Vintage Altec loudspeakers generate a lot of enthusiasm among audio nuts like me because they run circles around many modern loudspeakers in terms of musicality, at least once you get some Hiraga-style crossovers installed in them, and they are so sensitive that you can easily drive them with low-powered single-ended-triode or single-ended-pentode amplifiers to live-like levels.
Altec A5 Voice of the Theatre loudspeakers.
Whether it is my vintage Altec A5 Voice of the Theatre loudspeakers, my vintage Altec 832A Corona loudspeakers, or my incredible vintage "Stokowski" Altec loudspeakers, they always put a smile on my face when I fire them up for a little music or film fun.
Vintage Altec 832A Corona domestic loudspeakers.
I've been in a romantic swoon with the "Stokowski" Altec loudspeakers ever since completing the Duelund-Altec Project (HERE), almost a year ago now. How time flies!
I'll be writing a one year follow-up about them in the near future to give you a long-term report on how everything in the Duelund CAST tinned-crossovers are settling in over time.
Conductor Leopold Stokowski's custom Altec loudspeakers.
A pair of loudspeakers like the "Stokowski" Altec loudspeakers, equipped with the Duelund CAST tinned-copper crossovers, are dangerous beasts for someone who enjoys writing about hifi like I do, as they are so musically satisfying, and sound so good, that it would be easy to call it a day for reviewing audio gear.
The Duelund CAST tinned-copper crossover installed in the "Stokowski" Altec loudspeakers.
For whatever reason, the Audio Note (UK) Oto Phono SE Signature Integrated Amplifier (HERE) is such a synergistic match with the "Stokowski" Altec loudspeakers, that the combination has produced a level of musicality above anything I've ever experienced in my home, or any audio shows I've been to over the last decade or so.
I really didn't see that one coming.
Audio Note (UK) Oto Phono SE Signature Integrated Amplifier with the Audio Note (UK) CD 2.1x/II Level Two Red Book CD Player.
I mentioned this happy synergy result to Peter Qvortrup (Audio Note (UK)), and Peter said, "What is truly remarkable, Jeff, is the fact that you can take a pair of 50 – 60 year old speakers and combine them with a currently made amplifier and CD player and get a result that probably beats 99% of the equipment made today, especially the speakers. If that is not an illustration of just how completely side tracked the industry has become by all manners of misconstrued ideas about what good sound really is, then I am not sure what is?"
I'll tell you what, I could stop playing audio games right now with this combination of gear and live happily every after. This combination of speakers and amplification is really that good, staggeringly good, if your tastes in audio are like mine.
Altec 804A (left) and 802D (right) high-frequency compression drivers.
However, just like some of you, sometimes I just can't leave things alone, no matter how good they are.
Today I got the wild idea that I should try swapping the 804A high-frequency compression drivers in the "Stokowski" Altec loudspeakers with the 802D high-frequency compression drivers in my Altec 832A Corona loudspeakers just to hear what would happen.
The Altec 804A and Altec 802D compression drivers are essentially the same design, and are shown together in Altec literature.
The Altec 804A / 802D both use large diameter (1.75") aluminum ribbon edge-wound voice coils coupled to a large (2.25") aluminum diaphragm having tangential compliance. Both have a mechanical phasing plug with two exponential acoustic slots, which provides the proper phase relationship from sound emanating from the center & outer edges of the diaphragm and voice coil assembly, to give maximum high-frequency reproduction and a smooth overall response.
Altec 804A compression driver diagram from an Altec brochure.
Like the 803B low frequency drivers in the "Stokowski" Altec loudspeakers, both the Altec 804A / 802D are rated for 30W. The Altec 804A / 802D frequency response is 500Hz to 22,000Hz, voice coil diameter is 1.75", impedance is 16 Ohms, and diameter is 4.5".
The primary difference is their magnets, as the 802D uses a 1.2 lbs., 15,250 Gauss magnet and the 804A uses a 13 oz. 13,000 Gauss magnet, which reflects their intended use as compression drivers for sound reinforcement in large spaces with high ambient noise levels (802D), or smaller spaces, like home listening rooms or smaller recording studios with moderate ambient noise levels (804A).
The Altec 804A compression driver is optimized for loudspeakers, "... located in non-reverberant space having moderate ambient noise levels, the Altec 804A driver proves a perfect match (Such conditions would be analogous to the average listening room or smaller broadcast and recording studio)", and pressure sensitivity is rated at 109.5dB at 1W and 124.2dB at 30W.
I imagine Dr. Stokowski chose the 804A compression drivers because that was the best fit for the room he listened to music in at home.
"Stokowski" Altec 802D installation.
Removing and replacing the 804A high-frequency compression drivers from the "Stokowski" Altec loudspeakers is a breeze, given I can access them from the open back of the high-frequency horn section of the loudspeaker.
Removing the 802D high frequency compression drivers from the Altec 832A Corona loudspeakers is a chore, as you have to take the loudspeakers completely apart to get the compression drivers out. Dismantling 832A Corona loudspeakers is not my idea of fun, but I just had to try the 802D compression drivers in the "Stokowski" Altec loudspeakers!
Altec 802D compression driver in the right "Stokowski" Altec loudspeaker.
After getting the Altec 832A Corona loudspeakers dismantled, and removing their 802D high-frequency compression drivers, I installed them into the 804A compression drivers' place in the "Stokowski" Altec loudspeakers.
First Watt SIT-3 amplifier and Pass Labs XP-12 line-level preamplifier.
Then I powered up the First Watt SIT-3 stereo amplifier, and the Pass Labs XP-12 preamp (I'm writing the review for the XP-12 now), and let them warm up for a bit, then gave them a listen. The SIT-3 and XP-12 combination is superb, by the way.
I think a lot of guys who love tube amplification would love the SIT-3 and XP-12 combination too. They don't really sound like vacuum tube gear per se, being rather unique in their strengths, but still they convey superb musicality & sonics in a very natural presentation of the music, with no vacuum tubes to replace.
There's something to be said for the inherent reliability of solid-state amplification, I say as I'm cussing my Fender Princeton vacuum tube guitar amp that made some rather impolite noises as a tube started to fail. Sigh.
Ok, back on topic.
If the "Stokowski" Altec loudspeakers, with their Duelund CAST tinned-copper crossovers based on the Hiraga circuit, were a power amplifier, I suppose they would be a classic 300B SET amplifier.
They provide a musically natural, intensely beautiful presentation of the music, and an absolutely stunning midrange. They are a little soft on top, with powerful bass, although the bass doesn't go particularly deep. But that's ok, as they do this magic trick that have my ears believing I am hearing live music playing with all of its emotional impact, which is sort of the goal of this hobby for me.
I was expecting that the 802D compression driver would sound a little more forward and open in comparison to 804A, perhaps lending more of a 2A3 SET character to the overall sound.
I put Bireli Lagrene's Standards CD in the Audio Note (UK) CD 2.1x/II Level Two Red Book CD Player and pressed "play".
My aural observations were that both the 802D and 804A compression drivers have a silky, smooth, and natural presentation, with lots of presence at live-like volume levels, and really don't sound much different from each other. Maybe a little bit, but not much. They both sound stunning, which I guess is not so bad an outcome.
Altec 804A (left) and 802D (right) compression drivers.
That's not what I was expecting. This is one of those cases where a quick listen just didn't tell me a lot, so I'm going to do some extended listening with a wider variety of music and see what I can pick up on.
I'll also follow up by putting the Audio Note (UK) Oto Phono SE Signature Integrated Amplifier back into the system, after I finish up the review for the Pass Labs XP-12, and see if the different amplification reveals anything about differences in the compression drivers.
While I'm at it, I may also try the Altec 803A low-frequency drivers from my Corona 832A loudspeakers in the "Stokowski" Altec loudspeakers, in place of the 803B Altec low-frequency drivers that are in them now.
Some of you might remember me writing about my conversations with Keith Aschenbrenner of Auditorium 23 in Germany, way back when. Keith has impeccable taste in audio, and he told me once about how the Altec 803A low-frequency driver was his favorite Altec low-frequency driver, being more articulate and more nuanced than any of the other Altec low-frequency drivers, with the tradeoff being that they don't go quite as deep as the later 15-inch Altec drivers, like the 803B and beyond.
If I remember correctly, the 803A low-frequency drivers have a lighter and stiffer cone than the 803B, or later 15-inch Altec low-frequency drivers, giving them a more articulate presentation of the frequencies below 500Hz (the crossover point).
It's getting really hard to find Altec 803A low-frequency drivers in good condition, as nobody who has heard them really wants to part with them.
I have a mint pair of 803A low-frequency drivers in my Altec 832A Corona loudspeakers, and they are amazing, so I get it, I wouldn't want to part with mine either.
I'll have to look into taking the 803A low-frequency out of the Corona 832As, as it looks to be fairly involved given the design of Corona cabinets. Swapping drivers is a bit of a chore in the "Stokowski" Altec loudspeakers too, but it is easy to get at all the bolts holding them in place, which is not the case with the Coronas.
Ok, enough blathering about audio for now, it is time for a Martini.
As always, thanks for stopping by, and may the tone be with you!
