connecting sub to integrated with no rca out


i have a little dared tube/mosfet hybrid(precursor of fatman itube} bookshelves with 13wpc but not a sub out or any rca out. am using fostex 126 bookshelves with a little 8" sub that has all desired connections. what do you suggest as hookup options for this combo? i am concerned that running the speaker cable in to the sub and then out to the speakers will add sub electronics to the path that will spoil the speaker amp synergy.
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You can run 2 pairs of speaker cables from the binding post on the amp to both the sub's speaker level inputs and to the speakers. If your amp has different taps to account for the change in effective speaker impedance you may want to try the different taps.

Since you are going to need to buy/build an additional set of speaker cables anyway, try it both ways. Try connected through the sub and out to the speakers and try connecting both directly to the amp. Whichever you prefer is the correct answer.

Enjoy,

TIC
Hence the reason for a good sub crossover...
i am concerned that running the speaker cable in to the sub and then out to the speakers will add sub electronics to the path that will spoil the speaker amp synergy.

With only 13W to drive bookshelfs full range, you'll have so much distortion from both the amp and the speaker it's hard to imagine a sub's electronics being so bad that you wouldn't get a big improvement.
thanks reubent, your right, i will try them both ways. these speakers are very tube/low power friendly. the previous owner, a great goner jeff, used low power set 300b amp and enjoyed. i welcome any ones thoughts. i agree,that a better sub woulf help, but this is just a fun project for me, as my other systems are much more flexible but this is my first effort without an rca out to the sub.
I drove my Fostex-driver speakers with about 5 watts, plus tapped in a powered sub through the speaker taps ... turned out to be the best audio setup I'd ever had ... Almarro and Cains, along with a Lector player. Simply wonderful. Go for it, SD speakers can be amazing
arkproF thanks.

did you run speaker cable out to sub only, then split to two speakers? or two from amp to speaker and sub all 4 wires off the same amp outputs? probably the room i pick for them is the giggest questio on how they sound. will see.