Amp/Preamp Asylum

Posted by cin5 (A) on September 27, 2016 at 17:09:03

In Reply to: RE: Paralleled, Mr. Wayne, paralleled, not bridged. posted by jeffreybehr on December 30, 2014 at 20:12:08

Congrats Jeff with all of your audibly successful mods on the J2 amps. I also have a J2 amp and will use it to drive clones I'm building of a very successful two-way hybrid horn system. Designed by Gary Dahl and Lynn Olson, the mains are Radian 745 Neo/Be drivers in Azura 425 horns. They are passively crossed to a pair of GPA Altec 416-B midwoofers. The sealed cabinets cut the midwoofers off at just below 70Hz, where my pair of Rythmik 12" sealed servo subs take over. System sensitivity is 97db and impedance is between 8 and 7 ohms. My room is only 14 ft x 19 and my average listening levels will probably be between 68 and 75db @ 70Hz at 11 feet, before my subs kick in. https://en.wikipedia.org/wiki/Fletcher%E2%80%93Munson_curves So the J2 would hardly break a sweat pushing these speakers.

Two questions.

1.) Sadly, things have changed and after completing these speakers I won't be doing much more DIYing. But as you are clearly thrilled with the increased sound quality from your modded J2, might you or someone you know do these J2 mods to order? I'd want the mods that would most contribute to the improved sound.

2.) Have you ever heard the Pass XA30.5? If yes, how would you compare its sound to that of a stock J2 amp? More precisely, how would compare their sound when the XA30.5 is under load such that the needle of its front panel ammeter is very close to its center position-that is, where the amp is operating within its Class A bias region?**

Bigger soundstage in all dimensions? Deeper more robust midbass and low bass? More 3D imaging. More lifelike midrange? More extended and sweeter sounding highs? Better micro and macrodynamic detail? Better overall tonality?

Also, perhaps a rather silly question, but I am curious about which amp makes a better space heater.

** The Pass XA30.5 does 30 wpc and can handle 60 watt peaks, all in Class A. Beyond this output level it moves into Class AB where it does > 100 wpc.

Edits: 09/27/16