Sony PS1 + Magnavox/Philips NOS TDA1543 CDP Mod

 A revival of interest in CDs is imminent, sparked by Pope Francis' recent visit to a mom and pop record store in Rome.😉

from djmag.com

So before software and hardware prices go through the roof, here are two affordable ways to get maximum pleasure out of CD playback for thrift store/flea market and/or DIY-inclined souls.

Over ten years ago, this early first generation Sony Playstation 1 developed quite a following amongst audiophiles as a CD player because of Art Dudley's favorable write up in Stereophile. The market has probably softened up a bit since then, because I managed to snag two PS1s at '08 prices before the pandemic. 

Not all PS1 consoles were created equal - only the machines fitted with the AKM AK4309AVM Sigma-Delta DAC chip have audiophile credibility. Since I've seen some unscrupulous sellers asking $100+ for this obsolete game console, it pays to know two tell-tale features of the desirable PS1:

1. "SCPH-1001" designation

2. A pair of audio output RCA jacks on the back of the console

Don't forget the controller, which I pictured above and below, otherwise there's no way to command the player to play, stop or skip tracks. 

Sigma-Delta DAC chips never struck me as unbearably bright, strident or fatiguing. The main reason I reverted back to a multi-bit DAC in the Box in the 90s was because my bitstream'd Philips CD921, and later the sigma-delta Sony DVP NS755V, sounded boring and lifeless. That said, the Sony PS1 is the most exciting sigma-delta chip'd CD player I've heard! 

This is a must read: Michael Lavorgna's Sony PS1 Epitaph in Twittering Machines!

However, to my ears, here's a better machine for Digital Sound Processing Redbook CDs. 😉

In my thrift store CD player upload, these TDA1543-equipped twins stood out as very musical sounding machines, meaning, not for audiophiles, but more for people who love music. I actually prefer these Mexican-built non oversampling models over their slightly more upmarket Belgian sibling, the 4 x oversampling CDB610. 

 These were the entry level Philips CDPs from the late 80s up to the early 90s until they were superseded by inferior-sounding (at least to my ears) bitstream machines like my dreaded Philips CD921.😏 Stock, I'd choose these over the AKM chip'd Sony PS1 for sheer musical pleasure! 👍

I also highly recommend the Sony CDP190 with a TDA1543A + an in-house 4 x oversampling chip and filter. But in the 5 years I've been thrifting CD players, I've only found one, while I've managed to collect duplicates of the CD2000 and CDB492.

Grundig CD8150 analog output section

There is no known service manual or schematic for the Magnavox/Philips CD2000/CDB492, so I searched for other contemporaneous badge engineered Philips CD players. I found the Grundig CD 8150 service manual at HifiEngine.com, which employs a very similar, if not identical, circuit topology. I verified that the machine is indeed non oversampling. In lieu of the SAA7220P oversampling and filter chip, Philips engineered a brick wall filter in the analog output section, which they cleverly marketed as Digital Sound Processing.😊

I wonder if this circuit could have been the inspiration for Ryohei Kusunoki’s non-oversampling articles for MJ in the mid 90s.🤔

My audio buddy Ding R wanted me to improve his CDB492 with a tube output stage, since numerous DIYers have managed to shoehorn a tube analog output stage inside a plastic chassis CD player. But I wasn't keen on making a perilous fire hazard compromise. Besides, I'm also a purist and believe that only a tube-rectified and/or choke-filtered power supply should power tube circuits, nearly impossible to fit inside a CD player chassis.

8-pin DIP sockets, BB OPA2604 op-amps + Mylar capacitors

The inspiration for this simple-to-implement modification dates back to Walter G. Jung's article in the June 1987 issue of Audio. I removed the LM833 op-amps in the signal path of the analog output section, installed 8-pin DIP sockets and listened to check if the FET-input Burr-Brown OPA2604s and Mylar WIMA caps in place of the original electrolytics could improve the CDB492's musical performance. 

Magnavox/Philips CDP Teardown by msylvain59

The most laborious part of this modification is gaining access to the underside of the motherboard. Watch msylvain59’s wonderful video above for a detailed teardown of a very similar Philips CD player. Handle the ribbon cables and connectors carefully! Given the age of these components, a crack or tear is enough to render the machine useless.

The motherboard is now ready for upgrades.
 Take note of the op-amp orientation; otherwise, the machine may emit
smoke and nasty burnt electronic component odors!

 

 After handling over a dozen 80s era CD players, I have yet to encounter bulging or leaky power supply capacitors. These machines used high quality Japanese-made Nichicon capacitors. In contrast to current audio trends, I don’t endorse across the board capacitor replacement. I'm all for replacing parts judiciously!

Operational amplifiers (more info) or op-amps were developed during the vacuum tube era. Due to the inherent high gain nature of op-amp topology (video), negative feedback is necessary to control gain and/or linearize the circuit. Ever since I started DIY’ing tube circuits, I learned that negative feedback has to be implemented judiciously (or even dispensed with) in pursuit of ultimate sound quality, which also applies to solid-state. Because of this, I don't see the logic behind boutique-priced discrete op-amps. But if that's how you get your audio fix, have fun rolling! ✌️☮

To my ears, the Burr-Brown OPA2604 + WIMAs gave a smoother, cleaner, clearer and less grainy sound. The superior TDA1541 DAC chip in the Magnavox CDB465 with op-amp + output cap upgrade offers better resolution of detail + a marginal improvement in musicality. However, the most musical CD sound I've enjoyed to date is still from the digital stream of a JVC, Magnavox/Philips swing-arm or Sony transport piped into my nosTDA1541tube DAC. But then again, I'm biased! 😆

 

Ding called after his first listening session with his JE Labs-modified CDB492, "...are you sure that's all you did to this machine?"