Type 9540 Microphone Isolator

Sowter 3575 isolator Mumetal can


A transformer can virtually eliminate most types of noise generated when equipments are connected by preventing "ground loops". Balanced lines may be converted to unbalanced and vice versa. Signal voltage can be increased or reduced and unwanted loading effects can be removed by step up or down ratios. Mumetal cores ensure minimal distortion and a thick Mumetal can protects the transformer from hum fields. Multiple interleaved windings are used for high bandwidth and clean transient response. Faraday shields on most types ensure rejection of common mode noise. We offer a large range of products for recording, broadcasting, public address, instrumentation and equipment manufacturers as well as for replacement or maintenance.


We list our most popular types here but we have a design data base accumumated over the last 75 years and most of these can still be shipped within 3 weeks.
If you do not see what you need here please contact technical support or complete a custom design request form and we will be pleased identify an existing design or do a custom design at no extra charge.
Prices are for Mumetal cored transformers with Mumetal screening can and colour coded leads. Also available in other packages see Pro-package options. Grain oriented silicon iron (M6) cores used where indicated. Types indicated with an asterisk (*) do not have a screening can but this may be available as an option. PCB Pins instead of colour coded leads are available on most items.

RATIO 1:1ct
MAXIMUM LEVEL 0.5 % THD at 50 Hz (40 ohm source) dBu
DISTORTION at 50 Hz (Source 40 ohms) 0.05% at +20 dBu
TOTAL DCR (Referred to primary)  
INSERTION LOSS 10k ohm source 10k ohm load  
FREQUENCY RESPONSE 6k4 ohm source 10k ohm load +/- 0.25 dB 15 Hz to 60 kHz