Monitor 7b purchase now Mod time

F1nut

Sorry to hear that.

I'm not sure if he is still doing this, but lawdogg was offering to repair frozen Polk drivers. You might try reaching out to him.

This may be of interest to you.
https://forum.polkaudio.com/discussion/197152/diagnosing-fixing-shifted-polk-mw-drivers

Sumbrada69

Thanks what a detailed write up. I might try it myself if I get the 10s.

Sumbrada69

Just got another set of 10As. 2 MWs are good and 2 are very minor scratchy. They are in better condition than my 10As. So I am going to take the 2 good MWs and test the 7s unmodded. Then comes the fun for the 7s! Then if I get the other MWs (have 2 in my 10s also little scratchy) fixed will do a more major mod to the 10s. My wallet is getting much lighter.

Sumbrada69

Lawdogg agreed to fix some MW6500s I have from my 10As and the 10As I just got. I put 2 good MW6500s in the 7s and am listening to them now fully stock and aged what a difference from my 10s. Got my parts in so mod time. Thanks everryone for your help, suggestions. I will take pics.

Sumbrada69

Hello all, working on the mods, crossovers first. I am thinking on using Armacell foam tape for the component spacers like the grey foam that was on the original boards. Comments, suggestions? Also, as the Caps are much larger that the originals I plan on stacking them using zip tie to hold them. Is it ok to drill new holes in the boards to get straighter leads? There will be quite a bit of lead exposed, heat shrink tubing or not? On the drivers when dynamatting, Just strips on the vertical supports or all over metal? I have seen pics of both ways. Thanks

Gardenstater

Sumbrada69 wrote: »

Hello all, working on the mods, crossovers first. I am thinking on using Armacell foam tape for the component spacers like the grey foam that was on the original boards. Comments, suggestions? Also, as the Caps are much larger that the originals I plan on stacking them using zip tie to hold them. Is it ok to drill new holes in the boards to get straighter leads? There will be quite a bit of lead exposed, heat shrink tubing or not? On the drivers when dynamatting, Just strips on the vertical supports or all over metal? I have seen pics of both ways. Thanks

If I was going to stack capacitors without a valley to support them, I'd probably make some spacers out of 1/8" aircraft birch plywood (Midwest or other supplier) that is radiused to fit the caps, maybe with that Armacell also. Then for the cable ties I'd use a large enough size for strength and use a diamond point to make holes in the PCB, that are rectangular for the ties. I get the cheapo diamond points for a Dremel from Harbor Freight.

I don't recall what caps you are using....ClarityCaps? Anyways, I used Sonicaps and didn't have to stack. I left about 1/8" air gap underneath the resistors. I was able to use the existing holes for the leads but drilling new ones is fine. I put some heatshrink on which is purely OCD :

Sumbrada69

Sounds good, I will try to not stack. Thanks for the advice and pics.

Gardenstater

ClarityCaps are shorter and fatter than Sonicaps though.

VR3

You can drill holes in the pcb just be mindful of where exactly you are drilling

Toolfan66

I see no reason to use the PCB on the 7's..

tonyp063

FWIW, here's a dry fit picture of what to expect with Clarity Cap sizing. Same crossover as you have

Sumbrada69

Hello all, I did not finish the 7s crossover yet, I had shoulder surgery so don't have that hand for a few more weeks. At the polk forum it has schematics but appears none for 7A and early Bs with peerless tweeters. On my crossover and a few I have seen here it has a 4.5 ohm resistor on the tweeter (which I have Mills) but all the schematics are 2 or 2.5 and have polyswitch and the other tweeters. Is there that much difference in the tweeters? I am not switching but am surprised that schematic is not up there.
What gauge wire for tweeter and woofer connections.? I got 13G (2.5) supra classic wire from Madisound. [OFC stranded] Should it be smaller? Stranded or Solid (like Danny GR Research) Litz is too much for me.
I got gold plated push on connectors for the MWs, Passive, Binding posts. Ok? Or only solder joints?
What do all use just use; a soldering iron or also a soldering gun (higher output). I have both,iron is temp. controlled. Thanks

F1nut

The 7A schematics are MIA.
Wire gauge is fine.
Fastons are fine.
Soldering iron.

Gardenstater

Sumbrada69 wrote: »

Hello all, I did not finish the 7s crossover yet, I had shoulder surgery so don't have that hand for a few more weeks. At the polk forum it has schematics but appears none for 7A and early Bs with peerless tweeters. On my crossover and a few I have seen here it has a 4.5 ohm resistor on the tweeter (which I have Mills) but all the schematics are 2 or 2.5 and have polyswitch and the other tweeters. Is there that much difference in the tweeters? I am not switching but am surprised that schematic is not up there.
What gauge wire for tweeter and woofer connections.? I got 13G (2.5) supra classic wire from Madisound. [OFC stranded] Should it be smaller? Stranded or Solid (like Danny GR Research) Litz is too much for me.
I got gold plated push on connectors for the MWs, Passive, Binding posts. Ok? Or only solder joints?
What do all use just use; a soldering iron or also a soldering gun (higher output). I have both,iron is temp. controlled. Thanks

It's too bad the early schematics aren't there but it is what it is and I've never heard the why. It's not just that the tweeter is "that much different" (which it is) but also that they designed the crossover for the Peerless to be voiced with the MW6500 which has different T/S parameters from the MW6502 which they went with when they went with the SL2000 and even with the SL1000 for a short transitional period.

OEM wire gages were very small. From memory maybe 22 awg for the tweeter, 18awg for the MW. I have to double check. I went with Neotech solid 12awg for the MW (pretty non flexible to say the least) and Cardas Litz 15.5awg for the tweeter and Cardas Litz 11.5awg for the binding post to PCB wires.

Litz has to be soldered with the aid of a solder pot, unless you strip it. I tried both stripping it with a wire wheel on a dremel and then tinning with Wonder Signature (many use Cardas Quad Eutectic) and the solder pot and I preferred the results with the former.

You don't need connectors for the Passive lol, but I used the gold plated fastons for the drivers. I purchased Cardas Binding posts, the short ones (I'd use long next time) with the flash rhodium over heavy silver plating and the best method I believe was to use gold plated copper ring terminals along with the gold plated nuts supplied by Cardas. Soldering to these heavy posts is difficult and requires a very high powered soldering iron or better yet a torch which is what I did on one of them, trying to decide what is best. I'd just use the ring terminals really.

For doing the soldering on the PCB and back flowing the crimped connectors I used a temp. controlled soldering iron station. I have a higher powered Weller Soldering Gun which wasn't really adequate for the heavy Cardas binding posts so I used a torch, but again I'd just use the ring terminals because it is easier and makes a solid connection. Oh and I had to drill the ring terminals out for the Cardas posts which was a bit of a PIA because they had to be held down with a couple screw heads onto a piece of plywood for drilling with the drill press.

F1nut

Oy vey

Sumbrada69

Thanks guys. Your answers were what I was thinking. Now just get a steady hand and arm.

tonyp063

take a look at this.
https://forum.polkaudio.com/discussion/180627/7a-crossover-question-difference.

My 7A's have this schematic