So...I was working replacing the stock front channel JRC5532D opamp in a Klipsch 4.1 preamp after already finding and upgrading the stock sub output ST TL082CN opamp with an AD 8066AR and all replacing all 6 resistors on the little board with Nichicon 10uf 25 volt (aluminum audio grade, mainly due to height restriction when closing it back up).
After searching for a replacement for the 5532D that would make it worth my while to bother with it, I decided on a dip 8 LME 49860NA. I don't know if it is the dual channel version of the single channel LME49990 or something close but reviews were okay with it. Remove some cement and then desoldered the 5532D and its accompanying (2) resistors soldered to the backside legs (inputs?), apparently helps eliminate oscillations. Hoping the new 49860NA opamp would not need them. Went well, installed a DIP 8 socket. Left the other stock rear channel 5532D in place until the results are in. Defluxed everything and recoated with spray silicone. I figure I can do as good a job as any Chinese 10 year old slave laborer. Went to my mess of opamps and thought I picked out one of the two new 49860NA but no by mistake had a LM 4562NA (didn't even know I owned one) what are the chances?
Install it, turned it on and I go, "What a waste of time and money this was." Lows were missing, highs were clear to the point of being shrill, mids nowhere to be found. If it needed breaking in, I doubted it would ever recover. Having the DIP 8 socket installed, I begin digging for some old standby opamps to checkout and discover I have two 49860NA in the mix. Go check the occupied DIP socket and confirm it is a 4562NA sitting in it and grab the eBay $5 special yellow handled opamp tweezer/removers and install the 49860NA and turn the system back on.
The difference is between night and day. Clarity with clean highs and lows and mids mixed right in between, nothing really stands out unless there is a flute playing or bass drum hit. Vocals are clear and true. If I am missing warmth or am hearing sibilance, hard to tell, may be the recording(s) but the great detail adds to the separation (staging).
After a year or two, I am still getting use to the clarity in lows. No longer am I hearing thuds and booms but musical bass notes by using decent opamps plus at low power points (don't have to turn it up for lows). Also I find movies or audio tracks that use AAC audio are the most compact and best at reproducing sounds. I have to use Foobar for playing AAC back (added the plugin? Can't remember) but can't edit the properties i.e names, dates, tracks but there is absolutely no degradation when I rip an audio track from a movie or off You Tube now (mp4 files). I can still convert to other formats via Foobar with some warning message that the new music file won't be any better except a larger file which it always is compared to the original AAC file.
Testing mostly with a CD album, Title : Morph The Cat (2006) Donald Fagen. Has good ranges and some tight bass, well recorded. Ripped: Baby, It's Cold Outside from the ending movie soundtrack ELF (2003), kept it in its AAC format, sounds better than the CD movie sound track album.
Edited by razzz42 - 4/29/14 at 9:23pm