Scientific Conversion, Inc. - Transformers and Inductors

We use the highest quality materials, special precision winding, and 100% testing.
Our design eliminates high capacitance plastic injection molding or varnish impregnation.
Our parts have substantially decreased capacitance and 12 - 36 dB better CMRR vs. other transformers.
The result is greatly reduced interference susceptibility, noise, jitter and pulse aberration.

2. What is the difference in electrical characteristics between Surface Mount (SMD) and Thru-hole (TH) parts?

SMD transformers have the best CMRR and HF noise rejection.
Our SMD parts excel at higher sample rates, e.g. 96 and 192 kHz.
TH parts have greatly extended LF bandwidth, down to 700 Hz, for special applications and designs.

3. How are they packaged?

SMD transformers are in IC tubes of 25/50 per, for use with pick-and-place machines.
TH parts are packaged on styrofoam sheets of 100 per.

4. Where can we buy them? Do you have local representatives or distributors? How can we pay for them?

5. How can your transformers improve jitter?

They increase high frequency common mode noise rejection, reducing the receiver and clock circuit jitter.
Greatly reduced pulse aberration further improves jitter.
Low SP/DIF and AES3id signal levels can be increased by use of the 1:2 ratio stepup of our SC982-04 and SC944-05 transformers.

6. How can we interface to unbalanced connections e.g. SP/DIF and AES-3id?

SC961-04 1:1.20 ratio shielded for 75 to 110 Ohm conversion.
SC982-04 1:2 ratio unshielded 75:300 Ohm boosts low level on SP/DIF and coax lines up to the optimum for most AES receivers. See fig. 18 in our AES 1998 paper.

7. We need a transformer to provide phantom power to digital microphones.

Our SC983-05 (SMD) and SC981-04 (TH) include a center tap specifically designed for phantom power. See the application note in our AES 1998 paper.

8. What transformer to use for our particular sample rate?

All of our SMD parts can work over the entire range of sample rates 32 - 96 kHz.
You can use thru-hole or SC937-02 SMD for lower rates e.g. 32 - 48 kHz.
96 kHz requires the SMD versions, e.g. SC937-02 and SC979-03.
SC937-02 is general purpose and best at rates 28...96 kHz, SC979-03 is optimized for higher rates, 48, 96 and 192 kHz.
Our new SC947-02 "Super" transformer is optimized for use over the entire range 32 - 192 kHz.

9. How can we reduce EMI emission and susceptibility from long AES/SPDIF cables?

Use SMD parts: SC937-02, SC947-02 and SC979-03 with shield, and low capacitance.
Use good RF layout practice, e.g. split groundplane, and short and direct traces. See our AES 2003 paper fig. 40.
Separate chassis and digital ground from the TX or RX IC's groundplane.
Use transformers on unbalanced coax connections to break chassis to circuit ground connection (Please see our application note in the AES 1998 paper).

10. How can we drive 2 AES/EBU outputs from an AES/EBU source without using active circuitry, e.g. to make an adapter?

Use our SC945-01 "SuperSplitter" to make a passive splitter (only for 110 Ohm balanced applications).
A complete splitter requires the transformer, a resistor and a few connectors, please see the spec sheet.
Optimized over the entire range 32 - 192 kHz! Very low jitter and low aberration.
Only 3 dB loss from input to each output! Far surpasses any other digital audio splitter available!

Last revised: 03 May, 2007