Z19 Crossover

[ricohman]

You should go with the schematic, as a pictorial layout may not show all the connections clearly. If that is the original Z-19 schematic, follow that, because I built serial numbers 001 and 002, and they work as per the schematic.

My layout is different, but works as designed. Yes Zilch is the man. :thmbsp:

Nice. Do you have a pic of the front of the face plate? I am looking for ideas while I wait for my parts.
With the face plate being that thick one could router a recessed opening for the lpad knob. I was thinking about aluminum but maybe wood is the way to go.

 

[Zonker92]

Thanks, 4343 and Skywave! Very helpful!

Oh, and as for this revised drawing:

Here's what the schematic looks like to me:

All I can say is THANK YOU! That makes so much more sense to me.

 

[Zonker92]

My idea for the installation (on my 846Bs) is to put the crossover into some sort of hobby box (the ones at Parts Express don't sound like they're quite large enough) or custom MDF box, with the $1.70 two-knob L-Pad faceplate from Parts Express mounted on the top of the box (which would wind up as the back side of the box upon installation, below).

I would set a plate of five-way binding posts into the box, either next to the knob plate or on the side of the box, depending upon how you want the speaker cables to hang. I think my preference would be the side so that upon the box installation they'd hang sideways, toward the middle of the speaker cabinet. (I'd use two binding posts, but I guess you could use four if you're bi-amping.)

I would then remove the stock crossover and its cables, leaving a hole in the back of my speaker. I would screw an MDF plate over the inside of that hole using the four factory mounting screw holes inside the cabinet. That plate might, or might not, have a square piece of MDF on it to fill in the hole in the back of the cabinet. That doesn't really matter for my purposes. The outside of the plate would be sealed with speaker gasket or foam weatherstripping, where it met the cabinet.

I would run four new wires from the drivers, out of a sealed grommet in that MDF plate, so they ran out the back of the speaker. I would probably bundle them in some sort of sheath.

The MDF plate would have two or maybe four T-nuts set into it. Over the hole, on the outside of the back of the speaker cabinet, I would attach the crossover, running bolts through it to connect to the T nuts in the plate. The speaker wires would come into the bottom of the crossover box. You could use a four-pin connector to attach the wires, or just screw them into terminals on the crossover. Where the back / bottom of the box rested on the speaker cabinet, it would be sealed with speaker gasket or foam weatherstripping (not really needed, but what the heck). I would paint the crossover boxes to match the back of the speaker (sort of brown or tan), or paint them black.

The resulting set-up should have each crossover inside a box bolted to the back of the cabinet, without drilling a single new hole into the cabinet. It would be 100% reversible, quickly removable as a sealed unit for transfer or sale, out of sight, and not reduce the cabinet volume. It would also leave the stock crossovers and speaker wires intact for replacement or sale.

Of course, this approach is no good for Model 19s.

 

[skywave-rider]

Nice. Do you have a pic of the front of the face plate? I am looking for ideas while I wait for my parts.
With the face plate being that thick one could router a recessed opening for the lpad knob. I was thinking about aluminum but maybe wood is the way to go.

Mine are ugly, but meant to be mobile. I use them primarily on Altec 9844-8Bs. But have used them on a variety of other projects. So they sit on top. If I make them permanent I will mount the L-pads to the back of the cabinet to keep the box looking original from the front. I drilled a set of binding posts into the back, next to the original speaker terminal screws which allows for connection to the drivers. This method allows you to make an air-tight connection which does not affect the cabinet tuning. So, at this point, I drilled 2 holes in the back panel of my Altecs.

Post your pics when you are done, please.

 

[ricohman]

Mine are ugly, but meant to be mobile. I use them primarily on Altec 9844-8Bs. But have used them on a variety of other projects. So they sit on top. If I make them permanent I will mount the L-pads to the back of the cabinet to keep the box looking original from the front. I drilled a set of binding posts into the back, next to the original speaker terminal screws which allows for connection to the drivers. This method allows you to make an air-tight connection which does not affect the cabinet tuning. So, at this point, I drilled 2 holes in the back panel of my Altecs.

Post your pics when you are done, please.

I will post some pics but I will be another week or two waiting for parts.
I need to mount the Z19's and whatever face plate I come up with into the original 19 xo location. I have the material for wood or aluminum.
I don't think the xo will look near as good as whats pictured here but I will post a pic anyways.

 

[Zonker92]

I just want to make (or, better, find for cheap) some small MDF boxes to house my (planned) Z19s. I spent hours last night on line, looking for small wooden boxes that would hold at least a 6 x 9-inch board. No real joy. The "project boxes" at Parts Express are too small. No one else seems to make one. I guess I'll have to make my own.

 

[ricohman]

I'd follow the schematic, as Skywave suggested.

Board layouts are great for saying where the components physically fit, the schematic is king of what wire connects where, in my book.

It does appear to me that R3 should not connect to the junction of R1 & R3 at the bottom end, but rather should have a green line leading to HF- (ground). Further, the Mid L-Pad M1 connection labeled G should not be grounded, but rather should connect to the junction of R1 & R3, per the schematic.Here's what the schematic looks like to me:

This may sound dumb, but the revised layout shows now G connected to R1 and R2. Should it be R1 and R3?
Also, is 18 gauge solid wire suitable for this project?

 

[Zonker92]

This may sound dumb, but the revised layout shows now G connected to R1 and R2. Should it be R1 and R3?
Also, is 18 gauge solid wire suitable for this project?

Not as I read the original schematic. If you look at the "bottom" lead of R1 and R2, you should see that they both connect to leg 1 of the midrange L-Pad, which is G. By contrast, one leg of R3 connects to leg 2 of that L pad, and its other leg goes to ground.

By coincidence, I made my Z19 Parts Express order today, and bought two vintage cigar boxes to house the crossovers on the backs of my 846Bs.

I'm not an expert at all, at all, but while I think 18G would be OK (I suspect the original wiring is 18 or 16), I plan to use 14G wire, just because.

 

[ricohman]

Not as I read the original schematic. If you look at the "bottom" lead of R1 and R2, you should see that they both connect to leg 1 of the midrange L-Pad, which is G. By contrast, one leg of R3 connects to leg 2 of that L pad, and its other leg goes to ground.

By coincidence, I made my Z19 Parts Express order today, and bought two vintage cigar boxes to house the crossovers on the backs of my 846Bs.

I'm not an expert at all, at all, but while I think 18G would be OK (I suspect the original wiring is 18 or 16), I plan to use 14G wire, just because.

Yes yes, now I see it.
I have 18 gauge on hand so I will stick with that. I will use it to the drivers as well since the original Altec wiring is so light gauge.
I am waiting for parts but I am going to make a face plate and mount the lpads and the plate pictured above in it. Then bracket the Z19 to the back. I was going to TIG a bracket on the back but I may use body adhesive.
I am still looking for a suitable board. I may end up using wood.

 

[Zonker92]

Lucite, baby!

 

[Zonker92]

I was wondering (and I sent a PM to Zilch but I feel terrible bugging him; he may not have time to reply), do the schematics above represent the final word on the Z19? I know Zilch is going to be putting these into some form of production, and I'm just wondering if the production models will be the same as this schematic.

I'm curious because I just ordered the parts to make my own, but maybe I should have waited for the production version. Thanks.

 

[Dr. Beaker]

I think it's safe to say that in this DIY hobby we all play in, nothing is "FINAL". That said, the Z19 is a highly developed crossover that has been validated by many builders and test data. Build it as is and it will always produce great results. If a newer version apears down the road, it won't be such a big deal to modify what you have, if that is what you must do.

Build it, enjoy it, and brag about it.

 

[Zonker92]

Yeah, that's kinda what I was thinking, too. Thanks!

 

[ricohman]

My parts finally arrived and I am about to create the Z19!

three questions.
1. I can see how heavy these will be. There is no way I can hang them from the back of the 1/4 aluminum face plate as the wood is not strong enough. Can I mount them on the inside of the front baffle and run longer wires to the L-pads on the face plate?

2. Has Zilch seen the updated board layout? I realize those that know a lot more than me have corrected the wiring however could Zilch have designed it that way for a reason?

3. I am going to run one set of input wires for + and -. Do I just make the 4 into 2? The schematic shows one set of inputs and the board layout shows four.

I want to get this right the first time.

 

[Zonker92]

Ah, you're killing me, man. My parts arrive Friday. Fun weekend! What kind of backing boards are you using there? Are they 6" x 7"? The dude in the Parts Express warehouse must be wondering why he keeps filling the same damn order again and again and again ... Happy Groundhog Day!

I offer these inexpert responses to your questions; others are free to correct me:

(1) I see no reason why not. Zilch's photo in the very first post of this thread shows longer cables running to his L pads. If you ran really long cables with really small-gauge wiring the impedance would climb, but short runs are fine.

(2) I don't know, but I get the impression that he's contributed so much time on this project already, that I'd hate to bug him about that. (And I quote, "DONE, DONE, DONE!!!!") I do believe that the corrected portion of the board layout accurately corresponds to that part of the schematic, while the original layout did not. I also know that the Z-man himself said his board layout is not a schematic.

(3) Yes.

 

[donprice]

I think the idea of Z's board layout drawing was to fit a particular sized printed circuit board (PCB). Somewhere on AK is a thread about how to etch you own circuit boards...or maybe someone will run off a small batch of them like the eWave crossover boards.

 

[Zonker92]

That would be cool. So easy then. I think Z is making some up as we type. I plan to use Masonite or plywood or something along those lines.

 

[ricohman]

Z has put a lot of time into this. I was thinking the other day that if it wasn't for him my 19's would probably never sing again.
And this would all be an impossible task years ago before the internet.
God bless Al Gore.......

Thanks for the reply zonker!

 

[Zonker92]

My pleasure; I hope it helped.

When I do mine, I'm gonna sit there with the parts list, the board layout and the schematic, and check everything about twelve times. Looks like you're about to do the same.

I bought a pair of these boxes on eBay for mine.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=310271329514

 

[ricohman]

I trimmed the boards down to 16x20cm so they would fit in the Altec 19 XO opening.
I've got them all mounted and I am going to solder all the connections up in the next few days. I also think I may be able to mount them to the plate I made but I need to mount the L-pads first and see how much room there will be. But at least I won't have to remove the woofer to remove the XO.
But about the input. Here is a pic of the boards I'm building. I would like to keep the bi-amp option open so can I run a jumper between the terminals on the strip? Or just leave some blank.
I only have one set of inputs so the board layout is a bit confusing to me.
New XO's!

This is what I don't get. Can I just combine them into one set of + and -?