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Dominator II Model 723

J

Jim Graham

Guest
Has anyone defeated the 50 us PRE-emphasis in an Aphex Dominator II Model 723? This unit has a defeat switch for the De-Emphasis ONLY. No switch or inside jumper for pre-emphasis.

I have no schematic.

Thanks!
Jim
 
Jim,

I have a 723 with 75uS pre-emphasis for our school radio station. I don't know if my manual has a schematic for the unit but I can look when I get back to the office on Monday.
 
The idea with the 723 is that if you don't want pre-emphasis, simply turn the de-emphasis ON.

Pre + de = flat response.

If you wish to totally remove the pre-emphasis then find the "Clipper + pre/de-emp" PCB, which is mounted at the rear of
the unit. It's the one that carries the "de-emp" switch that sticks out the back of the unit.

Remove IC U3 and IC U4 (both NE5532).

Find plug H1 - it's the 10 pin plug that comes off this board. Link pins 1 & 2 together, and 9 & 10 together.

Leave the de-emp switch in the OFF position.

This should do what you want.

I have the service manual here, let me know if you want a copy of the diagram for the clipper board.
 
Studio1. I know I have a 723 but not the full schematic. Perhaps you can post it via some sort of fileshare so those of us who could use it could add it to our engineering files? Thanks much.
 
The manual I have is for the "Dominator II" which covers the 720 and the 723 - the only difference with the 723 is the addition of the clipper - pre/de emp board.
I'll try to get some time over the next few days to scan the relevant pages and upload somewhere.

Cheers.
 
That would be great, Studio1. Perhaps I can add it to the resources section on my site, since most of the materials are for either outdated gear or companies who have gone to the grave.
 
Thanks Studio1

I'm going to test this unit on my web site, www.FunRadio.us. I run very gentle processing and am afraid that Pre + De might result in a dull, squished sound.

Thanks again.
JG
 
I haven't gotten back to the studio build for the high school leaky coax FM, but I'll be using the 723 right before the 5 watt transmitter feeding the coax within the building. The output of the console will first feed a CRL Labs Stereo AGC prior to the phone lines feeding up to the "shack" where the transmitter is.
 
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