RTi6 Crossover Rebuild

I decided to have some winter fun and rebuild the crossovers on my RTi6's. There is another thread here that goes over this as well but I thought I'd add my 2cents. :rolleyes:

Parts List: (Clarity caps from Madisound, the rest from Parts Express)

2 Clarity Cap 12uf
2 Clarity Cap .47uf
2 Dayton Audio MP 7.5uf Cap
2 2.5 ohm Mills resistors
2 5 ohm Mills resistors
2 .5 ohm Milss resistors

I couldn't find Clarity caps in a 7.5uf - my options were either 6.8 or 8.2 and since I didn't have a schematic I decided not to decide and went with the exact value in another brand. Nor could I find a Mills resistor in 5.7 ohms and I don't like using Mundorf resistors (too long, leads are too short) so I compromised with a 5 ohm in series with a .5 ohm for 5.5 ohms instead of 5.7.

You'll also want to order some type of batting - a pound of Acousta-Stuf (Parts Express) should be fine. I just got done pulling the fiberglass batting out of a Dahlquist DQ-10 so I used a couple handfuls of that. There is one small piece of an excuse for batting in these speakers and I think it should have something more reasonable.

1) Remove the woofer - this requires a hex screw in a 3.5mm size I think. A 1/8" will work but not fit very tight - any other inch type hexs didn't even come close. Insure you mark which connector held which color of wire - I'm usually not shy and just use a big sharpy and write on the magnet.

2) Remove the wires from the tweeter - Mark which connector held which color. You do NOT have to remove the tweeter.

3) Remove the input terminal - four screws and she's outa here! Now we're going to have some fun!

4) Remove all of the input terminal cover's and the brass input jumpers.

5) Remove the 4 black screws from the circuit board - it won't come off yet but should be slightly loose.

6) A 5/16" nut driver will take out the 2 nuts under the board holding the circuit board to the input cup - make sure you catch the washers.

7) I used a needle nose plyers to hold the back nuts against the wire connector underneath the board and then used my 1/8" hex key in the terminal hole to remove the nuts from the back two input terminals - this is no fun, please be careful. Hold the nut with the plyers and spin the input terminal with the hex key. This way you won't make a mess of the threads. Once done the circuit board should come free of the input cup.

8) Now for some real fun :mad:. Somebody at the factory has a huge tube of silicon calk and has been told to apply liberally. You'll have to clear the back two wires from the mass of silicon. Eventually I found that a sharp knife will cut through most of it and once you get some of it free it might be possible to just pull it off the board. You don't have to free it from the front terminals - just enough to get two the connections between the wires for the very small cap. You'll also find it handy to completely free these 2 wires - it will make reassembly much easier. Go easy here...;)

10) In your favorite manner remove the three capacitors and two resistors. Mine were held on the board with something sticky - just pull once you have the solder free - they'll come! :eek: Each component is marked on the board so you don't have to get fancy and mark or remember anything.

9) You'll need a drill - a Dremel tool works great - to open up the holes in the circuit board - a 1/16" bit works perfectly. I opened all 10 holes just to make life easier.

10) Bend one lead of the 2.5 ohm resistor all the way down over the body of the resistor - it won't leave much exposed wire but enough to feed both leads through the holes - solder him in.

11) Twist one lead from the 5 and .5 ohm resistors together - don't solder yet. Work the other leads through the holes in the 5.7 ohm place and solder those down - I'd leave a little clearance between the board and resistors so you can move it around later to fit the large cap in. Once soldered to the board - solder the top and cut off any excess.

12) Strip off all of the insulation from the .47uf cap - right to the body and bend the leads all the way back to the body - this cap fits almost exactly into the holes in this state. Solder, cut off the excess and save these two long copper leads.

13) Solder one of the saved copper leads into the hole closest to the resistor on the 7.5uf side leaving almost all of the wire poking up through the hole towards the component side. One issue is that the caps don't have enough lead wire to sit them on the board and reach the holes.

14) Solder the other saved copper lead into the hole furthest from the resistor on the 12uf side leaving almost all of the wire poking up through the hole towards the component side.

If you don't get these right it's not that big a deal but it will make positioning
the caps on the board easier.

15) Pick a cap...any cap. Bend one lead completely over the side and strip the other lead all the way back to the body of the cap (the 7.5uf won't need this striping step ) and straighten it out completely from the body of the cap. Insert the straight lead into the remaining hole on the appropriate side. You will have to bend that copper lead around so that you can push the cap down as far as possible. Work the cap into position - you can leave a little bit hanging over the board but not much - the hole in the cabinet is almost exactly the same size as the board. :mad:. Once positioned work the copper lead and the remaining lead on the cap together and solder this connection together - solder the other connection to the board.

16) Repeat that step for the other cap.

Should end up with something like this:



17) I use hot glue to insure that nothing can vibrate against anything else and am probably guilty as the person in the factory for using as much as I feel is necessary to complete that task!

The New and Old:



Reassembly:

1) I'm hoping you have two wires that are freed from their adhesive base - remount those two connections back on the input cup - watch your polarity - it is marked on the cup. Black to - and Red to + (for those of you who weren't sure! ) Use the 1/8" hex key to keep the hole in the terminal facing forward as you tighten them down - I used a bit of Permatex blue to insure they don't come loose - don't forget the washer!!

2) Work the last two wires (still anchored in their adhesive homes) to the input cup and secure those to the terminals - if you are careful you can use a nut drive to get these tight - use the 1/8" hex key to hold the terminal in place as you tighten them down.

3) Now put the screws to the board and secure it to the input cup - I put a dab of hot glue on each of these when done to insure they don't wander out of thier holes.

4) Apply 1/2 pound of Acousta-Stuff to each speaker - don't block the tube inputs.

5) Somewhere along this process the gaskets have fallen on the floor - you should have one for each speaker. Make sure you have these in place before you put the input cup back into the speaker.

6) Mount the input cups back into the speaker - insure you have them rightside up (or down if you have the speaker upside down).

7) Reattach the speaker wires - blue's go to the tweeter, green's to the woofer but you should have marked the polarity and I'm not taking mine back apart when you call and ask what should go where!

8) Remount the woofer.

Plug 'er in to your most expensive amp and with the volume all the way up...JK - don't do that...:D:D

Test - low volume - make sure the woofer is vibrating and that when you cover the tweeter with your hand you stop hearing the upper registers.

I'm hoping that when done and after a reasonable amount of time for break in that your RTi's now sound a bit closer to LSi's! :cool: