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

je2a3

Junior Member
Has anyone tried any phenolic diaphragms on they're 32 horns (like what was done with the original WE 753c)? @je2a3
The memorable WE753 experience I had was a 2-way version with a WE713A (aluminum diaphragm) compression driver. I had a chance to listen to another WE753 that supposedly had a phenolic diaphragm'ed compression driver but it wasn't a WE713B. The driver had a shorter (smaller) magnet, maybe a WE720A(?) and a Jensen RP302 super tweeter. I think this unit was botched up and should have had a WE713B + a WE752 super tweeter. This unit was not as impressive.
 
The memorable WE753 experience I had was a 2-way version with a WE713A (aluminum diaphragm) compression driver. I had a chance to listen to another WE753 that supposedly had a phenolic diaphragm'ed compression driver but it wasn't a WE713B. The driver had a shorter (smaller) magnet, maybe a WE720A(?) and a Jensen RP302 super tweeter. I think this unit was botched up and should have had a WE713B + a WE752 super tweeter. This unit was not as impressive.
Thanks for your recollections @je2a3.
I first listened to the 32 metal horn with my 9 metal element diaphragms in my Coral M100 drivers (almost the same as at the 2410 and 2420 JBL drivers). From memory they seemed to have more speed and clarity and a little more air to the phenolics.
But when i put the phenolics in i quickly forgot / lost interest in what the metal diaphragms did. The phenolic has enough of these things to still be wonderful in these areas but also added deep tone and timbre and a coherence to the Atec 414 16b I'm using.
Violins guitar string tone is wonderful on my reel to reel copies of master tapes and even trumpets/ saxophones just sound real. They don't seem to have that slight metallic hash/overtone and sizzle that metal diaphragms seem to have.

The next thing i want to try is the bakelite back plates that cover the diaphragms in place of the larger rear cap. Most people report that this was done to limit excursion on drivers and that it sounds worse but the 713 drivers had a similar cover back plate so i would like to try it and see what it does.
 
The memorable WE753 experience I had was a 2-way version with a WE713A (aluminum diaphragm) compression driver. I had a chance to listen to another WE753 that supposedly had a phenolic diaphragm'ed compression driver but it wasn't a WE713B. The driver had a shorter (smaller) magnet, maybe a WE720A(?) and a Jensen RP302 super tweeter. I think this unit was botched up and should have had a WE713B + a WE752 super tweeter. This unit was not as impressive.
Could you describe the sound of the 753 speakers (the memorable experience you had) How did the sound differ from what you have experienced with your 414 / 32/ 802 experiences? Where there large similarities or differences? Thank you.
 

je2a3

Junior Member
Could you describe the sound of the 753 speakers (the memorable experience you had) How did the sound differ from what you have experienced with your 414 / 32/ 802 experiences? Where there large similarities or differences? Thank you.
I don't think it is realistic to make a direct comparison to my present 414/614/802/32 system because I heard that WE753 almost 20 years ago. It was memorable because it was tonally similar to my main speakers then (OB/Altec 755A) but more extended at both frequency extremes and a lot more dynamic.

I've lived happily with my present set up for at least 8 years. But whether it measures up to that WE753 system can only be settled if I could compare them side by side.
 

marantzfan

Administrator
Staff member
Time to start putting together a shopping list for crossover parts, binding posts, dampening material, veneer, etc.

Starting with the crossover, what considerations need to be given, based on the fact that I have 16 ohm woofers and 8 ohm CD’s. I see that @je2a3 has shared a 16 ohm and an 8 ohm versión of the crossover. Do I choose the one which matches the impedance of the CD or do I need to marry the two somehow?

Probably a stupid question, but I’ve never spent much time learning the intricacies of crossover design.
 

TubeHiFiNut

Administrator
Time to start putting together a shopping list for crossover parts, binding posts, dampening material, veneer, etc.

Starting with the crossover, what considerations need to be given, based on the fact that I have 16 ohm woofers and 8 ohm CD’s. I see that @je2a3 has shared a 16 ohm and an 8 ohm versión of the crossover. Do I choose the one which matches the impedance of the CD or do I need to marry the two somehow?

Probably a stupid question, but I’ve never spent much time learning the intricacies of crossover design.
Since I have multiple 8 ohm and 16 ohm CDs, I plan on following the advice given by @J-ROB and use one of the Autoformers offered by @dave slagle as the level control on the horn.

Sould provide a constant load to the crossover so I can use either 8 ohm or 16 ohn CDs without having to swap out parts on the high-pass filter.
 

Wntrmute2

Junior Member
You can figure your values for each driver.
Decide where you want the crossover points. What order crossover. For instance 2nd vs 3rd. Butterworth 2nd order was my choice. Once you have those numbers you can plug them into a simple crossover calculator and the cap values and inductors are spit out. I have 16 ohm CD and two 16 ohm LFs in parallel equalling 8 ohms.
VH audio has a nice calculator here: www.v-cap.com/speaker-crossover-calculator.php#secondOrderCalculator
 
When I get around to it, I plan on using my 414Z full range (nothing between speakers and amp) with support on top with 32C/902 through single cap/L-pad per J-Rob. Bottom support with dual subs.
 

je2a3

Junior Member
Time to start putting together a shopping list for crossover parts, binding posts, dampening material, veneer, etc.

Starting with the crossover, what considerations need to be given, based on the fact that I have 16 ohm woofers and 8 ohm CD’s. I see that @je2a3 has shared a 16 ohm and an 8 ohm versión of the crossover. Do I choose the one which matches the impedance of the CD or do I need to marry the two somehow?

Probably a stupid question, but I’ve never spent much time learning the intricacies of crossover design.
Run your 414s full-range, use the cap values for the 8 ohm compression driver.

 

Wntrmute2

Junior Member
I tried the above crossover with less than stellar sound. It was easily bested by the N800-F clone but of course my set-up is different than Je2A3's. Jeff Mathers had good results with that set-up on two of his systems so be willing to try different things is my take home message.
 

marantzfan

Administrator
Staff member
I tried the above crossover with less than stellar sound. It was easily bested by the N800-F clone but of course my set-up is different than Je2A3's. Jeff Mathers had good results with that set-up on two of his systems so be willing to try different things is my take home message.
Thanks for the tip.

I was toying around with the idea of also trying the 9849 crossover as well for a side by side comparo before closing up the cabinet. We’ll see...
 
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