# Adding an EQ to a Receiver w/o preamp outs



## shorn

(Excuse this post if it should be in another subforum, and redirect me if need be.)
I can see the need for adding equalization to a sub out, to correct any nodes or nulls based on SW position, room size, etc. But there is also a need in some cases to add EQ to the mains (LCRs) in order to affect a house curve of some sort. What I cannot figure out is how to insert an equalizer (DSP1124P or equiv) into the pre-out/ main amp in loop if there is no main amp in. My rcvr (Denon 5803) has pre outs but no main ins (and no Audyssey firmware). My only idea at this point is to modify the AVR and tap into the audio path at the volume control to essentially break that path for the LCR chans and add outputs and inputs that would be jumpered when no EQ is in the loop. (In the "old days" receivers had those jumpers on the back of the rcvr.). Have I missed another way of adding an external equalizer to a receiver? (Maybe this is a good argument for separates. )


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## Kal Rubinson

I think you have a good grasp of the situation, unfortunately.

Kal


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## Wayne A. Pflughaupt

Welcome to the Forum, shorn!

Like Kal said, you have the right idea. Equalization has to be inserted in the signal chain between the pre amp and amplifier.

If your skills permit you open up your receiver and add a connection point between the pre-outs and amplifier sections, then go for it. Not sure how feasible it is these days, though. In the old days you could open up a receiver and easily locate the wires coming off the volume control back to the amplifier section. These days most volume control is done digitally or electronically (not sure which), so I expect that finding that insertion point will be a challenge unless you’re trained in board-level electronics.

Short of that, you’ll have to do what others do who want full-rang equalization: Add outboard amplifiers as well.

Regards,
Wayne


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## shorn

Well, at least I wasn't overlooking something obvious to others and not me. I'm not above popping the top to see what can be done to add the pre/main loop. In fact, I had previously tried to locate a schematic for the beast... without success. But I figure with a test signal and a o'scope I can trace it to a logical insertion point. I'm old enough to remember doing this sort of stuff in the pre-digital days.
Thx.
Steve


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## lsiberian

The simplest solution is still separates. I plan to use the Sure 4x100w for my DIY Speakers

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=320-302 is a link to the amp.


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## shorn

That's a great idea for a Plan B. And certainly economical.
Thx!
Steve


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## weverb

I posted this in another thread for Wayne to comment on. Maybe he missed it. :huh:

I had a NAD T754 that had pre-outs (see picture below) with jumpers (on left of image). I am wondering if you could go out of the T754 to an external eq and then back into the T754? I would be very curious to read Wayne's thoughts.


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## Wayne A. Pflughaupt

Wow, I’ve never seen a receiver or integrated amp with main-in access for _all_ channels! Yes, you can add an equalizer (or other processor) to any receiver or integrated amp that has pre-out and main-in jumpers like that. :T It’s a great feature that was never all that common, and it’s getting scarcer all the time. I could have gotten by with a lot less of a receiver than the one I have, but I wanted a center channel EQ and Yamaha’s lower tier receivers didn’t have a center-channel amp input.

Regards,
Wayne


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## shorn

Exactly! That's the loop that I wished my Denon had.


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