ALK modular networks AP12 and ES

[Deang]

"After removing a glued-on copper-coloured circle, I can see K-55-V. How do i know whether it's a dual phase plug/solder lugged or single phase plug?"

Peter, if the driver has those spring loaded jobs that push down to put the wires in -- that would be the single port phase plug design. If the wires are soldered to the driver, then it's the dual phase plug design.

[psg]

"After removing a glued-on copper-coloured circle, I can see K-55-V. How do i know whether it's a dual phase plug/solder lugged or single phase plug?"

Peter, if the driver has those spring loaded jobs that push down to put the wires in -- that would be the single port phase plug design. If the wires are soldered to the driver, then it's the dual phase plug design.

Thanks Dean, spring-loaded it is. []

Guess that means I might benefit from a 4500 Hz crossover. It sounds like I might like the Type-A modded to 4500 Hz. In that design, does the mid-horn still run free at high frequencies? Or does it have a low-pass filter such that it doesn't step on the tweeter's output in the range of 4500 Hz to 6000 Hz? It seems to me that we don`t want both playing...

Given that I`d to try the 4500 Hz crossover frequencies, does either the modded Type-A or ALK Jr turn out to be a much better choice?

[Deang]

There is a low pass on the squawker in that design -- just a single .50mH coil that runs between tap 4 on the autoformer and squawker positive on the terminal strip.

All of this stuff is so subjective, that's why it's so difficult to give solid advice, and why for the most part I just don't say much about it anymore. Things get especially complicated when you factor in the different gear people run and the varying listening habits. I suggest starting with the Type A mod because it costs the least, and is extremely responsive to parts upgrades.

[psg]

Many, many thanks Dean.

I know it's hard to give advice, but yours is very much appreciated! [Y]

[mark1101]

PSG, I don't think I read what your reason was for wanting to change out networks. You have recapped AAs now.....I read that. So what's wrong? What don't you like and what are you attempting to do? If you already posted this stuff I'm sorry.

[psg]

There's absolutely nothing wrong. It's all good.

But it was all good too because I recapped my AAs and discovered how much better they sounded then.
I will kick myself if I wait 10 years to find out I was a hundred dollars away from even bettr sound.

But to be honest, it sounds amazing to me now.

[mark1101]

Well that is good information. Then I would further suggest you look at the ALK JR or ALK universal once again. Not exactly a $100 upgrade but worth the extra you will pay and if you like the stock AA you will love the ALKs. Why would you want to experiment with changing crossover points?

[psg]

Well that is good information. Then I would further suggest you look at the ALK JR or ALK universal once again. Not exactly a $100 upgrade but worth the extra you will pay and if you like the stock AA you will love the ALKs.

Interesting point. Thanks.

Why would you want to experiment with changing crossover points?

Because I have CT-125 tweeters and everyone raves about how much better they sound than the sqwaker for that frequecy range.

I'll admit that the two simple solutions are (1) order parts and build an A-type or (2) buy the ALK Universal kit and built it (no hard-to-find parts to chase down).

[mark1101]

I have used CT-125s in all my Heritage speakers in the past and I currently use them in my MWM setup (avatar) with an ES5800 crossover. I really like the way they sound with my current setup. I tried them at 5000 and I can't really hear any significant differences between 5000 and 5800. I have not experimented much with tweeter crossover points though.

If you are a handy guy networks are easy to DIY. The most important point is to use good components and be sure they are all matched sets so each network is identical.

There is another good point to going with something like an ALK JR or ALK universal. Resale. They are standard nets that everyone can use and will offer you a chance to experiment further later on for less money.

[psg]

Thanks Mark! All good points!

[Erik Mandaville]

"Thanks Dean, spring-loaded it is. "

That is nevertheless a very good driver, and I would not give undue worry about it. There have been reports of a peak in the response on some of those drivers at around 9kHz, and even then some inconsistency was found. Series notch filters have been used for a long time, and one was developed for just this problem (if it is a problem). It's a frequency discriminating device referred to in Klipsch applications as the 'P-Trap'. Easy to make if needed, which I did with my K-55s, and found no difference whatsoever. I've compared some notes with others with the same driver, and they also had no problem.

The 4.5kHz modification is called a 'bandpass', which is needed since an acoustic roll-off of the squawker is not used because of the lower crossover point for the tweeter. The inductor in series after the autoformer (on Bob's design) operates at the higher frequencies to block highs to the driver, where the capacitor (in front of the autoformer) functions on the low end. Very simple modification. With the Bob's tweeter, you can go as low as 3.5kHz.