Processing and Control for Professional AV Installations
Legacy Hardware

450 Dual Zone Priority Mixer

The 450 Dual Zone Priority Mixer is designed for paging and music sound systems in clubs, restaurants, hotels, conference facilities, houses of worship or anywhere multiple audio inputs must be combined and distributed. There are two mono mic/line inputs (with phantom power and low frequency filters) and four stereo line inputs. Each input may be assigned to a stereo output zone, a mono output zone or both.

FAQ

To disable phantom power from microphone input #1:

1. Disconnect power from the 450.
2. Remove the 0-ohm jumper R48 in the extreme left rear corner of the 450.
3. To disable phantom power from microphone input #2:

Disconnect power from the 450.
Remove the 0-ohm jumper R172 in the left center area of the 450 circuit board.

Greater than -60 dB when measured at 1000 Hz.

Greater than -35 dB when measured with a 18 kHz tone.

Disconnect power from the 450.
Solder a insulated wire jumper to the rear half of JP8. Be careful not to bridge the gap between the front and rear portion of JP8.
Solder the other end of the wire jumper to the rear half of JP9. Be careful not to bridge the gap between the front and rear portion of JP9.

Increase the value of the following resistors for the appropriate priority:

Priority 1: R229 and R230
Priority 2: R321 and R322
Priority 3: R141 and R142

The amount of time increases in direct proportion to the amount that you increase the value of R229 and R230. For example, if you double the value of Priority 1’s R229 and R230 (from 536K to 1Meg – O.K., its approximately double), then the length of time for the muting circuit to release and allow signal from the lower priorities will also double (from 2-3 seconds to 4-6 seconds).