Altec 420 questions.

[charly1944]

Hi guys,
Few days ago,i had the opportunity to listen to a pair of Altec 420 in 11cbf BR cabinets 2 vents of about 4 inches diameter in each speaker and 2 good tweeters(JBL2405).
To me it sounded great , with very natural timbres,a lot of homogeneity in the music,very convincing bass and finally much more musical,if less spectacular, that my 604 D.I tried to look for information back to 2010 about the Altec 420 on the site but did not find any.Any reason why nobody talks anymore about these full range drivers?

[Old Guy]

There is no recone kit available, so if damaged they have to turn into 416's. 420 is a good speaker, just not as common, and get less so with every blown one or torn cone. They do not go as low as 416. So the chance of their following getting bigger is quite low.

[Altec Best]

Yup no new cone for them.They don't handle lots of power either.. They are For low power amps,like tube amps. I like the sound of the 420 BiFlex speakers. If you ever find a pair of Madrids with original speakers they should have 420's in them Y maybe 420-Y's.. They have very good clarity IMHO.

http://altecpro.com/pdfs/vintage/Spe...%20Speaker.pdf

[charly1944]

Thanks to both of you for your fast replies.Any difference between the 420-A and the 420-Y?
Charles.

[Old Guy]

Isn't the Y the one with the tweeter on the front? The Z is OEM version, no mag cover.

[Altec Best]

Yup the tweeter has a bracket over the woofer section.Here are a couple old threads with folks that have had some experience with them.

http://www.hostboard.com/forums/f700...ew-member.html

http://www.hostboard.com/forums/f700...t-updates.html

http://www.hostboard.com/forums/f700...pressions.html

[charly1944]

Thanks a lot for taking the time to send me these threads.They pretty much answer the questions i had about the differences between 420-A and 420-Y.On top of it in "Altec 420 Biflex listening impressions "our good GM gives suggestions about the desired cabinet dimensions.Funny enough,what he calls the "small boy" is not very far, in terms of volume, from what i have listened to.The proportions and the vent are different though.
I would be interested if some members could suggest appropriate tweeters to replace the stock ones and at what ideal frequency the 420 should be cut in order to operate on what it does best.In the different threads i have reviewed it varies between 2500 hz and 10 000hz with very different types of tweeters suggested so i am a little bit at loss.Any experience on this topic would be welcome.
Charly 1944.

[Old Guy]

I did a pair a while ago...used these...

Zaph|Audio

It's 4 Ohm...so a series non inductive resistance is needed..

Vifa BC25SC06-04 1" Textile Dome Tweeter 264-1028



Dayton DNR-3.7 3.7 Ohm 10W Precision Audio Grade Resistor 004-3.7

I would trash the original xovers and build new. I used the stock 3 khz

[Altec Best]

Nice job OG !

[charly1944]

Thanks Old Guy,
This is very useful information in few words and pictures.Within the selected tweeters in the comparison the Vifa BC 2506....seems to fit pretty well in the picture and are indeed very inexpensive.Few questionsid you fix them in the center of the speaker on the metallic(?) bar ( the way they are in the stock 420-Y) or on the front baffle and, if this is the case, where.
Regarding the crossovers,i understand they were cut at 3 khz,i could easily trash them but dont have the ability to redesign a cross over.I can though change the original components for better one keeping the same values.Is that what you mean by" rebuiding" or do they require to be redesigned?
Last,what type of enclosure did you use:BR,Sealed or OB?
Thanks again,
Charly1944