Problem with K2 Crown Amps and Nexo PS8's

[barbloc]

Hi There,

 

First time poster, hope this is the appropriate layout.

 

I have a small 200 capacity music venue in Glasgow which has been operating for 10 years.

The sound system has been superb over this duration until very recently.

I have 2xK2 Crown amps powering 6xNexo PS8's and started to get a hissing sound through my speakers every morning when they got powered up, much like a fire extinguisher going off, sometimes lasting upto 20 minutes at a time.

I got a technician to take a look at the amps and he said they were too powerful for the speakers?

I queried this as they had been fine for the last 10 years. He gave me a replacement amp while he looked at my K2 amps and told me they were just about finished, hence the problems. It has now been brought to my attention that 3 of my 6 Nexo speakers have blown and need repaired asap.

can anyone recommend a good repair shop for my speakers close to Glasgow?

Also does anyone have any experience in using this combination of amps and speakers and if so have they come across any similar problems?

Any help on the above information would be greatly appreciated.

 

Thanks in advance

 

John Burns

[james.sealey]

I got a technician to take a look at the amps and he said they were too powerful for the speakers

 

How much too powerful? Most speaker manufacturers recommend an amplifier of 1.5x the rated power of the speaker, some even 2x.

 

He gave me a replacement amp while he looked at my K2 amps and told me they were just about finished, hence the problems. It has now been brought to my attention that 3 of my 6 Nexo speakers have blown and need repaired asap.

 

Depending on the spec of the amp he put in, if it was driven hard and potentially into clip this could results in blown drivers.

 

I can't recommend any repairers local to you, but it would interesting to know the specs of your original amps (which have served you well for 10 years you say) and the specs of the replacement amps supplied by your tecnician.

[dougjm]

If it is blown woofers then I you'll probably need to send the drivers back to Fuzion or maybe SSE now they're a dealer too. If it's HF drivers then Sound Acoustics in Glasgow would be a good start as they stock GeoS8 which uses the same HF. If they can't help I have some in Edinburgh.

[TimmyP1955]

During the hissing, did you disconnect the inputs to the amps? If not, you don't know whether it was the amps, the Nexo processor, or something upstream that was causing the hissing.

 

At the theater we have eight K series that are likely as old as yours. Only one has ever had a problem (power supply died, silently). I doubt that yours are "about finished".

[KevinE]

Is the guy who told you the K2's were 'just about finished' quite trust worthy?

 

Crown K2s are a much sought-after amp that command very decent prices on the second hand market due to their reliability and performance.....

Why should they suddenly be too powerful after 10 years of service??

Seems an odd thing to say if you ask me.

[Matt Riley]

1. They're Nexos. That means that you should have a little blue box of tricks installed between your sound source (ie a dj mixer) and the amps. This is very important, cos otherwise you invalidate the warranty, they sound nowhere near as good as they should, and they are more likely to break. It will be called a PS8TD (or possibly a black NX242/241).

 

2. IF you've got a blue box of tricks correctly installed then this will not only make them sound better, but it will also intelligently sense how much juice the amp is putting out and limit the signal in if the amp is spewing out too much power.

 

3. These are only 500w@8ohm amps. Click here for specs. The recommended spec for these speakers is 200-500w for use at 8 ohms on one channel, or if you've paired them up then you want an amp that spews out 400-1000w per channel @ 4ohms. The K2 is perfectly matched for these recommendations.

 

4. I think you should probably look for a second opinion as it sounds like your "technician" clearly has no experience of systems in this league which simply cannot, when implemented properly, be damaged in that way due to the controller design.

 

5. If the amps are hissing for a bit on startup, that is well into the realms of fixable by a competent service tech. My initial guess would be some capacitors drying out or something like that.

[ChazHS]

Crown K2's are exactly what I'm using to power my PS8s and LS400s, they are perfectly suited to the job. They supply the recommended amount of power (with plenty of headroom) and sound lovely with the PS8/LS400 system.

 

I've never had a problem with mine, even when pushed hard they sound great and the controller sorts everything out if someone is stupid. I think there will be something else at fault in your system, because it's unlikely for all of the K2's to exhibit the same hiss on startup, I'd say that there is something else amiss.

 

As for the 'technician' I'd say that he simply wants your amps and a shed load of cash because he's put in an underpowered amp while he looks at your K2s and has blown your speakers through clipping/underpowering.

[Sound In Gloucestershire]

the only strange part is the 6 speakers over 2 amps, how have you got them wired? Its possible youve had 2 getting alot of juice?

[ChazHS]

the only strange part is the 6 speakers over 2 amps, how have you got them wired? Its possible youve had 2 getting alot of juice?

 

What I'd have done is wire on with 4 x PS8 on the left channel (input Y) and the one with 2 x PS8 on the right channel of the TD controller.