From: ianchan@leland.Stanford.EDU (Ian Hin Yun Chan)
Subject: CD op-amp upgrade
Summary: Result of upgrade from 5534 to AD847
Organization: DSG, Stanford University, CA 94305, USA
Date: Wed, 22 Jul 92 21:30:17 GMT

After reading about those 'fantastic` op-amps, I decided to give 'em a try.
I own a Philips CD840, which uses a pair of 5534's (rather crummy, I thought,
for one of their better models). I mail-ordered a pair of AD847jn's from
Sonic Frontiers of Canada for about US$15, postage included (rather nice of
'em, since their minimum order is US$25!). As I was unsure of my soldering
skills, I decided to play it safe and get a chip socket for the op-amps, and
as an added advantage, I could switch the op-amps back and forth to test,
as well as upgrade in the future. To cut a long story short, the results are:
The AD847's are definitely MUCH clearer and more detailed. The textures of
instruments are more naturally and convincingly portrayed, eg the piano on
Rachmaninoff's Piano Conc. 2 (by Ashkenazy) is very delicate and musical -
the notes seem to carray much more emotion with them now! Treble is extended:
eg the airy sustains on Dire Strait's Bro. in Arms, and Cyndi Lauper's
Time After Time have more presence, and the atmosphere of the songs are
conveyed more realistically. The greatest thing I think is the portrayal of
massed instruments/voices with the AD847. Playing Mozart's Requim, I simply
relished the detail and reality of the hundreds of people doing the singing.
I can hear distinctly the 'many-ness' of the choir, rather than just a confused
deluge of sound. The excitement of Mozart's contrapunctal use of the various
parts of the choir are given a lot of verve with the new op-amp. The recording,
BTW, is Karajan with the BPO (or maybe VPO, I forget). If I may venture to
say, my CD player sounds positively analog-ish! The strings are quite sweet,
although they do sound 'squeeky' at certain times - better than anything I've
heard though, except perhaps the Audio Alchemy DDE with it's own transport.
The only unceratinty I had was with the bass - it seemed to be more recessed.
At first, I thought it was because I was hearing more treble content, but in
fact, I was listening to less bass. The reason? The 5534 was not too tight
in the bass, so my Legacy Satellites could reproduce some loose rumblings that
came out of the CD player, but now with the AD847, everything's a lot tighter,
and the bass notes seem to drop and octave, resulting in my speakers inability
to reproduce those truly low notes. Playing George Michael's Faith album
demonstrated that the AD847's were really producing really tight bass - it's
just that I can't hear the lowest ones! 
The AD847's have my heartiest approval as replacement for the 5534's - hands
down!
As for testing.... I didn't! I have ferrite RF blockers on my interconnects, so
any RF instability should be killed by them.... Maybe, just for safety sake,
I'll borrow an oscilloscope from the physics lab and test it out for sure.
Maybe.
The rest of my equipment - Arcam Delta60 amp, Legacy Satellite speakers,
MASterlink Black interconnects, AQ IdigoBlue spkr wires, and a PowerWedge
for the CD player (the Philips CD840).
That was the best and cheapest upgrade I've ever done! Fabulous!

- Ian