💙HAPPY VALENTINE'S DAY!💙
To commemorate this special day, here's a recording of Salut d'Amour by Sir Edward Elgar performed by yours truly on the violin, assisted on the piano by my friend and colleague Albert Tiu from our CD Sentimyento for Bookmark Audio recorded in 2000.
PLAYBACK EQUIPMENT:
CD Transport: SMSL PL100 CDp
DAC: DIY nosTDA1541tube DAC + UTC A20 line transformers
Line preamp: DIY 12B4A + Sony/TamRadio transformers
Line Attenuator: Intact Audio Nickel AVC
Amp: DIY 6F5 direct coupled SE2A3 amp
Speakers: Altec 406Zs in Coronado cabinets + Altec 3000H super tweeters
Video by iPhone 12 mini
The Altec 10" 406-8Y driver was a sleeper until ca. 2005 when Altec aficionado, Tom Brennan, started talking about the Altec Bolero in Audiokarma. However, I'd be remiss if I didn't mention that it was Arnold Cruz, a compatriot based in Manila, who brought them to my attention a year or two earlier. I've kept my eyes peeled since but only got the chance to hear these wonderful drivers when we returned to the States in 2016.
Fortunately, over a decade later, I was able to procure a pair each of the drivers pictured above sans cabinets. To the left is the earlier 406Z with a smaller 2" voice coil, while the 406-8Y to the right has a larger 3" voice coil. Both use the same alnico magnet found in the Altec 414A. The 406Z (+ matching passive radiator) was fitted to the Bolero 890B supplemented on top by the Altec 3000H. Early Maderas were also fitted with 406Zs, albeit with the Heppner horns. The 406-8Y (+ matching passive radiator) + Heppner horn tweeters were fitted to the Bolero 890C.
While researching online, I discovered the first generation 406A pictured above, built on a stamped steel chassis instead of the cast aluminum chassis shared by the 406Z and 406-8Y. The earliest Bolero 890A came with a 406A, passive radiator + Altec 3000 horn tweeter. There have also been references to a 406B but I have yet to encounter one virtually or in the metal.
After many years of searching for a Bolero or Madera, I finally landed the above pair of Maderas loaded with 406-8Ys + Heppner horns. Even if they sound quite decent, IMHO, the small sealed enclosure is a limiting factor in realizing the fullest potential from these drivers.
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| Altec Madera: 406-8Y + Heppner horn |
That said, I don't endorse hacking the few Boleros and Maderas that are still in good condition since not too many were manufactured to begin with. Despite not being a fan of the Heppner horn, I'm keeping mine in their original configuration for posterity!
Loaded in the ~ 2.75 cf ported Coronado box, both the 406Z and -8y sound more transparent, offer better resolution of detail and micro/macro dynamics (perhaps due to a gain in efficiency?) + significantly improved low frequency performance. I actually tried both 406 drivers in my ~ 2.5 slant front sealed box I designed for my Altec 756B but still preferred their sound in the Coronado ported box above, even if the port tuning wasn't optimized.
Listening to Sound Bytes
Normally, I don't encourage visitors to my YouTube channel to use my video uploads for serious listening evaluations. I explicitly note that my videos are merely proof of concept in my "about" section. However, after recording and listening to the next three 37-second Piazzolla musical excerpts, I realized that in this particular case, using decent headphones like Koss Porta-Pros (or better), enough of the tonal signature, especially in the upper midrange, of each driver from the 406Z, 406-8Y to the 756B, was captured by the iPhone 12 mini. I still would like to emphasize that many other factors crucial to high quality reproduced sound, including the extension at the frequency extremes as well as dynamic range, are still compromised. As an example, in my man cave, the pianissimo was a lot softer while fortissimo was much louder. It's still best to evaluate hifi in person. But for now, please listen intently as to how the three drivers present the upper midrange register.
Altec 406Z
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| This trace is courtesy of this Japanese blog. |
My former piano trio playing the opening bars of Piazzolla's La Muerte del Angel played via my mono rig - Magnavox CDB650 CD transport > Audio GD R2R11 NOS DAC > 2 x Altec 15356 stereo to mono mixer > JE Labs mono line stage > JE Labs mono CCC SE2A3 amp > Altec 406Z in a Coronado cabinet
Altec 406-8Y
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| This trace was borrowed from the same Japanese blog. |
Please note that the 406-8C is just a cosmetically deluxe version of the 406-8Y sporting a painted chassis + magnet cover. Electrically, they are the same - much like the difference between a 414A and a 414Z.
Same Piazzolla excerpt and mono hifi setup driving the Altec 406-8Y housed in the Altec Coronado cabinet
Altec 756B
Just for fun...😊
Piazzolla 37 second excerpt again + mono rig but this time driving the Altec 756B with the Altec 32C horn/806 driver disconnected. What do you think?😉
Filling up the top end harmonics
The beauty of using drivers like the Altec 414A, 406Z, 406-8Y and the 756B is, none of them shout or break up in the critical upper midrange. Thus, they don't necessarily require top end roll off filtering. All they need is a little bit of top end reinforcement, which can be done using a simple high pass filter. Many commercially available speaker systems were designed in this manner up until the early 80s. I surmise that one of the reasons these fell out of fashion even if they usually sound good (and are much easier to drive) is because this design approach doesn't look flattering on test equipment. Besides, by this time, drivers with the qualities of the aforementioned models have started to disappear.
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| C1 and C2 are starting point values, for example: 406Z + 3000H, C1 = 1µf Listen to lots of music and season to taste! |
I haven't found official specs on the sensitivity of the 406Z and 406-8Y. Given that I can enjoy listening to them with my flea powered SE45, 46 and 2A3 amps, I'd guess they're close to mid 90s/1W/1M.
Altec 406Z
Although not quite as authoritative in the lower range as the 406-8Y, the 406Z has more presence up to the upper midrange region.That's why I prefaced this article with the Elgar video featuring the 406Zs + the airy and silky smooth 3000Hs. Unfortunately, working 3000 tweeter units are hard to find and very expensive when available. They're very fragile and can no longer be repaired because the special jig required to install replacement diaphragms went AWOL.😔
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| L>R: Selenium ST324-SLF, Sansui T104, Radio Shack 40-1310 and ElectroVoice Wolverine TW35 |
Here are some affordable tweeters that aren't quite in the Altec 3000 category but produced satisfying results on top of the 406Z. Starting from the left, the Selenium is a low cost adaptation of JBL's classic 2405. It's the smoothest of the bunch crossed above 5 kHz. Perhaps the Sansui T104 isn't quite as extended in the extreme top but it can arguably sound even smoother and less grainy. The Radio Shack 40-1310 is a close relative of the Fostex FT17H, which isn't quite as refined as the previous two. However, if you're not anal retentive and can disregard crossover and L-pad calculators, try installing a 0.5µf PIO coupling cap on the positive terminal of the 40-1310. Aside from serving as a high pass filter, the low µf value cap provides a very gradual slope which has an attenuating effect on the more sensitive high frequency driver. IME, the tizz from this horn tweeter is minimized when used in this manner. Same thing with the stinging EV TW35 if the cap value is reduced to 0.22µf.
My current favorite horn/driver combo for the 406Z because of the seamless blend is a mystery horn with a Frazier decal I acquired from my buddy, Michael V., at Hifi Haven + Renkus-Heinz SSD1400 1" compression driver (smaller magnet brother of the SSD1800) as featured in the Billie Holiday video above. As an aside, the cello obligato solos in the recording were performed by the young David Soyer who would later be a founding member of the Guarneri Quartet. I was fortunate to have been mentored in chamber music by these great musicians!
Turntable: Thorens TD124
Tonearm: Stax UA3NL
Phono cartridge: Shure V15 Type IIIG
Phono preamp: DIY RCA derived 6SL7-passive RIAA EQ-6SL7-6SN7
Line preamp: DIY 12B4A + Sony/TamRadio line output transformers
Line Attenuator: Intact Audio AVC
Amp: DIY 6F5-DC-SE45 + KA6625ST OPTs
In the past, I've also enjoyed using the Azzolina KS12024 + Altec 806A. Any of the Altec 32 horns also work well as long as the crossover point chosen is above 5 kHz. Lower than that, the sound can get congested since the 406Z is still quite energetic past 4 kHz.
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| L to R: Altec 32C, Azzolina KS12024, Emilar EH500 + EH800 |
Altec 406-8Y
The sonic signature of the 406-8Y is very similar to the 12" Altec 414A, albeit reduced to 10" proportions. Just like the 414A, it's best paired with horns with a lower frequency cut off like the Altec 32, Azzolina KS12024, Emilar EH500 and EH800. However, since it's quite a few dB less sensitive than the 414A, I recommend the Altec 806 compression driver as an ideal partner while the larger and more efficient 802 is just plain overkill due to wasted heat on padding resistors.
Here's the complete La Muerte del Angel by Astor Piazzolla from the CD Concierto para Trio my trio recorded in 2002 for Northbranch Records in NJ - Albert Tiu, pianist, yours truly, violinist and Sean Katsuyama, cellist.
PLAYBACK EQUIPMENT:
CD Transport: SMSL PL100 CDp
DAC: DIY nosTDA1541tube DAC + UTC A20 line transformers
Line preamp: DIY 12B4A + Sony/TamRadio transformers
Line Attenuator: Intact Audio Nickel AVC
Amp: Radiotron SE2A3 with Finemet FM6WS OPTs
Speakers: Altec 406-8Ys loaded in Coronado cabinets + Emilar EH800 horns and Altec 806 drivers fitted with GPA 34852 diaphragms
This is the French version of Windmills of Your Mind sung by the composer himself for whom I had the honor of playing solo obligatos to his compositions as concertmaster over two decades ago!
For the finale, I installed the most recent addition to my horn and driver collection - a pair of OJAS 1211 horns (Thanks, Devon and Trieu!) + Dukane labelled Coral M100 compression drivers on top of 406-8Ys in Altec Coronado cabinets. This pairing offers a closer-to-the-stage perspective compared to the EH800/806A combo above. It blended into the system without much fuss requiring only a minor touch up on the L-pads. See the details of the hifi setup below.
Turntable: Thorens TD124
Tonearm: Bokrand AS309
MC phono cartridge: Entré EC15X
MC Step Up: Entré ET100
Phono preamp: DIY RCA derived 6SL7-passive RIAA EQ-6SL7-6SN7
Line preamp: DIY 12B4A + Sony/TamRadio line output transformers
Line Attenuator: Intact Audio AVC
Amp: 6C8G CCC SE46 + PMF15WS OPTs
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