Polk 4's with Peerless Tweeters

alkermes

I thought folks might like to see these. I am guessing these are early models, from what I've been able to research. The crossovers are marked 14 Jul 1982. Peerless tweeters and MW6500 woofers. Sound is not exactly what I called balanced, it's weighted heavily towards the trebly side. That said, listening to a Wynton Marsallis trumpet piece was really quite beautiful.

Faustin

I found a set of early 4's a few months ago with Peerless tweeters. My crossover configuration is different than yours but they are from 1982 also. When I bought them one had a MW6500 and the other a MW6502. After looking in to the different 6.5's I was informed the 4's are 4 ohm speakers and should have the MW6502 which is 4 ohm not the MW6500 which is 8 ohm. When I looked at the original schematic for the 4a and the revised schematic they both show the MW6502. I found another 6502 and replaced the 6500. Still have to redo the crossovers but they still sound very good.

StantonZ

Have a pair of 4's with peerless tweets (original owner) BUT the emblem is on the grill cloth (not the cabinet). The previous poster is correct in that they should have MW6502 woofers (don't know how yours ended up with 6500--maybe that explains some of the sound issues). Even though I re-built my 10B XO's, I've decided not to touch my 4's: they sound too good as is!

alkermes

Thanks, that's interesting to know. I'll take another look and see if it says anything about 8 ohms vs. 4 ohms on the back of the speaker. If I recall there wasn't much of anything there in the way of text. I've only opened up one of the speakers, I'll check the other and see if the woofer code matches (visually they do match).

I meant to mention, in the speaker I opened up there was some black foam which was sticky and a little moist; on removing it, the foam crumbled like a relic from a desert tomb. Any recommendations on re-stuffing it?

Also, these are protected with external fuses on the rear. One of the tweeters wasn't producing any sound when I first got them, but it turned out to be a tarnished fuse contact.

Mystery

Yes you are correct.
They are very bright and strong at it.
Without a subwoofer, they sound irritating but with a sub, very very nice.
Here is mine:

Faustin

My 4's had the black foam in them also. I removed it and loosely filled them cabinets with polyfil that I bought at Walmart. Generally used to stuff pillows etc.

Nightfall

Mystery wrote: »

Yes you are correct.
They are very bright and strong at it.
Without a subwoofer, they sound irritating but with a sub, very very nice.
Here is mine:

Stop teasing me!

alkermes

<Yes you are correct.
They are very bright and strong at it.
Without a subwoofer, they sound irritating but with a sub, very very nice.
Here is mine:>

Yupp, that's it all right! I just checked the serial numbers on mine, they are #05819 and #05820. The second woofer is also an MW6500. Date codes on the woofers are May 1982. Are these 4 ohm speakers? How would I check?

alkermes

Faustin wrote: »

My 4's had the black foam in them also. I removed it and loosely filled them cabinets with polyfil that I bought at Walmart. Generally used to stuff pillows etc.

Thanks for the info, that's the same foam. We have some polyfill hanging around the house somewhere I'll can try.
As far as I can tell my XO only has one cap in it. But it is tightly glued together, maybe there's another cap stuffed in the bottom.

boston1450

I would love to hear the 4's with peerless. Those ^^ all look very nice. I have the 4's series 2 & the tweets dont sound too aweful bad buti know that with the peerless they gotta sound clearer . The 4's are amazing little speakers IMO

Faustin

Here are the schematics. Maybe someone can give their opinion about 4 ohm vs 8 ohm. Maybe wesmassguy?

alkermes

Faustin wrote: »

Here are the schematics. Maybe someone can give their opinion about 4 ohm vs 8 ohm. Maybe wesmassguy?

Thanks for posting these. Looks like the date on the m4a original schematic is 1984, so unfortunately this is later than the ones I have. Also they list MW6502's. I didn't write down the value of the cap but I am pretty sure it wasn't 12uf. So it seems my 4's pre-date this.

westmassguy

Something is amiss here. The Peerless, are 8 ohm, and the MW6500's are also 8 ohm. None of the schematics here match what you have. The MW6500's T/S parameters are vastly different than the MW6502s. The VAS alone is more than double the 6502s. I can't see how the 6500s are operating anywhere near optimum efficiency in that small enclosure. You will need to measure the Inductor values, find the capacitor and any resistor (if any) values for us to figure out what's going on.
BTW, the Peerless shown in the photo doesn't appear to fit properly either. It should be flush with the speaker baffle.

Faustin

It appears that the Peerless tweeters in my 4's are 8 ohm. Should they be 4 ohm tweeters?

westmassguy

To my knowledge, that only Peerless model Polk used was 8 ohm.

Mr. Bubbles

Mystery wrote: »

Yes you are correct.
They are very bright and strong at it.
Without a subwoofer, they sound irritating but with a sub, very very nice.
Here is mine:

My very first pair of Polks looked just like these. however the label on the back says 5 Jr. i have never removed the drivers to measure or verify models, etc because shortly after these I found my SDA 2A's then RTA 12's and so on. It has me curious though that mine look like these but are labeled a different model. Does this sound reasonable to anyone here knowledgeable about these smaller models?

Mystery

Mr. Bubbles wrote: »

My very first pair of Polks looked just like these. however the label on the back says 5 Jr. i have never removed the drivers to measure or verify models, etc because shortly after these I found my SDA 2A's then RTA 12's and so on. It has me curious though that mine look like these but are labeled a different model. Does this sound reasonable to anyone here knowledgeable about these smaller models?

5Jr either had a port just like the 4's above or a 6.5" passive radiator.
5Jr had Peerless, SL2000, SL2500 (may be) etc... tweeters but never had triangle plastic tweeter that 4 series II uses.
The cabinet of 5JR is taller than 4 and the gap between the port and woofer as well from port to the bottom is much larger than in 4's .
That's only on the physical characteristics.
Here is what 5Jr's look like:

Mr. Bubbles

Mystery wrote: »

5Jr either had a port just like the 4's above or a 6.5" passive radiator.
5Jr had Peerless, SL2000, SL2500 (may be) etc... tweeters but never had triangle plastic tweeter that 4 series II uses.
The cabinet of 5JR is taller than 4 and the gap between the port and woofer as well from port to the bottom is much larger than in 4's .
That's only on the physical characteristics.
Here is what 5Jr's look like:

Thanks, that would seem to make sense. Mine have the Peerless tweets. its been a while since i actually looked at mine and didn't really judge the spaces between port and driver and bottom, etc. Can't remember if mine are beveled like the ones in picture or not but do have the grille that stops short of bottom of cabinet.

TNHNDYMAN

I believe the 5jr always had a port and not a passive radiator. The 5's had the passive radiator same size as the driver whereas the 7's had a larger than driver passive radiator.

markamerica

TNHNDYMAN,

That's not so. Here is an example with 6.5 passives: http://www.ebay.com/itm/Polk-monitor-5-JR-Junior-Speakers-PAIR-Classic-1990s-Great-speaker-/331050361334?pt=Speakers_Subwoofers&hash=item4d1423a1f6

(Not in any way affiliated with listing.)

Mystery

TNHNDYMAN wrote: »

I believe the 5jr always had a port and not a passive radiator. The 5's had the passive radiator same size as the driver whereas the 7's had a larger than driver passive radiator.

Nope.
5Jr came with port or a 6.5" PR.
5's have 8" PR.
7's have 10" PR.

TNHNDYMAN

Well there you go, I stand very corrected. Sorry. I've had a pair of the 4's, 5's, 3 pair of 7's, and 2 pair of 10's, but only one orphan 5jr that was ported and still I get the models and drivers confused.

westmassguy

Mystery wrote: »

Nope.
5Jr came with port or a 6.5" PR.
5's have 8" PR.
7's have 10" PR.

The 5Jr+ has the 6.5" PR

westmassguy

And let's not forget the 4.6s which have the SL2500, a MW6502, and an actual port, not just the port hole. I picked up 3 pairs of them to flesh-out the rest of my home theater surrounds

Mystery

I have one orphan 4.5 and had a pair of 4.6.
Just to make less confusing.

westmassguy

Mystery wrote: »

I have one orphan 4.5 and had a pair of 4.6.
Just to make less confusing.

I'll tell ya, the 4.6s are sweet. Too bad they were the last Monitors from that era.

alkermes

westmassguy wrote: »

Something is amiss here. The Peerless, are 8 ohm, and the MW6500's are also 8 ohm. None of the schematics here match what you have. The MW6500's T/S parameters are vastly different than the MW6502s. The VAS alone is more than double the 6502s. I can't see how the 6500s are operating anywhere near optimum efficiency in that small enclosure. You will need to measure the Inductor values, find the capacitor and any resistor (if any) values for us to figure out what's going on.
BTW, the Peerless shown in the photo doesn't appear to fit properly either. It should be flush with the speaker baffle.

Here are a few more pictures. I checked the tweeters, that is in fact how they sit in the cabinet, not quite flush. There is a thin foam gasket underneath the tweeter but not enough to make it poke up. There is a single 5.8uf cap and an inductor. Pretty simple. I don't have any way to measure the inductor value, I have an Fluke DMM but I don't think that is sufficient.

Also - how does one get the pictures to show in the post?

westmassguy

alkermes wrote: »

Here are a few more pictures. I checked the tweeters, that is in fact how they sit in the cabinet, not quite flush. There is a thin foam gasket underneath the tweeter but not enough to make it poke up. There is a single 5.8uf cap and an inductor. Pretty simple. I don't have any way to measure the inductor value, I have an Fluke DMM but I don't think that is sufficient.

Also - how does one get the pictures to show in the post?

Is there another inductor around the outside of the binding post cup/spool?

alkermes

westmassguy wrote: »

Is there another inductor around the outside of the binding post cup/spool?

It's hard to see because of the hot glue, but yes there is a second inductor wound around the assembly.

westmassguy

alkermes wrote: »

It's hard to see because of the hot glue, but yes there is a second inductor wound around the assembly.

5.8uf with bypass inductor, equals a 2nd order on the Hi-Pass, and is about right for a 2k crossover point. Without knowing the inductor values, there's no way to tell the Lo-Pass crossover frequency.

alkermes

westmassguy wrote: »

5.8uf with bypass inductor, equals a 2nd order on the Hi-Pass, and is about right for a 2k crossover point. Without knowing the inductor values, there's no way to tell the Lo-Pass crossover frequency.

Thanks for the info, is that typical for this sort of two-way design with these tweeters?

Seems quite likely the current caps have drifted high by now. What do you think, would it be likely to sound better with some new caps? It looks like it would be easy find correct values to parallel.