What to do with Altec 420Y Drivers?
- Thread starter mxlews
- Start date
>95 dB, use the high-sensitivity variant:
http://audiokarma.org/forums/showthread.php?p=1856214#post1856214
MartinV56
Well-Known Member
Hi Zilch, thanks, here my list parts, is correct for 95db variant
Contents of Shopping Cart
Image Part Number In Stock Description Qty. Price Ext. Price Remove
004-16 Yes Dayton DNR-16 16 Ohm 10W Precision Audio Grade Resistor $1.25 $2.50 *15ohm in XO schematic
027-422 Yes Dayton DMPC-4.7 4.7uF 250V Polypropylene Capacitor $2.41 $4.82
027-430 Yes Dayton DMPC-12 12uF 250V Polypropylene Capacitor $4.57 $9.14
255-040 Yes Jantzen 0.60mH 20 AWG Air Core Inductor $4.19 $8.38
260-255 Yes L-Pad 50W Mono 1" Shaft 8 Ohm $9.70 $19.40
266-552 Yes 1.5mH 18 AWG I Core Inductor $8.22 $16.44
004-25 Yes Dayton DNR-25 25 Ohm 10W Precision Audio Grade Resistor $1.25 $2.50 *24ohm in XO schematic
264-270 Yes Selenium D220Ti-8 1" Titanium Horn Driver 8 Ohm 1-3/8"-18 $43.66 $87.32
Subtotal: $150.50
Contents of Shopping Cart
Image Part Number In Stock Description Qty. Price Ext. Price Remove
004-16 Yes Dayton DNR-16 16 Ohm 10W Precision Audio Grade Resistor $1.25 $2.50 *15ohm in XO schematic
027-422 Yes Dayton DMPC-4.7 4.7uF 250V Polypropylene Capacitor $2.41 $4.82
027-430 Yes Dayton DMPC-12 12uF 250V Polypropylene Capacitor $4.57 $9.14
255-040 Yes Jantzen 0.60mH 20 AWG Air Core Inductor $4.19 $8.38
260-255 Yes L-Pad 50W Mono 1" Shaft 8 Ohm $9.70 $19.40
266-552 Yes 1.5mH 18 AWG I Core Inductor $8.22 $16.44
004-25 Yes Dayton DNR-25 25 Ohm 10W Precision Audio Grade Resistor $1.25 $2.50 *24ohm in XO schematic
264-270 Yes Selenium D220Ti-8 1" Titanium Horn Driver 8 Ohm 1-3/8"-18 $43.66 $87.32
Subtotal: $150.50
Bill Murray
Active Member
I am coming in with some facts 13 years later !! I have a pair of Altec 872A's mounting 15" 420Y's. They were made in 1973 and I bought them about 2 years later. First, the baffles ARE removable. They are screwed, but not glued in. Peek under the damping and you will see the wood screws. Second, the original caps were 14uf. One of the pair is faultless and has been for 45 or so years. The other has been a problem in that I have a buzzy sound coming from the big cone. It rubs when you flex the cone, seems to be at a frequency used in the outer ring. The low bass is fine, the tweeter works ok, but somewhere in the midrange is this buzz, which is, btw, not constant. If I need a new voice coil I seem to be without options. Anyway, if any of you are still around, that's my input.
bowtie427ss
Lunatic Member
Old thread. I picked up a pair of 879A Santana's with 420A's sometime shortly after this thread died. Sent the 420's overseas, and re-purposed the boxes.
As i still have the original tweeters with their original 25V Callins wax sealed caps on them, i can concur they were indeed 14uf.
There's a post in another thread somewhere back in the AK closet that shows what i did with the 879A cabinets as they also have removable baffles.
As i still have the original tweeters with their original 25V Callins wax sealed caps on them, i can concur they were indeed 14uf.
There's a post in another thread somewhere back in the AK closet that shows what i did with the 879A cabinets as they also have removable baffles.
I had a 420Y that did this (slight rubbing), and since it was a situation where there wasn't much to lose (it already wasn't working properly)- I decided to try a rather unorthodox repair.
In my case- I surmised that the speakers probably had been stored in a damp environment- and the cones had gotten damp and had sagged a bit... so, my thought was- maybe a little of something like the proverbial hair of the dog might fix it?
I removed the dust cap, found the correct thickness plastic sheet to tightly shim the voice coil (between the coil and the pole piece), and gently spritzed water on the base of the cone, near the voice coil- not drowning it, but enough to soak in and slightly soften the paper. I took a heat gun, and gently heated the area, while it was still wet, to just about the point where it was uncomfortable to leave my hand on the paper (maybe 150 degrees F or so?). I then left the assembly, with the shim still in place, to dry for several days (until there was no question as to whether it was completely dry).
I pulled the shim out- no more rubbing. I carefully reinstalled the dust cap (I used a new one, as the original one had slight damage), and still- no rubbing.
Several years later, and apparently the speakers are still working properly, last time I heard.
I understand if this seems beyond the pale to some people- but it worked!
Regards,
Gordon.
alteclipsch
Super Member
Great idea!
Brave and brilliant solution there Gordon.
I have nothing to contribute to this thread other than the fact that I have 420Y's ]Edit: 420a, they don't have the tweeter] in my cobbled-together A7's in 828H cabinets. Originally had some heavy CTS woofers in there till I could find something Altec without breaking the bank, and the 420's popped up from another AKer. Much nicer in the midrange than the CTS were (xover at 1000 Hz to 811b horns with Renkus-Heinze drivers). All of which is to say that the 420 is a nice legit woofer in my book.
I have nothing to contribute to this thread other than the fact that I have 420Y's ]Edit: 420a, they don't have the tweeter] in my cobbled-together A7's in 828H cabinets. Originally had some heavy CTS woofers in there till I could find something Altec without breaking the bank, and the 420's popped up from another AKer. Much nicer in the midrange than the CTS were (xover at 1000 Hz to 811b horns with Renkus-Heinze drivers). All of which is to say that the 420 is a nice legit woofer in my book.
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Bill Murray
Active Member
Today I removed the tweeter and popped the dust cap. It is quite visible that the voice coil tube and the magnet do not line up properly. I tried manipulating the tube and the cone for several hours but the rub, if anything, got worse. Now I am wondering if I can remove the magnet by unscrewing the screw (tight as hell) and move it and the tube somehow to reach alignment. I hope it is just that screw that keeps the magnet on the basket !!
bowtie427ss
Lunatic Member
6 screws under the spider, or epoxy, or both.
If you take the screw out of the pole piece and loosen it from the rest of the motor assembly, it may(likely) adversely affect the magnetic charge of the alnico slug.
Don't remove the bolt! As bowtie says, it will destroy the charge on the alnico magnet- meaning it will, at the least, need to be sent off and re-gaussed! At the worst, it may shift and bind up the voice coil- at which time, it's probably just dead, unless it's sent off, un-gaussed, taken apart completely, the magnet re-set and re-glued, regaussed, and reconed (which is impossible as a 420Y, since there are no exact kits- it would have to be reconed as a 416 or something similar).
The procedure I mentioned, may still work. It's not something that can be done immediately- you need to take the time to let it dry and set- but if you want to take the time to do it, it may help.
Also- once you've taken the shim out- I usually take a piece of masking tape, and slip it between the voice coil and the pole piece, sticky side toward the pole piece, Run that all the way around the pole piece- and it will grab onto dirt that may be in there. That also helps get rid of an occasional rub.
Regards,
Gordon.
Bill Murray
Active Member
Gordon and Bowtie, thanks very much for the warning. It is a good thing I checked out this forum before I went back today determined to get the bolt out. I will not try to remove the magnet then, I will stick with trying to eliminate the rub by restoring the gap all around. This is getting very frustrating. I haven't yet given up on somehow reshaping the voice coil tube. When I removed the dust cap I ended up on the inside of the tube, in other words I haven't seen the coil windings so I don't know if they are OK or not. I suspect they are OK because sometimes my speaker sounds good..... for a little while. I can see the spots where the rub is.... about 2 o'clock and 9 o'clock, with the VC wires at 12 o'clock. Would there be anything to be gained by calling Great Plains and picking their brains ??
Bill Murray
Active Member
I am going to try your method. Put in shim where needed, wet base of cone short of saturation, dry with hair dryer until dry, then let sit (overnight?) then remove shims. Wish me luck.
Bill Murray
Active Member
GordonW I am going to try your idea again. I talked to Bill at Great Plains today and he said he is trying out the idea of making new biflex cones. So if his cones are made, I could recone with them, or I could also recone with a 416. I forgot to ask him.... do I buy the recone kit and do it myself, or do I send the speaker to him and he does it? However it works, I will try rewetting the cone again.
Bill Murray
Active Member
I think I said this somewhere else in AK, but in any case, I bought a 420 bi-flex cone from GA and re-coned and it sounds very good. GA did have bi-flex cones made, perhaps as an experiment, and I was the first customer (and maybe the only) to re-cone with it. That was prolly a year or so ago, and it still sounds great.
rider33
Active Member
old threads never die…
So I have a pair of Altec 879a (Madrid) with the tweeter strapped across the 420y.
For the most part, they serve as stands for my Bozak Symphonies as I was never that found of the high end. When I finally got around to recapping them (14uf, really?) I decided to disconnect the tweeters all together. You know what, that’s a much nicer sounding speaker w/o the little paper cone tweeter. I seriously doubt as the late, great Zilch observed they go that high but w/o the tweeter, what’s there is really rather nice. Perhaps one day I‘ll play with adding another tweeter but given the number of speakers I have now, I sort of doubt it. Anyway my point is if you have a pair laying about you might try disconnecting the tweeter (two spade plugs right in front). I get the impression whoever designed the 420y knew what they were doing and the cheap little paper cone tweeter was more of a marketing department thing.
So I have a pair of Altec 879a (Madrid) with the tweeter strapped across the 420y.
For the most part, they serve as stands for my Bozak Symphonies as I was never that found of the high end. When I finally got around to recapping them (14uf, really?) I decided to disconnect the tweeters all together. You know what, that’s a much nicer sounding speaker w/o the little paper cone tweeter. I seriously doubt as the late, great Zilch observed they go that high but w/o the tweeter, what’s there is really rather nice. Perhaps one day I‘ll play with adding another tweeter but given the number of speakers I have now, I sort of doubt it. Anyway my point is if you have a pair laying about you might try disconnecting the tweeter (two spade plugs right in front). I get the impression whoever designed the 420y knew what they were doing and the cheap little paper cone tweeter was more of a marketing department thing.
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Removing the tweeter turns it into a 420a, which was in the original santanas.
Absolutely sounds much better without those tweeters.