Altec 420 questions.

**Old Guy** · June 25th, 2012, 08:03 AM

I did 872b where the tweet mounts above the LF unit.
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**RonSSS** · June 25th, 2012, 03:39 PM

There is also a 420-8B. I have a pair. They came in the Santana model. The frame and magnet look like a 416-8B. Was a surprise when I removed them from the cabs.
Very nice drivers.
I actually tried them in my 19's.......interesting experiment. I know the T/S parameters are wrong for the box, but I wanted to see how the Biflex worked with the 1200hz X-over of the 19. It was quite nice. I should try it again this winter.
I actually like the Santana's though.

Ron

**charly1944** · June 26th, 2012, 04:03 AM

Hi Old Guy,
Thanks for the pics.Do you think the Vifa you used could be mounted in front of the 420 on the bar in order to keep the one point source advantage and do you remember what crossover schematics and components you used?
Charly 1944.

**charly1944** · June 26th, 2012, 04:56 AM

Hi RonSSS,
Interesting.Actually as i said before a lot of people have tried to change or add tweeters to their 420 and the suggestions vary a lot both in terms tweeter's location, type(compression,dome,ribbon...) and crossover frequency.I have so many problems with the cross over of my 604 D that i hesitate getting involved in a new crossover adventure!That why i try to get specifics about optimal crossover design and components for a selected tweeter before pursuing.
Charly1944.

**Old Guy** · June 26th, 2012, 08:21 AM

Originally Posted by charly1944

Do you think the Vifa you used could be mounted in front of the 420 on the bar in order to keep the one point source advantage and do you remember what crossover schematics and components you used?

I doubt it. Looks like the curved part on the back of the tweet will interfere. I just did a 'textbook' crossover, you could likely do as well with a pre-made. I used 3 kHz.

**charly1944** · June 26th, 2012, 09:54 AM

Thanks OG,
I would not know how to build a" text book" crossover.Too bad.
Regards,
Charles.

**RonSSS** · June 26th, 2012, 02:18 PM

The crossover in the Santana is a capacitor. That's all.

**Old Guy** · June 26th, 2012, 03:11 PM

Ron is correct. Better than just a cap would be this unit from PE

Crossover High-Pass 8 Ohm 3,000 Hz 100W 260-174

Replace the cap though- electrolytics are awful, even a cheap 3 dollar polyester or polypropylene cap is better

Dayton Audio DMPC-4.7 4.7uF 250V Polypropylene Capacitor 027-422.

A good beginner site for DIY, car stereo oriented but the physics are the same.
Passive Crossover Networks

The reason I suggest using the 12 dB/octave instead of a cap which is only 6 dB/octave, the Vifa is slightly horn loaded. The Vifa has about 6 dB more in the 10-20K octave than the original tweet, they sound much more "open".

**charly1944** · June 26th, 2012, 04:49 PM

Thanks,
Very practical and inexpensive suggestions.I think i can go and hunt for a good pair of 420 and start getting ready for buiding big boxes.All that is going to take me a little bit of time but that is fun.Thanks again for your help.
Charly 1944.

**kwingylee** · July 13th, 2017, 08:42 AM

Originally Posted by 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.

I know this is an old thread but maybe there is still interest on the Santana/420A driver. I picked up a set of the 420A drivers on the cheap a few years ago and finally put them in a pair of 828 cabinets. Like others on this thread, I tried them with different tweeters such as JBL 2404H, EV T350s etc. I used an EV Merlin ISP-100 crossover to best match the tweeters to the 420A/828 combo. The sound that yield the most phenomenal results was putting a 1000Hz LeCleach horn on top of them with a TAD2001 driver. Crossing over them at 3300Hz with a third order butter worth filter, the voices sound absolutely real. Myself and people that have heard this combo are amazed my the quality. I know this is an overkill, so this weekend, I am swapping the TAD out for cheaper drivers (ex. 902-8B) to see if I can get similar results.

Awhile back there was a gentleman on ebay selling an quasi A7 system using 420A woofers in a 825 cabinet, 511B horns with JBL drivers and ESS tweeters. He was asking very high price for the combo....but maybe he was onto something..