Overnight Sensation build

[tomzarbo]

Maybe plug the tweeter hole with a darker, contrasting wood, and redrill correct size for tweeter hole. Turn mistake into design feature.
TomZ

[Millstonemike]

Got a little work done on the build. Let the glue dry, rounded the edges, and hit em' with some 60 grit. I like the way wood feels soft after a rough sanding. One problem, tweeter cutout is about 1/4" overall too large. How's the best way to fix this?

If you're using the Dayton tweeter, perhaps you could switch to the OS TMM design that uses the HiFi T20 tweeter. It's 0.3" wider than the Dayton.

[Jeff F.]

If you're using the Dayton tweeter, perhaps you could switch to the OS TMM design that uses the HiFi T20 tweeter. It's 0.3" wider than the Dayton.

Good thinking Mike. I've built OS's with both the Dayton and the HiVi tweeters. No noticeable difference in sound. I do prefer the HiVi though, I like that it mounts with screws instead of the Dayton's press fit.

[Kornbread]

Solid Pine board, which stain?

[richard t]

That's all up to you but If you haven't done this on the test board yet, I would put a seal coat down first. pine tends to blotch when stained if a sealer isn't used first. The stain will probably lighten up a bit when the wood is sealed so do another test board before you make your decision.

[Kornbread]

First try at building a crossover, how bad is it? Is it anything like the diagram? The woofer side sounds right but nothing through the tweeter hooked as marked.

[Millstonemike]

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Solid Pine board, which stain?

I vote for no stain (or a light Danish oil).

[Dewmiester]

[ATTACH=CONFIG]n1300020[/ATTACH] [ATTACH=CONFIG]n1300017[/ATTACH] First try at building a crossover, how bad is it? Is it anything like the diagram? The woofer side sounds right but nothing through the tweeter hooked as marked.

Is the wire from the cap coming across the b4n mid+ touching.

[Kornbread]

It's only touching the common where the - input, + tweeter, and both - sides of the b4n's connect. Is this correct? To get the large inductor as far away as possible I had to use a jumper wire from the cap input; I'll shorten the large coil lead in and lengthen that wire to help insure no issues there.

[Carbon13]

There's some crossover schematics and pics from my build in this thread if it's helpful: http://techtalk.parts-express.com/fo...m/63068-os-tmm

[Kornbread]

Thanks for the help. Other than some differences in resistors and positioning, aren't they the same?

[Kornbread]

Mounted and wired crossovers in the base. Mounted and wired drivers. Glued a piece of pvc into the oversized tweeter cutout, the tweeter then fit into the pvc sleeve fairly snug, then added a bit of poly glue to be sure it staid. Luckily I hadn't cut the hole bigger than the tweeter flange.

Haven't done any real listening yet but with the DTA120 they sounded too bass heavy. The right tweeter still wasn't working. I'll get some pics and measurements up later with a better opinion of how they sound after the tweeter issue is fixed. The left one with the crossover wired the same way worked fine. Since the tweeters were glued in it's not an easy tweeter replacement without destroying it so I grabbed another tweeter and tried both crossovers. It works find on the left side, not at all on the right unless it is connected between the first 8ohm resister and last 2.7uf cap. Works fine then so the resistors seem to be the problem.

Is it safe to assume one or both of the resistors are bad? Is there a way to test them with a simple multi-meter? Will they have to be pulled out of the crossover to test?

Shot down by a $1.38 part! Unsoldered the resistors, the 6ohm checked 6.7, the 8ohm wouldn't check.

[Millstonemike]

Shot down by a $1.38 part! Unsoldered the resistors, the 6ohm checked 6.7, the 8ohm wouldn't check.

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You can measure the resistance of the resistors while connected. I would have simply disconnected the lead to -tweeter to measure. If the 8 ohm is bad that would explain why your not getting output from the tweeter - you seem to have found that already. Hope that fixes it.

If these are PE's audio grade resistors, they're spec'ed to be within 2%. The 6ohm is ~12% out of tolerance. I might measure all the resistors in both XOs to insure they're within spec. Then file a claim with PE to get replacements on their dime. PE can't measure every resistor that comes into their stock and it's not unheard of for an mfg to have a bad run.

You indicated electronics is not your forte. If you're not very adept with the soldering iron, you could be overheating the resistors (pretty hard to do). It should only take a few seconds to make the soldered connection. You can always put a needle nose pliers on a component's lead - next to the component. That will bleed off heat before it gets to the guts. I use a heavy rubber band on the pliers' handle to form a "clamp". It would also be more of an issue with the capacitors, but not with the inductors (unless your using a blowtorch )

And we're all waiting for finished pics. The unfinished cab's are very nice - very warm in that pic from earlier.

Edit: It seems I can't reply to your PM (another forum issue?). And I didn't notice the PM at all yesterday (delayed delivery?)

[Kornbread]

Thanks Millstonemike. My soldering skills are basic at best. I've desoldered/soldered on a few boards; had to replace the convergence board on a RPtv, then later replaced its driver chip. Started to use small alligator clamps as heat sinks, but the crossover soldered up so quick and easy it wasn't worth the bother of trying to find them.

I've always wanted to better understand how those electrons get from one place to another and do what they do. In fact, I wanted to build my own amps from scratch as a teenager, it's just, other things in life seem to have come first. I can wire a house, but other than that, my understanding of electrons is very basic.

Yes, they are PE's audio grade resistors. I'll give PE the benefit of a doubt to their specs as the Radioshack multi-meter doesn't seem to be the most trustworthy.

REW measurements were taken on the back deck about 14' from the wall of the house, open on three sides, mic was on tweeter axis @1 meter, amp was the DTA120. Does this look normal or did I mess up?

[Millstonemike]

Thanks Millstonemike. My soldering skills are basic at best. I've desoldered/soldered on a few boards; had to replace the convergence board on a RPtv, then later replaced its driver chip. Started to use small alligator clamps as heat sinks, but the crossover soldered up so quick and easy it wasn't worth the bother of trying to find them.

I've always wanted to better understand how those electrons get from one place to another and do what they do. In fact, I wanted to build my own amps from scratch as a teenager, it's just, other things in life seem to have come first. I can wire a house, but other than that, my understanding of electrons is very basic.

Yes, they are PE's audio grade resistors. I'll give PE the benefit of a doubt to their specs as the Radioshack multi-meter doesn't seem to be the most trustworthy.

REW measurements were taken on the back deck about 14' from the wall of the house, open on three sides, mic was on tweeter axis @1 meter, amp was the DTA120. Does this look normal or did I mess up?





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To me, the 20db hump between 40 and 200 hz is an issue especially with no room gain. The measurement gurus will be able to surmise what's up.