[victim]

Hello people

I am new to this forum, and i would like get the opinion of you guys perhaps you can advise me of what to do, recently i purchased a brand new, Roksan Caspian pre amp and 2x monoblocks, together with monitor audio RS6, the system has never functioned peoperly despite all the great reviews and awards in the audio magazines, shortly after i purchased the system i noticed that monoblocks keeps on tripping meaning it goes to protection mode, it won't work again untill the power is swtiched off and then back on. untill one of the amps started producing a very audiable noise, anyways after so many attempts and phone calls both to Roksan Audio and the "authorized distributer" they decided that the mono amp is defective and they will replace the pcb's in both monoblocks.

It took about 6 weeks to replace the pcb's but when i got them back they were still tripping i.e going to protection mode, so I contacted the distributer right away and he said not to worry it could be a bad CD, try another cd and if the problem persist, swap the amps and see what happens? so i listened to his advice and the problem stayed when i played another CD and even when i swapped the amps.

The next day i sat down and played the 1812 overture and all of a sudden i smell something burning, so i jumped and turned everything off. I thought the amps are gone again, but the smell was coming of the speaker, after a while i turned it on and the whole thing sounded different but for sure there is no terebel in the affected speaker.

At this moment I am not sure what is going on, I would like to invite those who are interested or those who are knowledgable to participate and give me some advise of what to do



I look forward to your participation.



Regards

[BradJudy]

I'd say you definitely fried the tweeter in the speaker.  Hopefully the dealer will replace that for you since you're using all equipment from him. 

I'd be suspicious of the pre-amp sending nastiness to the amps (DC getting through?). 

Get the tweeter replaced and ask for a service check or swap-out on the pre-amp. 

[mcrespo71]

You could also post this query on the Roksan forum.  They may have more insight into the particulars of your amps than here.

[macrojack]

You should start by changing your username and the attitude that caused you to choose it. Then put the dealer's feet to the fire. It's his job to provide support for the products he sells.

Your choice of the 1812 Overture hints that you may be looking for fireworks from your equipment and it seems that you got some. Tweeters are usually damaged by amplifier clipping. This means asking your amp to provide more amplification than it has the capacity to generate. In short, I think you are playing your music way too loud.

[victim]

thanks for the replies,

I choose the usename victim, not necessarily victim of manufacturer or distributors or equipment reviewers.

If the amp was clipping and the damage caused by the tweeter was due to that, how come only one side of the speaker is damaged and the other is not.

Also, for those who are familiar with roksan amps and according to the manufacturer literature, they are equipped with protection circuits that should put the amp in a protection mode in the amp is overworked.

Right and left channels are not the same but even when i played mono recordings the amps would still trip at different times.

participation is highly appreciated

[Bemopti123]

V, you need to specify how the problem happened, especially at what volume you played the amplifiers.

I just read the specs and if I assume what I think is the worst, that you like to play things like the 1812 Overture cracking, the amplifier is not up to task. 

There are limitations of what an amplifier can deliver in terms of current and power and what the loudspeaker will demand from it. 

While not explicit, most people will back out at reproducing dynamic orchestral classical tracks unless they safely know what their equipment can handle without damage. 

Protection mode is there to prevent extensive damage to the amplifier and also to the speaker, but when speaker asks what the amplifier cannot provide, it can fry.  The amp is protected but the speaker is not from damage. 

Perhaps you will need a more powerful amplifier, if you want to experience all impact you are striving for. 
Try some digital amps, they are cheap for the power delivered. 

[victim]

well i played the volume around 12 oclock, that is half the scale would you consider that unreasonable?

[Bemopti123]

I saw the specs for your loudspeakers.  According to figures, it is fairly sensitive, not necessarily being a heavy load.  Spec says 91 db, in reality it might be close to 89 db according to what was found at a Stereophile review.  In the scale of things, what it considering loud might be different with different speakers, amplifiers, preamplifiers and also the source. 

I run a couple of drivers, Open baffle.  Depending of the driver, my preamp is very sensitive giving me high volumes really fast.  I never got past 12, usually I do 9-10.  The only instance I passed past 12 was because I was playing a record and I needed more gain.  I have never cracked a full orchestra scale on LP or CD past 12.  If you ran a CD recording of that passage, it would have been loud for short bursts.  Eventhough the amp is rated to provide down to 330 watts at 1 ohm per channel, a full orchestral work could have asked for a lot more wattage than what was expected. 

Not too many amplifiers are designed to provide CONTINUOUS watts for more than short bursts, I mean milliseconds.  The passage was louder than what the speaker was given in terms of watts, and it must have scaled really fast. 

Work with the dealer or not, I am sure that you will face the same problems with a brand new pair.  What amp or system did you have before?  What sort of music do you play? 

BTW:  If you also listen to an Ipod, ask yourself if you can hear your favorite song leaking through the headphones from lets say 10 feet.  If the answer is yes, then perhaps you play music louder than most people.

If you want to crack the whip with loud orchestral works, you will definitely need more than 100 watts at 8 ohms. 

[markC]

Do the amps trip when you are playing music @ lower volumes? I'd also be interested in knowing how loud your listening. Do you have access to an spl meter? 12 o'clock volume setting on one pre can be a lot different than on another.

[Hogg]

It sounds like either the preamp is sending DC to the poweramps thus tripping the protection circuit or the power amps are faulty.  I'd bet on the later.  Since Roksan or your dealer for that matter is unlikely to reimburse you for speaker repairs, forget who's fault it is and have the electronics inspected by a competent tech.

I once owned a Randy White LLano amp.  It went bad and drove DC through my Tannoy dual-concentric.  It costs $450 per driver for re-coning by a competent tech.  $1000 later and a new LLano boat anchor for LI Sound, I was up and running.

                                                                        Jim

[JLM]

You've blown a tweeter (melted the voice coil), apparently from feeding it a high wattage distorted signal.  Repeated tripping of protection circuits should have been your first warning that something is seriously wrong and to not continue.  The 1812 Overture is notoriusly brutal test for turntables, amps, and/or speakers.  Without resolving the amp issue, you should never have played anything like that CD.  My guess is that you've been listening WAY TOO LOUD.  Did you hear distortion prior to the protection circuits engaging or the tweeter going? 

There's probably not an audiophile who hasn't "cranked it up" to determine what their system is capable of, bu       pically takes abuse to engage protection circuits or to blow a tweeter.  In 30+ years I've never blown a tweeter, but have engaged protection circuits (when driving two pair of very large speakers at a college dance for hours with a McIntosh 6100 integrated amp.  I even heard my system (being played by others) from 4 floors down in the dorm (with no damage and no tripped of protection circuits).

I'd take the pre-amp and monoblocks (and your source) back to the dealer and try them with some of his speakers.  This would tell if the speakers are to blame.  From there you can swap out one piece at a time and hopefully figure out which component is to blame.  He should have a spl meter or instantly tell if you're listening too loud.

Continued exposure to more than 85 dB will result in permanent hearing loss and possible permanent pain.