Model 19 crossover caps

[sburke]

Thanks Ron. The pegboard has the added benefit of allowing for ease of routing the wire.

All six inductors cost me around $120 from Sonic Craft. This is a while ago so prices may not be the same now.

All told I have around $225 in the pair plus my time.

[Earl K]

Hi Ron

What do mean by " They were painful" when you refer to the "Zens" that you tried out ?

I've wondered about these caps - so, any insights gained by hands-on experience would be much appreciated . ( The "copy" on the NorthCreek website says all the right things .)

<>Earl K

[GM]

Greets!

> Anyway, the point I'm trying to make is that I think horns are really revealing, and the caps will have a great effect on what you hear.
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Ya think! Those who don't learn from history are doomed to repeat it! PIO caps, accept no substitutes! There's a reason the pioneers of all things electrical chose this construction and it wasn't cost! http://members.aol.com/sbench102/caps.html
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>Coils:
I didn't try different coils. Too much money for the flat wound coils. But how about simple wirewound air coils? We can make those ourselves.....
====
Magnet winding wire is the best wire us mere mortals can afford and is cheapest when bought in bulk, so beg/borrow/buy a decent inductance meter and head on over to the appropriate wire distributor and get buddy-buddy with a salesperson so they will let you measure spools of whatever gauge(s) has ~ the series R you want, picking the ones that measure a bit high so that you can later unravel/measure it to find the exact inductance rather than settling for 'close enough'.

If you think you can audibly improve on their winding quality, then there's on-line and downloadable spreadsheets to calc them so you can 'roll your own'.

Use the scrap for your other wiring, the proper use/gauge selection of which requires a lengthy post of its own when I have the time. There's a good technical reason why Altec used tiny hook-up wire to the horns.........

GM

[GM]

Greets!

I'm saying that ideally all caps in the entire audio system would be PIO, but price/availability ain't what it once was so yes, they should at least be in any network after the amp.

If you mean electrolytics, aluminum.

GM

[RonSSS]

Hi Earl,
By painful I mean that the sound got real edgy and sharp. This was on my Duplexes. So I put the stock caps back in the HF path only, and was happy. I didn't mess around with reversing the polarity on the caps.
It was frustrating because the Zens, although cheaper than some high end caps, still cost me over a hundred bucks, and more than a few hours installing them only to not like the sound. And it's doubly frustrating because maybe there are better caps to be used, but the cost of experimenting is just too high.

GM....Ya think?
How about teflon.....now that could get into really big bucks....and realy BIG crossovers.
I have a great capacitance bridge, and have access to a many thousand dollar HP inductance bridge, so winding coils is not a problem. Well, the actual winding is a pain......but a guy could rig something up with a slow motor and the correct bobbin.

sbb....I actually found a source for the Goertz inductors less than a hour from where I live.

Fun Stuff!
Ron

[Earl K]

Hi Ron

Thanks for that insight. It's good to know that the Zens aren't the answer to compression driver caps . Still I'd like to hear them / dc biased before writing them off .

I haven't bought any of the new PIO types - simply because of the cost . But mostly, I've been able to get very nice results with bypassed MPP(s) in oil .

- Right now those ASC caps that sbb displayed are getting a lot of press ( even for use as power supply caps in SET amps. )

<. Earl K

[DonM]

GM,

Are you saying that the Paper-in-Oil (PIO) is a good choice for an Altec crossover capacitor?

Following that thought do you recommend the DC with aluminum or copper?

I have noticed that many others refer to Solen and Auricaps.

Don M

[RonSSS]

I just got a pair of N1201-8A crossovers from Ebay. These are identical to the Model 19 crossovers, with the exception of 2 resistors that have been changed from 3.9 to 4.0 ohms. Which I doubt is significant at all.
Cap and inductors are the same between the two.
Anyway, one of the units is pristine, the other a mess. One of the 8uf caps had been blown up...real good...... and repalced with junk drawer electrolytics. There was paper shrapnel all over the insides. I should have asked about the condition before bidding......
I wonder how in the **** one could blow up a crossover cap! I'd hate to see the horn driver.
So this will give me a chance to rebuild these with better/different parts and experiment.
I'll take the inductors to work and measure them to see if I get the same numbers on the schematics. I did measure a few of the caps, and they were actually within spec!
Ron

[Richard C.]

Hi all,

I looked at the capacitor test on the O-scope and read that he used about 26 ma of current. I feel the test for crossover caps should be ran at about 100 times more test current (2.6 A). This would be much closer to the max current seen in a filter that has an attenuator after the cap. I have used 25uf caps that have axial leads no larger than the .1uf cap used in the test! I haven't broken one of the big ones apart to see how the leads are attached to the foil, but I think it would make you wonder how good they really are. Several smaller caps(5uf or so), would probably be better considering how much current can flow.

I can see where motor run caps could be much better at handling the high current (low internal resistance).

Richard C.

[Richard C.]

Hi Again,

Here is a informative link to the American Capacitor Corporation:


Capacitor Technical Terms

(ESR)Equivalent Series Resistance and (DF)Dissipation Factor are very important, and it is difficult to find these specs on typical caps used for crossovers. However good motor run caps would usually have these specs available to compare to the other types. Good luck in finding this data for your favorite cap!

Richard C.