Monitor 10 Crossover help

dpage

Decided to replace my caps and resistors on my Monitor 10's. First time doing this or any soldering for that matter. One speaker turned out great, but the other has static in the tweeter. Cutting in and out, sounds "staticy." I know it's nothing to do with the tweeter itself or my amp. I was hoping someone may know exactly what would cause that that. I'm assuming I have a bad solder joint but I can't tell by looking. Can anyone suggest which leads would cause the tweeter issue.I'm guessing the joints where the one resistor and cap are wired in parallel or where the large coil connects to the board. I'd hate to redo all of them. Or maybe something else entirely? Any advice would be greatly appreciated!

Toolfan66

Remove the poly switch, and replace it with a piece of the leads you cut off one of your capacitors, if it works your poly switch is bad.

They are junk for the most part anyways. I would just throw them out, and replace with a piece of the leads that you have left over, or replace with a .5 resistor..

dpage

Thanks toolfan. I didn't know what the polyswitch was lol so found another thread that showed a picture of it and I definitely don't have those on either crossover. But I also don't see anything replacing them. I just have the two resistors and three caps and coil. How would I add the piece of wire? What does it connect to? Thanks again

Toolfan66

After I posted I was wondering if yours would have a poly, if I was you I would go back through and look for a bad solder connection.

Have you swapped the speakers to see if the same thing happens on the other side? If so I'm betting on a bad or loose solder connection..

Toolfan66

I would even swap the tweeters and see if it happens in the same speaker, if the sound follows then it's the tweeter..

dpage

I have 10A's. I don't think they have the polyswitch. I guess that's what the fuse is for instead. I'm at work today but I'll try your suggestion soon as I can.

Toolfan66

Swap the fuses as well, can't hurt ..

jimbo1421

reported^^^^^

StantonZ

My guess is it's a bad solder joint or worse: you accidently lifted one of the solder pads off of the PCB; I did the same thing when I rebuilt my 10B XO's (except my problem was in the mid/bass section, not treble). You'll have to track down connectivity from node-to-node with an Ohm-meter. The good news is it's a small circuit; the bad news is it sounds like you haven't exactly done this before. Good luck.

BTW, 10A's have an external fuse (not a PS).

westmassguy

What wattage soldering iron are you using? I low wattage iron will not heat the copper trace and wire sufficiently for a good joint.

dpage

I'm using a cheap 30 watt solder iron from parts express.

I guess I need to learn about soldering. Hopefully just bad solder joint too. Especially since first time soldering. There are couple places where I had to solder the new leads over some thin solder that remained from previously. I couldn't get it all sucked up. Is that an issue? Also I drilled a new hole in each board because the new resistors are so much longer the leads wouldn't reach into the old holes. I assume that's ok though I made sure to drill into the same copper trace.

I'm just going to redo a couple suspect looking connections. I also worry I don't have a good connection with the leads that are run in parallel. I just have them side by side and soldered, not twisted first. That is how the original ones were so I just copied. Thanks for the help guys.

StantonZ

dpage wrote: »

I guess I need to learn about soldering. Hopefully just bad solder joint too. Especially since first time soldering. There are couple places where I had to solder the new leads over some thin solder that remained from previously. I couldn't get it all sucked up. Is that an issue?

It is if the solder is "spattered" onto another connection/trace.

dpage wrote: »

Also I drilled a new hole in each board because the new resistors are so much longer the leads wouldn't reach into the old holes. I assume that's ok though I made sure to drill into the same copper trace.

It isn't OK if you drilled out the pad/copper connection to the hole. Don't want to be the "bad guy" here, but you need to Ohm-out your connections as previously suggested before you destroy your PCB.

A 30 Watt iron should work, but a 40 Watt iron would have been better for thru-hole components.

TennMan

Can you post some high quality close up photos of the boards? Sometimes people here can spot problems from the photos.

dpage

I fixed it. Re-soldered a couple suspect looking joints. Static is gone! Haven't done any critical listening yet to check the effectiveness of the upgrades but will soon. But I have Steely Dan playing now and sounds fantastic. In case anyone is wondering I used Clarity PX caps and parts express audio grade resistors. Daytons perhaps.

Interestingly these had the wrong tweeters in them when I bought them off CL but didn't realize it until this project! They are Monitor 10A's but had the sl2500 tweeters in them. I upgraded to the rdo-198's soon after buying them. Polk said I can keep the 198's but just had to replace the 2.5 om resistor that's wired in parallel with the 12uf cap with a 2.7ohm. Weird though cause I thought they sounded great before. I'm guessing the 2.5 to 2.7 ohm resistor would just slightly change the tweeter volume.

Thanks for the help guys!

dpage

Well it could be completely subjective but I would say I gained some clarity in the midrange, more detail. And wow these tweeters are smooth! The speakers sound awesome. I'm using a Marantz nr1602 slimline and an Audiosource amp one powering the fronts.

dpage

I used to think my Monitor 4A was a great match as a center for the 10's. Now it sounds so dull and lifeless. Phantom center sounds dramatically better. I guess I should upgrade the 4's crossover or buy a new center. Like a csi a4 or something.