New Autoformer Modules
One of the biggest complaints about the $200 autoformers is that they are a real pain in the you know what to wire up. In one of my many discussions with John Chapman of Bent Audio we came up with a simple switching arrangement to make the units a breeze ot install. They are dual mono units with 1.25dB steps and give a maximum attenuation of 41.25dB. Complete details are available Here
Introductory Price: $350 a pair fully assembled and tested.
The $200 Autoformer Volume Control (AVC)
Pictured above is our first off the shelf device. It is intended as a high bang for the buck entry into the magnetic volume control arena. It allows attenuation from 0dB to -42db in -3dB steps. It has an 80% nickel core, all brass hardware and sounds every bit as good as our custom units. For more information please check out the FAQ, Wiring Directions and visit the Forum.
Price: $200 a pair
Speaker Level Autoformers
These tapped units make a perfect replacement for resistive L-pads and can be tapped in a number of various ways to provide the precision in level matching needed for any specific situation. Cores available are nickel, amorphous and 2mil steel C-cores. Full design support and spice simulation available.
Price: From $400 a pair.
The $400 Autoformer Volume Control (AVC)
The Demand for more positions and finer attenuation steps has brought about a second product. This device has 28 steps and provides attenuation from 0dB to -52dB in 2dB steps.This uses a similar approach as the $200 kit but has a 28 pin bobbin in place of the 14 pin. When wiring this device to a switch with fewer than 28 taps you simply assess your gain structure and choose the appropriate steps.
Price: $400 a pair.
The $20 switch.
I sourced a bunch of these two deck 24 position shorting switches and will include one with any autoformer purchase for $20. (Click on either picture for a larger view)
The 16 step balanced Autoformer Volume Control (AVC)
This is essentially two of the 16 step versions above on a common core. This provides true balanced attenuation and if needed each unit can be reconfigured into two discrete autoformers. (please note that the nature of the core geometry the maximum inductance is ~75hy's end to end.)
Price: $500 a pair.
Custom Magnetic Volume Controls.
For those of you who need a bit more control or a special taper, we can offer the perfect MVC to fit your needs. We can help you choose between transformer and autoformer and help you select the proper values of inductance and attenuation to best fit your system. All of our custom MVC's are wound with Cardas magnet wire and have all brass hardware. Please check out the $200 autoformer FAQ and join us on the forum to discuss your needs. Please note that the leads of the custom volume controls should not be cut under any circumstances!
Price: Starting at $400 a pair.