Late last year, I acquired the classic AS309 tonearm for my Thorens TD124 MKII from Alfred Bokrand. I really can't hear a difference between the AB309 and AS309, even if I'm forced to split hairs. I'm just happy to own both!
A couple of blog readers and Instagram contacts have reached out regarding long delivery times from Alfred Bokrand. All of my transactions with him were done through eBay and on the average, delivery was within two months. I highly recommend that buyers order via eBay since it has a buyer protection guarantee.
Bach Chaconne from Partita No. 2 in D minor for Solo Violin
An important lesson I learned as a classically trained violinist was that music theory evolved from the analysis and study of great masterpieces from Bach to Bartok. Great composers broke theory to reach new heights in musical expression. Just like any artistic pursuit, music continues to evolve through individuals who are not afraid to go against convention for a greater good!
On the other hand, audio engineering, for the most part, has always been theory driven. Audio design simulators are significant modern conveniences but don't guarantee musical-sounding circuits even if the metrics look great. Creativity in audio design is when human ears are still the final arbiter, at least in my experience and opinion, which is why my hifi system is a hodgepodge of mostly obsolete technology, some of which date back to almost a century ago.
Last year, a Juilliard-trained pianist turned lawyer visited my man cave and listened to various amps + a couple of speakers I built. On his second visit, he brought his amps for comparison. At the end of that session, he commissioned a pair of Altec 753C speakers, the second pair I built in collaboration with John Piro of Hommage Audio, who crafted the speaker cabinets.
The chosen amp was the Radiotron SE2A3 - a topology from the pre-WWII Radio Designer's Handbook, 3rd edition. This circuit was from an era in which calculators were but a dream and engineers computed complex equations aided by a slide rule.
!!!WARNING!!!
The voltages found in the following circuit can be lethal! Build at your own risk!
Although this pentode-driven circuit sounded fine as is, to my ears, its fullest potential was only realized after I adjusted the plate and screen grid voltages to achieve a 2:1 ratio as suggested by my Ukrainian internet buddy, Sergey Didkovsky in the winter of 2007.
"Try please, to increase the cathode resistor (1,2k-1,5k ohm) and reduce anode resistor (to75k-82k). It will allow to increase Ua up to 150V and to receive Ua:Ug2 = 2:1 ratio. The sound should become more 'interesting and old.' That is especially good for jazz. Still mine 5 cents...use good NOS oil capacitors in G2. I use TCC Visconol. I think oil caps in the grid - adds bass. Reduction of the anode resistor - improves the hi range a little."
I'm pretty sure the 2:1 ratio wasn't a number crunched by a simulator, it was a figure painstakingly chosen by Sergey's ears because of his love for music!
Sergey, wherever you are, I pray that you and your family are safe. Freedom-loving people around the world are very grateful, yet very sorry that Ukraine is all alone in shielding the free world from the atrocities of a megalomaniacal autocrat!
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!
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.
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.😊
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.
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 listenedto 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.
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! ✌️☮
A well worn 78 rpm shellac disc of a Cole Porter classic recorded in 1938 by Artie Shaw spinning on a Gray Research HF500 turntable + a GE RPX cartridge amplified by my DIY je2a3 mono integrated fitted with a Hashimoto H203S output transformer driving a GE A1-400 speaker in a "vintage DIY" tuned pipe enclosure by Raymond H. Bates from Audio Magazine May 1955.
With the blessing of Early Bender of Hifitown.com, I uploaded two articles written in the 1980s for The Absolute Sound by his parents, Walt Bender (1944-2008) and Lennice Werth.
I've owned quite a few of the components discussed and still listen to a couple. This is a reflection of the articles' profound influence on my pursuit of the audio hobby. Since I believe that they are as relevant then as they are now, I added them to the JE Labs Arkiv.
