Amplifiers??

[Loz 0]

Hi everyone, I just wanted to know about the quality of amps, is it the old senario you get what you for. The reason I'm asking is I have a carlsboro 500w amp and so far it's blown 2 lots of cabs. The first set starting smouldering during a kids party, admittedly the jbls I was using were only rated at 150w RMS but it was'nt exactly loud. The second time which was last night, again I boobed by allowing the singer to plug into my mixer but anyway the set up was 1x1500w peavey amp driving some 350w 4ohm bass bins and I had a pair of Studio spares (they're based on the same spec as the jbl eon range) these are rated at 350w rms which I was driving with my carlsboro 550w amp. I used two separate outputs on my mixer for the amps. Anyway some clot decided to turn all my volumes up on the mixer so consequently the sound was awful, soI ran over to my mixer and turned everything back down again but noticed the Studio spares cabs were'nt workimg and smelt burnt. I haven't had chance to have a look at the cabs yet, but just wondered if the amp is'nt right for the job?? http://www.dj-forum.co.uk/html//emoticons/533.gif

[DJ Marky Marc 0]

sounds like you have a mixture of problems.

 

lets assume your speakers are 500w RMS 1000w Program 2000w peak in thery you could for a very very short time put 2000w up them with no damage but not recommended.

 

when an amp reaches its maximum out put it starts to do something called "clipping" this clippng is the thing that burns your speaker coils.

 

so in an ideal world you would ave a 1000w amp and 500w speakers so that you never get the amp so loud it clips.

 

using a compressor limiter setup for your sound system will automaticy reduce the volume if it gets too loud so you don't need to keep an eye on the lights on your amps.

 

this limiter is far cheeper than new speakers. and means you can let people mess with your mixer and not have problems.

 

but most of all use your ears, if the music sounds muddy or distorted then something is turned up too far.

 

if you can't get the system loud enough for the type of gigs you play then hire more sound or invest in bigger kit before your repair costs get bigger than the cost of a new setup.

[superstardeejay 0]

I agree wholeheartedly with marky regarding using a limiter, they are virtually mandatory if you're going to do an installation where a DJ or performer is concerned and vital if there's a band on.

 

Most bands (respect where it's due) will play as loud as the system will let them and if its not their equipment then it's usually 'foot to the floor' all the way.

 

It also allows you to safely use a larger amp than you need (for headroom and SOA reasons) without burning out your voicecoils. Believe me a larger amp, 'throttled down' and ultimately capped by a limiter to the size of your speakers will always sound sweeter than a poor specimen that's made to run flat out all night.

 

Formula Sound's industry standard AVC series limiters used to have a description on the blurb which stated: "....protects your sound system from accidents or recalcitrant DJ's....".

 

 

I've had many, many phone calls from pubs etc with sick sound systems where the conversation starts: "....I think we've blown some speakers, we had a band on last night...."

 

 

 

 

 

 

[HeadlineDJ 0]

I still have my TWO BK amps for sale in the erm.. for sale section.

 

Absolute monsters and built better than the Bismark.

 

Only downside is you need two of em for Stereo and they're a bit heavy, but boy do they run very well.

 

In keeping with the thread however...

 

Too many DJs run low amps thinking their playing safe, and most of the time it's far easier to blow a speaker using an underpowered amp than an overpowered one.

 

Overhead is your friend,

Compressing, Clipping and DC shorts are your enemy!!!

 

 

[superstardeejay 0]

Well I've logged on, its boxing day and I thought I'd mention I was called out to a blown Carlsbro Powerline amp in a pub on Christmas Eve, all panick stations becuase of the festive season. It's back in the workshop now, (output transistors gone) and the pub has a loan amp to see them through.

 

I have to say its the first Chinese Carsbro I've had actually blown (I've had several with seized fans), their UK built models were bombproof pretty much all round and are/were(?) sold as Kinetic through Academy.

 

BTW Carlsbro customer support is excellent and their UK model service manuals are available for download on their website.

 

 

[nrgize 0]

QUOTE

when an amp reaches its maximum out put it starts to do something called "clipping" this clippng is the thing that burns your speaker coils.

So when my Peavey Amp "DDT" light for clipping comes on, does that mean that its is burning my speaker coils ? I haven't noticed any smells from them when driven. My Amp matches the speakers exactly.

 

 

QUOTE

using a compressor limiter setup for your sound system will automaticy reduce the volume if it gets too loud so you don't need to keep an eye on the lights on your amps.

Any links of where I can see one please? Does it reduce the voume to steeply ?

 

 

Does anyone use a Numark Dimension Amp ? I am considering buying one for my new Soundlab Plastic Cabs.

 

 

Many thanks,

 

Nathan

[DJ Marky Marc 0]

QUOTE

So when my Peavey Amp "DDT" light for clipping comes on, does that mean that its is burning my speaker coils ? I haven't noticed any smells from them when driven. My Amp matches the speakers exactly

 

DDT is compression/anti-clipping protection, basicly a compresser limmitor built into your amp...

 

when this lights up it means the AMP has reached its maximum and the gain is reduced to protect your speakers from DC clipping...

 

so at this point you need a bigger sound system to get more volume or run the risk of damaging your gear.

 

pushing the levels up when DDT is active will just result in distortion and poor quality sound...

 

if you see this DDT system working lots then you have been a very lucky man so far.....as its not perfect and your amp can still clip....

 

Behringer make a simple 1u rack mount limmiter thats ideal for most DJs, this goes between your mixer and amps so that in an ideal world you never see the DDT system active on your amp.

 

if you end up with a multi amp setup (tops and subs) consider a crossover with limmiter built in so the sound is balanced and clean

 

 

in and ideal world your amp should give twice the RMS power of your speakers at any given Ohms eg

 

100w RMS 8ohm speakers need an amp that gives 200w RMS into 8ohms

 

my 500w RMS 4ohm speakers get 960w RMS from my amp

 

if you do things this way it will sound sweet.. but dont clip the system things cook fast when you run high wattages like this

[ChrisPointon 0]

One of the best pieces of equipment I ever bought was a Compressor-Limiter, set correctly to kick in before your amp hits clipping and you'll never inflict painful distortion on your audience, and reduce the chance of a painful repair bills on your wallet http://www.dj-forum.co.uk/html//emoticons/biggrin.gif . But the setting up correctly is important, fitting a compressor limiter which is incorrectly set and you may as well not bother, thats almost as bad as setting up a graphic EQ to make a smiley face http://www.dj-forum.co.uk/html//emoticons/rolleyes.gif

 

Don't run your amp continuously at clipping, that is almost one sure fire way of killing your speaker and possibly your amp, however high it's rated. If you find the need to run your amp at full whack, then it's time to upgrade your P.A.

 

When choosing P.A, get the best you can afford, it's more important than lighting!.

 

Choosing P.A is just like the car analogy, a Sports car with a top speed of 150mph is far likely to cruise at 70mph with no sign of strain or being overdriven, than a citoren 2CV with a top speed of 75mph which will be straining and overheating to maintain the same speed.

[nrgize 0]

My DDT light comes on occasionally. When it comes on I turn it down a little. BUt never really understood it.

So if i was to buy a cheaper amp that has one light on it that says "clip", when that light is lit that means it would be too late ??

 

Does anyone have a Numark Dimension 3 Amp ? I am thinking about buying one before new years to help push the extra power out. Or would it be better to pay that extra £100 for another PV-1500 ?

 

I need another amp to power my new Plastic Soundlab Cabs. I have been using them with my peaveys. 8ohms and 4ohms, which doesnt allow as much power.

 

 

 

 

Thanks for the advice! http://www.dj-forum.co.uk/html//emoticons/cool.gif http://www.dj-forum.co.uk/html//emoticons/thumbup.gif

[DJ Marky Marc 0]

QUOTE

So if i was to buy a cheaper amp that has one light on it that says "clip", when that light is lit that means it would be too late ??

 

yep if you did this then that red light means you are doing some damage...

 

 

QUOTE

I need another amp to power my new Plastic Soundlab Cabs. I have been using them with my peaveys. 8ohms and 4ohms, which doesnt allow as much power.

 

get the biggest amp you can afford and also get a limmiter so that you have the power but also have the protection.

[ChrisPointon 0]

The DDT protection is basically an intelligent compressor limiter monitoring the operating parameters of the amplifier. Usually the compression technology will take effect a few db's below the level of clipping and gradually increase the level of compression as the signal reaches the design maxium of the amplifier.

 

The limiter section is usually a hard-knee clip limiter which kicks down the volume more agressively than compression, and is used as a last ditch method of protecting the speakers from severe clipping. Obviously gradual compression is more desirable and transparent than the sudden reduction afforded by clip limiting alone, which is why the DDT system which Peavey uses is quite a useful feature, and doesn't degrade the audio. It is normal to see the DDT system flickering during average operating levels, but if the DDT system is running so high that the led's appear to be permanently lit, then you are feeding a signal which is too high into the amplifier. http://www.dj-forum.co.uk/html//emoticons/smile.gif

 

The DDT technology is patented by Peavey, but in addition to just being a compression system I think it also monitors the speakers loads and behaviour, which is often not a facility offered by stand alone add-on's such as Behringer which just monitor the signal input / output.

 

Personally, I don't think replacing a Peavey Amp with a Numark could be considered as Upgrading http://www.dj-forum.co.uk/html//emoticons/fear.gif . My advice is to either get another Peavey amp with similar characteristics to your existing one, or to run the smaller wattage cabs consider something along the lines of a Behringer EP1500

[transeurope 0]

I have taken a few deep breaths before making this post!

 

I have in the past used absolutely numerous troublesome Peavey amps and indeed when I purchased amps, purchased Numark amps.

 

When the Peavey amps worked, which for me was a rare event, I would say they were marginally better than the Numarks.

 

If you happen to own by some incredible mischance a Peavey amp that works perfectly then I would say keep it in preference to replacing with a Numark.

 

If on the other hand you are thinking of buying another amp to use alongside your existing Peavey, it should be noted that numerous people apart from me report them as troublesome.

 

These days I use Behringer amps, btw, I am not unhappy with the Numarks, but the Behringer is noticeably better, indeed better than the Peavey amps also I would say.

 

Despite the fact that DDT does more than compress/limit, as Chris has said...in reality I do not feel that it is substantially better than just using a compressor limiter.

 

I am open to correction on that by someone technically qualified, but as a user it didn't seem to be in anyway superior.

[ChrisPointon 0]

One benefit of the built in DDT compressor is that it is not user adjustable and generally automatic. As I have said earlier in the thread, you can only benefit from adding an external compressor limiter if it is set up correctly, and that means reading instructions, and learning about what the features do. Some just tend to open the box and fit as supplied, or worse still just set them up in such a way that all the little lights look pretty http://www.dj-forum.co.uk/html//emoticons/smile.gif .

 

I use a seperate Behringer unit myself, and have promoted their use in the past, but they shouldn't just be expected to operate on any given system straight out of the box.

[nrgize 0]

Thanks for all your help and advice.

 

 

 

 

 

Have started a Thread up asking any advice on Numark Dimension Amp.

[superstardeejay 0]

QUOTE

Personally, I don't think replacing a Peavey Amp with a Numark could be considered as Upgrading

 

 

No I agree with Chris.

 

There are many rock bands and nightclubs who run on Peavey amps, and some are very old indeed!! I dont know many clubs who would ever consider installing Numark, they are a generally a 'mobile DJ' product and with the greatest respect that usually means 'value for money' above performance. PV amps are built either in the USA (eg PV and CS range) or, latterly, in China (eg CS/S range) and they sound fab and are great quality albeit at a price. I consider them up there with Crest and Crown.

 

Nightclub-worthy amps usually go thump-thump-thump solidly from 10pm till 3 or 4am, 6 or 7 days a week and are rarely even hoovered-out, please take this as an endorsement of the levels of quality that's out there! It's where legendary marques such as Citronic PPX, HH V900, Crown MA, LabGruppen, QSC etc have earned their reputation.

 

 

 

 

 

 

 

 

 

 

 

 

[nrgize 0]

Hi,

 

I have brought this amp for a backup for my Peavey Failing, or if DJing at a larger venue I have the Amp to run an additional pair of speakers I recently bought. I have posted a picture of what the AMps looked like on New Years Eve. Any comments would be appreciated. Luckily I was in a DJ Booth so party goers couldnt see all the cables you can see in the photo.

 

When money situaution is better will buy another pair Of Peavey UL-15 speakers and another Peavey Amp. But this time I think I might go for the GPS range amps yet. But not sure of the differences between the GPS and the PV range as I have currently got as seen in the picture below =

 

http://img431.imageshack.us/img431/626/dscf09185wz.jpg

[norty303 0]

QUOTE

Formula Sound's industry standard AVC series limiters used to have a description on the blurb which stated: "....protects your sound system from accidents or recalcitrant DJ's....".

 

Technically the AVC is a dynamic level control as it actually reduces the gain rather than just compressing with a infinite ratio. I own one and it's probably the favorite single piece of kit i own.

 

Do not place too much faith in limiters to save your drivers. A lot of people have a false sense of security with theirs.

 

Compression effectively squashes the peaks down meaning you can raise the input level without the amp clipping. This increases the average power going to the speakers. Average power is FAR more damaging to driver voice coils than the occassional peak causing the amp to clip and you frequently see drivers welded up solid with the owner saying 'I don't know why it happened, the limiter was working really well!' (meaning lots of gain reduction showing on the meter)

 

Remember, everything in moderation, the occassional clip light flicker is not going to kill a speaker, likewise, a little bit of gain reduction on a limiter shouild be ok. Start pushing this and you're pushing your luck.

[superstardeejay 0]

QUOTE

Technically the AVC is a dynamic level control as it actually reduces the gain rather than just compressing with a infinite ratio. I own one and it's probably the favorite single piece of kit i own.

 

Yes they're a good unit, a bit dear but good. But if the ratio were infinite, wouldnt that just shut off the music when the threshold was reached (bit like the old PM80 sound limiter..?)

 

Most PA limiters (as opposed to broadcast) can be set to act just like an AVC2 anyhow, you just set a short attack time, large release time and a large ratio. That way, when the threshold is reached, the limiter gain reduces the entire signal, not just the peaks (like a compressor) and keeps it lower till you back off your mixer master.

 

I agree a compressor is best not used as a limiter because it does what it says on the tin....compresses the dynamic range for Radio Broadcasts or A-D Conversion or Studio mastering or 'artistic effect' ..(remember Erik Prydz Call on Me, that awful bass-beat firing off the compressor) and is more likely to make the amp and speakers work harder for their watts. However, proper PA limiters as included in an Omnidrive, Driverack, Ultradrive etc etc are designed exactly for protecting your speakers by gain reduction, they often have a fixed instant attack, and variable threshold (like the AVC2). The Behringer has an LCD version of the AVC's led ladder which, like the Formula Sound, does not pump up and down.

 

Some compressors are good enough to allow you to adjust them into the realms of a limiter but many wont let you.

[norty303 0]

QUOTE

The Behringer has an LCD version of the AVC's led ladder which, like the Formula Sound, does not pump up and down.

 

Is that the Dynamic EQ you're talking about? The limiter screen does pump with the music.

 

It was the the limiter on the DCX which caused the blow on my sub incidentally. If it was a DLC you would be able to hear the level drop as you wind up the input level.

As it is, you continue to hear the bass (haven't driven any of my other sections that hard yet) level go up as the average level increases, even with the limiter lights showing.

 

The dynamic EQ on the other hand will apply a decrease (or increase) to the level but i've found it flaky and a pain to set up for consistent use. For £150 the AVC2 was the better option.

[superstardeejay 0]

QUOTE

Is that the Dynamic EQ you're talking about? The limiter screen does pump with the music.

 

If the limiter bar is pumping, you may need to set the release time higher. It comes as default set quite fast, (in milliseconds, acting like a compressor). You need to turn it to 'slow' to protect the drivers. I set it to its maximum which is 4 seconds. That way, any offending bass-beats will keep it in gain reduction which is essentially always going to be less than unity gain (ie if the limiter were switched out). It should only pump if the release time is much less than the interval between signals that exceed the threshold. After all, that is exactly what the limiter is for. Behringer have included it to protect your drivers, not for artistic effect.

 

 

 

 

[Steve_Mitchell 0]

Just off the subject a little,

 

 

Nice big Avatar Loz

 

 

http://www.dj-forum.co.uk/html//emoticons/toot.gif