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I just bi-amped my khorns this weekend, using DCX2496 unit (it has 6 channels so can tri-amp as well), and the DEQ2496 with ECM8000 as measurement aid, I was curious to see what effect the delay might have, also wanted to be able to use that tube sound I love for the highs and that controlled SS bass for the lows. but ended up this weekend with both amps being SS due to a missing cable. At this point of this experiment, I left the passive Klipsch crossover for the squawker and tweeter in place for protection, connecting that part to the high fr amp, and connected the bass bin directly to the low freq.amp. Getting the levels right using two different amps was relatively easy, with pink noise and tones and the mike. I started out with steep Butterworth(?) 48db slopes at 447hz, tuning the crossover point from about 380 to 550-600hz did not yield any significant changes in how music sounded. The automatic calibration of the DCX decided to invert the woofer, and apply 9msec delay on the high section, (an Altec 511b sitting on top of the high khorn section so maybe a little more distance from the bass which I thought should have been 7msec) . Enabling disabling the delay gave a very subtle effect, when watching the speaker you can tell sounds are coming from the bass unit and the treble unit, but when delay is on, then more of the sound appears to be formed in front of the speaker instead of separately, but this was very very subtle, hardly worth the trouble of bi-amping, I also twiddled abit with the delay adding and subtracting msecs with no real audible benefits when listening to music. (perhaps plotting signal sweeps would have shown something, but we are listeing to music not excel sheets) Later I ran quick tone test signal sweeps between 300-600hz, and by ear I thought I heard a dip at the crossover point. I played with the crossover points the low part crossed at about 500, and the top being crossed at about 400hz overlapping until the dip was gone, it could be that 48db is too steep, and I should try 24db curves next experiment rounds. also this time when I ran the auto calibration, the dcx decided not to invert the woofer, delay stayed the same. my conclusion for this short weekend experiment is that if you like lots of knobs leds, DIY , and turning your stereo into a complicated spacecraft, then this is for you, for audio Nirvana I'm not convinced there is any benefit apart from driving tubes for the high, and SS for the lows. with both channels run with SS, there was no significant change in audio enjoyment worth the extra bother and expense. Khorns seem to be perfect as they are, its true one can argue that I was still using the upper section of the passive crossover, but I doubt this would have made a significant change if at all. one day I might try tri-amping,better have a spare k-77around just in case, it is risky. On another note, I am not familiar with the dx38 capabilities , but I find it odd that you might have a very expensive audiophile cd player with a special pure DAC to convert 44.1 to analog, only to be converted back from analog to 48khz for the dx38 internal process and then its own DACS back to analog, with the dcx unit, you can use direct digital at any data rate 44.1 to 96khz, from a transport, without this double (D to A and A to D and then D to A again) conversion. its only one D to A after processing. also one unit is enough for tri-amp, or bi-amp with sub or mid channel.

I thought I posted an answer last night yet I dont see it in this thread so hope its not double or im in trouble.... You can easily connect it to RCA using XLR to RCA cables, they aren't expensive, I'm running vintage tube gear this way. I also used to use the RCA coax digital signal out from my CD player and computer to the AES XLR digital input and it worked great although its not entirely compatible with AES AFAIK. Now Im using the SPDIF digital toslink (optical). The analog input also works great with any analog source,but it doesn't make sense to convert a digital source to analog and then back again for processing and then to analog once again if you can avoid it,but if you must, the results are far superior to analog EQ or tone controls. I would try to avoid an active preamp if possible, and only use passive attenuators for volume limiting, any active preamp even the best contains active electronics that add some degree of noise and distortion, so having the Behringer act as DAC directly into the power stage is a good option to to limit extra stages There is a possibility to have a passive tone control, but the CD out wont have anought voltage for it, plus the circuit has capacitors.

Not only tone control, Imagine a device that can change frequency response only at LEVELS where a change is needed, Some examples: * increase bass amplitude but only if the bass is below a certain threshold, Gradually leaving it alone and untouched when levels pick up. (SOLVES the problem of missing low level low frequency bass while high dynamic bass does exist and kicks, but you miss that ambient rumble that follows a kick) * Reduce some treble but only if it’s very loud like -6 or -3 db and above (helps reduce sibilance) * improve ambience reflections at the 300-500 Hz range but don’t touch the music. Imagine the same device can notch filter certain frequencies such as a bothering room node at 82 Hz, or remove anything below 28 Hz to keep your khorns safe and linear, or remove 60 Hz hum from an old recording. Imagine this device can level the sound volume for easy nighttime low volume listening, while retaining dynamic feel, yet not lose a note, great for dynamic classical music at low volume. Imagine you have a poor compressed recording, or you just don't have klipsch speakers, (you have new cabbage style compressing speakers :-) ) and yet you can still bring back some of that lost dynamic range using the expander function. Suppose you cobbled up a loudspeaker from parts you had lying around with zero box design and just a cap for the tweet, Sounds horrible doesn't it, Imagine you could automatically EQ this contraption and get acceptable sound out it using this devices automatic correction function with the measuring mike. Imagine you could feed this device with pure digital stream directly from your player or pc, to avoid any conversion losses. everything would happen in the digital processing realm without adding analog noise and distortion (albeit some of the software does function very similar to analog circuitry so I’ll give it a 9 out of 10). If you want to add your own sugar and spice to your music, there are 30 channels of digital graphic EQ. and 10 channels that can be (each one ) either a notch filter, or a parametric EQ, any bandwidth on any frequency, any control +-15db but you can overlap, so if you really want that +30db at 40 Hz (why?), you can!, and no distortions as long as you get the levels right. and if you make a mistake and overload, there is a softlimiter to keep you safe. If all you want is a very good DAC. then that’s all it can be. It’s also a very good A to D converter, I use SPDIF input to my pc to convert analog tapes to digital instead of using the lower quality pc card. The output is also digital, so you can use an other DAC(why?) or continue the chain to a digital crossover. Such a device does exist, it’s the Behringer DEQ2496. took quit while to learn how to use it, and am still learning. To keep signal purity, I feed it from my PC (or cd player), with tosslink (digital optical cable) its analog output is attenuated by an ALPS Pot and goes into the Tube power amp, or when I use my other pro solid state amp, then use its on board level control. this is sometimes a called passive preamp.

Currently runnig them in a small 10x14f room, and I sit against the oposit wall. For some yet unexplained reason, seem to have less neighbor disturbing sounds emanating outside the building than what I had before with conventional 15" non Klipsch speakers (which means now I can go louder :-)).

I might be able to help, send me a PM if your interested.

I meet people who think "I'm not quit with it" for using 40 y/o amps, and then they tell me nasty stories of them throwing away old tube gear, OTOH maybe it encourages the/or an industry to make new tubes and OPT's for people who can afford to buy new.