eq wiring question

[valhallax]

heres a dumb question..on the back of this 8553 eq, is a barrier strip for input and output. the input has hi/lo/grd on it. when refering to the manual...thank you todd..it shows thathi is positive, lo is negative and grd is the sheild. if not using the ground, one should connect it to the lo, or suffer a 6db loss in gain. currently i run my ground to the phono ground on my preamp. am i doing this right? can someone explain how the lack of a sheilding ground can cause a 6db loss in gain? was i wrong all this time in thinking that the hi/lo sections in the barrier strip were hi or lo pass filters. ive just now stumbled upon the fact that lo means negative..i think

[donaldpatten]

You have an active ballanced ( IC chip ) input. This what we use for Lo Z microphones. The mic connector is normally a 3 pin XLR. Connect: pin 1 to shield, 2 to high and 3 to low. If you also connect either 2 or 3 to the shield , you will short half the input and loose 6 dB.
If you had a transformer input , you could make this connection and not loose anything. This connection unballances the input; and is the normal hookup for a phono in.
Since your phono cartridge is a coil... connect it the same as a 3 pin mic. You will have to bypass the TT RCA plugs & jacks . I suggest replacing them with stereo plugs ( TRS ), XLR , or a barrier strip. See RS # 274-678 and 2C+Shield, cable. Connect the TT shield cable straight thru to your amp input. If you want to get the exact polarity; play a record w/ solo kick drum, an connect the hi & lo wires to get positive pressure ( the woofer cone jumps away from the magnet ).
Don

[whitebroncoii]

The input circuit of the 8551A, 8552A and 8553A is connected in the typical manner . . .
balanced: High = positive
Low = negative
grnd = shield
unbalanced: High = positive
short low and grnd for negative

The output circuit is a different breed of electronic balance device . . .
balanced: High = positive
Low = negative
grnd = shield
unbalanced: High = positive
Low = not used
grnd = negative
6dB loss
You can invert the output by using low and grnd. Do not short the unused terminal to ground. It will damage the output IC.

Altec was very unhappy with this output circuit, however, these equalizers were relabeled MicroAudio products and we had little control over the design. They offered very good analog eq using a computer or a special controller (no front panel controls).