Hey all, my system got a boost recently, when through a loan from xcortes (thanks, dude!), I rolled a pair of 80hz hypex Edgarhorns into the picture. They'll be on their way back this week, but the experience has created a new set of criteria, going forward. The Edgarhorns, with some nice EV 15" drivers, produce a very lively sound. They're designed to sit on the floor, but I installed them horizontally atop the bass-bins, where they were more like midrange horns. Then on top of those went some JLC/Seddon 550hz horns with B&C, DE25-16 drivers. As an approximation, the Edgarhorns are about 105dB and the 550hz horns, about 108dB/1W/1m efficient. Well, the first thing that happened was that I could suddenly and clearly tell the difference between the two S.E.X. monoblocks that were driving the EH's. These use the driver from a 6DN7 and the output of a 6EM7, into some exo-045 OPT's. One is shunt-regulated via the output triode of the 6DN7, and the other, not. For the first time, I could hear the difference between the two, the SR one having a sense of greater transparency and headroom to it. Now that I've heard the difference, I need to go back and SR the other one. BTW, in the meantime I helped finish one of a pair of Paramour SR45 and rolled them into the system for an evening. Whoa, that's an amazing amp! The volume control on the stereo tweeter amp (S.E.X. with MQ M3 and C4S upgrade) was now at around 7 o'clock, so I removed the driver stage triode and cap-coupled the input RCA's to the grids of the output triode stages. In that amp the input cap now creates a 700hz lowpass and the parafeed cap, a 500hz one (see pic for resulting response). The B&C tweeters are 16 ohms, and even with all that, the volume control sits at 3 o'clock. Removing one triode stage created a more transparent sound. My two new questions to resolve are 1) at what frequency do I abandon 1/4WL spacing between drivers and 2) at what frequency do I get to make that leap to very-high-efficiency? Spoiler alert: I think they'll both happen simultaneously 
The bass-bins use (about 95dB/1W/1m) AE TD15X driver and 300B Paramounts with exo-050 OPT's and Brainiac plate chokes. At the moment they are low-passed LR4 at 220hz via a Marchand line-level XM46. There's still a little midrange grunge in their sound, which I'll be listening for going forward as their low-pass drops in frequency. It would be nice if I can get away with a 100hz LP, but it might have to be even lower. I hope to keep them in the mix, though, since their LF extension is amazing. The XM46 presents a 2.5K load, and I've been using either one, two or three pairs of them. And this leads me to the pre-amp, a Smack outfitted with 15K:600 B7's and RCA outputs, which produces an awesome sound even driving that beastly line-level load. For a while my goal has been to maintain a functioning, stereo system as I waded my way through different configurations. This, since previously I'd spent a lot of time with everything in pieces and no tunes! So, I'll be continuing in that vein, but now with some notably better results. The experimental platform of the fixed-volume Paramounts and the variable-volume S.E.X. amps, the XM46's (all low-passes, at 60, 220, and 2200hz -- 2.5Kohms, but as I adjust their frequency with new caps and resistors, that load will change), and the Smack amp to drive it all, was intended to provide maximum flexibility and great sound, and that it has!
The bass-bins use (about 95dB/1W/1m) AE TD15X driver and 300B Paramounts with exo-050 OPT's and Brainiac plate chokes. At the moment they are low-passed LR4 at 220hz via a Marchand line-level XM46. There's still a little midrange grunge in their sound, which I'll be listening for going forward as their low-pass drops in frequency. It would be nice if I can get away with a 100hz LP, but it might have to be even lower. I hope to keep them in the mix, though, since their LF extension is amazing. The XM46 presents a 2.5K load, and I've been using either one, two or three pairs of them. And this leads me to the pre-amp, a Smack outfitted with 15K:600 B7's and RCA outputs, which produces an awesome sound even driving that beastly line-level load. For a while my goal has been to maintain a functioning, stereo system as I waded my way through different configurations. This, since previously I'd spent a lot of time with everything in pieces and no tunes! So, I'll be continuing in that vein, but now with some notably better results. The experimental platform of the fixed-volume Paramounts and the variable-volume S.E.X. amps, the XM46's (all low-passes, at 60, 220, and 2200hz -- 2.5Kohms, but as I adjust their frequency with new caps and resistors, that load will change), and the Smack amp to drive it all, was intended to provide maximum flexibility and great sound, and that it has!
