Dead amp

[funkymike]

Does anyone know where I can get my QSC amp repeaired, using it last night and it just died! no warning lights came on! The power light is on but its just dead:( Thankfully I had a spare amp so the show went on, like a true pro:D

cheers chaps

Mike

[Solitaire Events Ltd]

Is it still in warranty Mike?

[funkymike]

Is it still in warranty Mike?

No its not in warranty

but on the good news, it appers i just over loaded it and its fine now.

Cheers paul for the info and instructions:D

[nigelwright7557]

If its an expensive amp then a repair is in order.

If its a cheapie then bin it and buy a new one as the repair will probably cost nearly as much.

[Solitaire Events Ltd]

Mike's already said that it's a QSC which I would have thought was worth repairing.

[nigelwright7557]

It depends whats wrong.
A blown fuse is pennies, a new torroid could be £40 upwards.
Add the repairmans time and you could be talking well over £100.

[colint]

think you might find it just got to hot & went to sleep for a while! they tend to do that and it takes a while for them to cool and come back on.

might be worth getting your self a rack plate with a couple of fans on it and fitting it to th back of your rack i got mine from adam hall & never had the problem since!
also I take it you have the clip limitors turned on (if fitted) because this will help to if your pushing it real hard.

[colint]

It depends whats wrong.
A blown fuse is pennies, a new torroid could be £40 upwards.
Add the repairmans time and you could be talking well over £100.

I think £100 for an amp that cost around a grand would be cheap! and even a cheap amp is worth repairing if it's not to old.

[nigelwright7557]

I agree !

[Excalibur]

I agree !

Now there's a novelty!

[colint]

Now there's a novelty!

:eek:

[Corabar Steve]

Now now :sj:

[CRAZY K]

think you might find it just got to hot & went to sleep for a while! they tend to do that and it takes a while for them to cool and come back on.

might be worth getting your self a rack plate with a couple of fans on it and fitting it to th back of your rack i got mine from adam hall & never had the problem since!
also I take it you have the clip limitors turned on (if fitted) because this will help to if your pushing it real hard.

Is this normal with this kind of amp?

Im not knocking the make--but I couldnt afford to have an amp like that anywhere near any of my gigs.

Since I gave up using valve amps-:eek: -- in the last 20 yrs I have never had a problem like that---used HH and an old American Mixer Amp, last 3 years Peavey---not a blink--

CRAZY K

[nigelwright7557]

I have never heard of an amp that "went to sleep"
Unless it has some sort of auto resettable fuse.

If you have damaged it then its not going to come back to life without a repair.

[Corabar Steve]

Never heard of thermal cut outs then?

[nigelwright7557]

Thermal cut out ! lol

That term went out with the ark !

[Excalibur]

Never heard of thermal cut outs then?

I think you'll find you meant " Auto re-settable fuse! ":p :D :D

[CRAZY K]

I have never heard of an amp that "went to sleep"
Unless it has some sort of auto resettable fuse.

If you have damaged it then its not going to come back to life without a repair.

Not much help when your playing the first dance for the Bride and Groom

:eek: :eek: :eek:

I would arrange an immediate funeral:D

If you have to start modifying the manufacturers original spec it sounds like trouble.

CRAZY K

[colint]

what is ment is a system whereby the amp will shut down the power to the outputs when the amp gets to HOT! ie thermal cutout! what ever you call it it's still thermal.

[nigelwright7557]

what is ment is a system whereby the amp will shut down the power to the outputs when the amp gets to HOT! ie thermal cutout! what ever you call it it's still thermal.

What this means is the designer skimped on heatsink and/or fan !

If yo uare flogging an amp tha thard its time to buy a bigger one.

[Corabar Steve]

Thermal cut out ! lol

That term went out with the ark !I just thought I'd use a term that somebody who's been out of the gae as long as you would recognise
What this means is the designer skimped on heatsink and/or fan !

If yo uare flogging an amp tha thard its time to buy a bigger one.

Not everyone has the luxury of buying equipment that is above budget standard (or clever enough to design & build their own)

[Corabar Entertainment]

What this means is the designer skimped on heatsink and/or fan !

If yo uare flogging an amp tha thard its time to buy a bigger one.I'm certainly no expert, but couldn't it just mean that the air-flow isn't too good? ie the location you've got it in isn't allowing enough cool air to the fan?

[Jiggles]

your correct there Angela! Poor air flow. you could have the biggest heat sink and amp and have it in a flight case and it will still get hot and possibly "cut out"

[nigelwright7557]

There are a few things that would make an amp run hot.

The fan exhaust is blocked or partly covered.

Someone is running a 4 ohm system into 2 ohms or less.

The amp was just designed badly with insufficient heatsink and fan configuration.

They usually recommend running an amp well inside its power rating to ensure transients are not clipped causing distortion.

[colint]

What this means is the designer skimped on heatsink and/or fan !

If yo uare flogging an amp tha thard its time to buy a bigger one.

so people never overdrive power amps then, or a fan's never broken down or been obstructed in a rack?

all these thing do happen, in a perfect world all would be dandy but it aint perfect really is it?

in years gone bye I used to use HH s500D amps & lots of them (crude but powerful at the time) and going thermal was pat of the course if they were overdriven but the out of date now thermal cutout always saved the amp from distroying itself and would re-start when cooler!

[Corabar Entertainment]

There are a few things that would make an amp run hot.

The fan exhaust is blocked or partly covered.

Someone is running a 4 ohm system into 2 ohms or less.

The amp was just designed badly with insufficient heatsink and fan configuration.

They usually recommend running an amp well inside its power rating to ensure transients are not clipped causing distortion.So you agree that you were incorrect to say...
What this means is the designer skimped on heatsink and/or fan !

If yo uare flogging an amp tha thard its time to buy a bigger one. as that's just 1 possible cause.

[nigelwright7557]

No, if an amp is designed properly it should be very hard to block the air flow.

[nigelwright7557]

The amps I have have cables hanging out the back which stops you banging the amp up against a wall.
The front should be open anyway to see bar leds and volume controls.

If someone is stupid enought to put a coat over the amp then they deserve everything they get !

[Corabar Entertainment]

TBH, I'm getting a bit fed up with you contradicting yourself on threads!

[nigelwright7557]

Well your the one replying to them !

If you want sensible good advice then your gonna have to pay for it !

Would you do a disco for free ?

[colint]

The amps I have have cables hanging out the back which stops you banging the amp up against a wall.
The front should be open anyway to see bar leds and volume controls.

If someone is stupid enought to put a coat over the amp then they deserve everything they get !

why would someone put a coat on an amplifier?

[nigelwright7557]

It does seem odd that you dont like my advice.

It was certainly good enough for BT, Marconi Command and Control and many other blue chip companies ! My advice paid my wages for a good quarter of a century.

[Corabar Entertainment]

Well your the one replying to them !

If you want sensible good advice then your gonna have to pay for it !

Would you do a disco for free ?

What exactly is the point of you joining a forum if that is your attitude?

Maybe you might feel more at home somewhere else...... such as BT, Marconi Command and Control and many other blue chip companies.

[colint]

It does seem odd that you dont like my advice.

It was certainly good enough for BT, Marconi Command and Control and many other blue chip companies ! My advice paid my wages for a good quarter of a century.

Nigel, it's not that we don't like your advice!

advice is always good when corect, as stated in an earlier post there are many people on this site who have a wealth of experience with sound (& Lighting) and although I have been involved with sound for many years there's always going to be someone who's more clued up than me (or you for that matter) if people think your wrong with something they will tell you
I don't profess to know everything but well willing to learn!

[nigelwright7557]

So why does anyone input anything then if you have the top expert on here?

I have put forward my views and people can consider them for themsleves then go away and make up their own minds on matters.

Its not like I started in electronics and discos last week.
I have been around for over 30 years.
I build my own gear mostly, speaker boxes, amplifiers, sound to light etc etc
My gear never breaks down so I cant be too far away from getting it right.
I havent let a single booking down in 30 plus years.

[Corabar Entertainment]

So why does anyone input anything then if you have the top expert on here?Who said that?

[colint]

So why does anyone input anything then if you have the top expert on here?

I have put forward my views and people can consider them for themsleves then go away and make up their own minds on matters.

Its not like I started in electronics and discos last week.
I have been around for over 30 years.
I build my own gear mostly, speaker boxes, amplifiers, sound to light etc etc
My gear never breaks down so I cant be too far away from getting it right.
I havent let a single booking down in 30 plus years.

I think your getting the wrong end of the stick here!

Thats just the point no one is proclaiming to be top expert! we are just a load of people doing the same job and helping each other where we can,
I to build a lot of my own kit like speaker cabs etc,

I don't know enough about electronics to build an amplifier or anything else like that for that matter so I know my limitations and wouldn't advise someone how to do it, but I do have a great deal of experience in the sound installation field and can advise on stuff like that!

and I've been a Dj since 1970

[Corabar Steve]

Its not like I started in electronics and discos last week.
I have been around for over 30 years.
I build my own gear mostly, speaker boxes, amplifiers, sound to light etc etc
My gear never breaks down so I cant be too far away from getting it right.
I havent let a single booking down in 30 plus years.

You've been away for the best part of 20 years, technology has changed since then. There are a lot of people on here who have up to date experience with up to date state of the art equipment, but you give the impression that you know better than all of them because you started 30 years ago.

[nigelwright7557]

You said that there were people on here with much better knowledge than myself.

If that is the case why not limit the forum to only one person giving advice.

You are always gonna get different answer from different experts on things.
You need to accept that.

I have to say some of the things said on this group are stupid beyond belief especially that amps should be twice as powerful as the speakers you drive.
I think someone has misunderstood. In my realm of reality teh speakers are always twice as powerful as the amp to stop distortion and keep the speaker within safe limits.

[Corabar Steve]

and I've been a Dj since 1970

Had any time away from it Colin?

[Danno13]

So its ok for you to dismiss other people's opinions and advice as stupid then?

And I think you'll find the 2x(well 1.5-1.8x) amp to speaker power rule is widely accepted throught the pro audio world... I'd explain it, but apparently you're already an expert so perhaps work it out for yourself.

[Corabar Steve]

I have to say some of the things said on this group are stupid beyond belief especially that amps should be twice as powerful as the speakers you drive.Well in that case I'm at a loss as to why you would want to stick around.

We're all obviously well below you.

[CRAZY K]

so people never overdrive power amps then, or a fan's never broken down or been obstructed in a rack?

all these thing do happen, in a perfect world all would be dandy but it aint perfect really is it?

in years gone bye I used to use HH s500D amps & lots of them (crude but powerful at the time) and going thermal was pat of the course if they were overdriven but the out of date now thermal cutout always saved the amp from distroying itself and would re-start when cooler!

Whatever the problem I really think it would be a good commercial decision to buy a new amp because--

1. It might go wrong again:eek:

2.You spend years building up a reputation so it would be a shame to lose the benefit of that:D

3. A new amp is a tax deductable capital purchase:D

4. You will probably be using it for many years to come in the future so it will be a good investment.

I wouldnt worry about the technical bits too much:D

CRAZY K

[nigelwright7557]

Well in that case I'm at a loss as to why you would want to stick around.

We're all obviously well below you.

It just upsets me that fellow DJ's are being given very bad advice.

[colint]

Had any time away from it Colin?

Not really I ran a local pub for three years!
a music pub so not was still involved with the disco thing but also live music 7nights per week,
talk about in at the deep end cleaning the loos one min then doing sound for the bands next what you might call an extreme learning curve!
so no not out at all really but I stopped working at parkers about 8 years ago I think

[Corabar Entertainment]

You said that there were people on here with much better knowledge than myself.Where has anyone said that?
If that is the case why not limit the forum to only one person giving advice.So long as it's you, eh?
You are always gonna get different answer from different experts on things.
You need to accept that.Of course we accept that people have differing points of view - there wouldn't be much activity on a forum without that, would there? But there is a difference between giving a viewpoint and giving the impression that you are the only person with a valid point, and that what you say is always right - which IMO, you have done. However, when questioned further, you have contradicted yourself on several threads, but still trying to say that YOU ARE RIGHT. That doesn't go down very well with the members on here, and nor does calling the membership stupid...
I have to say some of the things said on this group are stupid beyond belief

[nigelwright7557]

You have to remember that some companies dont want to give good advice.
They are in the business of selling amps and speakers.

I have no ulterior motives.

[Corabar Steve]

So getting on for 40 years in the biz. Nice one Colin! :approve:

[Dragonfly]

Colin you legend enough said :D :D

[Excalibur]

You said that there were people on here with much better knowledge than myself.

If that is the case why not limit the forum to only one person giving advice.

You are always gonna get different answer from different experts on things.
You need to accept that.

I have to say some of the things said on this group are stupid beyond belief especially that amps should be twice as powerful as the speakers you drive.
I think someone has misunderstood. In my realm of reality teh speakers are always twice as powerful as the amp to stop distortion and keep the speaker within safe limits.

Now with the greatest of respect, and saying this really carefully so that I don't call you anything impolite, that is absolute rubbish. Many people on here have told you two things which we all know.
1) Whatever rating your speakers are in no way could eliminate distortion. I have a pair of Eurosys3's, 150w RMS. When I run them on my 100w mono mixer amp, if I were daft enough to wind it up far enough I get distortion which I can hear. Three times the amp power doesn't seem to stop it there, the only answer is intelligent use of the volume control, which we all advocate on here.

2)I'm sure we have all blown up speakers with amps rated way below the speakers. I know I have. A badly clipped and distorted signal from an underpowered amp is quite capable of taking out a big high power speaker.

[Excalibur]

You have to remember that some companies dont want to give good advice.
They are in the business of selling amps and speakers.

I have no ulterior motives.

If the big companies were giving out duff info which resulted in their products failing on a regular basis, don't you think the consumers might vote with their wallets, and buy something else?

[colint]

So getting on for 40 years in the biz. Nice one Colin! :approve:

yes to long really but can't leave it alone, still get a real buzz for putting all the gear together and I get total support from my present wife (unlike the previous one) I really don't know how she puts up with it!

compression drivers on the kitchen table,
Large P.a in the hall,
pair 1 x 18" cabs in the batheroom
rack in the bedroom,
tools everywhere,
constantly needing new stuff,
and a steady flow of Dj's coming for speakers
She's the perfect Dj's wife!

[Corabar Steve]

rack in the bedroomSteady now! This is a family friendly forum :sj:

[nigelwright7557]

If the big companies were giving out duff info which resulted in their products failing on a regular basis, don't you think the consumers might vote with their wallets, and buy something else?

But abusing the equipment doesnt kill the equipment of soon.
It just means it doesnt last as long.

The sooner it dies the sooner the manafacturer sells new equipment.

[Excalibur]

yes to long really but can't leave it alone, still get a real buzz for putting all the gear together and I get total support from my present wife (unlike the previous one) I really don't know how she puts up with it!

compression drivers on the kitchen table,



Bet that makes your cornflakes jump about a bit!:D

[Excalibur]

But abusing the equipment doesnt kill the equipment of soon.
It just means it doesnt last as long.

The sooner it dies the sooner the manafacturer sells new equipment.

Isn't not lasting as long very similar to failing soon, or am I missing something?:confused:

[colint]

yes to long really but can't leave it alone, still get a real buzz for putting all the gear together and I get total support from my present wife (unlike the previous one) I really don't know how she puts up with it!

compression drivers on the kitchen table,



Bet that makes your cornflakes jump about a bit!:D

I know it's bad really but I got a cab for them now so will be using them real soon! it really is that bad though even the garden gate is turbo blue! (had some paint left)

[Corabar Entertainment]

Isn't not lasting as long very similar to failing soon, or am I missing something?:confused:Yes, I was thinking the same thing when I read it.

[Excalibur]

Yes, I was thinking the same thing when I read it.

Just don't reply though, it'll only stir up trouble.;) :D

[colint]

See here section 5:

http://www.doctorproaudio.com/doctor/temas/powerhandling.htm

[Danno13]

Good find and I bet you could find 100 more articles saying the same thing.. but its obviously because they have ulterior motives :D

[colint]

Yup! :bang:

[Corabar Entertainment]

Just don't reply though, it'll only stir up trouble.;) :Dand
Good fine and I bet you could find 100 more articles saying the same thing.. but its obviously because they have ulterior motives :D:lol:

[Corabar Steve]

There's backhanders & bungs going on everywhere

[Excalibur]

There's backhanders & bungs going on everywhere

So where's mine then? It's conspicuous by its absence so far!:(

[colint]

Where's mine then? I'll have a jamesons & coke please! (large)

[colint]

sorry was away for a bit, this is what i was looking for! these people know naff all about sound engineering and this doc is about 10-15 years old?

http://www.jblpro.com/pub/technote/lowpower.pdf

[gillo]

But abusing the equipment doesnt kill the equipment of soon.
It just means it doesnt last as long.

The sooner it dies the sooner the manafacturer sells new equipment.

so what about clipping a speaker and amp like mad im sure this wont shorten the life of a speaker it will just kill it:confused:

I dont think there is anyway of telling this guy that hes not correct at everything:D

[sleah]

Right....here goes....


I have never heard of an amp that "went to sleep"
Unless it has some sort of auto resettable fuse.

If you have damaged it then its not going to come back to life without a repair.

Nigel seems to have missunderstud that the "sleep" comment refered to the time an amp will stay shut down while it cools down, controlled by a thermal fuse / circuit etc.


Thermal cut out ! lol

That term went out with the ark !

:eek: Staggering! Any decent quality amp will have a thermal cut out of sorts, it stops the amp being literally fried if it overheats for whatever reason.
A budget amp may not have one to cut costs, and many budget amps are so cheap you can afford to chuck them away anyway:rolleyes:
Many lower power (150ishW and lower) may not have thermal cut outs 'cause they don't need them as they won't get that hot anyway, even under fault conditions.:)
A thermal cut out will not protect an amp from say a shorted speaker cable or blown internal device, unless the fault causes it to get hot!
There are other protection circuits to do that, DC protection being the other major protection device. If DC gets to a driver - say goodbye to the cone:eek:


There are a few things that would make an amp run hot.

The fan exhaust is blocked or partly covered.

Someone is running a 4 ohm system into 2 ohms or less.

The amp was just designed badly with insufficient heatsink and fan configuration.

They usually recommend running an amp well inside its power rating to ensure transients are not clipped causing distortion.


No, if an amp is designed properly it should be very hard to block the air flow.

I famously did the first thing - and the thermal cut out did, and saved it to play another day:D


If someone is stupid enought to put a coat over the amp then they deserve everything they get !

Gotta agree with that one:D


so what about clipping a speaker and amp like mad im sure this wont shorten the life of a speaker it will just kill it:confused:

I dont think there is anyway of telling this guy that hes not correct at everything:D

It could shorten the life in as much as it can suffer damage to the voice coil, which will eventually kill it. That said minor damage to a voice coil is as good as a dead coil as it will sound awful:( until it dies:(

Going back to my "famous" comment.

I aquired a second hand HH V800 some years back and stuffed it into a nice plastic SKB nobbly flightcase.
The first gig I did with it cased it cut out half way through:eek: Luckily I was bi-amped so a quick re-patch got me going within seconds, albeit with out sub bass.
I'd neglected to realise the V800 vents out it's sides and the case was only about 1mm from each side, so virtually no air flow:eek: and it over heated.
The 'ole thermal cut out kicked in and saved it's life.
When I checked the amp the following day it was perfect:D and still is to this day (close on 10years since:cool: ) I also rapidly modded the case so the air flow was clear:)

I'm not entering the watt debate, I've mentioned before I believe in matching speakers and amps watt for watt.

[Excalibur]

Right....here goes....



Nigel seems to have missunderstud that the "sleep" comment refered to the time an amp will stay shut down while it cools down, controlled by a thermal fuse / circuit etc.



:eek: Staggering! Any decent quality amp will have a thermal cut out of sorts, it stops the amp being literally fried if it overheats for whatever reason.
A budget amp may not have one to cut costs, and many budget amps are so cheap you can afford to chuck them away anyway:rolleyes:
Many lower power (150ishW and lower) may not have thermal cut outs 'cause they don't need them as they won't get that hot anyway, even under fault conditions.:)
A thermal cut out will not protect an amp from say a shorted speaker cable or blown internal device, unless the fault causes it to get hot!
There are other protection circuits to do that, DC protection being the other major protection device. If DC gets to a driver - say goodbye to the cone:eek:





I famously did the first thing - and the thermal cut out did, and saved it to play another day:D



Gotta agree with that one:D



It could shorten the life in as much as it can suffer damage to the voice coil, which will eventually kill it. That said minor damage to a voice coil is as good as a dead coil as it will sound awful:( until it dies:(

Going back to my "famous" comment.

I aquired a second hand HH V800 some years back and stuffed it into a nice plastic SKB nobbly flightcase.
The first gig I did with it cased it cut out half way through:eek: Luckily I was bi-amped so a quick re-patch got me going within seconds, albeit with out sub bass.
I'd neglected to realise the V800 vents out it's sides and the case was only about 1mm from each side, so virtually no air flow:eek: and it over heated.
The 'ole thermal cut out kicked in and saved it's life.
When I checked the amp the following day it was perfect:D and still is to this day (close on 10years since:cool: ) I also rapidly modded the case so the air flow was clear:)

I'm not entering the watt debate, I've mentioned before I believe in matching speakers and amps watt for watt.

In most things there Sir, I agree wholeheartedly with you.

[sleah]

In most things there Sir, I agree wholeheartedly with you.

Eye thank you very muchly indeedey:D

I'm betting it's the very last line you have a differing opinion on:rolleyes:

Without wishing to sound arrogant, my comments about thermal cut outs are based on facts, I'll gladly open an amp, photograph it and point out exactly what and where the thermal devices are.

They are often in addition to the other protection circuitry, such as DC protection I mentioned and anti-thump protection.
The latter two you can buy as a kit and retro fit, something I've done in fact:cool: The amp I fitted one to didn't have thermal protection though:(

My nice Yamaha P2700 has anti-thump, DC protection and thermal protection:D Still managed to blow one side of the bugger though:( never did find out what the fault was:confused:
It cost about £250 for a replacement amp module (good design Yamaha:cool: ) which was about the same price as a new version of the amp.
But the P2700 is bigger, heavier and worth every penny of the repair:D :D

[Excalibur]

Eye thank you very muchly indeedey:D

I'm betting it's the very last line you have a differing opinion on:rolleyes:



Actually, that's how I try to run mine, although I'm leaning towards having a little more amp output than speaker rating, and not running with all the red lights flashing!

[sleah]

Actually, that's how I try to run mine, although I'm leaning towards having a little more amp output than speaker rating, and not running with all the red lights flashing!
:lol: Leave the red flashing lights to the fire brigade when they come to put the fire out:D :D :D

[Corabar Steve]

Aren't their lights usually blue?