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egosbar

cooling fan for my onkyo is it needed

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Yeah.........put a decent sized fan blowing across it or install a fan in the back of the cabinet to suck the hot air out.

You can get a cheap ceiling exhaust fan to do the job.

They have a plug on them that you can just plug into a power point to switch it on when the volume goes up!

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1. Why do you want a noisy fan running to cool your amp.

There is no reason why a fan cannot operate silently.

2. Running a fan with an amp that is clearly not designed for one is likely to create more problems than it solves.

Nonsense. Keeping electrolytic caps cool will ALWAYS prolong their life. Always.

Onkyo is not a bad product. Those amps don't have a habit of just overheating for the sake of it. People dont spend hundreds (up to thousands) on an amp that needs a D.I.Y. tack-on fan to keep it running. You need to find the cause of the heat problems rather than patch/band-aid "fixes" that will create more problems than they solve.

Amplifiers can overheat for a variety of reasons. They include:

* Poor design (unlikely, in the case of Onkyo).

* Difficult speaker loads, combined with continuous high power operation.

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Yeah, but he's at bloody Cobar!.............not the Snowy Mountains.

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There is no reason why a fan cannot operate silently.

Nonsense. Keeping electrolytic caps cool will ALWAYS prolong their life. Always.

Amplifiers can overheat for a variety of reasons. They include:

* Poor design (unlikely, in the case of Onkyo).

* Difficult speaker loads, combined with continuous high power operation.

Fans always create some noise, and in a listening room that is not desirable.

The amp has been built to a certain design spec. If a user stuffs with that design and puts -say- a fan on top, what if the case is cooled in some parts more than others. Temperature changes and temperature differences will hurt more than consistent, stable heat! Heat stressed and cracked circuit board anyone? What if the fan's airflow creates an air-lock and another part in the amp then this seriously overheats?

You can rest assured Onkyo have spent quite a bit of effort on cooling, probably computer-modelling the convection characteristics of the enclosure and predicting all possible scenarios. Don't stuff with this lightly!

The thing is - Onkyo have designed the amp a particular way and (as you say) it is eminently likely they have designed it to be fit for the purpose for which it was sold. That is why I suggested consulting the manual to verify this.

Of course, part of Onkyo's design would be cost saving - and I'm not saying their design cannot be improved upon, but if you are going to try then you'd better be damn straight sure you know what you are doing. Otherwise I hold - you'll do more damage than good.

Edited by amey01

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Fans always create some noise, and in a listening room that is not desirable.

Incorrect. Fans can be made to operate at levels that are equivalent to background noise.

The amp has been built to a certain design spec. If a user stuffs with that design and puts -say- a fan on top, what if the case is cooled in some parts more than others. Temperature changes and temperature differences will hurt more than consistent, stable heat! Heat stressed and cracked circuit board anyone? What if the fan's airflow creates an air-lock and another part in the amp then this seriously overheats?

Nope. Such things do not occur. Heat damages electrolytic caps and, under extreme conditions, solder joints. A constant air flow will tend to alleviate such conditions.

You can rest assured Onkyo have spent quite a bit of effort on cooling, probably computer-modelling the convection characteristics of the enclosure and predicting all possible scenarios. Don't stuff with this lightly!

Bollocks. Whilst I have a fair amount of respect for Onkyo, generally, they are no different from any other mass market manufacturer. They build their (particularly low end) amplifiers down to a price. Heat sinking is designed to do the job, without a lot of reserve for unusual conditions. Hence, they (and most other manufacturers) carefully spell out the safe operating conditions of their products. More air flow can only be a good thing.

The thing is - Onkyo have designed the amp a particular way and (as you say) it is eminently likely they have designed it to be fit for the purpose for which it was sold. That is why I suggested consulting the manual to verify this.

Of course, part of Onkyo's design would be cost saving - and I'm not saying their design cannot be improved upon, but if you are going to try then you'd better be damn straight sure you know what you are doing. Otherwise I hold - you'll do more damage than good.

And adding a couple of fans to move air around the cabinet is not going to do any damage whatsoever.

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I used to sit a 240v 125mm fan on top of my Panasonic before I moved it out of the cabinet, no problems at all. with the rear of the cabinet open the fan could only just be heard if you got within a metre of the receiver and the receiver was not playing anything, even normal level TV viewing drowned out the fan, perfectly acceptable to me.

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Incorrect. Fans can be made to operate at levels that are equivalent to background noise.

I guess it depends on what you call "background noise" - if your house is near a highway maybe.......

Nope. Such things do not occur. Heat damages electrolytic caps and, under extreme conditions, solder joints. A constant air flow will tend to alleviate such conditions.

Delta-T is a very real issue. If your DIY fan is blowing on one side of the circuit board say - then differences in expansion and contraction can cause very real mechanical damage. Convection cooling can be quite precisely balanced and blowing air perpendicular to convection patterns can block airflow, much the same way as an air curtain over a door keeps air conditioning inside.

Not saying this will happen in every case, but it is a possibility.

they are no different from any other mass market manufacturer.

Very true - which is why in my earlier post (#25) I suggested the O.P. consider some professional-grade speakers/amps such as Mackie/RAMSA/JBL if he is attempting to seek operation beyond the spec of the Onkyo.

Edited by amey01

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perfectly acceptable to me.

.......Totally unacceptable to me......... - maybe I'm just too much of a purist?

That sort of noise serves only to eat away at your dynamic range and takes resolution out of quiet passages. Even if you don't realise it consciously!

And the fan adds electrical noise and vibration to your electronics also. There are very good reasons why high-end manufacturers (and most mass market manufacturers) do not use fans!! Heck - slapping a fan on the back would save them a lot of money compared to heavy, expensive heat sinks! They would if they could!

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I don't use the HT Receiver to listen to music though as it's not in the same league as the Copland. I did say at normal TV viewing levels not music.

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I guess it depends on what you call "background noise" - if your house is near a highway maybe.......

The last time I measured a (prpoperly and carefully implemented) fan in an amplifier, I performed the measurements at 4:00AM. I threw a Doona over the amplifier and used a professional, calibrated microphone to measure the noise of the amplifier with the fan non-operational than operational. The result was the the fan produced less noise than the main power transformer in that amp. The transformer is an epoxy potted, toroidal type and is VERY quiet. It is perfectly possible to arrange a fan to be as near to silent as it gets. Most manufacturers don't bother however.

Delta-T is a very real issue. If your DIY fan is blowing on one side of the circuit board say - then differences in expansion and contraction can cause very real mechanical damage. Convection cooling can be quite precisely balanced and blowing air perpendicular to convection patterns can block airflow, much the same way as an air curtain over a door keeps air conditioning inside.

You may care to note that my suggestion was for the original poster to place a couple of fans at the top of his cabinet. This will cause gentle circulating currents of air to draw warm air from the cabinet. As for you comments about temperature variations, I believe you are overstating the importance of the effect, relative to consumer grade products and under-estimating the importance of good cooling with electrolytic caps in consumer equipment.

Not saying this will happen in every case, but it is a possibility.

Very true - which is why in my earlier post (#25) I suggested the O.P. consider some professional-grade speakers/amps such as Mackie/RAMSA/JBL if he is attempting to seek operation beyond the spec of the Onkyo.

Emphatically agreed. His speakers seem to be severely under-rated for the intended purpose.

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The last time I measured a (prpoperly and carefully implemented) fan in an amplifier, I performed the measurements at 4:00AM. I threw a Doona over the amplifier and used a professional, calibrated microphone to measure the noise of the amplifier with the fan non-operational than operational. The result was the the fan produced less noise than the main power transformer in that amp. The transformer is an epoxy potted, toroidal type and is VERY quiet. It is perfectly possible to arrange a fan to be as near to silent as it gets. Most manufacturers don't bother however.

How about trying it in reverse. With the fan ON, try turning the fan OFF and see if you notice a difference in this case. A transformer and fan emit sounds from very difference frequency spectrums so it is very easy to hear one over the other. But I guess it's personal preference - for me - I wouldn't want it. If it makes you happy, go for it.

You may care to note that my suggestion was for the original poster to place a couple of fans at the top of his cabinet.

Duly noted. However, as per post #22, his amp is not enclosed. I took his question to be mounting fans on top of his amp case - above vent holes or the like. I may be wrong?

Edited by amey01

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How about trying it in reverse. With the fan ON, try turning the fan OFF and see if you notice a difference in this case. A transformer and fan emit sounds from very difference frequency spectrums so it is very easy to hear one over the other. But I guess it's personal preference - for me - I wouldn't want it. If it makes you happy, go for it.

I didn't just run an SPL measurement. I ran a full sweep, from 10Hz - 40kHz. There was no discernable difference between the two spectra. The graphs will be stored somewhere on a hard drive. I may be able to locate them. Or not.

Duly noted. However, as per post #22, his amp is not enclosed. I took his question to be mounting fans on top of his amp case - above vent holes or the like. I may be wrong?

Either way, a fan will certainly not harm the amp in any way. It will prolong the life of the electrolytic caps and possibly the rest of the amp.

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Gees guys, this thread appears to have degenerated into a mine's bigger than yours fling fest.

Just reading the OP's posts it would appear that -

  • The Technics speakers are a bit low on the power handling scale than what the amplifier is capable of dishing out (70W speakers - higher powered amp.)
  • The OP's mates like to "turn the wick up" to max. Probably driving the amp close to full power if not into occassionally clipping.
  • The amp runs a little on the warmer side - probably due to the hammering it's getting.

So what's the solution? Well there have been plenty of suggestions - some of which may have questionable use.

Forced fan circulation of air can help. There has been some comments on fan noise. Perhaps here's an opportunity to dispell some myths.

  • Of the muffin type fans, generally the larger diameter models are better. They move more air at a lower rotational speed and therefore can be quieter than smaller fans. Hooked up to a suitable temperature sensor and controller, they can be made to operate at lower rotational speeds providing a constant but quiet flow of air through the amplifier, speeding up only when the temperature rises.
  • If the OP or his mates are playing music at ear splitting levels I doubt if they would notice the noise generated by most fans. ZB is pretty much correct in saying most fans are quieter than the background noise in most rooms. We also might need to take into context the OP's listening tastes and habits. Does he listen late at night to chamber music or does he like to turn up the wick on rock 'n' roll or dance music?

Digital optical input or analogue input? This is a no brainer. The optical input isn't likely to be causing any overload unless the amplifier is faulty. Connecting the source via the analogue inputs won't solve the problem.

IMO there is probably not enough info to draw a definitive conclusion as to the best possible approach to solving this problem. Perhaps the OP needs to re-think his listening criteria. If he likes to listen loud and long, then perhaps more efficient higher power handling speakers and a more powerful commercial grade amplifier is what is perhaps more appropriate???

Cheers,

Alan R.

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IMO there is probably not enough info to draw a definitive conclusion as to the best possible approach to solving this problem. Perhaps the OP needs to re-think his listening criteria. If he likes to listen loud and long, then perhaps more efficient higher power handling speakers and a more powerful commercial grade amplifier is what is perhaps more appropriate???

Yep - already dealt with as per post #25. But a little healthy debate is a good thing from which we can all learn something extra! I certainly like my prejudices being challenged and thought provoked.

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Following on from the insights of the topic, "SOME IMMUTABLE LAWS OF THREADS",I suggest the following investigation be made.With no inputs to the amp turned on and with the volume at zero(speakers connected);leave the amplifier turned on for say 2 to 3 hours.After this quiescent running period investigate if the Onkyo is warm or is actually as hot as when it is seemingly cooking.If it is hot,then you do indeed have a problem and this can be due to several causes,faulty amplifier,misuse, speaker mismatch or even r.f. injected via the cables.The last point made is an attempt to resolve the issue,as while a fan would assist cooling the problem seems to relate to having chosen the wrong gear for the intended purpose.

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I think it's one constant party up there Van!

It never gets a chance to cool off.

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He must live in the house between the two "For Sale" properties.

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Hi guys had an Onkyo 875 in a cupboard with rear cut out and front doors open. Temp was regularly around 40-42 cel. Put a small 125mm computer fan above the 875 sucking up and firing backwards above the hottest point. The 875 never went above 34 cel again and I only ever heard the fan when everything was switched off.

Hope this helps Chewie

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wow some interest here thanks all for taking the time to read and try to help

Edited by egosbar

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1. Why do you want a noisy fan running to cool your amp.

2. Running a fan with an amp that is clearly not designed for one is likely to create more problems than it solves.

Onkyo is not a bad product. Those amps don't have a habit of just overheating for the sake of it. People dont spend hundreds (up to thousands) on an amp that needs a D.I.Y. tack-on fan to keep it running. You need to find the cause of the heat problems rather than patch/band-aid "fixes" that will create more problems than they solve.

To this end, look at:

1. Are you running the amp in a cupboard or enclosed space - if so, get it out!

2. Are you running the amp with not enough space for ventilation - if so, allow it room to breathe

3. Are you running too many speakers at the same time - if so, reduce it to specification (read the manual)

4. Is something emitting heat below your amp - if so, move it.

5. Is there a problem with the amp - if so, get it fixed.

i wouldnt think in this day and age with technology so good that i cant find a small fan that certainly wont sound louder then the music im playing haha

Edited by egosbar

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Okay - let's just get this straight.

You have a problem with speakers blowing? RCA leads or any other cable will not change this. Nor will the heat in your amp or placing a fan on top.

What makes speakers blow is DC - that is, when the amp is driven past it's ability to generate sinewave (music) it clips that signal and sends DC (at the maximum rated output) to the speakers. That will blow any speaker pretty well immediately.

What also happens just before clipping is that the signal composition will change. Where a speaker is rated at (say 100w) it means that (for normal music) the woofer might be getting 95w and the tweeter 5w. Just before clipping, this output changes to about 50/50. So you can see what will happen if you are using 50w amp with your "100w" speakers - suddenly the tweeter will be getting 25w (when it is rated to about 5w) and again - it will blow instantly.

I don't quite know what you are trying to achieve by this. You've asked for advice - you've been given a lot of great advice - you choose to ignore it all and swap to interconnect cable to try to stop your speakers blowing. I don't get it.

I too tried to offer some advice, but now it is clearer. The problem is drunken people in your house that have no respect for your property.

So now I'm in a place to offer some more advice. Maybe you could:

* Lock the amplifier in a VENTILATED enclosure

* Purchase some amplified PA speakers like Mackie, JBL or Ramsa that are designed to handle this sort of abuse (and will go DAMN LOUD too)

or just don't invite disrespectful people to your house!

wow this has generated some responses but i have to reply to this one , and then i will go through all the posts after

ok lets get this straitht then , i appreciate your well written post , i dont think any of the posts before this have maken it so clear as to what is going on but i dont appreciate being told that i have ignored advice , i have take the time to post answer question think about and decide the best course of action to take to remedy my problem , in the next few weeks with all the info people have been kind enough like yourself to give i will make decisions starting with the easiest and cheapest and finishing if need with the most expensive and time consuming (sending my amp away) , i think what you need to remember amey is that just because you get answers on forums like these sometimes they are not nessasarily the right ones , i have a lot of info i have learned over the last few weeks and the reason i thought about changing my leads (and remember i seem to be only having these problems after changing from rca to digital optical ) the reason i considered changing back to rca leads is simply from a post earlier in this thread , now right or wrong its a pretty simple task to do , i have learned that high volume may be the problem but one speaker blew from high volume the other weeks later blew from a steady medium volume around 35 which had been happily pumping away for about 5 hours and there was no increase in sound , so although im not ignoring any advice i ask a new question

can a single song mp3 recorded bad or whatever cause a speaker to blow because the song is corrupted or just plain wrong etc ? ive never heard of it but the more i learn about digital music and i have been playing music like this for as long as mp3 came out without no problem the more i wonder now , is there one song in my 800 album collection causing this problem or one album , possibly not but it is worth thought and shows you that im not ignoring advice im searching and diffusing all the advice im given and in the end i will sort my problem out by reading and listening.

Not everyone has the knowledge you have and although it may seem easy for you to understand it will take me a few weeks of asking and listening NOT IGNORING advice and taking the appropriate actions

so far i have changed the position of my amp and given it more room to breathe - hope that works

i have moved the amp to a higher place and tomorrow i will take some pics and you will see how much i care about music and my gear

the people i invite do not mean to be disrespectful by turning up a 2 inch round volume control after having alcohol a quarter of a turn or half a turn which may see it go from 40 to 55 or 60 very quickly

i think amey you are the one that hasnt really read and understood every post in this thread if you had you would never have wrote im ignoring good advice when im actually doing the opposite , the reason i started this thread was from advice to put a fan on it , if the fan helps keep it cooler during long sessions i cant see it hurting .

you have mentioned a few points in your previous post

1. Are you running the amp in a cupboard or enclosed space - if so, get it out!

if heat isnt blowing my speakers then that is not the answer (dont get me wrong i know heat cannot be good and ive done the right thing and moved my amp) by listening not ignoring these posts by the way

2. Are you running the amp with not enough space for ventilation - if so, allow it room to breathe

same question as the first

3. Are you running too many speakers at the same time - if so, reduce it to specification (read the manual)

if youve been following my posts in this and similar threads you will see its only 2 techinic floorstanders and now only 2 little sonies with a sub , and you will also see that i mentioned i have read the manual

4. Is something emitting heat below your amp - if so, move it.

never been asked this but no

5. Is there a problem with the amp - if so, get it fixed.

Again small country town , life without music for months id rather go through all the options that may fix the problem before i send my amp away , im ready to accept a couple more blown speakers that i dont use any more trying options that may work (not because i ignore advice but because i read listen and try to deciper good advice from not intentioned bad advice

so amey i guess i took offence at being told i ignored all the advice from people here when in actual fact i have listened with a keen ear and appreciate every bit of time all have taken in trying to fix my problem

keep an eye on this post i pretty much finished my jukebox build today at least the body work , i have a couple more knobs and buttons to go on when they arrive and i will be sending it to get painted by my mate whos a great spraypainter , you may see how much i enjoy music and begin to understand why im actually looking here for answers

i will post some pics in the next few days im really happy and proud of what i have achieved in a few days work and cant wait until i finish

oh by the way do you think a pair of adelaide ascertion timber wolves 2103tax as seen on their websit would handle the long sessions i inevitably will put them through?

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Gees guys, this thread appears to have degenerated into a mine's bigger than yours fling fest.

Just reading the OP's posts it would appear that -

  • The Technics speakers are a bit low on the power handling scale than what the amplifier is capable of dishing out (70W speakers - higher powered amp.)
  • The OP's mates like to "turn the wick up" to max. Probably driving the amp close to full power if not into occassionally clipping.
  • The amp runs a little on the warmer side - probably due to the hammering it's getting.

So what's the solution? Well there have been plenty of suggestions - some of which may have questionable use.

Forced fan circulation of air can help. There has been some comments on fan noise. Perhaps here's an opportunity to dispell some myths.

  • Of the muffin type fans, generally the larger diameter models are better. They move more air at a lower rotational speed and therefore can be quieter than smaller fans. Hooked up to a suitable temperature sensor and controller, they can be made to operate at lower rotational speeds providing a constant but quiet flow of air through the amplifier, speeding up only when the temperature rises.
  • If the OP or his mates are playing music at ear splitting levels I doubt if they would notice the noise generated by most fans. ZB is pretty much correct in saying most fans are quieter than the background noise in most rooms. We also might need to take into context the OP's listening tastes and habits. Does he listen late at night to chamber music or does he like to turn up the wick on rock 'n' roll or dance music?

Digital optical input or analogue input? This is a no brainer. The optical input isn't likely to be causing any overload unless the amplifier is faulty. Connecting the source via the analogue inputs won't solve the problem.

IMO there is probably not enough info to draw a definitive conclusion as to the best possible approach to solving this problem. Perhaps the OP needs to re-think his listening criteria. If he likes to listen loud and long, then perhaps more efficient higher power handling speakers and a more powerful commercial grade amplifier is what is perhaps more appropriate???

Cheers,

Alan R.

i guess we need to get one thing straight here , definitely not ear splitting music just loud , definitely not near max , i think if i remember from reading the manual the onkyo volume control goes from 0 -79 my top end is around 50-55 and that will only be for a couple of songs then back to 40-45 , when the first speaker blew i think it was turned up to 60 for about 20 seconds ( I would of turned this down after one song) and bang , when the second speaker blew weeks later it became distorted for about 5 seconds or so but before i could get to the amp to turn it off it just wend dead in this case the volume was medium loudnes around 35 -40 and had been constant with no volume increase for hours.

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oh this was a response to the house in between the twoo for sale signs lol very funny my answer is

great neighbours ,solution invite neighbors to the party lol , besa block walls shut the door and really only muffled sound even at loud levels ,again ill take some pics of my bar room and juke and you will see no open windows etc make for no cops no cranky neighbors etc , and i do warn them and ask permission for a party and if they dont want to they put earplugs in lol

Edited by egosbar

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