RDO-198-1 Bright????

Braddles

I managed to pick up a pair of RTA11tl speakers that had both SL3000 tweeters blown thanks to someone slipping with the volume at a party so the previous owner said. I replaced them with some RDO-198-1 tweeters.

They seem a bit bright and forward. I thought it would get better with some run in time but while its improved slightly (they have been in for a few months now) i find i can only listen a fairly moderate levels or they are quite harsh.

Any suggestion on whats happening? Could the xo caps been damaged when the tweeters blew and affecting the sound of the new tweeters?

Ive done some searching and havent found anything but positive reports on the rdo's. So im wondering whats up?

Cheers
Brad

drumminman

Bright and forward are not terms I would use to describe the RD-0198 tweeters. I replaced the SL3000's that were original equipment in my 2.3TL's and the improvement was immediate: more relaxed, smoother treble with increased deinition, and a more spacious soundstage.

There must be something else going on here. What are you driving your speakers with?

If the tweeters were blown when you acquired the speakers there could be damage to the xover. Some Polks came with polyswitches in the xover to protect tweeters, and after these have tripped a number of times they can seriously degrade the sound from what I've read here on the forum.

If the polyswitches are bad you can replace them. Or, if you have quality amplification, you can get rid of them altogether.

heiney9

So you never had a chance to hear the speakers with the sl3000's? What tubes are you running in the Ming Da integrated amp? What type of digital files are you listening to from the laptop?

If the sound gets worse as the volume goes up it sounds like it could be a gear problem. Have you done anything to the x-overs? Perhaps they were damaged when the tweeters were damaged. The polyswitch as mentioned could be a real possibility as well.

H9

fbm211

Perhaps you should get rid of the polys and replace the resistors with mills since the mills are said to be on the warm side.
And use those .05 mills in place of the polys or whatever value other polkies have used.(Sorry, I dont remember the value your supposed to use for that mod.)

Braddles

Sorry guys i didnt update my sig for a while. I have a Quad 99/909 and raysonic CD128.

The Sl3000's were cooked when i got them.

I have also tried my Luxman and Marantz CD6002 with the same results give or take.

Is it possible to disconect the poly switch to see if this helps without damaging anything else?

Can anyone point me to which on is the poly switch on the xo please?

I do plan to upgrade the xo at some stage in the future too.

agfrost

No polyswitches on the RTA11TL. There was one on the 11T. I've got the 11TLs with the RDO-198s, and I've never found them bright, either before or after modding the crossovers. Good luck figuring out what's going on!

Jay

Schematic

DarqueKnight

Braddles wrote: »

Could the xo caps been damaged when the tweeters blew and affecting the sound of the new tweeters?

Yes, the caps could have been damaged. The reisistance of a polyswitch always increases after it has been tripped. It appears from the picture and schematic agfrost posted that your speakers may not have polyswitches.

You need to look and make sure. Sometimes there were model variations that differed from the published schematic. This is particularly true of "transitional" models that were made at the beginning of a new version of an existing speaker model. Since the RTA11 had a polyswitch, if your pair of RTA11TL's is one of the earliest made, it may have a polyswitch. Polk may not have decided to remove the polyswitch until later in the 11TL's production run.

Braddles wrote: »

Is it possible to disconect the poly switch to see if this helps without damaging anything else?

Here is a link to a thread which has pictures of polyswitches:

SDA Polyswitches Are Nasty

The polyswitch is in series with the tweeters. If you remove it the tweeters won't get a signal. You can either remove the polyswitch and replace it with a short piece of wire or leave the polyswitch in place and short it out of the circuit by soldering a short piece of wire across its terminals.

Replacement polyswitches are provided free by Polk's Customer service department.

Braddles

Thanks for all the replies guys.

I had another look at the xo and there is no poly switch. I suppose i will know when i recap the xo and see what happens.

Its a bit stange though. Like i said at average levels its well balanced sound but as i increase the volume the highs become more and more prominent and in your face and i have to turn it down again. Im not talking excessive volume or anything. Just louder than what most would call average levels.

Thanks again for the advice.

Systems

Have you replaced anything else as of late?
Cables/components?

Braddles

Yes pepster i have tried a different amp and cdp with much the same results.

I am just in the middle of swapping some ic's around and see if that helps.

skrol

I did the switch from SL-3000 to RDO-198 in my RTA11TL's and do not find them bright. I had also upgraded the XO components. I highly recommend the upgrade. I was amazed at the difference. Your original electrolytic caps are getting old and they may have been over stressed.
Stan

inspiredsports

I'm thinking the event that blew out the SL3000's must have compromised something else in the crossover too.

I would not characterize the RDO198-1's in my 2B's or SRS 2's as being bright.