Subwoofer Connection: Speaker Level Amp to Line Level on Sub?

I have this same sub running with an AN amp this way. Very simple. The Russound is good and it’s cheap.

The LOC is nothing more than two resistors per channel. One typically about 10k ohm to drop speaker volts down to line level, and another typically about 1k for load. Here is how it works and what it looks like https://www.epanorama.net/circuits/speaker_to_line.html

This circuit can be anywhere. It can be in a LOC box, or you can do like I did and wire it inside the amp. See the pic on my system page. https://systems.audiogon.com/systems/8367 Also if you can find the circuit diagram of any sub with speaker level input you will see the same resistors are the first thing on the board when speaker level inputs are used. 

I had a friend build me a little adapter like the one linked above. Essentially it’s a handful in f resistors in series. Pretty easy. a small price and Bob’s your uncle!

imhififan & millercarbon

Thanks for this.  I'll def keep this in mind as I go forward.  

It should be fine if you connect the sub line level rca inputs to your amp speaker blinding posts via a LOC (line output converter).

https://images.crutchfieldonline.com/ImageHandler/trim/1736/1129/products/2008/543/x543ADP12-f.jpeg

Tape out is not the same as pre out. If you use tape out it will bypass the volume control on the EVO!

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+1

On any tape out, that I've used.

Yea I see your dilemma. Do you already own the SVS SB3000?

The LOC would work good too just use the binding post connection you're NOT for you speakers and use that for the LOC.. Easy Peasy, Good idea MC..

It's adding a great option for a very small price.. Can add as many subs as you like. As good as a pre out.. You could add an EQ, DSP, or even a DCX2496 OXO (A)

Regards

summadoggie, all you need to do is get a proper 2 way crossover. MiniDSP makes one which is very inexpensive. 

Oh dear, sorry to make that mistake, thanks for correcting me.

This:

It should be fine if you connect the sub line level rca inputs to your amp speaker blinding posts via a LOC (line output converter). 

https://images.crutchfieldonline.com/ImageHandler/trim/1736/1129/products/2008/543/x543ADP12-f.jpeg

Hook wire from the speaker terminals to the Russound line level adapter to RCA’s to your sub. Crank that thing until you shake the house. This Russound is just like what’s found inside the Rel subs that are loved for this feature. Pump up the volume, dance. Enjoy.

TAPE OUT or REC OUT take the signal before it's attenuated.  Tape recorders are built to handle this; not so much subs.  Which is why some preamps and some integrateds have more than one pair of PRE OUTs.

Tape out is not the same as pre out. If you use tape out it will bypass the volume control on the EVO!

Google is your friend.
speaker to line level output

Your Prima has ’Tape Out’. That is the same as ’pre-out’, which is ’line-out’.

Your SUB has ONLY line-in/out (no alternate speaker wires in/out).

You can use the Prima Tape Out to go to the self-powered sub’s line-in. It has it’s own crossover so it ’ADDS’ ONLY low bass to your system as any sub is designed to do, job done!.
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Note: the Prima (40 wpc/8 ohms) will still amplify any source’s low bass (as well as everything else), and the Main Speakers will also try to produce all frequencies, therefore neither the amp or mains get a break from the low bass job.
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To give a low powered amp and smaller main speaker’s a break, (or because you are driving low sensitivity (efficiency) or low impedance mains perhaps) you need to get line level out, to a crossover (separate or in the sub) that takes the low bass. The crossover then sends all frequencies EXCEPT low bass via it’s line out back to the amp’s line level in (main-in, tape in, processor loop). Your Prima does NOT have tape-in, main-in, processor-in, so you cannot do this.

Raven says bass is 65% of power needs, which is why moving the job of low bass to the sub, and everything else BACK to the AMP is better than using speaker wires.

Line out/Line In (outsourcing the low bass job) is the best way to get more out of low powered amps, thus a great way to try tube amps.

I often split the pre out to supply line level to both speaker amp and sub.

Thanks for the input.  There are better solutions for this situation than fooling around with adapters.  Gonna drop back and punt.

from speaker level on the amp to line in on the sub using an adapter?

It should be fine if you connect the sub line level rca inputs to your amp speaker blinding posts via a LOC (line output converter).

https://images.crutchfieldonline.com/ImageHandler/trim/1736/1129/products/2008/543/x543ADP12-f.jpeg

You should not do that. Speaker level voltage can be much higher than line-level audio voltage, and the speaker outputs are expecting to see an impedance load in the 10 ohm range, while the line-level input is probably in the 10,000 ohm range.