Wednesday, April 12, 2017


Resistance isn't futile... It is downright evil!  One of the big offenders in the resistance camp is the humble L-pad so here is a magnetic solution.

This particular unit goes from -6 to -16.5dB in 0.5dB steps which is perfect for padding that horn down to the bass.  The "coarse" steps are 1dB and the toggle allows for a 0.5dB trim.
Of course it resides on a permalloy core and allows the end user to select the desired impedance presented to the crossover by selecting the shunt resistor.

Wiring is simple with the same 3 connections as an L-pad.  More info to come!


  1. I should try mine again and put it into the crossover.


  2. But why permalloy? The saturation level is much less than in a good steel, and it's a headroom first...

    1. saturation and headroom are not an issue but low level signal behavior is and for that permalloy is King!

  3. Hi all-wanted to say that I'm the owner these. I just swapped out the L-pad and they are so good it is silly. VS an l-pad there is much less haze, more bloom around treble and strangely, more coherence (?) like a more integrated sound--can't explain the last bit, but its almost like the XO is doing its job better. If you are even remotely close to thinking about this, contact Dave/Jeffrey asap. Killer upgrade.

  4. Awesome value for money upgrade. I've had mine for a week now (the simple version, just bare autoformersw ith flying leads) and at first just hooked the crossovers up to a signalgenerator and scope to find a tap to set the level where it was before and calculated a shunt resistor and hoked them up and listened. Yeah baby, "better" highs, "better" bass, more life, more music. Today I actually measured the speakers and played around with shunt R and taps ending up not far from the original settings. The autoformers really clean up impulse response.


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