Sowter 8347 and 9055

DAC Interface Transformers

PACKAGE OPTIONS Part Number
Coloured Leads 8347-F / 9055-F
8347 frequency response Size f Style F
APPLICATION Designed for use with Burr-Brown PCM67, PCM1702, PCM63 or similar Digital-to-Analogue Converter. Provides current to voltage conversion with approximately 25 dB gain. 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.  If two DACs are use in complimentary mode (driven by true and inverted data) transformer type 9055 has twin identical bifilar wound primary windings. This gives the ultimate in cancellation of quantisation noise.

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 Accurate phase splitting (balance) on output for driving differential (push-pull) amplifier. Mumetal core for minimal harmonic distortion. Internal electrostatic shield for rejection of digital noise. Mumetal can for magnetic shielding.
RATIO Type 8347  1:18.7
Type 9055 1+1:18.7
QUIESCENT INPUT CURRENT (MAXIMUM) -0.6 mA
PEAK SIGNAL CURRENT (using circuit below with 25 ohm resistor) +/- 2.0 mA
I/V RESISTOR Type 8347  25 ohms
Type 9055 50 + 50 ohms
OUTPUT BALANCE >70 dB
FREQUENCY RESPONSE Using application circuit. +/- 0.25 dB 10 Hz to 50 kHz
PHASE SHIFT <15 degrees at 30 KHz
83478347 application circuit
9055

9055 DAC TRNASFORMER LEAD COLOURS

E A Sowter Ltd
PO Box36 IPSWICH IP1 2EL England
Tel: +44(0)1473 252794
Fax: +44(0)1473 236188