Mod thoughts, regarding stock ALTEC Model 19 crossovers.

[juniper]

Low ohms, my m19s came with xovers that copy the original but use foil and air core inductors, audio cap Thetas, Dayton caps and mills and Dayton resistors. The weird thing is that they still use the m19s attenuators. They do sound better than the original ones i have and measured a little flatter. It's a shame you don't have the time for a new project. I have heard a7s a couple of times and although the midrange was great, I prefer the m19s by a big margin. One thing though the two sets of a7s were not modded and were using unacceptable eq. Good luck!!!

[LowOhms]

Low ohms, my m19s came with xovers that copy the original but use foil and air core inductors, audio cap Thetas, Dayton caps and mills and Dayton resistors. The weird thing is that they still use the m19s attenuators. They do sound better than the original ones i have and measured a little flatter. It's a shame you don't have the time for a new project. I have heard a7s a couple of times and although the midrange was great, I prefer the m19s by a big margin. One thing though the two sets of a7s were not modded and were using unacceptable eq. Good luck!!!

Liked your post. Guess what, everyone sees a "C" in a crossover, and puts a single cap, of "appropriate " value, in place, and THINKS they are done . Not so !! Any single cap will NOT play the entire musical experience in a wideband manner. Most film caps will never get the highs as right as they can be.

Very LITTLE work has been done in multiple bypassing of film caps. Most everyone I meet is unaware of how to do it in any " pristine " or effective way. Yet, I find, it takes not just ONE cap, the main cap, but about four additional caps, to play back the musical experience with the fullest musical expression of the mids and high end. Look at most crossover schematics, and you will see " one " cap in a position.

If you are lucky, you may see a single by pass cap, maybe a 0.1 or a 0.01uF in parallel with a "main" film cap. I say, it takes , depending upon where in the crossover, one to four or more bypasses added to EACH cap position in the compression driver or tweeter circuit, to get the ALTECS ( or any speaker ) to play the music as they can and should.

Various SIZES ( in uFs) of caps, play various parts of the spectrum, that a single cap " misses". Cap quality , not just size, counts heavily, not all caps are designed to parallel well. Few in the audio world ever discuss this, or implement it fastidiously. I only know of one manufacturer who knows how to do this well.

Maybe, in a year or two, I will get my hands on a Model 19 and give it a go. Right now, I am still experimenting with the VOTT A7-800s, and have at least 6 more months to go !! Parts for my system attenuator arrived today, MXL timing belts.. Maybe I will post photos when I get it done, construction photos.

Have fun, I am !!


Jeff Medwin.....Low Ohms.

[RonSSS]

With regular 802's, and the wrong dust caps in the woofers, in my opinion you wouldn't be listening to real M19's anyway.
The woofer cone needs a vent.
And the older 802's are not as extended.

[bowtie427ss]

I'd state them as generic 416-8C ( ferrite ) woofers with the wrong dust-caps ( but with desirable cones ).

I think this is spot on. Not the best of times at Altec, paper labels in place of foilcals, loading caps in place of rear motor covers on the ferrite compression drivers, etc..

[LowOhms]

I think this is spot on. Not the best of times at Altec, paper labels in place of foilcals, loading caps in place of rear motor covers on the ferrite compression drivers, etc..

416 8C. Thanks for that input !! Helpful.

Jeff ....Low Ohms

[bowtie427ss]

416 8C. Thanks for that input !! Helpful.

Jeff ....Low Ohms

Purely a guess on my part here...........

But, i would offer as an explanation for the non-stock dustcaps the fact that early ferrite 416's borrowed most if not all of their magnet structure from the 421 type MI speakers.

One modification that was made to these magnetic structures is that a metal disc was glued over the vent hole on the front of the pole piece. These are infamous for coming loose which drops them into the voice coil former just behind the dustcap, imagine what that sounds like when played. A repair is easily made by carefully cutting away the original dust cap, either removing or re-gluing the disc, and then gluing on a new dust cap.

FWIW, i believe the 416-8Z designation was probably correct "in house" at the time. As much as i would like to protest and say "no no no, 416-8Z is an alnico driver" i have to have faith that the people at Altec at the time probably knew more about what they were building than me. I think the reality is that "Z" in an Altec woofer model probably has a very parallel meaning to "PL" on a JBL woofer, simply "plain label", no magnet covers or bumpers, no foilcals or otherwise fancy dress.

[LowOhms]

Purely a guess on my part here...........

But, i would offer as an explanation for the non-stock dustcaps the fact that early ferrite 416's borrowed most if not all of their magnet structure from the 421 type MI speakers.

One modification that was made to these magnetic structures is that a metal disc was glued over the vent hole on the front of the pole piece. These are infamous for coming loose which drops them into the voice coil former just behind the dustcap, imagine what that sounds like when played. A repair is easily made by carefully cutting away the original dust cap, either removing or re-gluing the disc, and then gluing on a new dust cap.

FWIW, i believe the 416-8Z designation was probably correct "in house" at the time. As much as i would like to protest and say "no no no, 416-8Z is an alnico driver" i have to have faith that the people at Altec at the time probably knew more about what they were building than me. I think the reality is that "Z" in an Altec woofer model probably has a very parallel meaning to "PL" on a JBL woofer, simply "plain label", no magnet covers or bumpers, no foilcals or otherwise fancy dress.

Thank, thanks again. The dustcaps were done recently, by a speaker repair place in Springfield, MO., for the prior M19 owner, as a kid put his finger through the stock one.

Jeff ....Low ohms.

[Altec Best]

Jeff can you post some pics ? Don't use hostboard to do it though. Use Photobucket,Flickr,or Image shack.. Something like that or any image hosting site.. and just post the IMG links. Hostboard resizes them to thumbnails practically.

[LowOhms]

Jeff can you post some pics ? Don't use hostboard to do it though. Use Photobucket,Flickr,or Image shack.. Something like that or any image hosting site.. and just post the IMG links. Hostboard resizes them to thumbnails practically.

I am so sorry, but the M19s were sold about four hours ago. I HAD lotsa photos in the Craigslist Kansas City ad, which I referred to you folks in this post, but I have since deleted the ad. Had the drivers been correct and matching, I would possibly have not " flipped" the purchase.

As it was, it was a LOT of fun to buy and sell it .

The new owner is a typical ALTEC fan, but , like many I see, he knows NADA about correct / best possible amps. He is an Electronics Technician, says he can build a DIY tube amp if I give him a schematic, so, I will have him over in 90 days, when I get my two monaural Direct Coupled 2A3 amps finished, just to see if I can blow him away ! Would be fun to witness his listening response, and also very instructive to me. Will he recognize and hear what " I " hear. I think he might.


Jeff .... Low Ohms

[Elitopus1]

OT: Speaking of hearing, checkout this site. The "blind test" section is good. Take the tests and then tell us how you did! Some of the tests have very small changes that are hard to hear.

Free Online Audio Tests, Test Tones and Tone Generators