Altec 2 Way Build ala JELabs - 802/32/414

Discussion in 'High Efficiency' started by marantzfan, Mar 8, 2018.

  1. New member to this forum but a long time Altec groupie. I've been running GPA 414's with GPA 802's on 32 aluminum horns for a few years. I use a derivative of the Joe Roberts first order high pass idea and full range on the woofers. I recently stepped up my game with a set of Petite Onken cabinets. Nothing really petite about them. Couldn't be happier with the results. I have several other CD's and horns that I swap around with the 414's but keep coming back to the 802/32 combo. Really fun stuff.

    You guys have a great forum going here. Lots of good info and friendly people. IMG_2547.JPG
     
    SPL db, Bernie, rogerfederer and 9 others like this.
  2. Beautiful cabinets Mike414!
    Very well done. I thought about building Onkens but never did. What were you using before and what differences did you notice?
     
  3. Thanks

    I had Barzilay cabinets of about 3.5 ft3. I cut a slot port in them at around 40Hz tuning. They may not have been optimized. The Onkens go lower with much more authority. I’m still getting used to them and I may have some new speaker bias. They are visually stunning, which also enhances the experience.
     
  4. TubeHiFiNut

    TubeHiFiNut Administrator Staff Member

    Gorgeous speakers @Mike414 :)

    First rate work!
     
  5. J-ROB

    J-ROB Senior Member

    Nice Onken! If my most recent Petit Onken cabs looked as good, maybe Joyce wouldn't have made me sell them.

    Hey they were free , ya know. So what if there were animals living in them in my friends barn?

    Anyhow, that combo with my eponymous one part crossover sure worked out great here. Very organic and natural.
     
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  6. je2a3

    je2a3 Junior Member

    Welcome to the club @Mike414 and beautiful Onken!
     
  7. marantzfan

    marantzfan Administrator Staff Member

    And I just bought a pair of 808-8b’s (with Manta Ray horns, that I may use later on another project) for the princely sum of $200.
     
    je2a3 likes this.
  8. TubeHiFiNut

    TubeHiFiNut Administrator Staff Member

    That's the spirit! :)
     
  9. marantzfan

    marantzfan Administrator Staff Member

    Those are gorgeous! I’ve always loved the look of the Onken cabinets.
     
  10. Audionut

    Audionut Next Round Is On Me

    You could totally build a set of cabinets like those!
     
  11. Audionut

    Audionut Next Round Is On Me

    Cough, cough..enabler...;).
    I keep telling myself I won’t be roped into this one. No shenanigans here! (As I start shaking and sweating profusely..)
     
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  12. je2a3

    je2a3 Junior Member

    Good buy! :smile:
     
    marantzfan likes this.
  13. marantzfan

    marantzfan Administrator Staff Member

    Ok. So, to convert the 808-8B’s to 802-8G’s, I need to lose the loading caps. Line the rear cap with felt and swap out the symbiotic for some new GPA diaphragms. Easy enough.

    Question though, does it matter what kind of felt I use? I see some in ebay that comes with a peer and stick backing. Seems those could easily be cut to size then just stuck in.

    Or, is there a preferred type of felt or method I’m just not finding anywhere?
     
  14. J-ROB

    J-ROB Senior Member

    I have some 1/4" thick wool felt that I can send you. It is denser than what Altec used but will probably work fine. PM address if you want some.

    You will also need shorter diaphragm screws since the ones from 808s are quite long in order to go through the loading cap, then the diaphragm surround.

    One option is to send them to GPA, who will provide felts, screws, remagnetize if necessary and install diaphragms for no additional charge beyond diaphragm price, plus return shipping.

    I have trashed two Altec diaphragms installing them over the years. Yeah, I'm a klutz. It is almost worth it to me to send to GPA so avoid the risk.

    If you do it yourself, hold the screwdriver tight, because it will really want to fly out of your hand and penetrate the nice virgin aluminum dome, so to speak! Last year I trashed one NOS 70s diaphragm trying to slide it onto the locating pins

    I'm thinking about picking up a non-magnetic philips head screwdriver if I can find one before installing expensive and ever more scarce NOS JBL 2440 diaphragms!

    One advantage of field coil drivers is you don't have to worry about magnetism when installing diaphragms.
     
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  15. marantzfan

    marantzfan Administrator Staff Member

    You know... When you put it that way, I’m probably better off just sending them to Bill. I didn’t realize he did all that for just the cost of the phrams.

    Plus, wouldn’t hurt to have them looked over and regaussed.

    Thanks @J-ROB
     
    ICTWoody likes this.
  16. ICTWoody

    ICTWoody Junior Member

    Getting excited. My buddy just sent me this pic. Going over after work to check out the progress. 3/4" Baltic. Lap joints. True to the original plans. Considering a chamfer on the woofer opening since my 414's will mount from the rear.

    I have all the other parts. Just waiting on the boxes to be finished.

    - Woody

    54317750060__6DAC17F6-72AF-47CA-9D6A-5E4940F116E6.JPG
     
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  17. marantzfan

    marantzfan Administrator Staff Member

    Looking really good! I’m getting close to the point where I’ll be building cabinets... little by little.

    How are you planning to finish them?
     
  18. ICTWoody

    ICTWoody Junior Member

    We're going to talk about finish tonight. He said this batch of baltic has some nice figure and he could finish them to make them look "holographic." I don't doubt it, he used to be a cabinet maker for Bombardier Aviation doing the fancy cabinets for 20+ million dollar jets.

    Since my place is pretty MCM, I'm definitely keeping the ply edges exposed, but I was considering a veneer on the top and bottom and sides... we'll see.

    - Woody
     
  19. J-ROB

    J-ROB Senior Member

    Definitely put a wide round over on the woofer cut...if you don't the thought will haunt you forever.
     
    mhardy6647 likes this.
  20. je2a3

    je2a3 Junior Member

    Nice cabs Woody!
     
    ICTWoody likes this.

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