RTA 11T's Mids/Highs die with new Onkyo, blown tweeters?

Jab
Jab Posts: 7
edited March 2009 in Troubleshooting
Hello.

I recently bought an Onkyo a-9555 stereo integrated amplifier to replace a late 80's/Early 90's Technics receiver. From the beginning, the differences/improvements were very noticeable and I thought it was a good buy.

After about of a week I noticed that the Onkyo had developed some kind of distortion when ever the volume knob was moved around the 10 - 1 o'clock area. The crackle would only happen when the source (FLAC from PC) was outputting a signal. When there was no music playing there was hardly any crack or pop coming out of the speakers from me turning the volume knob. I continued to listen to music at moderately high volumes when suddenly the high's and midrange just DIED after a very dynamic piece of music, just a loud muddy mess. After turning the amp down with the remote the highs and mid's came right back, but whenever I would turn it up to around 12 o'clock the same thing would happen after a loud dynamic section of music occurred.

I thought the new amplifier was defective/damaged, but then my father suggested switching the RTA11T's out with another pair of older sony speakers to make sure it was the amplifier. After doing some testing we found the problem wasn't happening with this set of speakers and crack/pop was gone, even after putting earplugs in and cranking the amplifier to around 2 o'clock.

For a while I have thought about swapping the 17 yr old tweeters out for the new silk dome replacements, but now I'm worried that's not the only problem with my speakers. I'm really surprised they aren't completely fried after what happened. Maybe the crossover (I have limited knowledge of speaker technology) is toast?

Now I'm worried that if I order the new RDO194-1 tweeters they may end up being destroyed by some other faulty component. One thing to consider is that this set of 11T's has never really been driven by this much wattage (They literally sat in a closet for a decade until we rediscovered their awesomeness). The previous Technics receiver had an output rating of 30 wpc. This onkyo is rated at 100 wpc.

I love the sound quality of these speakers but now I'm afraid that I'm damaging them just my listening to music. This mystery has gotten me very confused and I have no idea what happened or what to do. Does anyone have any clue what is wrong with my 11T's?

Thank you for any support.
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Comments

  • treitz3
    treitz3 Posts: 19,029
    edited March 2009
    Jab wrote: »
    The crackle would only happen when the source (FLAC from PC) was outputting a signal.
    When you switched speakers, did you ever change anything with the source?

    Welcome to the Polk forum BTW.
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
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  • F1nut
    F1nut Posts: 50,554
    edited March 2009
    You are triggering the poly switches, which protect the tweeters from frying. It could be that they are simply old and worn out or there could be a problem with the new integrated that is causing excessive distortion. A good rule of thumb, never turn the volume knob up past 12 noon.

    You can replace the poly switches. Call Polk and ask them to send you some new ones.
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  • MillerLiteScott
    MillerLiteScott Posts: 2,561
    edited March 2009
    Do what F1 says.

    Are you using the tone controls? I have a pair of RTA 11T's and could never imagine needing to turn up an amp that much unless you are using them in a gymnasium.

    Scott
    I like speakers that are bigger than a small refrigerator but smaller than a big refrigerator:D
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  • george daniel
    george daniel Posts: 12,096
    edited March 2009
    Like they said,, The President has spoken,, you must comply,, quickly,,if you value your hands ;):)
    JC approves....he told me so. (F-1 nut)
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  • Jab
    Jab Posts: 7
    edited March 2009
    treitz3

    When you switched speakers, did you ever change anything with the source?

    Welcome to the Polk forum BTW.

    The source is a horrible Creative elite pro sound card. It was kept at the same volume (96) and we tested the second set of speakers with the same music.

    The sound card must be outputting way below line level because I thought it was crazy having to put the amp up to around 12 noon for a nice level. It's not anywhere as loud like I imagined it would be at that level. I should use it with a standalone DVD/CD player as the source to compare levels.

    I don't care how difficult it is to replace the poly switches, these speakers are well worth it.

    Could the problem not be happening with the sony's because of how the amplifier reacts differently with them? I mean the problem could possibly be with the amp.

    thank all you guys for replying!
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  • George Grand
    George Grand Posts: 12,258
    edited March 2009
    Don't worry about it. If you don't heed that "No going past 12 on the volume knob" advice, you are going to become intimately familiar with those speakers. You need to re-evaluate your priorities in that area.
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  • Jab
    Jab Posts: 7
    edited March 2009
    Don't worry about it. If you don't heed that "No going past 12 on the volume knob" advice, you are going to become intimately familiar with those speakers. You need to re-evaluate your priorities in that area.

    what are you trying to say?
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  • cfrizz
    cfrizz Posts: 13,415
    edited March 2009
    He's telling you to turn down the volume or keep going until you do real damage to your speakers. If you really like blasting it, then get a separate amplifier, because a receiver is going to damage either itself and/or the speakers from being overdriven!

    Welcome to Club Polk.
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  • Jab
    Jab Posts: 7
    edited March 2009
    This integrated amp is basic compared to most other mid-range integrated receivers. It's only 2 channel, and has a "Pure Direct" mode which when engaged, bypasses the bass and treble tone control circuits.

    http://www.stereophile.com/integratedamps/907onk/

    Having the volume knob up at noon on it is not insanely loud. I just tested it with a CD player as the source and it was just slightly louder than the sound card at the same knob position. The volume increases exponentially as the knob is turned at a constant speed. Most of the music I listen to is from well mastered CD's that have not been destroyed by excessive compression or limiting. I don't understand why I would need a separate power amplifier to drive these. I care very much about my hearing and would never want to listen to music at crazy hearing damaging levels.
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  • George Grand
    George Grand Posts: 12,258
    edited March 2009
    It's a very nice Onkyo piece you have, and I mean that.

    With most rotary knob volume controllers, the 12:00 position is approaching rated output levels. At 2 or 3 o'clock, you are pretty much operating at rated power output. 85 watts is not an awful lot to be throwing at an RTA 11t. I've had three pair of RTA 11t, and one pair of RTA 11TL. The least I drove a pair with was 150wpc, and what they really seemed to like was 375 wpc. You will probably find in your owners manual they are only rated to handle either 225 watts or 250 watts.

    Not everything is as it seems.
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  • Ender
    Ender Posts: 603
    edited March 2009
    As noted by previous posts, you are stressing the amplifier and the speakers at the same time. You have to remember that, when electricity flows through a circuit, it is one continuous flow. That's regardless of whether you are underpowering or overpowering.

    EDIT: Oops. Forgot Onkyo even makes integrated amps lol.
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  • F1nut
    F1nut Posts: 50,554
    edited March 2009
    I'd like to point out to 2 of the posters here that he is using an integrated amp, not a receiver.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • Jab
    Jab Posts: 7
    edited March 2009
    Even though these speakers are 17 years old, they have very few hours on them. I'm looking at the cabinets and I can't find where I could open them. It looks like I may need to take out the all of the speakers.

    So it's most likely my problem is due to old poly switches? Is it possible it could be just the tweeters? I can't think of a reason it would be only them, but that would be nice.

    Where are the poly switches located, are they part of the crossover? I have no idea what the component looks like.

    Once I have the cash I'd like to rebuild the crossovers and get the new silk dome tweeters.

    Thanks
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  • danger boy
    danger boy Posts: 15,722
    edited March 2009
    I think it it's the poly switches too... those speakers even though as you claim have not been used much since you've owned them.. still are 20+ years old, and the poly switches lose their effectiveness over time..

    it does sound like you are turning up the volume to high too.. 12 0'clock is the highest you should do with them. They probably require more juice than your Sony speakers..

    to replace the poly switches.. you need to remove the crossover from the rear of the speaker.. unsolder it, then resolder in the new one in each speaker. That would be a good place to start... if that does not solve the problem.. then we'll have to look somewhere else for the cause. but it sounds like you are over driving the Onkyo
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  • Jab
    Jab Posts: 7
    edited March 2009
    Seems I should of done more research about what they require, I only remember a large suggested wattage range of something like 10 - 250 watts. Coming from the Technic's 30 wpc to the Onkyo's 100 wpc seemed like such a large increase in power. Indeed, things aren't always as they seem.

    I'll have to give Polk a call as soon as I save up some money. Hopefully I can get them back into great condition for under a few hundred bucks. :)
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  • MillerLiteScott
    MillerLiteScott Posts: 2,561
    edited March 2009
    Polk will send you new Poly switches for free.
    I like speakers that are bigger than a small refrigerator but smaller than a big refrigerator:D
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  • Jab
    Jab Posts: 7
    edited March 2009
    Wow!

    What a great company :)
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