Components for DIY


From time to time I may have pairs of my quad-filar wound EI120 line and output transformers available as I have to have the bobbins wound in minimums of 10 pieces (I will not have any input transformers available).

Please note that my prices will be 30% to 50% higher than for the similar part from Sowter as I do not have their economies of scale for the purchase of the materials used in the construction of the transformers.

So I therefore recommend purchasing these items from Sowter as they are set up to build on demand and have online ordering and credit card facility which greatly simplifies payment of these high value items.

Please refer to Susan Parker's Zeus amplifiers when enquiring or placing an order. This will ensure that Sowter are aware of the project you are working on and will help them to supply the correct parts and be able to inform you of any design options (e.g. lamination materials, screening cans, etc.) specific to Zeus.

All recommended Zeus transformers are now available to order online from Sowter.

N.B. I do NOT get a commission on any transformers sold by Sowter for my designs.

I also use the S&B TX-102 stepped attenuator transformer for the Zeus Pre-Amp. I do not have the volume or payment facility to handle these items and you should buy these direct from S&B or their local agents.

Stevens & Billington Limited
Audio transformers

Note: At time of writing the schematic for the TX-102 shown on the S&B TX-102 webpage is for their Mk II design, whereas the current part is a Mk III which features 2dB steps descending from the 0dB position, not 3dB as shown. I.e. Attenuation is: 0 db, 2 db, 4 db, 6 db, 8 db, 10 db ...

N.B. I do NOT get a commission on any transformers sold by S&B for my designs.

Copyright Notice.

Please note that Sowter are the only authorised manufacture to make the multi-filar transformers to my designs for commercial sale and copyright of these designs remains mine.

You may commission some person or business to make transformers for you for your personal use as per my standard terms. Please ensure that they know that the design is a one off and not to be used as a standard stock item without my express permission.

Please however let me know so that I can keep track of who makes what and where they are and can then provide links on this website so others may benefit as I appreciate that shipping large lumps of steel around the globe is expensive (and not environmentally friendly).

Custom Attenuator & Source Switches.

These are designed to provide the "perfect" switching of audio signals with the minimal possible effect on the signal. No switching (as well as no capacitors) in the audio path is the preferred method but pragmatically this is not usually possible or convenient and some form of volume control will almost always be required.

My attenuator and source selection switches use individual reed elements which are actuated by a small permanent magnet on a rotating arm. No electrical field (i.e. a coil) is used so there is no magnetic flux coupling between signal path and the coil which happens in a conventional reed relay.

Each switch unit is hand built by myself from the best quality commercial components and materials. The mechanical parts of the switch are in the main made from aluminium, and for production will be black anodized. Each wafer is premium grade double sided FR4 with plated through holes.

If you really want to throw lots of money in my direction I will make you a custom version with ceramic wafers and pure silver metalwork. You should expect to add at a absolute minimum an extra zero to the prices indicated below and probably double the amount as well. The silver will be assayed and hallmarked, you get a unique product of real value, and we get the deposit for a mortgage on a small cottage with a garden, roses and cats.

N.B. property described is our aspiration, but we reserve the right to change the dwelling and other specifications due to circumstance, availability and other "factors of life".

Multi Pole 24 Way Reed Switch for Attenuator

Ultimate attenuator switch, electrical signal path will not wear or degrade with operation. Lifetime of user guarantee.

  • Discrete Sealed Reed Switch Make before Break Attenuator Switch.

  • "Infinite" life time expectation - no dirty or oxidised/corroded contacts possible.

  • Suitable for Stereo, Ladder or other attenuators including Sowter and S&B TVCs

  • Dedicated (empty) SM resistor patterns on PCB.

  • Custom design by Susan Parker for High End Audio applications.

  • Weight: TBD


1 off 2 Pole 24 Way - SPRS: GBP  795.00 each
1 off 4 Pole 24 Way - SPRS: GBP  995.00 each
1 off 6 Pole 24 Way - SPRS: GBP 1075.00 each
1 off 8 Pole 24 Way - SPRS: GBP 1245.00 each

Populated Ladder/Divider network per wafer - please enquire by email.

+ VAT and Carriage as appropriate.

2 Pole 8 Way XLR Reed Switch Module for Source Selection

Stereo balanced source switching plus tape selection per channel.

Note: This is a complete module with mechanical components.

  • Discrete Sealed Reed Switch Break before Make Balanced Source selection Switch.

  • "Infinite" life time expectation - no dirty or oxidised/corroded contacts possible.

  • Includes 2 additional ways for tape loop.

  • Custom design by Susan Parker for High End Audio applications.

  • Weight: TBD


1 off 2 Pole 8 Way Module -SPRS: GBP T.B.D.

+ VAT and Carriage as appropriate.

Order Option: Optical Position Encoder for Attenuator Switch Unit

  • Binary position encoder for switch position display and/or remote control operation.

  • Includes IR emitter array and IR detectors with TTL logic outputs.

  • Custom design by Susan Parker for High End Audio applications.

  • Weight: TBD


1 off Encoder-SPRS: GBP T.B.D. each

+ VAT and Carriage as appropriate.

Order Option: Stepper Motor for Attenuator Switch Unit

  • Allows remote control operation with external controller (not supplied).

  • Single anti-clockwise limit switch for setting zero position for controller on power up.

  • Custom design by Susan Parker for High End Audio applications.

  • Weight: TBD


1 off Stepper Motor - SPRS: GBP 245.00 each

+ VAT and Carriage as appropriate.


  1. Prices are provisional and subject to availability, please email to confirm.
  2. Some made to order items have long lead times.
  3. Packing, particularly for the larger and heavier items will add appreciably to the shipping weight.

The information contained here is given in good faith but I cannot take any personal liability for the building or use of any of the items described.

Prices are indicative and subject to change without notice. Please email for a confirmed price, delivery expectation and shipping costs.


All design and other information, drawings and images on this website are
Copyright 1992-2010 Susan Parker MIET (unless otherwise credited).

These designs and other information may be used to construct systems specifically for personal NON commercial use only.

N.B. Personal liability disclaimer applies - see T&C.