Upgrading Monitor Xovers to use the RDO-198

kcoc321

This discussion came up in another thread, and since the original OP's thread was about something totally different, I thought I would start a new thread.

First question: As far as replacing a SL2500 with a RDO-198, once you have rebuilt the cross over to match the Series II specifications, would there be any difference?

I personally would like to know as well, as I am going to do the same thing to my Monitor 7's, (and Monitor 5jr's) and plan to use the RDO-198's also, since I am already going to be upgrading the Xovers anyway.

Big Dawg's comment that prompted the question:

Big Dawg wrote: »

I have the 5Jr+ with SL2000 tweeters. The Monitor 5Jr+ Series Two came out using the same passive and same mid (MW6502?), but with the SL2500. The crossovers use the same inductors, but with slightly different caps and resistors. If I follow the Series 2 schematic for the speaker with the SL2500, could I then use the RDO198 instead of the RDO194 in my non-series 2 5Jr+? Face (Mike) says no. All thoughts on this topic very welcome, as I want to order parts and begin upgrading!

I do not know near as much as Face, and I am not going to tell you to go against his advice, But again I think there must be some confusion. But that is why I created this thread.

Big Dawg

Thanks for starting this thread, Kcoc321.

Here's the schematic of the speaker I have:

http://www.polkaudio.com/forums/attachment.php?attachmentid=18770&d=1155784674

And here's the schematic of how I was planning on modding the crossover:

http://www.polkaudio.com/forums/attachment.php?attachmentid=18771&d=1155784674

Note that the only differences are the tweeter, the C1 capacitor, and the poly-switch (the Series 2 doesn't have one).

Looks straightforward, right? But Face, who knows more about this stuff than I can ever hope to know, told me that I can't (shouldn't?) use that schematic, but rather I should use this one:

http://www.polkaudio.com/forums/attachment.php?attachmentid=18767&d=1155784608

That schematic is for upgrading the 5B from the SL2000 to the SL3000. My 5Jr+ has the same drivers as the 5B drawing, but different inductors, etc.

I'm feeling a bit lost.

BTW, assuming I am able to manage this upgrade, I too have a pair of 7Cs waiting for their upgrade.

As always, any (hopefully informed) opinions invited and encouraged.

Dawg

ben62670

Use a 12uf cap and a 2ohm resistor. Omit the poly switch.

kcoc321

Well here's hoping he will explain it to us noobs.
I knew about the 5.8uF bypass cap on the LF resistor.
(it's a 8uF on the 7's series II)
http://www.polkaudio.com/forums/attachment.php?attachmentid=18774&d=1155784729

ben62670

If you have the 7's keep them at stock values.

kcoc321

ben62670 wrote: »

If you have the 7's keep them at stock values.

...but add the bypass cap, right?

thanks

ben62670

Its not a bypass cap, but yes keep the 8uf in it.

kcoc321

What IS the correct term for the Cap that loops around the resistor?

heiney9

The 5B never used the sl3000 so why not just stick with the original X-over schematic and do it that way?

That's what I would do and is my .02c

H9

Big Dawg

heiney9 wrote: »

The 5B never used the sl3000 so why not just stick with the original X-over schematic and do it that way?

That's what I would do and is my .02c

H9

Not sure I quite follow you. I have a 5Jr+, not a 5B. The Series 2 version of the 5Jr+ uses the SL2500. If I modify my crossover to mimic that one, can I then replace my SL2000 with an RDO198, and will I be happy with the result?

heiney9

Have you called Polk CS to discuss with the people who engineered the speaker? That's what I'd do as get the answer from the horses mouth.

Good luck

H9

Big Dawg

heiney9 wrote: »

Have you called Polk CS to discuss with the people who engineered the speaker? That's what I'd do as get the answer from the horses mouth.

Good luck

H9

Thanks, I'll call today.

Big Dawg

Just got off the phone with Ken, who suggested I follow the 5Jr+ Series 2 schematic (for the SL2500) pretty closely.

Ken was great, carefully explaining everything. I highly recommend calling him with questions. Thanks for the advice, H9!

Meanwhile, George Daniel has kindly offered to talk me through it as well.

As soon as I talk with him, I'll order parts and try it out.

ben62670

Ken is back?

Big Dawg

ben62670 wrote: »

Ken is back?

My bad, it was Kim I spoke with.

He was still great....