Monitor 5A 1983 USA Peerless crossovers

pkquat

I have a set of the above that I plan on redoing the crossovers on eventually. What is the difference between the long back caps vs the dark blue light blue versions? Was one potentially better than the other back in the day? I also ask because I picked up a spare pair of crossovers from the same year speakers and they are a mix of the two. One crossover has both black caps, and the other has one of each. They I think they are both original. One of mine has both blue caps, also original.

I have also been looking for history on the 5's. It seams there was a lot of variation, mixing and matching in the early 80's including MW's, PR's and a change in cabinet size. Has any of this been cataloged anywhere. I have yet to find it. I found a reference to "Stan's threads" but I am not sure which those are.

http://forum.polkaudio.com/discussion/158975/monitor-5a-crossover-oddity-and-other-weirdness

Did the Monitor 7's have the same variations? I don't think the cabinet size or the PR changed, but I gathered the MW's and tweeters did.

pitdogg2

long black should be a Mylar, the blue should be Electrolytic bi-polar

Pictures would help a bunch

F1nut

Caps came in different colors then just as they do today.

pkquat

Thanks for the info. So the mylars were a little better back then. I wonder why they switched, but I suppose every dollar counts. Attached are the mixed spares I got.

pkquat

I realized I did have a pic of one of my crossovers with me, and I was wrong. Mine have one of each. I know these have not been changed. Maybe I had seen a pic with two black ones elsewhere.

westmassguy

Those are all Electrolytics

pkquat

I've been trying to read up on crossover rebuilds, and mods in general. I assume leaving the inductors as is would be fine. I don't really have a way to check them. If the resistors measure fine, can I leave them, although it appears replacements are not very expensive.

Part of the reason I got spares is I think my 5's currently sound pretty good overall other than the lacking bass. I think I confirmed it this weekend when I got my Newform Research R830's assembled again. They gave them a run for the money on the mids on up. The bass of course is lacking. I think my M5 tweeters might be a little off because they seam to have a bit more upper highs, and have a little more of the "hiss" sound when cranked. For the most part though they were close. I haven't checked the R830 crossovers. I did get them used, and I would assume for their price new they didn't use electrolytics.

I also read about rolling the poly-fill up here when searching inductors. http://forum.polkaudio.com/discussion/171345/new-sda-2bs-larrys-rings-dynamat/p2

Mine appears stuffed in behind the PR below the crossover wires. Is rolling it up the best or easiest solution? Should I move it above the crossover behind the MW or is it supposed to be in between? If you use the BH material behind the MW do you leave the poly fill in?

westmassguy

You should change the Resistors to Mills MRA 10 or 12 watt, and double check the values. The Peerless Crossovers had different resistor values than the later SL1000/SL2000 revisions

pitdogg2

I would recap them with film caps as well as resistors all new. The poly fill needs to be behind the mids and tweeters never behind the passive. If you use black hole or something similar still use the poly as well. a little black hole goes a long way so be careful

pkquat

I found one reason the poly fill was stuffed in at the bottom. There were a spiderwebs of glue, and loose glue chunks along with stalactites. I cleaned all that out. I moved the poly fill roll up to the poly fill behind the tweeters. It was only covering about half of the MW's. I am guessing it should be behind all of he MW. The mids are too bright now. There is a little peak in them that was not there before. Then again it might be the crossovers.

The bass the lower bass is a little more noticeable, and I can feel a little more thump. I think there was an extension, but the roll off is starting sooner, too soon, and is not as steep. Or maybe its that the mids are a little louder. It appears there is less MW effort too.

I replaced my stock black 1983 PR's with silver basket ones, and I noticed a little bass. I think there may be a small difference between them. The feel lighter, but the baskets also feel thinner and have no paint. I have another 1983 one coming, so I'll see if that makes a difference.

How do the SL2000 version Monitor 5's with the slightly larger cabinet sound compared to the 5A's (MW overlaps the PR) in the mid to bass region? Is there any improvement? There is a pair near be for $50. I am thinking of picking them up.

westmassguy

The overall frequency response of the large 5s is about the same. The great thing about the later 5s, with the Sl2000s, is they can be fully upgraded, with RDO-198 Tweeters.

pkquat

I was hoping they might have a little more impact, but guessed as much. I really need to find some 7's, but for $50, its a worthwhile upgrade project.

Should I move the poly fill down some or unroll it a little to so it is completely behind the MW? Could I add some?

westmassguy

The Dacron should be from the bottom of the woofer opening all the way to the top.

pkquat

TY. That is what I speculated. I'll change it when my spare PR arrives.

The $50 5's were gone before I had the chance to check them out.

xschop

westmassguy wrote: »

The overall frequency response of the large 5s is about the same. The great thing about the later 5s, with the Sl2000s, is they can be fully upgraded, with RDO-198 Tweeters.

WMG, is that due to the crossover design difference or cabinet fitment of later 5's?

westmassguy

The Tweeter upgrades, whether the drop-in RDO-194-1, or RDO-198-1 with modifications, are possible due to the later crossovers.

xschop

So would a later crossover physically fit the early boxes?

pkquat

I forgot to measure the crossovers, but I think they are the same size / mold.

I got my spare PR, thanks Adam, it was from the same lot as mine. It appears they were mounted in the same orientation too FWIW. The bad news is the very small crack that was starting in my good PR was larger than I remembered. I will need to find yet one more PR in the future. I also verified that surrounds on the 1983 PR's are stiffer than the earlier silver basket ones I had.

I unrolled the poly fill some so it was still touching the poly fill behind the tweeter, and there were about two layers behind the MW. The wires to the MW prevented it from going any lower. This quieted the mids down closer to what they were before, but they are still a little bright, and there is some muddiness that was not there before. Its probably cross over time unless they were supposed to have poly fill behind the PR from the factory during this time.

The correct PR's did improve the mid bass some, or maybe it was rolling the polyfill down. Don't want to do too many swaps until I can get hurricane nuts or Larry's rings. I am really surprised at how much bass you can feel after moving the poly fill. the roll off is till sooner than I remember, but there is more low bass impact, bur sadly not volume. I am guessing the impact is because the base of the cabinet is vibrating more and transmitting that to the floor.

xschop

I bookmarked this thread for future mod. Thanks for clarification and insight.

pkquat

The crossover plastic mold that gets screwed to the cabinet is the same between a M5A and a M5jr+ series. They are physically interchangeable. However, the M5A uses plastic standoffs for the circuit board, and the M5jr+ is screwed to it on risers.