Adding a Pre-Out to an integrated tube amp

millercarbon,

     Please simplify your life and buy 2 Dayton Audio SA1000 sub amps.  You'll save yourself hours of aggravation and possibly electrocution.

     The best new price I found is $409 each on Amazon.

     However, I came across this shop in St. Louis selling 2 used for $600.

https://reverb.com/item/6598543-2-dayton-sa1000-home-theater-subwoofer-amplifiers

     It's on the Reverb site and the ad states the seller is temporarily away.  But this looks like a very good deal worth waiting for and you can message the seller.

Tim
     

That's exactly what I have. The Dayton accepts line level inputs only. My options are add a pre out or use a Line Out Converter to drop speaker level down to line level. That's what I've been doing with my current sub which has a plate amp that accepts speaker level. The Dayton's don't and I thought adding a pre-out might be easier/better but maybe not. Checking around it seems the right LOC might be the way to go. They look kinda tacky but if it works I could hard wire it inside using existing unused RCAs which would be an improvement on the cheap ones on the LOC and look a lot better too. 

LOC may be the way to go. http://www.epanorama.net/circuits/speaker_to_line.html

millercarbon,

     I may be mistaken, but I thought the main benefit of speaker level connections was for powered subs, that accept speaker level inputs, with the sub's input coming from the speaker level outputs of your main speakers' amp or amps.  The idea being the matching or blending of the sound and characteristics of your subs and mains more seamlessly.
     Of course, it's your system but I just wanted you to know, imho, that if there are any sq benefits they will be very subtle and likely not worth the effort. 
     Prior to the Swarm, a local dealer here in Indy let me borrow a couple of smaller REL powered subs for 2 weeks that had both line and speaker level inputs.  I experimented with many different locations for these subs in my room and I compared using line vs speaker level inputs at each new positioning of the subs. Both methods sounded very good to me but I honestly couldn't convince myself I heard a benefit to either method.  I switched to just line level inputs rather quickly, mainly to save time but I honestly could not distinguish between the two.  You may be able to but I'd still suggest not setting your expectations too high.
     I run all my subs via line level and the bass response quality and integration with my mains is exceptionally good.  The hookup is simple and easy.  Just thinking of what you're planning on doing is hurting my head.

Best wishes,
    Tim

     I may be mistaken, but I thought the main benefit of speaker level connections was for powered subs, that accept speaker level inputs, with the sub's input coming from the speaker level outputs of your main speakers' amp or amps

I think of it more of a convenience feature. They don't implement a high pass filter since that would be expensive and prone to error due to variable nature of speaker impedance from model to model.

Line level crossovers can implement low and high pass filtering more consistently.