Results 1 to 6 of 6

Thread: Altec 1234 restore help needed

  1. #1
    Junior Member
    Join Date
    Oct 2017
    Location
    Tennessee
    Posts
    5

    Altec 1234 restore help needed

    I am rebuilding a pair of 1234's. I cant find a crossover schematic for these. There is a number on the aluminum crossover plate 391922. I have installed a cheapo diaphragm from EBay in one horn. I see there is also a set available from people who claim to be using Altec equipment to build them now but 10 times the price. I went ahead and installed one diaphragm tonight and it ohms at 6.3 and sounds good with the sweep generator. The woofer sounds good but I get basically nothing out of the HF side. Before I just switch things around I want to know what goes where first. The one crossover has red,wht,grn and blk wires and from what I read rd to pos horn wht to neg horn grn to pos woofer and blk to neg woofer. The other crossover has a white wire where the grn one is on the other crossover and all the wiring looks really undersized. Original caps in here and I only checked the end one of I believe 6uf and it was OK. I stopped there and did not test the others.

    Before I start testing all the caps I thought I would ask here and see if perhaps the diaphragm might be the problem. A schematic would be nice to if anyone has one. I lean towards a cap myself since they are well over 20 years old. I think the caaps should be 28, 10 and 6uf but I am not sure.

  2. #2
    Junior Member
    Join Date
    Oct 2017
    Location
    Tennessee
    Posts
    5

    Bump

    If anyone knows the answer or who does know or where to go online for an answer please respond. I have Altec parts in my shop waiting on information.

  3. #3
    Senior Member spkrman57's Avatar
    Join Date
    Feb 2005
    Location
    Columbus, Ohio
    Posts
    2,018

    Is that a electronic bi-amp or passive crossover?

    I have a pair of Altec N501-8A passive crossovers if you need passive.

    Send pics if you can so we can see it.

    Regards, Ron
    JBL Pro for home use!

  4. #4
    Senior Member gdmoore28's Avatar
    Join Date
    Jan 2014
    Location
    Arkansas
    Posts
    245
    427, Earl, or some of the other Altec experts will know exactly which crossover you have and how it needs to be wired. You need to post your enquiry on the AudioKarma site, as they and others seem to respond a little faster there. Otherwise, hold tite for a bit and one of them will see your post.

    Good luck.

    GeeDeeEmm

  5. #5
    Junior Member
    Join Date
    Oct 2017
    Location
    Tennessee
    Posts
    5

    1234 update

    here are pics of the crossover.Name:  DSC_0001.jpg
Views: 537
Size:  88.0 KBName:  DSC_0003.jpg
Views: 631
Size:  87.5 KB

    I have replaced the diaphragm both of which were toast and used a Chinese knockoff part commonly found online. There are also some at ten times the price made on old Altec equipment. I have no idea of the difference between these two for sound and would REALLY like to hear from users who have tried both to know.

    Recapped the crossover and it is a different sound than I am used to with my La Scalas. It seems as though the sound is improving over the course of a couple of hours after I got it all back together and fired it up and they are pretty darned good especially with classical organ and Stevie Ray Vaughn.

    So any suggestions as to what would improve the sound quality further?

  6. #6
    Senior Member gdmoore28's Avatar
    Join Date
    Jan 2014
    Location
    Arkansas
    Posts
    245
    1. I can't find the references now, but I've read two reports on the Chinese diaphragms where they were tested and diagnosed. The results were that they are not suitable for the sometimes low crossover frequencies Altec used (500-800Hz), but from 1200Hz and up they were acceptable. Long term reliability, though, is an unknown at this point.

    The GPA diaphragms you referenced are top notch and exceed the performance of the originals. And, yes, they are made by former Altec folks on Altec machinery. There is also the Radian brand. Also made in the USA, get great reviews, and about the same price as the GPA diaphragms.

    2. Sound improvement: your next logical step is to install the Altec 30923 equalizer network between your crossover and the horn. The network is cheap and easy to build and will make one of the most significant contributions to a hifi-like response that you can perform. (It consists of only three resistors and one capacitor. Do a search and you will find the schematic.)

    GeeDeeEmm

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Questions on an Altec 1234
    By rockman in forum Lansing Product Technical Help
    Replies: 3
    Last Post: 11-01-2017, 12:03 PM
  2. Altec Lansing 1234
    By netminder60 in forum Lansing Product General Information
    Replies: 9
    Last Post: 02-13-2015, 05:42 AM
  3. altec/bms project help needed!
    By stuck.wilson in forum Lansing Product DIY Forum
    Replies: 2
    Last Post: 11-23-2008, 04:05 PM
  4. Altec Valencia Help Needed
    By DanTana in forum Lansing Product Technical Help
    Replies: 18
    Last Post: 07-05-2005, 04:54 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •