hallsound Posted May 22, 2002 Share Posted May 22, 2002 Hey Everybody, I have a pair of La Scallas and I keep blowing the squaker and the tweet. I have the correct fuses in them but for some reason after about a month each time they say buy buy. The amplifier I am using is a QSC 1602 with the input gains at -20db. This is really costing me a lot cause when they are on its soooogoood! Any suggestions? Quote Link to comment Share on other sites More sharing options...
lynnm Posted May 23, 2002 Share Posted May 23, 2002 I took a look at the amp you are pounding those La Scalla's(800w./ch),with. IMHO I suspect that you are simply whacking them with too much power. Most quality speakers will handle more than their rated power handling as specified by the manufacturer but given the La Scalla's 100w rating with a 400 watt instantaneous peak power rating -It is not suprising that an amp rated as being capable of delivering 800/w/ch continuous is burning up drivers. Bear in mind also that responsible amplifier makers tend to rate their products conservatively so that amp likely does not begin clipping until about 1000 watts/ch. and is likely capable of delivering instantaneous peaks well above that. Generally speaking it is clipping that destroys speakers but in this case I suspect clipping is not the cause of your problems - just plain excessive power input to the speakers. This message has been edited by lynnm on 05-23-2002 at 10:55 AM Quote Link to comment Share on other sites More sharing options...
JohnA Posted May 23, 2002 Share Posted May 23, 2002 If you have La Scalas hooked to an 800 watt/channel amp and you keep blowing the squawker and tweeter, you're getting what you deserve! Turn it down! John Quote Link to comment Share on other sites More sharing options...
Mighty Favog Posted May 23, 2002 Share Posted May 23, 2002 what? ------------------ Tom's Money Pit Quote Link to comment Share on other sites More sharing options...
Dave in Nashville Posted May 24, 2002 Share Posted May 24, 2002 No offense intended Hallsound, but as someone far wiser than I once said, "You can make something fool-proof, but you can't make something damn-fool-proof." Just out of curiousity, where are you playing your LaScalas loud enough to destroy the speakers? Dave This message has been edited by Dave in Nashville on 05-24-2002 at 12:10 AM Quote Link to comment Share on other sites More sharing options...
lynnm Posted May 24, 2002 Share Posted May 24, 2002 tblasing I'll bet you can hear those poor La Scallas in Cinci. Quote Link to comment Share on other sites More sharing options...
djk Posted May 25, 2002 Share Posted May 25, 2002 A QSC PLX1602 is 300W/8R .While this is a lot of power, if some common sense is used it ought to be safe to use. I have used the 450W/8R Carver PM1.5 on Klipschorns without problems. The biggest problem you have is the QSC is clipping, yes I said CLIPPING. This is because you have the gain control set at -20dB. There are two op-amp stages before the gain control. You need to attenuate the signal to no more than 2V RMS before it goes into the amplifier. Quote Link to comment Share on other sites More sharing options...
JohnA Posted May 25, 2002 Share Posted May 25, 2002 djk, That sounds like good advise. not knowing the amp's particulars, I discounted clipping and the normal culprit due to the -20 setting. He might easily be overdriving the inputs, though. John Quote Link to comment Share on other sites More sharing options...
lynnm Posted May 25, 2002 Share Posted May 25, 2002 I stand corrected on the power rating of that amp. I went purely by the photo on their site and failed to look up the actual specs. djk could you elaborate a little on the gain issue ? Are you saying that -20db. attenuation will still result in an excessively high input signal? ------------------ It is meet to recall that the Great Green Heron rarely flies upside down in the moonlight - (Foo Ling ca.1900) Quote Link to comment Share on other sites More sharing options...
djk Posted May 26, 2002 Share Posted May 26, 2002 The gain controls in pro amps are after the balanced inputs. Turning the gain way down makes you have to drive the input real hard to get any output. It is very easy to drive the input into clipping under these conditions. Worse, if the amp has FET op-amps like the LM353 or TL072, when overdriven they will latch up to the negative rail, oscillate, and make disgusting sounds that will damage your speakers. And the 'limiter'? It won't do anything, it is after the volume control and thinks everthing is fine! Quote Link to comment Share on other sites More sharing options...
lynnm Posted May 26, 2002 Share Posted May 26, 2002 djk That clears it up for me. Thanks Quote Link to comment Share on other sites More sharing options...
hallsound Posted May 29, 2002 Author Share Posted May 29, 2002 Thanks for all the great and honest responses. I will make changes to my power I thought it was ok to have more power than rated. I am glad the bass driver is 100% Hsound..... Quote Link to comment Share on other sites More sharing options...
HDBRbuilder Posted June 4, 2002 Share Posted June 4, 2002 hallsound, If you intend to use Klipsch Loudspeakers, you have to adjust the standard "bigger/more is better" mindset so many people tend to have!! Think of a loudspeaker's continuous power rating as the redline on a car's tachometer. You don't want to push it beyond that point! So, don't use an amplifier that has a continuous power rating that exceeds that of the loudspeaker! Speakers can handle peaks above their continuous power rating by most amplifiers that have the SAME or LOWER continous power rating as the speaker has. Just like a car engine can be MOMENTARILY pushed to rpm's over the redline on its tachometer, but can't sustain rpms over that redline without at least blowing the head gasket on the engine...and possibly destroying the engine in the process! Do you take your car out and run it above redline all day?? I hope not!!!! Another thing to consider is this...a speaker does not NEED all the power that is listed in its "continous power rating" (especially extremely efficient speakers like LaScalas!!)...just as a car engine does not need to be kept at redline to run!! Speakers have a minimum power rating too, but that minimum on Klipsch "heritage series" speakers is actually below one watt!! With an amp that just puts out 60 watts of continuous power rating, LaScalas will still impress the neighbors enough at high volumes that summoned men with badges may soon be knocking on your door!! So there is really no need for more power than 105 watts continuous rating, is there? Think about it!! ------------------ I can now receive private messages Quote Link to comment Share on other sites More sharing options...
michael hurd Posted June 4, 2002 Share Posted June 4, 2002 HDBR builder: quote: just as a car engine does not have to be held at the redline to run!! That is, unless you own a decade old, worn out honda civic hatchback 86 , carbureted, still turns 7500 rpm... just for fun held it to 7000 rpm for roughly 3 miles - it just won't die ! I must have horseshoes in my pocket or something... hehehe Quote Link to comment Share on other sites More sharing options...
lynnm Posted June 4, 2002 Share Posted June 4, 2002 Further to what HDBRbuilder has said: I run KLF 30's that are rated as having about the same sensitivity as the LaScalla,(102db/w/m)and use a 30 w/ch tube amplifier and trust me they are capable of playingVERY LOUDLY!I am sure that your LaScallas would be capable of upsetting the neighbours if driven by any decent quality amplifier. (Disclaimer the following paragraph is not an attack on SS amplification) 8~)> If you decide to swap out your present amp I suggest you consider a good tube based amp as a possibility simply because Klipsch horn loaded speakers and tubes tend to sound especially nice together. ------------------ It is meet to recall that the Great Green Heron rarely flies upside down in the moonlight - (Foo Ling ca.1900) Quote Link to comment Share on other sites More sharing options...
Klipschguy Posted June 4, 2002 Share Posted June 4, 2002 Have a speaker shop check your crossovers. The tweeter I can understand, but not the mid. Quote Link to comment Share on other sites More sharing options...
lynnm Posted June 4, 2002 Share Posted June 4, 2002 It certainly would not hurt to have the Xovers checked but I would be very suprised if they were the problem. Given that the tweeter and the mid in the LaScalla are compression drivers I have no problem in believing that excessive power combined with severe clippimg could take out both tweeter and mid. While it is true that the mids would be expected to be able to handle more power than the tweeters - We are talking about a 350/w/ch amp whose inputs are being driven into clipping and which is therefore amplifying clipped waveforms. ------------------ It is meet to recall that the Great Green Heron rarely flies upside down in the moonlight - (Foo Ling ca.1900) Quote Link to comment Share on other sites More sharing options...
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