SRS 1.2 & 1.2tl questions

davis419b

I have 2 sets of srs 1.2s. First set, the SL-3000 tweeter is dated 1989 and thw second set the SL-3000 is dated 1991. First set on the back is labeled srs 1.2 and the second set is labeled srs 1.2tl. Are both sets tl,s and the first set is mislabeled ? My second question is the crossovers appear to be different. The one on the left came from the set marked 1.2 and the one on the right came from the one marked 1.2tl. Either the first set has been modded or Polk made some changes from 1989 to 1991. I thought about swapping crossovers to do an A-B comparison but before I do I would like to get some opinions. I am attaching pictures.

Thanks, Don

bluecomet

If the set has SL3000 tweets and the prongs that go into the SL3000 tweets have one fat prong and one thin prong then they are 1.2tl's. I have the same type of speakers. If the prongs are both thin that go into the tweets then someone switched out the SL2000's with SL3000's. How do the speakers sound. Are there any issues with the speakers.

davis419b

bluecomet wrote: »

If the set has SL3000 tweets and the prongs that go into the SL3000 tweets have one fat prong and one thin prong then they are 1.2tl's. I have the same type of speakers. If the prongs are both thin that go into the tweets then someone switched out the SL2000's with SL3000's. How do the speakers sound. Are there any issues with the speakers.

Thanks bluecomet,


Both sets have one fat and one thin prong on each tweeter. The 89 set sounded fabulous when I got then 2 months ago. Lately it seemed as the highs went away. Last night I took a paper towel roll and listened to them.
The second tweeter down on the left was not working and neither was the third one down on the right. I was considering swapping the tweeters out from the 91,s to see if it was just 2 bad tweeters. I just wanted to be safe and check it out with you guys first.

Toolfan66

You can't swap out a 2000 tweeter with a 3000 tweeter without changing the female connector.

ben62670

Someone got in there for sure. Time for a rebuild. The left one has been poorly modded.

bluecomet

Both of his sets are 1.2tl's. You can swap them to test if it is a tweeter issue or crossover issue. It may be a polyswitch issue. Test the speakers at low volume and see if the tweets come back on. If they do the polyswitch reset and there is your problem. If not swap the tweets and see if the tweets are bad. If the tweets are not bad then something is going on with the crossover board. Good luck.

bluecomet

I was writing while Ben made his post. I guess it is a crossover issue. Send them to Ben. He will be able to help you. I have a feeling I will have to do the same thing with one of my sets. One of my 1.2tl sets, which is marked 1.2 on the back of it had a RDO 194 tweet stuck in it. Could that mess things up with the crossover. I have since corrected it with a SL3000 tweet. I am sure the previous owner called Polk and send one of his tweets went bad and on the back of it, it says 1.2, the RDO 194 is correct for that speaker. It makes you wonder how many speakers that are mismarked in the back have improper tweets and drivers in them.

Toolfan66

bluecomet wrote: »

I was writing while Ben made his post. I guess it is a crossover issue. Send them to Ben. He will be able to help you. I have a feeling I will have to do the same thing with one of my sets. One of my 1.2tl sets, which is marked 1.2 on the back of it had a RDO 194 tweet stuck in it. Could that mess things up with the crossover. I have since corrected it with a SL3000 tweet. I am sure the previous owner called Polk and send one of his tweets went bad and on the back of it, it says 1.2, the RDO 194 is correct for that speaker. It makes you wonder how many speakers that are mismarked in the back have improper tweets and drivers in them.

Screw the RDO-194's if they are in fact 1.2's, if they are 1.2's have Ben do the tl upgrade on the crossovers and order the RDO-198's it will cost the about the same anyway....

davis419b

bluecomet wrote: »

Both of his sets are 1.2tl's. You can swap them to test if it is a tweeter issue or crossover issue. It may be a polyswitch issue. Test the speakers at low volume and see if the tweets come back on. If they do the polyswitch reset and there is your problem. If not swap the tweets and see if the tweets are bad. If the tweets are not bad then something is going on with the crossover board. Good luck.

If it were the polyswitch would'nt it cause all of the tweeters to go out. I am only having the tweeter problem with one tweeter on each speaker

ben62670

On those speakers the volume of a few of the tweeters are very low. Test with a cardboard tube placed carefully over the diaphragm of each tweeter. Also you can replace a known good tweeter in place of the "bad tweeter".

bluecomet

I have two sets of the 1.2tl's. One of the 1.2tl sets had one RDO 194 tweet in the left speaker by mistake. I know it is an early 1.2tl set. It says 1.2 on the back of it but the speakers have the original SL3000 tweets and the prongs for the connection is fat and thin. Could having the wrong tweet in a speaker mess up the crossover is my question. I have no idea how long the original owner played the speaker with one incorrect tweet. Thanks.

F1nut

The crossover on the left has BE-2000 C printed on the white label, which means it is an 1.2TL crossover. Why it has 3 polyswitches and those funky caps is anyone's guess, but that is not factory work. The crossover on the right is an 1.2TL crossover even though it does not have a label.

The reason the one pair has 1.2 instead of 1.2TL is that Polk had a habit of using up older labels before using the newer ones.

If it were the polyswitch would'nt it cause all of the tweeters to go out.

100% correct. You have 2 bad tweeters. Replace all of them with the RD0198-1.

Could having the wrong tweet in a speaker mess up the crossover is my question.

No.

FTGV

Just curious ,in the xover on the left what are the values of the 2 series connected electrolytics and yellow series connected film caps?

restanim

F1nut wrote: »

The crossover on the left has BE-2000 C printed on the white label, which means it is an 1.2TL crossover. Why it has 3 polyswitches and those funky caps is anyone's guess, but that is not factory work. The crossover on the right is an 1.2TL crossover even though it does not have a label.

The reason the one pair has 1.2 instead of 1.2TL is that Polk had a habit of using up older labels before using the newer ones.

My SRS-1.2TL's label on the back of the cabinet read "SRS-1.2". They have the BE-2000 C sticker on the x-over board and they even have the three poly switches soldered in parallel just like the one pictured above. As far as the caps in series, I do not remember if mine are like that.

Mike

FTGV

restanim wrote: »

even have the three poly switches soldered in parallel just like the one pictured above.

I assume this is to allow higher current before tripping,and being parallel their series resistance will be lowered.

davis419b

restanim wrote: »

My SRS-1.2TL's label on the back of the cabinet read "SRS-1.2". They have the BE-2000 C sticker on the x-over board and they even have the three poly switches soldered in parallel just like the one pictured above. As far as the caps in series, I do not remember if mine are like that.

Mike

I dont know squat about electronics but it just does not look professional the way they are twisted together. Im with Ben on this one , it looks jacked up !

DarqueKnight

I never cease to be amazed at SDA "modifications". This is the first time I have seen the "three polyswitch" mod.

Don (davis419b), are you able to contact the previous owner(s) to find out what was done to the first set of 1.2TL's and why? You might also want to try to find as much info as possible on the listening habits (e.g. excessive volume) and the amplifiers that were used with the 1989 set. Blown tweeters and unorthodox modifications make me think those speakers have not been treated too kindly.

davis419b

DarqueKnight wrote: »

I never cease to be amazed at SDA "modifications". This is the first time I have seen the "three polyswitch" mod.

Don (davis419b), are you able to contact the previous owner(s) to find out what was done to the first set of 1.2TL's and why? You might also want to try to find as much info as possible on the listening habits (e.g. excessive volume) and the amplifiers that were used with the 1989 set. Blown tweeters and unorthodox modifications make me think those speakers have not been treated too kindly.

I bought them from the original owner (he said) but he really could'nt tell me anything about them. I had to come here and join the forum to learn anything about them. I went ahead and bought em, brought them home, hooked them up and loved the sound. One thing that is puzzling me is the color of the faceplate on the modded crossovers. Here are some pics. The first one is of the modded crossover and the second is the original crossover.
They look as though they have been rode hard and put up wet !!

F1nut

That's pretty common. Nothing to do with anything other than the anodizing process.

DarqueKnight

Some of the 1.2TL crossover plates would oxidize and turn purple. I don't know if the color changes are due to bad processing during manufacturing, environmental causes or a combination of the two. I have a pair of 1989 1.2TLs and the crossover plates are still black.

If the "original owner" doesn't know how your speakers came to have three polyswitches wired in parallel, I think it is safe to say he was not the original owner.

davis419b

DarqueKnight wrote: »

Some of the 1.2TL crossover plates would oxidize and turn purple. I don't know if the color changes are due to bad processing during manufacturing, environmental causes or a combination of the two. I have a pair of 1989 1.2TLs and the crossover plates are still black.

If the "original owner" doesn't know how your speakers came to have three polyswitches wired in parallel, I think it is safe to say he was not the original owner.

I have to agree with you. He told me he thought he bought them in 1991 so I didnt realize until today when I pulled the bad tweeters to check the ohm readings that they were actually from 1989. This might mean the original owner had them for 2 years and could have done a crossover mod. The guy I bought them probablly didnt even know where the crossover was located.

FTGV

davis419b wrote: »

could have done a crossover mod.

Just throwing it out there but the two electrolytics connected in series appear to be the same as the 27uf to the left of them.It's possible Polk just series connnected a pair 27uf's to get the 13.5 uf required for the shunt cap in the low pass section of the stereo array.

davis419b

FTGV wrote: »

Just throwing it out there but the two electrolytics connected in series appear to be the same as the 27uf to the left of them.It's possible Polk just series connnected a pair 27uf's to get the 13.5 uf required for the shunt cap in the low pass section of the stereo array.

There are also 2 small yellow caps that have been added just below those 2 that are not on the other set. They are strapped down with the same material as the coil looking devices are strapped with. Makes me wonder if in fact they are factory myself.

DarqueKnight

FTGV wrote: »

Just throwing it out there but the two electrolytics connected in series appear to be the same as the 27uf to the left of them.It's possible Polk just series connnected a pair 27uf's to get the 13.5 uf required for the shunt cap in the low pass section of the stereo array.

Looking at the close up pic of the 1989 crossover, and seeing how the two blue electrolytic caps are glued to the larger yellow 12 uF mylar capacitor with the same type hot glue that is used elsewhere on the board, that is likely what happened.

davis419b wrote: »

There are also 2 small yellow caps that have been added just below those 2 that are not on the other set. They are strapped down with the same material as the coil looking devices are strapped with. Makes me wonder if in fact they are factory myself.

That inductor with the two yellow mylar caps glued to it is supposed to be in parallel with a 0.25 uF mylar capacitor. Those are probably two 0.5 uF caps paralleled to give 0.25 uF.

If this is a factory job, I still don't know about the three polyswitches wired in parallel. I'm sure there is a reasonable and colorful explanation for that. Maybe these were assembled on a "drunk Monday".:)

Is the other 1989 crossover configured the same way?

It is a shame you either need to be, or hire, a detective before you buy a pair of these speakers.

FTGV

davis419b wrote: »

There are also 2 small yellow caps that have been added just below those 2 that are not on the other set. They are strapped down with the same material as the coil looking devices are strapped with. Makes me wonder if in fact they are factory myself.

That was my thought as well after taking a closer look at it.

As for the paralleled polyswitches this may not be the only instance as restanim's speakers also had them.It may be that for a time they were unable to a source a poly of the appropriate current rating so they improvised by paralleling three to achieve the correct value?.

I know from expeirience in electronics manufacturing there can be long lead times for certain electronics parts.So if inventory runs out companies have to find alternatives, atleast in the short term. It would appear Polk may have had some parts shortage issues during that period in 89?

davis419b

Both of the 89 crossovers are configured the same way !

DarqueKnight

Well, now we know that you have a set of factory customized "special edition"1.2TL's.:)

davis419b

Gee ! Now I feel lucky to have tne 89,s .

hearingimpared

DarqueKnight wrote: »

Well, now we know that you have a set of factory customized "special edition"1.2TL's.:)

Funny thing is, the way things were done back then, a "special edition" is not entirely out of the question!:eek:;)

OldmanSRS

The 27 uF cap in the dimensional array suggests you have the 1.2TL because the 1.2 version has a 40 UF cap in that spot.

Bobsama

hearingimpared wrote: »

Funny thing is, the way things were done back then, a "special edition" is not entirely out of the question!:eek:;)

Most/all Polk speakers (Monitor, RTA, SDA) were available in custom factory-ordered variations. Mostly it was veneer style and thickness.