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previous: Jim S. They're made by a German company, H... -- 8/24/1999 3:11 AM

Re: Red Box seaker cab simulator

8/24/1999 12:16 PM
GFR	Re: Red Box seaker cab simulator You can find the schematics for some of H&K preamps at "the unofficial H&K site". I believe the speaker simulator in these units is the same as the Red Box. The simulator uses 3 opamps from a TL084. First there's a ~100Hz peak to simulate the resonance of the cabinet. Then there's mid/high shelving boost for presence and two Sallen Key low pass filters that give a 24dB/octave treble rolloff. Maybe in the Red Box the fourth opamp is used to get a ballanced output. The newer "Red Box Pro" doesn't use batteries and also simulates the output stage distortion according to H&K so there must be some differences.

8/24/1999 12:16 PM

GFR

Re: Red Box seaker cab simulator

You can find the schematics for some of H&K preamps at "the unofficial H&K site". I believe the speaker simulator in these units is the same as the Red Box. The simulator uses 3 opamps from a TL084. First there's a ~100Hz peak to simulate the resonance of the cabinet. Then there's mid/high shelving boost for presence and two Sallen Key low pass filters that give a 24dB/octave treble rolloff. Maybe in the Red Box the fourth opamp is used to get a ballanced output.

The newer "Red Box Pro" doesn't use batteries and also simulates the output stage distortion according to H&K so there must be some differences.

Replies:

Mike Burgundy H6K unofificial site;http:/... -- 8/24/1999 12:48 PM