Tarkus Speaker design by Paul Carmody

[MrBoat]

Nice- didn't know your history with this stuff. Ever use the NBL (No Black Line) veneers?

Attitudes vary WRT veneering- I went to a WoodCraft store and asked a guy about their supplies and veneer stock but didn't expect someone who's there to sell products that are available in that store to let me know his opinion of it in such a condescending way. His reply- "No, I use the real stuff". My first thought was "So, the practice of veneering that started around 4000 years ago as a way to add decoration to the tombs of Egyptian Pharaos and later, on furniture for the living with examples of it are on display in museums around the freaking World isn't good enough for you?". I almost asked what he has made that might be considered 'impressive'. He might be a great woodworker, but he was a bit of a nobk about it (the k is silent).

Is that 'Leopard' Cedar on the larger cabinets? What finish did you use?

Your Imgur page shows two windows- one Art Deco and another that's Art Nouveau- is the Art Nouveau by McIntosh?

Plywood has been around forever as well. Any time wood is stacked to add dimension or collective, structural significance in layers, it is indeed plywood.

I only see two separate images. One is the Paul Carmody Speedster design in ribbon (Sapele) mahogany and a Fountek ribbon tweeter.

Second is Jeff Bagby design Continuum in Karelian birch.

Both have been pore filed with either epoxy/Cabosil, or a colored pore filler in the case of the mahogany and both sprayed with Mohawk brand, clear music instrument lacquer.

Haven't used a no black line veneer. Both of the examples in the photos are non backed so there is no lines.

 

[MrBoat]

Made a little snafu when summing the sides for rabbets. I had forgotten the front was face mounted and had counted it in the size of the panels. I could have cut it on the table saw, but that always manages to miss a little on the corners somehow, especially if the blade is not as sharp as new. Thankfully the error is was in the right direction which is on the large side of it. I could have used the drop in baffle and puttied everything up seamlessly, but I don't like having end grains (even with MDF that will be covered) in the front. I would essentially have to fill and block sand everything flat, and hope it didn't telegraph through 2-3 years down the line. If I use backed veneer, I can epoxy saturate the MDF and make the whole works one to where it will never swell or move due to humidity, because contact cement will stick to sanded epoxy very well. If I use an unbacked veneer though, the cold glues used for that don't stick to it as well as it does open wood.

Anyway, I ended up using the router table with a straight cut bit a .25" at a time until I was almost through. Then routed it all the way thru on the long sides, and cut the remaining 1/8" thru on the short sides with my razor pull saw. Turned out perfectly.

 

[MrBoat]

The Peerless drivers are actually pretty nicely built.

Nothing wimpy about the tweeter construct. It has a substantial weight and feel to it.

Got the cabinets all flush and sanded and the cutouts marked for the woofers and it started sprinkling. MDF won't tolerate that kind of moisture for too long before it starts to grow. Even high humidity can effect it over time which is why I saturate it with epoxy if my exterior treatments are compatible with an epoxy surface. Baffles and backs are just tacked on with brads currently so that I could finish machining eveything. I reckon I could have glued the baffles on, since the backs are still free.

Still have to make the ports. Fortunately I still have 4" PVC from gardening projects.

 

[MrBoat]

I think I goofed. I am partially blind and cannot read the schematics values on the Tarkus page. Plus there is schematics for two variations of the tweeter. What I ended up doing was ordered parts from the colored, suggested layout for the parts. If the values are different, than that confuses the suggested layout too. The larger I blow it up, the blurrier the numbers get.

If anyone with a sense for this stuff and a decent pair of eyes can tell me the difference. I haven't assembled anything with the crossovers yet but if the colored layout is way off, I have a bunch of parts to add to my extra parts box.

ETA: I found some additional resistors I had ordered that seem to coincide with the revised crossover. It has just been a couple years since reasoning all this out, or forgetting if I had actually done so when I ordered the parts. Will have to check the caps again.

 

[ryanosaur]

I think I goofed. I am partially blind and cannot read the schematics values on the Tarkus page. Plus there is schematics for two variations of the tweeter. What I ended up doing was ordered parts from the colored, suggested layout for the parts. If the values are different, than that confuses the suggested layout too. The larger I blow it up, the blurrier the numbers get.

If anyone with a sense for this stuff and a decent pair of eyes can tell me the difference. I haven't assembled anything with the crossovers yet but if the colored layout is way off, I have a bunch of parts to add to my extra parts box.

Which tweeter do you have? The G09 or G59?

 

[-Jim-]

I think I goofed. I am partially blind and cannot read the schematics values on the Tarkus page. Plus there is schematics for two variations of the tweeter. What I ended up doing was ordered parts from the colored, suggested layout for the parts. If the values are different, than that confuses the suggested layout too. The larger I blow it up, the blurrier the numbers get.

If anyone with a sense for this stuff and a decent pair of eyes can tell me the difference. I haven't assembled anything with the crossovers yet but if the colored layout is way off, I have a bunch of parts to add to my extra parts box.

I'll try to assist.

The tweeter has changed from DX25TG09 to DX25TG59. The diagam above is for the new part number which is DX25TG59-04. Your order would have been for it.

If this diagram is still too small, just advise and I'll bring it into an editing program and increase the Font Size of the components.

Happy New Year!

 

[MrBoat]

Which tweeter do you have? The G09 or G59?

The G59

 

[MrBoat]

What also confused me is I forgot to divide the doubled up resistors and took the R at face value so that made me think I really missed something.

 

[ryanosaur]

The G59

The only change I see is that for the G59, R2 is 4ohm value... If you had the older tweeter it is an 8 ohm value.

But as best I can tell, you are solid.

There were no other differences in the schematics that I saw. I think my eyes are still seeing.

 

[MrBoat]

I'll try to assist.

View attachment 59333

The tweeter has changed from DX25TG09 to DX25TG59. The diagam above is for the new part number which is DX25TG59-04. Your order would have been for it.

If this diagram is still too small, just advise and I'll bring it into an editing program and increase the Font Size of the components.

Happy New Year!

Yeah, that brown text goes to hell for me if I try and blow it up.
Thanks for the help. . .It looks like I got the wrong inductors too. if those are all different from the original as well.,

 

[MrBoat]

The only change I see is that for the G59, R2 is 4ohm value... If you had the older tweeter it is an 8 ohm value.

But as best I can tell, you are solid.

There were no other differences in the schematics that I saw. I think my eyes are still seeing.

Is the colored diagram the same except for the 4 ohm? That explains the 4, 8Ohm resistors I have 'extra' because paired like the colored diagram shows (I assumed they were paired for heat?) they would equal 4 ohms.

 

[ryanosaur]

Yeah, that brown text goes to hell for me if I try and blow it up.
Thanks for the help. . .It looks like I got the wrong inductors too. if those are all different from the original as well.,

The only difference I noted was the last Resistor (R2) value shunting the Tweeter... everything else is identical.

 

[ryanosaur]

Krikey.
OK, I see...
He did not update the "layout diagram." He only updated the schematic. So the Layout Diagram you used was for the old tweeter.
I can't speak to why he doubled up all the resistors... but it is consistent.

So that would mean the two 16 ohm resistors should be changed to two 8 ohm resistors for your newer Tweeter model G-59-04.

Correct?

 

[MrBoat]

The only difference I noted was the last Resistor (R2) value shunting the Tweeter... everything else is identical.

What also happened in the middle of all this is some parts were backordered without a known update and I had parts trickling in for 2 months. Just found 4, 4Ohm Zistors. Someone was out and the only way I could get 4 ohms with parts available was with the zistors but those got lost in shipping and magically appeared 3 months after. It's all coming back to me now.

 

[MrBoat]

Krikey.
OK, I see...
He did not update the "layout diagram." He only updated the schematic. So the Layout Diagram you used was for the old tweeter.
I can't speak to why he doubled up all the resistors... but it is consistent.

So that would mean the two 16 ohm resistors should be changed to two 8 ohm resistors for your newer Tweeter model G-59-04.

Correct?

Correct.

I think they double them up like that for heat tolerance possibly for the fact that these might get driven hard. I think they do that so they don;t have to buy the heat sinked Zistors.

 

[ryanosaur]

What also happened in the middle of all this is some parts were backordered without a known update and I had parts trickling in for 2 months. Just found 4, 4Ohm Zistors. Someone was out and the only way I could get 4 ohms with parts available was with the zistors but those got lost in shipping and magically appeared 3 months after. It's all coming back to me now.

So you should just be able to use the single 4ohm Zistor in that spot, ya?

 

[MrBoat]

So you should just be able to use the single 4ohm Zistor in that spot, ya?

Yes. . .that is my plan now that I found them.

 

[MrBoat]

You guys are a life saver, on NY's eve no less. I much appreciate the quick response. My eyes were watering from trying to see that. Been welding 30 years.

 

[MrBoat]

Dual 16s out, 4Ohm zistor in their place.

I was almost done when I remembered something about the tweeter. I was like, damn and then noticed my vision is that much worse than 2 years ago.

 

[MrBoat]

Got them all done soldered and wired up and just noticed the time. Will double check them after being away from it for a few hrs to get a fresh look. 3-way crossovers are considerably more work than the two-ways I have built. Been dying to get this part out of the way. Of course once the finish work starts I will have forgotten this part.