Several years ago I bought a handful of Dayton Audio passive speaker volume controls with small, tapped transformers (these are "impedance matching" and not a simple resistive element, aka: L-pad) and ended up not needing them. So they got stored.
Recently I attempted to put 2 of these into service and even when full up there is a noticeable bump in HF response on the speakers these are in line with. As the control is rotated CCW the volume changes (not very smoothly) and so does the frequency response.
These have jumpers that are used to match the speaker load to the desired/needed load at the amp. The directions leave a bit to be desired as far as clarity so I called tech support and sort of got my head around how these should be jumpered. But the change in frequency response and irratic volume level changes remain.
In the product description they say "Creatively combining resistive and reactive characteristics into the design, the hand wound autoformers incorporate far more turns than any other manufacturer."
Here is a link to the currently offered device (no difference other than manufacturer name):
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=302-205Anyone have experience with and insights into these ?
BTW - I tried several so it does not appear to be a malfunctiong device.