Sep 12th, 2017
I have written this letter many times before, here it goes. Bellari 282 had two ways it could be releases to public and operated. One way is as a true volume gain limiter, as it looks at signal after the compressor circuit making the compressor gain ride it’s own “Audio tracking level”. This can really, make the audio squashed because the threshold control actually works like old school design. It advances CCW into low signal levels (which can over trigger the compressor) so be careful a little threshold is a lot here. Yes the unit does overreact, I modify the circuit to be more forgiving. Also the 282 can be a vactrol pull down limiter version design, similar to countless others; old UREI’s, old teletronics etc. Basics detection of audio causes this vactrol resistor to antennuate like a vactrol resistor volume level up and down. But again the circuit is very reactive and again I re scale the audio detector to be more forgiving. I also equalize the circuit in the vactrol to “voice” the compressor to be really smooth, less loss of power, bass, and less suppression of high frequencies, evening levels. This as an overview, the tube circuit concept and design is actually well done, better than most, but the designer like most had trouble getting the “RMS” audio detector circuit to range nice. 3 things now, first no damn tube changes will do anything important. Second, no transformer changes will do anything important. Third, with a few corrections this unit will work as good or better than a $4000 thing. Part of the problem making the design for really pro +4 dbm average level operation. Obviously the threshold control may have have trouble with wrong signal level going into unit. But then again so do so many others, by the way I’ve seen Urie 1176 that engineers claim is the best sound, but when it’s on a test bench, the same unit clearly has defect. Vactrol or circuit never worked correct but people hear what they want. The Bellari has a lot of character, it’s all tube, but it is too dry to set decent compression. There’s a trick I actually talked to engineer about years ago and he accepted my ideas. Now they care. Everything about this unit is fixable, able to be modified etc. But the final problem is some unit has wrong parts in board, wrong control (I kid you not) so they worked weird. But I can fix that.
Inquire about this Article