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Pair Altec 420A 15” full range crossover-less from 1967-73 biflex tested see video

List price: $800.00
You save: $175.00 (22%)

It's a nice match, despite a slight age difference, both are 420A models, one is from 1967 and the other from around 1973. Both units cones are absolutely original, and for 40-year-old originals (see photo of speaker cone #s) -- they are beautiesonly a few blemishes normal for their age (study large photos below)  -- they're likely the nicest looking you’ll see online. They both play and sound great (see video below), Buyers NOTE: Unit #2 (1967) has slight intermittent on and off-axis rubbing -- a common problem for some 420A units. Unit #2 was tested extensively and swept 20-20K -- and no buzzs, rattles or distoration could be heard. This flaw could be temporary and may go away when mounted in a cabinet in a oposing direction for some time (gravity will self center the coil sometimes.) This slight rubing (only on unit #2) *may or may not* cause problems in future -- this is a really nice pair, ready to enjoy, though they are best suited for an experienced buyer, willing to utilize them  a not quite perfect pair.  On both, the dampener is clean and overall still tacky on both. And the original cork gaskets are excellent.  Unit #1 measures 5 ohm DCR, Unit #2 4.5 -- a very close match.

The edge dampener is clean still tacky not runny, cones are very clean. As always they will be thoroughly and carefully double  for safe domestic or international shipping. Carefully packed, bolted together, and double boxed for guaranteed safe arrival NO DOA.  Packed weight 40lbs, 18x18x18" dimensions. Please see our 100% rating for all vintage audio items.  

Inshrined in pantheon of Altec drivers is the quality Altec 420A 15” dual cone speaker. A crossover-less full range speaker with a dual compliance, mid cone.  The 420A 15" version deserves an honored place at that.  When you think about it, to get a really nice sounding alnico 15 inch driver the covers this frequency range (and having killer detailed mids) (you really don’t need a tweeter)  — options are few and far between! You will have to spend a lot more money than these 40 year old, hefty beauties! I think to do better than these you would really have to get a fragile RCA LC1 or 1A speaker (or the wimpier S1’s maybe) And….arguably your bass response (if you want it) won't be the same, with the LC1’s.  Other than this Altec series, I really can't think of any other worthwhile options. When people listen to these drivers in years to come; prices will be sure to rise as , with many other untouchable classic audio items. 

And until I re-listened to these (free air) this evening I had forgotten how excellent they are ... And will try to remember, so I can recommend them to friends.  For your money’s worth, and to avoid the crossover, and potential hassle with fragile diaphragms - give some considertion to these. That is if you’re about to buy 604 or 605, or really any coaxial drivers. These are pretty much just as efficient!! In the crucial 1000 - 2500 cycles range they very clear and not harsh. 
 What many consider to be a forgotten product of the 60s. The BiFlex, Altec’s excellent try at the dual cone design. It works especially well  on the bigger 15” format. Really,  mention of these it conjurers the idea of use only the Altec Santana system (and others) — which was a stuffy box. And really wasn't that spectacular. Allowing these drivers to sing on an infinite baffle, with wings, or horn projector will make for much better listening. And driven by a clean to tube amplifier you won't do much better.... Not without spending $$$$ thousands more, for something much more fragile than these rugged high-efficiency drivers. At anything below 1000 cycles the clever center midrange “driver” cleanly takes to task; acting as as a diaphragm. This gives an excellent voicing characteristic with plenty of detailed midrange, and allows you to avoid the messy chokes & phasing problems (crossovers usually kill detail). I would recommend using these with any low-power excellent single ended tube amp set up and give could thought to using them on a standard open baffle. The bestset up for  most any FR speaker.  
The specs as always were quite impressive.  And they use hefty alnico V magnets with a very impressive 11,400 gauss, and edge wound voice coils. Frequency response is 25 – 14,000 Hz. Very impressive , not to mention one rated at 111 dB SPL!
An nice match, despite a slight production difference of 3 years. Study the photos and descriptions above and below -- if they are right for you, it's and excellent sounding non-perfect pair.   They have been fully tested & checked over. Swept 20 to 20,000 cycles. Unit #2 sounds and works well, but has a slight rub.  Observe the pictures below for test reports; and see how faithfully and cleanly they're reproducing audio in the demonstration footage below.

pair Altec 420A - YouTube

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