Another Monitor 7b post -Sorry

bkreaume

Sorry if this has been answered man many times. I have looked and searched wither I find conflicting info or URls that have been reformatted.

I have a pair of monitor 7bs that look like they have peerless tweeter. Polk tech support that this model only had Sl-1000s. Can someone confirm which I have via the photo?

Also, My crossover is different than what I fond in the schematics.

1 fuse
1 34 uf cap
1 12 uf cap
1 2.7 ohm res
1 4.5 ohm res

I am not sure if someone changed things up on these or they were an in between model?

Any help would be great

Mystery

Not 7B, but here is crossover of my 7A with peerless.

https://us.v-cdn.net/5021930/uploads/attachments/1/7/0/6/5/5/80896.attach

mhardy6647

Your tweeter is a Peerless... but I don't see the trademark Polk "hole" in the center of the dome.

I have thought (i.e., I thought that I remembered) that very early 7Bs had the Peerless tweeter... but your "midwoofer" looks very old as well (i.e., Monitor 7A-old). Not sure what to make of that, either.

Do you have plastic "knobs" on the front baffle to hold the grilles in place, or do you have discs of "super-Velcro"?

Here's a 7A avec the original drivers (note the holey ;- ) Peerless) and the super-Velcro grille fasteners for comparison.

Polkmonitor7Asn4900 by mhardy6647, on Flickr

pitdogg2

I'm guessing that tweeter is an after thought...After they blew the SL1000's that they came with.

bkreaume

mhardy6647 wrote: »

Your tweeter is a Peerless... but I don't see the trademark Polk "hole" in the center of the dome.

I have thought (i.e., I thought that I remembered) that very early 7Bs had the Peerless tweeter... but your "midwoofer" looks very old as well (i.e., Monitor 7A-old). Not sure what to make of that, either.

Do you have plastic "knobs" on the front baffle to hold the grilles in place, or do you have discs of "super-Velcro"?

Here's a 7A avec the original drivers (note the holey ;- ) Peerless) and the super-Velcro grille fasteners for comparison.

definitely a 7b cabinet.




here is a closer pic of the tweeter. I would not call it a hole more like a dimple, unless it is clogged.

mhardy6647

Yup, you're right - on both counts. I vote gen-u-ine, early 7B. The mass loading (center "dust cap" provides most of the mass loading for the PR to tune it properly) of the PR looks like a 7B, too.

FWIW, I'd recommend assuming that the crossover was built the way Polk intended it to be and replace any components you choose to replace -- like for like :- )

Polk, like all small companies (and, in fact, many large ones, particularly in the days before ISO 900x standards!) made constant, and inconsistent, production changes in more or less real time (and not always well documented).

bkreaume

Thanks for the confirmation.

should that be a hole in the tweeter, I mean is it clogged and should I unclog it?

I plan on just going with dayton caps and mills resistors. I would like to go straight to the sonicaps. I am trying to limit the budget. Although I picked these up for $35, budget in tack.

pitdogg2

get the sonicaps they are worth the money and not that big a difference in price for what you are doing.

mhardy6647

I'd opine: Don't mess with the tweeter ;- )

bkreaume

pitdogg2 wrote: »

get the sonicaps they are worth the money and not that big a difference in price for what you are doing.

Do you recommend replacing both caps with Sonicaps. Maybe I am looking at the wrong Sonicaps 12 uF $22 each and 34 uF $49 each. vs. Dayton 12 uF $9 and 34 uF $10.

That's $100 a pair more. Will it make that much difference? If it is a Hell Yeah, I may consider it.

bkreaume

mhardy6647 wrote: »

I'd opine: Don't mess with the tweeter ;- )

Advice taken.. Stepping away from the tweeter

Mystery

bkreaume wrote: »

pitdogg2 wrote: »

get the sonicaps they are worth the money and not that big a difference in price for what you are doing.

Do you recommend replacing both caps with Sonicaps. Maybe I am looking at the wrong Sonicaps 12 uF $22 each and 34 uF $49 each. vs. Dayton 12 uF $9 and 34 uF $10.

That's $100 a pair more. Will it make that much difference? If it is a Hell Yeah, I may consider it.

Any new cap is better than old ones so both Dayton is fine but not as good as Sonicaps.
It's just a matter of how much you want to spend.
A better mix is use Sonicaps on the 12 uF's and get Dayton for 34uF.
Better cap in tweeter network is recommended.

Easy Runnin

You might want to bypass the fuse. I think the consensus is to put a .5 mill resistor instead of a fuse.

bkreaume

Easy Runnin wrote: »

You might want to bypass the fuse. I think the consensus is to put a .5 mill resistor instead of a fuse.

Interesting. What's the purpose of by passing the fuse

Faustin

I have a pair of 7b's with Peerless tweeters. Polk customer service (in my experience) refers to the Peerless as SL-1000 tweeters, even though the originals were made by Peerless. The brushed aluminum faced SL-1000 came after, and replaced the Peerless tweeters in later models. I have all the components to rebuild my crossovers and they have the 12uf, 34uf caps, 2.7 ohm and 4.5 ohm resistors. Perhaps other can chime in but I don't think you should be concerned about removing the fuse and adding a .5 ohm resistor in its place. The poly switches that were used in place of the fuses in later models are a problem and most people replace those with a .5 ohm resistor.

westmassguy

Some clarification here. The Peerless was designated the HF1000, the Polk tweeter that came after it was the SL1000. Technically they're not interchangeable, although Polk sent out SL1000s as warranty replacements, when Peerless ceased production. If your model has fuses and you want to eliminate them, you DO NOT add a .5 ohm resistor. If your model has a Polyswitch, and you want to remove it, you must add a .5 ohm resistor in it's place, or install a jumper, and increase the value of the shunt resistor directly down stream by .5 ohms. To remove the fuse block, drill out the center pop rivet with a 1/8" drill bit. The three holes that are left must be plugged. Polk used black painted pop rivets, and sealed the back side with hot glue. The hot wire coming from the red binding post, that used to go to the fuse block, must now be connected directly to the circuit board. If it were me, I'd leave the fuses in place. Clean the fuse block, and apply some DeoxIT. Buy some new 1 amp AGC Fast Blow Buss Fuses. They do make Audio Grade Fuses, that are quite expensive. I've not had ears on them, so can't tell you if the are any better than plain Buss Fuses.
As a side note, the pin hole was done by Polk, using a fine tip soldering iron. I believe it was done to mitigate some resonance peak, or modify (smooth out?) the overall frequency response of the tweeter.

pitdogg2

I'd also leave that fuse alone it'll save your tweeter on those days when you think you need a little more loudness.

mhardy6647

pitdogg2 wrote: »

I'd also leave that fuse alone it'll save your tweeter on those days when you think you need a little more loudness.

Yeah, that's kind of the way I feel about those fuses, too...

gdb

I've blown a few 1Amp fuses in my Mon. 10A's that reside in my workshop. (loudness required) The Peerless tweeters are still singing as a result.