Sowter 9545
DAC Interface Transformer

Coloured Leads 9545-E 
APPLICATION Designed for use with most current out Digital-to-Analogue Converters. Provides current to voltage conversion with approximately 20 dB gain. (26 dB if two DACs are used).  Presents a low impedance to the DAC output for best frequency response. Provides significant sound quality improvement when compared to other interface methods. Ensures full isolation of digital noise in ground and supply rails.  I/V resistors of 100 (or 200 ohms if two DACs are used) are suggested but there is sufficient inductance for good quality operation with higher values.  Can be configured to drive 9335 attenuator without loss of bandwidth.

The I/V resistor may be used across the secondary of the transformer instead of the primary.  The value of the resistor should be increased by the ratio squared.  Doing this may give a different sound by changing the filtering effect.


FEATURES Exceptionally large and high performance transformer.  Can be used with two DACs in complimentary mode (driven by true and inverted data) by means of twin identical bifilar wound primary windings. This gives the ultimate in cancellation of quantisation noise. 9545 may be used with a single DAC by connecting the primary windings in parallel. Twin secondary windings for driving differential (push-pull) amplifier. These may be used in parallel to improve the bandwidth and reduce the output impedance to 5K which is suitable for driving our type 9335 attenuator.  Mumetal core for minimal harmonic distortion. Internal electrostatic shields to maximise output balance and noise immunity. Mumetal can for magnetic shielding.
PRIMARY INDUCTANCE 6H (each primary)
PRIMARY DC RESISTANCE 10 ohms (in parallel)
SECONDARY DC RESISTANCE 1800 ohms (in series)
RATIO 1+1 : 5+5
SUGGESTED I/V RESISTOR  Parallel primaries  100 ohms
Separate primaries 200 ohms
FREQUENCY RESPONSE Using application circuit. +/- 0.25 dB 5 Hz to 50 kHz

9545 connections

E A Sowter Ltd
The Boatyard Cullingham Road
Tel: +44(0)1473 252794
Fax: +44(0)1473 236188