Posted by Bill Epstein [ 75.143.208.132 ] on July 14, 2008 at 18:16:47:
In Reply to: Re: Question about completed crossovers posted by Wayne Parham on July 12, 2008 at 20:52:58:
Played cut 1 of disc 1 Union Station Live, Let Me Touch You For Awhile, my number 1 treble edginess offender. Horrible! Windows broke all over the neighborhood! I hope Ms. Krause has insurance.
Played DK's vinyl release, (I can never think of the name) she sounded 8 years old. Sacre Bleu!
Pulled the ARC pre-amp and replaced it with the passive pot/switchbox. That's it! Filament voltage dropping resistors must be fried again. Now I can hear the crossovers.
The new crossover isn't exactly smooth, I would call it crystal clear and timbre-ific. On that same DK, wait a minute while I look at the album cover.............From This Moment On, Willow Weep For Me has the last refrain preceded by a Soprano Sax riff that, on various review systems has sounded from more or less real to a kids Kazoo: it now exhibits, not just exactly the right timbre but you can actually hear the "reediness" of it. Not in an ultra-detailed, audio-compulsive way, but rather just as though the instrument was right there. You do hear the reed when played live. The 1812s couldn't do that even with some of the super amps I had in the past. That's incredible!
Next I played the Szell/Oistrakh/Rostropovich Brahms Double for image and hall ambience. I can almost tell where the holes are in the respective instruments soundboards. This wouldn't be important by itself, indeed, it's an artifact of those 80 dB efficient, diamond tweeter speakers; but the sound with the new crossover places the whole output of the instrument including resonances of strings and wood body so perfectly in the performance space there is a marked increase in the emotion conveyed by the musician.
The passive pre-amp has resulted in some loss of the fullness of bass I heard with the LS-1, beyond what the 2226s have done in the past. With either passive or active control the bass has more authority than before though, especially apparent from kick-drum and tom-tom with better clarity of the resonances of plucked and bowed acoustic bass. There is little difference with electric bass apart from a smidge better separation of individual notes.
I infer that the 6.8 uF cap has raised the crossover point to 2000 Hz? Wayne? If so, the 2226 must be better over those 400 Hz than the DE-250; I'm thinking that the extra clarity and realistic timbre is coming from JBL and, perhaps, the Zobel is helping reduce the strain of the extra half-octave?
Everyone should keep in mind that these capsule impressions are with just under 10 hours on the parts. Also, I used nothing but Dayton caps and resistors except C1 (the attenuator) which is an Obbligato, a $4 part.
The Pomona speaker terminals I used (Allied part# 3770) fit the board well and at $7 a piece don't cost a fortune considering they're gold-plated tellurium copper. My total parts cost, including the very expensive 15ga. Jantzen coils, double the size for my 16 ohm woofers, was about $235. BTW, Parts Express was out of 1 mH Jantzen; the Perfect Lay I substituted were sent back due to really shoddy-looking winding. Fortunately, I had an old pair of Perfect Lay in the drawer. The old ones are red, these new ones are green and look so bad I wouldn't trust the winding count!
All the issues I've had in the past months with treble edginess, even with the passive, are gone. I now suspect my hand-wired crossovers have a fault: my fault. These new crossovers are just incredible sounding and should get better with more hours and maybe some tastier caps and resistors.
Wayne, you've done it again!
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