Monitor 5JR+ TL?

ambiophonics

I'm helping a friend modify his newly acquired monitor 5jr+ speakers. He wants to go all in on this upgrade and would love to bring the speakers to the TL level if possible. I'm looking for input on the crossover changes needed to TL these speakers. This is his crossover



I compared this crossover to the SL3000 version of full size M5 but see quite a few differences. Does anyone have suggestions on the changes needed to allow the RDO-198 to be used?

Here is the M5 SL3000 schematic as provided by Polk




I'd also like to delete the polyswitch, would you suggest jumpering that connection or adding a good quality .5ohm resistor in place?

Looks like space is pretty tight on the crossover, I'll have to do some research to figure out what binding posts will work and be creative with component placement on the PCB.

We are also going to reseal the cabs, add hurricane nuts or rings if available, replace the speaker gaskets, dynamat the drivers and pretty much anything else we can think of or you suggest. These are going to be great!

westmassguy

Don't use the 5BSL3000 schematic, use the 5JR+s_rev schematic

agfrost

Look at the 5jr+ series 2 crossover. It featured the SL2500 tweeter and the RD0198 should be a drop-in replacement for that circuit.

westmassguy

agfrost wrote: »

Look at the 5jr+ series 2 crossover. It featured the SL2500 tweeter and the RD0198 should be a drop-in replacement for that circuit.

I just said that

teekay0007

ambiophonics wrote: »

We are also going to reseal the cabs, add hurricane nuts or rings if available, replace the speaker gaskets, dynamat the drivers and pretty much anything else we can think of or you suggest. These are going to be great!

Obviously, Larry (toolfan66) is the one to ask about this, but I think in this case you'll need to go the hurricane nuts route. On the Monitor 5jr and 5jr+ speakers, both the driver and the PR are 6-1/2". For that reason, I don't think it would work to get the rings inside the cabinets. On the other speakers (ie. SDAs and other larger Monitor models), you get the 6-1/2" rings inside the cabinets by passing them through the larger PR hole. Then, you can get the larger PR ring in place by bending it - Larry makes them with perforations at 180 degrees, directly across from each other - to decrease the ring's diameter so you can pass it through its own bezel opening and flattening it out once again before fastening it in place.

I don't think the 6-1/2" rings are made with the perforations or would work as well that way. Again, Larry's the authority on this and if he says otherwise, my point is moot and should be immediately disregarded!

You could still use his tweeter brackets which do the job nicely.

If you go the hurricane nuts route, westmassguy had some good advice in a thread on drilling the holes properly so you don't splinter the bezel wood. I think the thread also gave the best place to source the proper H-nuts and screws/bolts (size and length) to do the job right.

agfrost

westmassguy wrote: »

agfrost wrote: »

Look at the 5jr+ series 2 crossover. It featured the SL2500 tweeter and the RD0198 should be a drop-in replacement for that circuit.

I just said that

You most certainly did. I most certainly did not disagree with you.

ambiophonics

westmassguy wrote: »

Don't use the 5BSL3000 schematic, use the 5JR+s_rev schematic

Wow, I totally missed that schematic. That makes the TL mod really simple, now I just need to decide what brand resistor and cap to put in.

westmassguy

Yes indeed

ambiophonics

I never realized that the RDO-198 replaced both the SL2500 and SL3000. I guess that makes the mod pretty straight forward and also eliminated the polyswitch.

Any thoughts on what binding posts would physically fit between the crossover and the mounting cup?

ambiophonics

Oh, and does anyone know a source for the 13.5uf cap, or do folks usually just combine two caps in parallel to get the correct capacitance?

westmassguy

Soniccarft has the exact value, otherwise two 6.8uf caps in parallel will get you there.
Put some Mills MRA-12 or Mundorf Mox Resistors in there too.

ambiophonics

westmassguy wrote: »

Soniccarft has the exact value, otherwise two 6.8uf caps in parallel will get you there.
Put some Mills MRA-12 or Mundorf Mox Resistors in there too.

Which sonicraft cap were you referring to? I see a ton of different caps on their site.

agfrost

The Sonicap Gen 1 Film Caps are the ones being referred to.

They'll custom-make a value for you if it's not on their list. IIRC, they charge the price of the next-larger cap for the custom value. Nice caps, nice service.

ambiophonics

westmassguy wrote: »

Soniccarft has the exact value, otherwise two 6.8uf caps in parallel will get you there.
Put some Mills MRA-12 or Mundorf Mox Resistors in there too.

The existing resistors are 5watt - do you recommend using 12 watt mills?

westmassguy

When you order the Sonicap Gen I off their website, check the box for custom matching, and tell them you want 13.5uf caps.
Mills 10 or 12 watt will both be fine

agfrost

If you have the sl3000, you certainly can. The 2500 and 3000 were both in production at the same time; the replacement for both is the RD0-198, so it should work (I can't say 'equivalent' or 'ideal', though).

If you don't have the sl3000 in hand, I'd order new 198's from Polk as it's superior to both the others.

agfrost

...and if you're only thinking of replacing one, I think you should somehow get a matched pair so you don't end up with imbalance.

westmassguy

la2vegas wrote: »

Sorry for the dumb question, but I'll ask it anyway. Can I replace an sl2500 from a 5jr with an sl3000 without modifying the crossover in any way? Hope I don't get crucified too badly.

There are no "dumb" questions. @agfrost is correct. If you have two SL3000s, replace both Tweeters. If not, then order two RDO-198-1 Tweeters from Polk.

Have we become so politically correct, rigid and intolerant, that a CP Member has to think twice before asking a simple question?

agfrost

westmassguy wrote: »

Have we become so politically correct, rigid and intolerant, that a CP Member has to think twice before asking a simple question?

Gosh, I hope not. But I'm a high school teacher and I see quite often that many questions my students have go unasked--they worry that the questions "aren't good enough" or will make them "look foolish". I tell them, "Hey, who's the most important person in this room?" Hopefully they point to themselves! "Then do whatever it takes to get yourself the necessary knowledge," says I.

So hopefully it's more a sign of human nature than the state of this board.

la2vegas, my first post here (in 2005) led to me getting a pair of RD0-198 to replace the SL2500s I had blown in my 5jr+ series 2. Sounded good! Later, I picked up a pair of RTA-11TLs and swapped the 198's and the 3000's the RTA's came with. The 5jr+ sounded good that way, too. So I think you'll be happy either way, as long as you've got a matching pair.

Jay

heiney9

Just to chime in a little late as far as deleting the poly switch. I have put in a .5 resistor in there, but it's not going to make or break the overall sound if you don't. I have bypassed a tweeter fuse with the same resistor as well in the older 5B's

H9

P.s. one thing for sure, because of the age of the xover I wouldn't leave the poly switch in. I'd either remove it completely or remove and replace with a .5 ohm resistor. They degrade over time and are past their useful life.

machone

heiney9,
Why would you bypass a tweeter fuse with a resistor?
Why not use a wire?

pitdogg2

machone wrote: »

heiney9,
Why would you bypass a tweeter fuse with a resistor?
Why not use a wire?

The resistor in .5 ohm replaces the polyswitch resistance. A straight wire path certainly can be done and many have, Some just find the tweeter will be too hot to their taste without that resistance in the circuit...

westmassguy

Real easy.... If it has a Fuse, leave the Fuse or jump it, makes no difference resistance-wise. If it has a Polyswitch, remove it, and replace it with a .5 ohm resistor. If it has neither a Fuse or Polyswitch, do nothing.

heiney9

machone wrote: »

heiney9,
Why would you bypass a tweeter fuse with a resistor?
Why not use a wire?

I misspoke about the resistor for the fuse. I deleted the fuse and ran a wire. You would only consider using the .5 ohm resistor in place of a poly switch, even then it may not be necessary.

H9

soundfreak1

You didn't mention it so replace the old wiring and connectors while in there as well.