Monitor 5B crossover capacitor advice

cortico · May 2015

Hi all,

I am planing to recap the Monitor 5b's crossovers. These speakers will be connected to a Marantz 2270. I am aiming looking for a warm sound with smooth top end and nice midrange.

Can you please recommend capacitor and resistors type/brand? Nothing to fancy or expensive...

Thank you in advance!
Best

westmassguy · May 2015

Sonicaps, and Mills MRA-12 Resistors.
If you want to cut costs a bit, use a Dayton or Solen for the large Lo-Pass Shunt Cap.

nspindel · May 2015

That's exactly what I just did with a pair of 5B's, here's a thread with photos of the finished crossovers:

http://forum.polkaudio.com/discussion/167490/my-newly-refurbished-monitor-5s

Here's another thread where we had a lengthy discussion about what to do with this crossover, not so much the particular brand but rather which spec to follow:

http://forum.polkaudio.com/discussion/166855/is-there-a-schematic-for-the-monitor-5a/p1

cortico · May 2015

Thank you for the advice. Nice work on your crossovers! Apparently sonicaps is the way to go, I may install Axons on the LF side to offset the cost.

I was also considering to replace the SL2000 tweeter with the RDO-198-1, as per my research, to do so I will have to change the cap value from 12uF to 13.5uF. is this correct?

westmassguy · May 2015

cortico wrote: »

I was also considering to replace the SL2000 tweeter with the RDO-198-1, as per my research, to do so I will have to change the cap value from 12uF to 13.5uF. is this correct?

No. The drop-in replacement for the SL2000 is the RDO-194-1. If you want to upgrade to the RDO-198, You'll be adding a 5.8uf Shunt Cap, and changing the Shunt Inductor, both in the Hi-Pass Section. Look in the vintage non-SDA schematics section, and find the m5b_sl3000mod schematic.

cortico · May 2015

LF cap spec is 34uF, I have troubles finding replacements with the exact capacitance. Would 36uF be fine?

F1nut · May 2015

Sonicap has a 33uF and if you request it they will try to find some that are closer to 34uF.

westmassguy · May 2015

34uf is stock now Jesse

teekay0007 · May 2015

F1 and WMG: I think you missed the part where the OP said he was thinking of using Axon caps (instead of Sonicaps) in the LF side "to offset the cost".

F1nut · May 2015

34uf is stock now Jesse

Ah, very good!

"to offset the cost".

Cost be damned, full speed ahead!!!

westmassguy · May 2015

teekay0007 wrote: »

F1 and WMG: I think you missed the part where the OP said he was thinking of using Axon caps (instead of Sonicaps) in the LF side "to offset the cost".

If he's ordering from Parts Connexion, they have the Solen Fast Cap, 33uf for $15.00

nspindel · May 2015

Dave, why wouldn't he want to go the same route I did and use the 7B SL2500 design with 8uF cap instead of the 5.8? Then he wouldn't need the 34uF, he'd use a 27uF. Would need to do coils as well.

nspindel · May 2015

I'll tell you one thing, I'm pretty amazed at how great these Monitor 5's sound just with an old receiver. I think these old Monitors are capable of sounding far better with lesser power sources than the SDA's. The SDA's will blow the Monitors away with better power, but my 4.1TL's sound just ok with this receiver.

nspindel · May 2015

I spent $208 at Sonicraft to do the 7B spec, including the Cardas Litz wire and some QE solder. That was for the caps and the resistors. Then the coils were $26 at Parts Express. I'd also advise doing the hurricane nuts with armacell gaskets. And the dynamat.

nspindel · May 2015

Should also mention that I only spent $60 on the speakers, so there was room in the budget to splurge on the upgrades.

westmassguy · May 2015

nspindel wrote: »

Dave, why wouldn't he want to go the same route I did and use the 7B SL2500 design with 8uF cap instead of the 5.8? Then he wouldn't need the 34uF, he'd use a 27uF. Would need to do coils as well.

Neil, the OP, said not too fancy or expensive. Sonicaps and Dayton or Solens will do nicely.

stogie · May 2015

On my m5 rebuild I used Sonicaps/Daytons/Mills per David's advice and they sound very nice. But I don't have another pair of m5's that were modded differently to compare them to.

nspindel · May 2015

westmassguy wrote: »

nspindel wrote: »

Dave, why wouldn't he want to go the same route I did and use the 7B SL2500 design with 8uF cap instead of the 5.8? Then he wouldn't need the 34uF, he'd use a 27uF. Would need to do coils as well.

Neil, the OP, said not too fancy or expensive. Sonicaps and Dayton or Solens will do nicely.

Yeah but I'm not referring to brand, I mean the spec. Why not do the crossover as I did but still use a Dayton or Solen for the shunt?

westmassguy · May 2015

You bought new Inductors Neil. That adds to the cost.

cortico · May 2015

Thanks for the much appreciated feedback, my goal is to keep the original warmth and smoothness I like , I'm not a treble junkie, but add longevity to the system.

My 2270 was recapped a year agod, but is 40 years would, sounds great, but probably I will not benefict using high-end caps.

I am leaning towards the a 12uf Clarity cap ESA, 33uf solen, 2.7 ohm 10w mills resistors. I may redo the wiring as well, 18ga ok ?

westmassguy · May 2015

So let's recap... You're replacing the caps with the same values, changing the resistors, and replacing the SL2000 Tweeters with RDO-194-1s?
Does your crossover have a fuse block, or a Polyswitch?
Where are you located, US or Canada?

cortico · May 2015

I am located in New York

Yes, I am keeping all original values and replacing the SL2000 with the RDO-194-1. There is no polyswitch the crossovers have a fuse block. I forgot to mention that I will also replace the grill cloth and add a few dabs of epoxy glue around woofer magnets.

Probably I will also replace the electrolytic caps on a 5JR+ I have. Do you have tips how to disassemble this crossovers so the components are exposed? The circuit board is reversed and seems to be glued I can't release it from the block.

Thanks

westmassguy · May 2015

If you're in NY, order from Madisound, not Parts Connexion. Their Clarity prices are less. I would also recommend Clarity ESAs for the Hi-Pass, and Clarity PX for the Lo-Pass. The PXs will blend much better with the ESAs than a Solen or Dayton. You would need a 15uf and 18uf in parallel to make the 33uf. It will also be easier to fit everything on the circuit board. Order the 2.7 ohm Mundorf MOX resistors from them as well.
You'll need to post a photo of the 5jr+ crossover.

westmassguy · May 2015

The 5B looks typical, and the 5JR is the last crossover version Polk made for that series. Everything is on the underside of the circuit board. Remove the two Phillips head screws, and it should lift off.

cortico · May 2015

I'll do that! Please see below crossover pics.

5B crossover pics:

5JR+ crossover:

cortico · May 2015

the monitor 5B sounds pretty amazing as is. I need to find a MW6502 woofer for the 5JR+, the one I have is frozen… and they're pricey on "flipbay"

ps: sorry for the triple posts, no idea how that happened.

cortico · May 2015

why Monitor 5B and Monitor 5JR+ crossovers circuit look so different, both speakers use same drivers?

Now the big dilemma, should I go:

a) Clarity Caps ESA with Mundorf resistor?

or

b) Sonicaps with Mills resistor?

[Deleted User] · May 2015

Hello,
There was something about your recent posting (probably the photo links) that caused it to be sequestered for moderator review. Since you had tried reposting three times when it was released all four copies were posted. I've made sure no future postings, of yours, would be set aside for review and deleted the surplus copies.
Cheers, Ken

cortico · May 2015

Now I see, i did that. Thanks Ken!

westmassguy · May 2015

cortico wrote: »

why Monitor 5B and Monitor 5JR+ crossovers circuit look so different, both speakers use same drivers?

Now the big dilemma, should I go:

a) Clarity Caps ESA with Mundorf resistor?

or

b) Sonicaps with Mills resistor?

The 5Bs were built prior to 85', the 5Jr+s much later. Look at the dates on the woofers. The woofers may be the same, but the cabinet size and PRs are different. Both were tuned differently. Also confirm the Jrs have SL2000, not SL2500s

cortico · June 2015

Yes, the Jrs have the SL2000.

Would you recommend me a grille cloth brand that has the same original vintage look?

Monitor 5B crossover capacitor advice

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