Next Project: floorstanders = Zaph Audio ZDT 3.5 build

[cjd]

DPDT ONLY if it has NO contact through transition - a center-off DPDT might do this.

If both amps EVER see each-other you're in trouble.

IMO it is not even remotely close to worth doing. Just get some banana plugs or spades or something to make swapping amps easy.

Or, in your case, why not run the pre-amp output for LR from your 5.1 receiver to your stereo amp instead of using the receiver amp stage for them?

[ThomasW]

Would a DPDT switch work? As long as I got one sized right, it seems like that could be an easy solution.

Again no, and there is no 'easy' solution.

First, you're dealing with switching an AC signal not DC.

Second, if either of the devices have a remote control they're not turned off unless they're unplugged, so you'd be switching 'hot' electronics.

Chris' recommendation regarding running the receiver's pre-out to an input on the stereo amp is the best low buck choice.

[Bent]

those switches are referred to as "break-before-make" switches, so at no time does it have a complete circuit between all contacts.

A "knife switch" is this kind.

[oneplustwo]

Thanks for the education. My receiver (JVC RX-9000V) is 10 years old and doesn't have pre-outs. So maybe this is a good excuse for an upgrade. Although it does have subroom pre-outs for L/R only which *might* work for this particular scenario. I'll have to read the manual and see.

[oneplustwo]

Well, the bondo worked like a charm.

Unfortunately, I have a new problem now. When I went to redo the recess for the mid, I forgot I had a larger bit installed. So the recess is about 1/8" too large. Is there an easy way to fix this?

I was thinking about just putting foam gasket around the flange a little too far to the outside so when I screwed it in, the gasket would essentially fill in the space. I suppose the other thing I could do is try to fill the gap in with something paintable after installing the driver. Maybe some putty or something like that. If I was ambitious, I could make a cutout from some scrap that matches my driver diameter and bondo around it to build up the recess. That feels like too a lot of work given I'm not sure this is much of an issue anyway... you probably won't be able to tell when it's all painted and everything. And I doubt there will be any significant sonic impact.

[Bear]

Unfortunately, I have a new problem now. When I went to redo the recess for the mid, I forgot I had a larger bit installed. So the recess is about 1/8" too large. Is there an easy way to fix this?

If you did this on each of the driver rebates, then you are most likely better off just redoing the baffle if you haven't glued everything up yet. Otherwise, more bondo (or other variations on wood filler), more sanding and some fun with a rabbeting bit are in order.

[evilskillit]

If the baffles aren't attached yet and it bothers you that might the quickest easiest method might be to make new baffles. Otherwise you've pretty much hit the nail on the head as far as solutions I can think of. If you paint the inside o the rebate black nobody is going to notice the extra space around the driver unless you point it out to them. If you are obsessive like me tho, it will bother you. I've redone enclosures because of that in the past.

[oneplustwo]

It's just one driver that's an issue. All the rest are spot on (thankfully.) I have lots of bondo left over though so maybe I'll just go ahead and do that. Good excuse to go buy a rabbeting bit I guess. Or maybe I'll just ignore it. Will have to ponder this a bit. Maybe I can steal some of my daughter's black play doh and fill in the gap after installing the driver. :P

[oneplustwo]

I got the front baffles painted today. I actually ended up using the truck bed liner spray as a primer and the textured rustoleum on top of that. The truck bed liner worked really well actually... went on nice and thick and even. And the textured stuff went on very nicely as well. I would say it's very forgiving.

Gotta get the crossovers built and installed now. Might be able to do the final glue assembly this weekend!

I'll get some pictures up this weekend too hopefully.

[oneplustwo]

I went to assemble my ports and realized there's no middle "connector" piece. (This what I expected from my Madisound SR71 kit.) Do I just butt glue the pieces together? That doesn't seem very strong. Or so I need to go to the hardware store and buy a piece of PVC or something. I could just use one half as the port only needs to be 100mm, but that means the inside of the port won't be flared. Maybe it doesn't matter that much?

[ThomasW]

No you don't butt the ends together.

I read the instruction pdf and it's a joke.

On the Madisound webpage that talks about the kit, it talks about a center straight section 2.25" long. So you need 2 flared ends, a center section and 2 slip rings to assemble the port. I you don't have these call Madisound

[evilskillit]

Which ports are you using? On the Zaph Waveguide TMM build, which I believe uses the same cabinets and ports as the ZDT3.5 he recommends the flared 1.5" ports. Those are just flared on one end and flat on the other and not meant to be joined. He recommends butting the two ends together and taping them. Seems pretty silly to me but it does work and its waaaay cheaper than buying the flared kit ports. Like $2 each vs $8 each.

[oneplustwo]

Actually, these are from parts express from the canned BOM on their project page. No center section which I had not noticed till now. (No ZDT kit from Madisound... the SR71 kit from them was my previous project.) Guess I gotta go find a center section at the hardware store.

[oneplustwo]

Yah, I thought about tape. I guess that would work if you used something beefy like a few layers of packaging tape or duct tape. Just gotta do a good job to make sure there's no vibration issues or anything like that. If Zaph says its ok, then who am I to disagree? (I don't remember seeing that reco BTW.)

[oneplustwo]

Well, good news is that I got the crossovers built and have glued the rear baffles on. Bad news is that I probably should have waited to paint the baffles until nearly the end.

You can see that I have some paper towel residue where I had to wipe some excess glue away. Not a huge deal... I may be able to brush it off, but the fibers get caught up in the textured paint pretty well. Plus, there's probably some excess wood glue helping there. I'll probably have to tape it off and do another coat to cover it up.

Also, I did end up taping the ports together. Seemed to work just fine.

[evilskillit]

Yup those are basically the same ports I used, except I got mine from Madisound. They're meant to be used individually as is with the flare being outside and the inside just not being flared. However Zaph just sugguests putting the 2 flat sides together and taping them.

[oneplustwo]

They're done! Sort of.

Got everything glued up and wired. I still have to fix the paint as I mentioned previously. And since taking the pictures, I've already made some little outriggers.

They sound pretty darn good. I'll reserve my thoughts for a more thorough review after they break in a bit and I get a chance to listen to a bunch of stuff. But initial impressions are that the imaging is very good even at close listening distances. The crossovers seem to be doing a very good job as I can't discern any distortion or other bad behavior. And I think there's enough bass response for my needs. I have yet to try any home theater stuff, but for music, I think I'll be happy.

As for build notes, I did make that one mistake with the mid recess but it's not too bad. Otherwise, I was very happy with the textured paint although I might polyurethane on top of it next time. It tends to hold on to dust and everything else pretty tenaciously.

More to come. In the meantime, here are some pics.











Moderators, perhaps you could change the title of the thread to Next project: floorstanders = Zaph Audio ZDT 3.5 build

[evilskillit]

Looking good sir. I'm going to go over to another forum members house tomorrow and hear his ZDT3.5 and compare them to my Waveguide TMMs. Should be lots of fun, I'll let you know what I think when I'm done, I suspect they'll be similar and equally good.

[oneplustwo]

Nice... are yours still bare MDF? Looking forward to your impressions.

I bought parts for a center ZDT... but I still need to build the entertainment center to hold it so it might be a while.