kaepplein@amber.DEC (09/11/85)
An article for tweak fans: As promised, here is my adventure modifying the Magnavox FD1040, aka Sylvania FDD104 and Phillips 104 CD players. This is the unit that Mission modifies to create the 7000 and 7000R models. My goal was to modify my $168.95 player into what Mission sells for $650+. The greatest potential for good sound lies with quad oversampling, dual D/A converter machines. That narrows the field to Nakamichi ($1000), and Phillips based machines including Mission and Meridian. The Magnavox is the least expensive of those and nearly the whole market. According to HFN&RR review on the Mission 7000R: "...Mission designers have carried out a number of modifications. Areas examined include the power supply performance, earth routing, the integration capacitors, gain/phase margins for the buffer and filter amplifiers, the audio coupling capacitors and the high frequency filtering. The laser servo system has also been reviewed, and Mission have fitted an extra filter, built in a sealed module, to improve the rejection of ultrasonic spurious signals." HFN&RR strongly urged Mission use a quality inter- connect which was not the case at the time. My service manual arrived UPS in three days after calling the helpful people in the North American Phillips (NAP) publications office. It contained complete schematics, top and bottom board layouts, and service procedures. Worth the $12.50. Unfortunately, neither Phillips or Mission could supply me with a Mission CD7000(R) schematic - one didn't seem to exist. My other information included reviews from HiFi News and Record Review (thanks dsj) and capacitor articles from Audio and The Audio Amateur. The first thing I did was eliminate the 22uf dc filtering electrolytic caps and used a pair of 6.8uf WIMA Metalized Polycarbonate caps just before the output cables. Musical Concepts replaces the 22uf with a 10uf metalized polypropelene, and the original Mission 7000 must have used 5uf to cause it to be down 3db @20 hz. Next, I listened. Big difference. You don't have to be a "golden ears" to hear this one. There is now much more detail. Dynamic range increased a little upwards and lots downwards. A lot more depth and ambience. Bass through the midrange was tighter and didn't break up on crescendos. However, the low-end improvements left the high end weaknesses glaring. The next job was smoothing out the high end. This required some observation. The power supply feeding the op-amps only has two 22uf electrolytics after the linear regulator. I replaced one pair with 220uf electrolytic caps and shunted with 2.7uf polycarbonate films. I also added the same films before the regulator. The sound got a little smoother. The last thing I did was change the cap in a RF filter at the very end of the audio circuit. I used a spare 120pf pp phono cap where a surface mounted ceramic had been. Should use a mica as Musical Concepts does. Maybe a little better sound, but still some edge, especially on piano. Actually, by this time there is more ringing than edge, though edge is still evident on crescendos. I stopped making mods here. Crescendos don't make me cringe as badly and additional mods are physically harder with diminishing returns. There are quite a few surface mounted capacitors and resistors. They make small Passport radar detectors possible, but sound lousy in audio circuits. Space is fairly tight on the 1040 and they were necessary for the designers to use. There is no room to change them to discretes. Obvious additional problems to fix include: beefing up all the power lines that the DACs and op-amps use, replacing all the surface mount resistors and capacitors with metal films and mica/films, and using an audiophile grade audio cable. The anti-aliasing filters use all polystyrene caps, but mix a metal film resistor with surface mounts. I called Musical Concepts(MC) and asked about their mods, telling them what I had done. They do what I did and more. They use better parts, beef up the power supply more, use good audio cable, replace more surface mount components, and replace the op-amps with "much more dynamic, better sounding" ones. They said the op-amp change smoothes the sound and tightens it a little too. They also said that they compared their modified unit to a Mission and "blew it away." I don't like to advocate a commercial operation, but these guys did a first rate job on my Hafler DH110 and DH500. Their installed mods cost $150 and go up to $185 October 1. This is a bargain compared to a Mission. One last thing MC suggested was that someone buy a FD2040 or 3040 player instead of a FD1040. It is a wider chassis, and the audio board is larger with more discrete components instead of surface mounted ones. They said it sounds a little better in stock form and modifies more easily. Oh, well, anyone want to buy a slightly hacked player? :-) I've discovered that CDs can sound much better than most players let them. With some tweaking, a player can sound more like the LP ( :-) ). Its really frustrating to see the simplest last 2% of electronics destroy all the magic of reading .6 micron divots. It amazes me that $30 more investment there becomes $500-$1000 difference retail. A serious alternative to Mission/Meridian/Nakamichi players would be a self modified Magnavox 2040 ($178) or sending it to MC for modification and saving a bundle. I would recommend this to anyone with the possible caveat that new Phillips 16 bit units are due out in several months and might be a better start, but at a higher price. MC continually refines its mods and plans a signature mod in 6 months perhaps when they can get custom small mica caps to replace the surface mount caps. Evaluation tools: CDs: DMP's Flynn and the BB's - Tricycle, Telarc's Chopin, Columbia's Dimeola, Delucia, McLaughlin - Friday Night in San Francisco. I also used the Telarc LP pressing and the Japanese Sony/CBS pressing of the Columbia recording. Equipment: Kenwood KD500/Grace 707/Grado signature 8M, Musical Concepts modified Hafler DH110 and DH500, modified M&K speakers, Signet TK33 electret headphones, Kenwood interconnects/Monster cable. Mark Kaepplein Kaepplein@Dec-Marlboro.arpa Kaepplein%amber.dec@decwrl
ark@alice.UucP (Andrew Koenig) (09/12/85)
> As promised, here is my adventure modifying the Magnavox FD1040, aka > Sylvania FDD104 and Phillips 104 CD players. This is the unit that > Mission modifies to create the 7000 and 7000R models. My goal was to > modify my $168.95 player into what Mission sells for $650+. [detailed description of modifications follows] You forgot the most important step: careful comparison of your modified machine to an unmodified one. I'll bet you can guess what I mean by careful: double-blind, with careful level matching. You have the opportunity to do what no one in this newsgroup has done to date: prove that it *is* possible for people to hear differences between CD players even when all the known variables are controlled. I hope I can convince you to take advantage of it. If you were closer to New Jersey, I'd even suggest you bring your player for another of our "abcd" comparisons...
GOT@psuvm.BITNET (09/14/85)
OPTIONS: NOACK LOG SHORT NOTEBOOK ALL
XOPTIONS: REPLYING to NETNEWS article
Date: 13 September 1985, 12:11:41 EDT
From: GOT at PSUVM
To: kaepplein at amber.DEC
Subject: Re: Modifying the Magnavox FD1040 CD player
References: 397@decwrl.UUCP
(This was meant to be sent to kaepplein, but my stupid machine kept
telling it didn't want to, so everyone can read it)
Your article was very enlightening! thank you!
A little while ago i posted an article on the net asking if anyone new
anything about the Magnavox 1040 CD Player. Service Merchandise had it on
sale for about $150 and i thought it was a good deal. No one responded to
my inquiry, so i decided not to purchase the unit. After reading your article
i decided that i'm going to buy the 1040 this christmas. Before i purchase the
unit, however, i would like some more information about it.
First, what generation is the 1040, and how many bits does it sample?
(that question may be a bit strange, but i really don't know enough about CD's
to ask it any other way!). Second, could you please send me the addresses of
Musical Concepts and the Phillips facility from which you purchased the
schematic diagrams. Third, do you know of any reviews in audio magazines
that cover the 1040 (or phillips/mission) CD players. Finally, could
you please tell me of a good mail order
house that stocks the components (caps, resistors, etc) that you list in your
article (if you know of any place of course!). I've been pulling my hair out
trying to order parts for my various small projects.
Thank you very much, Sunil Gupta (GOT@PSUVM)