This is a rather unique piece - an all-tube 3-way active crossover. I picked this up years ago with the intent of making it the basis of a second system (the 'romantic' one rather than the 'analytic' one), but it's now evident that this will never happen. I wasn't able to dig up too much background on it when I bought it, aside from a portion of a classic Gizmo piece extolling the virtues of tube-based crossovers. The only other similar unit I know of is the Marchand.
Each filter section is selectable as 6/12 db/Oct, and the center freq is controlled by an RC combination. The 'C' values are set by caps on plug-in cards which can be changed but require soldering. The 'R' value is switchable over a small range through front-panel controls, allowing moving the freq up or down by about 1/2 octave without changing the C values. The unit is currently configured for xover freqs of 90 Hz and 1kHz.
All tubes are 12AU7's.
The unit can be used as a 2-way xover by simply using the low-pass and high-pass sections, and ignoring the bandpass midrange.
I'm not the original owner, and this unit has clearly been modded. The xformer is housed in an external chassis connected by an umbilical. The diodes and power switch are still in the main unit though. All the power connections are hard-wired.
I have never really had this installed in a 'real' system, so I can't say too much about the sound quality.
I have verified basic operation. The only slight anomaly is that the midrange bandpass seems to drop in level a fair bit when switching the high pass from 6 to 12 dB/oct, but it seems to sound fine otherwise.
I have photos in my gallery page showing the basic views.
Given the rather unique nature of the piece, I really have no idea what it's worth. I'm putting the asking price at $400, but am open to offers. Feel free to PM me with further questions.
