance set to 15Ω (Apheta)
* Output load resistance 100KΩ
* Filter off (unless otherwise stated)
* Input sensitivity for 200mV output 61uV - 70dB gain setting I
118uV - 64dB gain setting II
* Gain input to output 64dB Minimum
* Input load 50, 100, 150, 300 & 400Ω
* DC resistance (Zobel network) 5 to 7.5Ω (6.25Ω nominal)
7.5 to 10 Ω (8.75Ω nominal)
10 to 12.5Ω (11.25 Ω nominal)
12.5 to 15 Ω (13.5Ω nominal)
* MC Transformer Sowter 8055
* Input overload @ 1KHz 8.7mV - 64dB gain setting
4.5mV - 70dB gain setting
* Maximum output level 14.7V RMS
* Rated output level 200mV
* Output resistance 100Ω
* Minimum output load resistance 1KΩ for –3dB point @ 15Hz
* RIAA accuracy (Better than) 0.2dB 100Hz to 40KHz
* Frequency Response 14Hz (-3dB) to 54KHz (-0.5dB)
* THD (Better than) 0.008% @ 1.5V 20Hz 20KHz
* THD bandwidth 100Hz to 22KHz
* Output noise level -85dBV
(64dB gain setting & 15Ω input load)
* Notch Filter centre frequency 8.5KHz
* Notch Filter maximum depth -6.5dB
* Notch Filter Q 2.5
* AC Supply 230V & 115V Nominal +/-10%
* Power Consumption 21 Watts