Altec Baby... coaxials. 601C’s

Salectric

Senior Member
I would try the GE bathtub caps first, then the Russian caps. I don’t think the oval GEs will sound as good as the other two, but of course you can try them all and reach your own conclusions.

I don’t know anything about the Altec wire, but I would certainly try it before the Duelund. I have not had good results with any type of Duelund wire.
 

Thermionics

Post Whore In Training
Caps with PCBs sound best. If the cap has any leakage, I would certainly replace it but this is unlikely unless it has been abused. And if you do replace it, get another vintage cap with PCBs. To be on the safe side I mount mine with the terminals facing up.
I'm surprised to hear this, given the mystique around the Sprague Vitamin Q caps (which did NOT contain PCBs).
 

ICTWoody

Junior Member
So I made some progress and had a little setback.

Progress was I got the 2nd driver mounted. Just need to pick up some flange nuts and lock washers tomorrow at the hardware store.

I decided to work on the networks. The setback was once the variable resistor was back in the network enclosure, there was no good way to mount the GE bathtub caps. So, I just decided to use the Russian caps since they were small and had nice terminals to solder to.

One thing I wasn’t sure of, since the old stuff was kinda potted in there, is does the inductor need to be isolated from the metal enclosure? It was in the tar crap before. I was able to use all the existing wires. I used some HD hot glue to mount the cap and also the inductor. I used a pretty good glob one the inductor so I’m sure it’s isolated either way.

The only thing left on the first network is I don’t know if the white or brown wire is the positive input? HELP. Im so bad with schematics. Here’s pics.

- Woody

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ICTWoody

Junior Member
I don’t know anything about the Altec wire, but I would certainly try it before the Duelund. I have not had good results with any type of Duelund wire.
Really? I’ve had good luck with the Duelund. My Onkens are fully wired with it as well as using it for speaker wire and ICs. Full loom I guess. It’s what I used from binding posts to the 414’s that were in these 614 cabinets.

The Belden I have as well and I find it noticeably rolled off and soft sounding. I don’t really use it anymore.

- Woody
 

Salectric

Senior Member
Really? I’ve had good luck with the Duelund. My Onkens are fully wired with it as well as using it for speaker wire and ICs. Full loom I guess. It’s what I used from binding posts to the 414’s that were in these 614 cabinets.

The Belden I have as well and I find it noticeably rolled off and soft sounding. I don’t really use it anymore.

- Woody
A lot of people like Duelund wire but it hasn’t worked for me. I would describe it somewhat like you described Belden—-rolled off at both ends, soft on transients, and lacking inner detail. A few years ago I tried Audio Note Litz wiring and I have never been tempted to try anything else. Their Lexus copper Litz wire has a warm tonal balance somewhat similar to Duelund but with more extended bass and treble and, most important, more see-through inner detail and better microdynamics. Lexus requires a solder pot to strip off the insulation on all the conductors so it isn’t as easy to terminate as Duelund but the process is pretty easy once you’ve done it a few times. I use Lexus for all of the internal wiring of my speakers and crossover connections.
 

ICTWoody

Junior Member
Interesting... I've found it to be very nice in my system. Maybe I'll get back to rolling wires... but for now I'm content with it.

Now... who can confirm that white is the POSITIVE wire to go to my RED binding post?

- Woody
 

Wntrmute2

Junior Member
It actually doesn't matter unless you are 100 percent sure that your phono-stage, preamp nor amplifier inverts phase. Hook it up either way and listen for a difference when you swap the speaker cables.
 

ICTWoody

Junior Member
It actually doesn't matter unless you are 100 percent sure that your phono-stage, preamp nor amplifier inverts phase. Hook it up either way and listen for a difference when you swap the speaker cables.
Really? The polarity in the network doesn't matter? I mean... what is the most correct? I really need to learn more about EE.

- Woody
 
I agree that it really doesn’t matter, as long as you connect them both the same way.

I suppose the white wire is the more correct positive input. The LF driver is run full range with the white wire going to the +terminal. For the HF driver there is a second order high pass, fed from the white wire, with an EQ thing and the driver is wired with reverse polarity. The second order high pass creates a 180 degree phase shift and the reverse polarity at the driver corrects for that shift to better phase align with the LF driver.
 

ICTWoody

Junior Member
I agree that it really doesn’t matter, as long as you connect them both the same way.

I suppose the white wire is the more correct positive input. The LF driver is run full range with the white wire going to the +terminal. For the HF driver there is a second order high pass, fed from the white wire, with an EQ thing and the driver is wired with reverse polarity. The second order high pass creates a 180 degree phase shift and the reverse polarity at the driver corrects for that shift to better phase align with the LF driver.
Awesome! Thanks for the clarification. I could see the LF driver was running full range... so I was inclined to go off that. I also notice that it seemed that the tweeter was out of phase, and your explanation of the network makes sense to me. Thanks. I'll do it the "more correct way." Haha...

- Woody
 

Salectric

Senior Member
I have never found absolute polarity to be important sonically. But relative polarity is very important. This arises two ways.

First you certainly need the two channels to be matched in terms of polarity. That’s pretty obvious with woofers but it applies to midrange and tweeters too. And sometimes vintage drivers have incorrect or inconsistent labeling. I once listened to some DIY speakers for several months before discovering the tweeters were out of phase with each other. Once I reversed the polarity of one tweeter, imaging was better even though the sound itself hardly changed.

Second, within each speaker you need to pay attention to the relative phase of the different drivers. For example woofer—midrange, and midrange—tweeter. For 2d order filters, the midrange polarity should be reversed relative to the woofer, but you can’t just assume the markings on the drivers are consistent. Some manufacturers mark the (+) terminal consistently across their models, but not all do, and different mfrs may use inconsistent markings. The bottom line is you have to test each combination. What I have found is that with 2d order crossovers changing the relative polarity of the woofer and midrange definitely affects the sound, but which way is correct? Each way can sound quite decent; there’s nothing obviously wrong with either one. With 2d order (12db) crossovers, the “correct” relative polarity is when there’s a slight dip in the crossover region. The “wrong” polarity has a slight peak in the same area. But with a particular speaker, you might actually prefer the “wrong” polarity so you need to listen both ways.
 

ICTWoody

Junior Member
Made some progress last night. Would have had them buttoned up, but the studs I installed (hanger bolts with 1/4" wood screws on one end and 1/4-20 Machine on the other) worked perfect, the standard nuts I got fit so close to the basket that I couldn't get my socket on them. I'm going to pick up some long coupling nuts today to make it easy to put them on.

Got the 2nd network buttoned up and mounted on the back. Was able to use all the original wires... networks are as stock except for the Russian cap in place of the questionable originals.

Reglued on the one piece of fiberglass batt that had come unglued from the top of the cabinet. I like the fiberglass on opposing sides of the interior - that is top, side, back... but if I did it over I'd put the batt's on the bottom instead of the top so it wasn't fighting gravity.

I have some knobs which will be here today for the HF Attenuator since the original ones were missing when I got them.

I figure in about 20-30min this weekend I'll have them wrapped up and will be able to give them a listen. Pretty excited to experience my first Altec Coaxials. Hopefully they'll tie me over until cabs for my 604's are done.

I'll post pics when they are done.

- Woody
 

UncleBingo

Senior Member
I like to maintain absolute polarity for the woofer (if the tweeter is inverted or not). I don’t want a transient bottoming-out the voice-coil.
 

ICTWoody

Junior Member
So I have run into a little issue. Hopefully it's little...

I hooked them up yesterday and immediately noticed that the right tweeter was not working... or seems to be not working. The left variable resistor in the other speaker seems to work, mostly but when I turn it to "0" where it clicks (I assume to bypass it) it is clearly working, but the one in the right speaker seems to make no difference and clicking it to "0" seems to still not produce any results. I haven't pulled the backs again, but measuring the DCR at the binding posts each speaker registers a DCR of 5.5-5.6. I would assume that if the VC on one tweeter was open that would register differently?

The tweeters were checked by bill when I dropped them off at GPA, and so I didn't check them individually when I got them home cause I assumed they were working fine after he swapped the bad one.

I'm hoping the variable resistor is the issue.

Any thoughts oh wise ones?

- Woody
 

Thermionics

Post Whore In Training
So I have run into a little issue. Hopefully it's little...

I hooked them up yesterday and immediately noticed that the right tweeter was not working... or seems to be not working. The left variable resistor in the other speaker seems to work, mostly but when I turn it to "0" where it clicks (I assume to bypass it) it is clearly working, but the one in the right speaker seems to make no difference and clicking it to "0" seems to still not produce any results. I haven't pulled the backs again, but measuring the DCR at the binding posts each speaker registers a DCR of 5.5-5.6. I would assume that if the VC on one tweeter was open that would register differently?

The tweeters were checked by bill when I dropped them off at GPA, and so I didn't check them individually when I got them home cause I assumed they were working fine after he swapped the bad one.

I'm hoping the variable resistor is the issue.

Any thoughts oh wise ones?

- Woody
Have you tried swapping the crossover from the working speaker to the non-working speaker? That should tell you what is broken.
 

ICTWoody

Junior Member
Have you tried swapping the crossover from the working speaker to the non-working speaker? That should tell you what is broken.
I haven't done anything yet. I discovered the issue and then had to leave cause I had stuff going on. Haven't gotten back around to it yet. Hopefully sometime this week. Time is in short supply these days. Just was hoping it was all going to work perfectly. I'm an eternal optimist.

- Woody
 
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