Monday, August 27, 2018

Magnavox CDB473 and Philips TDA1541


With barely 400 CDs and just a handful of SACDs and DVD-As in my collection, I didn't invest heavily on silver discs as much as I did on LPs. Likewise, I've spent much less on digital playback hardware.

However, due to the resurgence of interest in vinyl LPs and streaming, used CDs are available all over at bargain prices. Since I'm not committed to burning all my silver discs to a hard drive having had my own share of failures in the past, I was inspired to look into maximizing my CD playback system.


Sony DVP-NS755V

For the past 15 years, I relied mainly on this Sony DVD/SACD/CD player. It showed me that SACDs had an edge over CDs. Yet it proved that neither format was on equal footing with my LP set up. This is a polite sounding machine that also doesn't do anything great. Prior to the Sony, I owned an early bitstream (ca. '93) Philips CD921. It sounded sooo boring, I connected the digital out to an Audio Alchemy Dac IThe Box to spice things up a bit until it (the CD921) prematurely died.

Nevertheless, I was still missing the lively sound of my first CD player, a Magnavox CDB472 I purchased in 1987. I had an inkling that the "bitstream" buzzword of the 90s was not an effort to improve sound quality but a watered down technology/marketing hype for manufacturers to maximize profits. Since I was more interested then (as now) in older technology, I placed digital audio tech aside, focused on learning how to build triode amps and high-efficiency speakers.

Denon DVD-2910

To re-acquaint myself with the few DVD-A titles I have, I acquired this reasonably priced Denon DVD-2910 multi-format compatible relic from the mid-2000s. It weighs almost 10 pounds, is built like a tank, is mechanically and functionally more refined compared to my entry-level Sony above due to higher quality materials (more metal). If this didn't sound better, it can serve as a CD transport for an external DAC. Fortunately SACDs did sound better, but not sure about CDs though...

Time Travel Machine


Philips TDA1541A

Ever since I embarked upon improving my internet streaming set up, I had to refresh and update my knowledge of Digital Audio, PCM, DSD, DACs, etc. It was inevitable that I'd encounter R2-R vs. delta-sigma debates in internet audio forums. I also discovered that there's a sub-culture of CD collectors/music lovers/DIYers (as opposed to meter readers/latest is best audiophiles) who maintain that the most musical sounding CD players are those 80s machines fitted with the more complicated and expensive-to-manufacture 16 bit Philips TDA1541 chip.

Under the hood of a CDB473

Out of retro-tech nostalgia, it was only fitting that I trace my steps back to my first CD player in ca.'87, the Magnavox CDB472, which used this ubiquitous chip. I did a bit better this time around with the higher model CDB473 which is equipped with a co-ax digital out, and can also be used as a CD transport. Considering that this unit celebrated its 30th birthday in December of 2017, it is a glowing testament to Philips' excellence in engineering and manufacturing that it still works today. 

Let's see how the Magnavox's 16 bit DAC chip which was truly designed for Red Book CDs fares against the Delta-Sigma DAC chips found inside the Denon and Sony.

Magnavox CDB473

From the very first CD I fed into the tray, the Magnavox sounded more transparent and dynamic while the Denon and Sony sounded comparatively veiled and compressed. Even my wife heard its superiority. The CDB473 may not possess ultimate refinement but there's an honesty in its musical presentation that draws the listener into the music, just like analog LP does. 

Truth be told, I don't remember the CDB472 sounding this good back in the 80s. But I had a totally different system then and was just beginning to wean myself off of the influence of underground audio journals of the era, which were largely pro-vinyl LP/anti-digital CD. I guess hindsight is indeed 20/20 with regards to the Philips TDA1541. I was too young to learn and appreciate its virtues. Besides, a year after this CDB473 was manufactured, Philips introduced bitstream technology, followed in the late 90s by Delta-Sigma, both claiming greater linearity. These were the technologies that dominated the market from the 90s to the present and also the sound I associated with the playback of 16-bit/44.1kHz mastered CDs.








Friday, August 10, 2018

Parts Express 1" Horns and Waveguide Buy Out Specials


July was a hectic month - four 4th of July concerts with Harrisburg Symphony + two concerts at the Shippensburg Summer Music Festival. It was a welcome respite to receive an invitation from Joe Roberts to meet him at his mom's house in South Philly after I was done with all those gigs.

Leica II + Summitar 50mm f2
Ilford FP4+ in Kodak HC110

He gave me a tour of his old neighborhood, pointing out areas where he started his archeological expeditions as a kid. For lunch we stopped by this hoagie shop for really great Philly cheesesteaks. 

It was very interesting to listen to his recollection of South Philly as a kid, and how the area continues to evolve as people of different ethnicities, socio-economic and cultural backgrounds come and go.  


Before I-95 swarmed with rush hour traffic, I had to head back north with this box filled with horns from Joe. I didn't envision writing about 1" format horns again since I posted this blog entry last February. But after spotting the Azzolina KS12024s, it was hard to pass up this opportunity. Meanwhile, this post will focus only on the Parts Express horns.


Testing


I used Altec 802 1" compression drivers fitted with GPA 34852 16 ohm diaphragms mounted on top of Altec 614 cabinets loaded with 414A woofers (running full range) with the crossover below tying things together. All listening was done in stereo in the man cave.



High pass @ ~ 2500 Hz

I used these two horns as references and for the first time I was able to convince my wife, Tish, to indulge me with her sonic impressions.

Altec 32C


Tish and I love this descendant of the old school WE32A horn. She describes it as sublime.😉 

Emilar EH500

This is my favorite horn from the 70s. It was designed by Jonas Renkus who worked with John Hilliard at Altec Lansing. 

Parts Express Specials 

Round 1 

(deeper/longer exit Altec 802)

+
Altec 802

There is an ongoing thread at Hi-Fi Haven about cheap horns where this particular horn/waveguide was mentioned. Its specs are listed as a 600 Hz, 10" x 14" exponential horn waveguide with a 90° H x 40° H dispersion pattern, made out of heavy ABS plastic. Price: $12.88/ea.

Sound

Tish: Not bad, but not as lush sounding as the Altec 32C. It will eventually hurt my ears. 

JE: Tonal balance is reminiscent of the Emilar EH500. However the sound gets congested with complex musical passages (especially at higher SPLs) which can cause fatigue during long-term listening.



Community UC-1
part# 299-522
+
Altec 802

Dimensions: 10 3/8" W x 5 7/8" H x 6" D
Dispersion: 90°H x 40°V
Cut off frequency: 2000 Hz
Price: $4.48/each

 I had to DIY adapter plates to mount the 802 drivers.

Sound

Tish: Harsh and shouty👎👎👎

JE: Sounds better disconnected. What were you thinking J-Rob???🤣

Faital Pro revisited


Faital Pro STH100 + Altec 802
Dispersion: 80° H x 70° V
Dimensions: 7" W x 4 3/4" H x 3 5/8" D
Material: Metal
Price: $67/each!!!

Sound

Tish: I like this best among the three - easier on the ears compared to the other two, but not even close to the 32C.

JE: I am less impressed this time around despite the clean sound. It has less congestion, harshness and tizz than the B52/QSC clone 299-2303. But the presentation still falls far short of what I hear live. With the recent price increase, I can no longer recommend this unit.

!!!STOP PRESS!!!


Pasted below is a post by @ARX in this Hi-Fi Haven thread

Gentlemen,

Very interesting experiments with different types of horns and waveguides (the B-52 1" QSC clone is a waveguide), both vintage and more recent designs.

The 802D with the B-52 1" might not be an optimal combination. The original QSC PL-000446GP was designed by Mark Engebretson, former VP of Engineering at QSC, to be used with Celestion compression drivers. From the many measurements available online it's obvious this waveguide performs best with modern, pancake style compression drivers, that have a short exit instead of the deeper/longer exit of most vintage drivers like Emilar, Altec etc.

You might try B&C, Celestion, Beyma, BMS and similar 1" drivers.

There's much more to the underlying physics, but it should come as no surprise the EH-500 and Altec 32A/B do indeed sound wonderful with the vintage drivers. The gradual expansion of the wavefront from driver diaphragm to horn mouth is (almost) perfect. On the other hand, a pancake driver behind an oldskool horn, with a few exceptions, is unlikely to yield spectacular results.

Altec 802 (left) + Renkus-Heinz SSD1400-8 (right) 

The only pancake type (short/fast exit) 1" compression driver I have on hand is a pair of Renkus-Heinz SSD1400-8. This is a smaller magnet version of the SSD1800, which I got to know quite well in the attic. Hence, I had a gut feel that I was going to learn something important from @ARX. So the SSD1400-8 was pressed into service for another round of listening.

Round 2 

(short/fast exit Renkus-Heinz SSD1400-8)

+
Renkus-Heinz SSD1400-8

 According to ARX's post above, this is a clone of the QSC waveguide, which was designed to be paired with a B&C DE250 compression driver in the Econo-wave project at Audiokarma.

With the short exit R-H SSD1400-8 mounted, this waveguide was transformed. Although not quite on the same level, the sound now more closely resembles the Altec 802/Emilar EH500 pairing. The congestion I heard in Round 1 is gone with a substantial gain in midrange lucidity. Long term listening fatigue is no longer an issue since the sound has opened up with a nice airiness to it.  👍👍👍


part# 299-522
+
Renkus-Heinz SSD1400-8

This horn became a lot more listenable with the SSD1400-8 mounted behind it. It sounded even better crossed over @ 5kHz. Detailed and airy but the midrange isn't quite as vivid as the B52/QSC clone/299-2303. For the record, Community compression drivers are also short/fast exit (pancake) designs.

+
Renkus-Heinz SSD1400-8

Sadly, this tractrix horn became unlistenable with the SSD1400-8. Probably a mis-match? Faital Pro 1" compression drivers look more like old school Altec 802s and Emilar EA/EC175.


Parts Express Horn Wrap


Two important lessons learned:

1. Thank you very much @ARX for enlightening me! Otherwise, I would have joined the ranks of fake news bloggers. 🤣

2. My preference for matching harmonically rich-sounding components will always entail a classic pairing of units that are long out of production and are becoming more unaffordable as the years go by...😞