Ventilation for 100W

MattCassidy · « **on:** 23 Jun 2004, 06:00 am »

Hi all,

I am just getting started on building my 100W Nirvana, I have been down the local sheet metal worker, he is making a case for me. The heatsinks will be on the outside on the left and right of the case. This being the case I am wondering how critcal ventilation will be, the case itslef has a large contact area with the heatsink as the top and the bottom fold down inside the sinks and are attached with screws through the heatsink from the outside, if you get my drift. Do I still need holes in the top? Will a couple of lines of drilled holes do the trick?

Matt

andyr · « **Reply #1 on:** 23 Jun 2004, 07:22 am »

Quote from: MattCassidy

Hi all,

I am just getting started on building my 100W Nirvana, I have been down the local sheet metal worker, he is making a case for me. The heatsinks will be on the outside on the left and right of the case. This being the case I am wondering how critcal ventilation will be, the case itslef has a large contact area with the heatsink as the top and the bottom fold down inside the sinks and are attached with screws through the heatsink from the outside, if you get my drift. Do I still need holes in the top? Will a couple of lines of drilled holes do the trick?

Matt

Hi, Matt,

Sounds like you've done exackerly what I did. Given you have each AKSA 100 module on its own heatsink and the heatsinks are external to the case, you won't need any holes/slots in the top ... unless you wanted to use some sheet steel/sheet stainless which has rows and rows of holes predrilled in it ... just to make it look different!!

I actually have a 55w module and a 25w module on one heatsink, with the 100w module on the other ... and the heatsinks only get slightly warm (even when I turn up the wick when I'm listening to Pink Floyd!). The top of the case is solid.

Of course this assumes you don't have sun coming in through a window and shining directly on the case!!

Good luck,

Andy

Rhythm Willie · « **Reply #2 on:** 23 Jun 2004, 07:25 am »

I made some slots above each transistor and some small holes below the heatsink shelf on my monoblock amps & they just don't even get warm, so it's probably not necessary as long as the heatsinks are above the shelf. It really depends on how difficult a load your speakers are.

My speakers are 3 way, 5 driver Vaf I-93's which do drop below 3 ohms at some frequencies - the Aksa's can drive them to huge DB's ,hardly idling & i can only just sense some slight warmth in the heatsink after long periods of loud music.

PS have you been to a Dissociates Show(my daughter saw them last week).

MattCassidy · « **Reply #3 on:** 23 Jun 2004, 07:44 am »

Thanks Andyr and Willie for the replies, that is great to know was not too keen to drill and laser cutting would no doubt cost me a few bucks.

I am going to the dissociatives tonight in fact, can't wait, they are a truly original sound, nice recording too. Would recommend this album.

Matt

EchiDna · « **Reply #4 on:** 23 Jun 2004, 10:04 am »

Bah... I can only dream of seeing bands like the dissociatives over here in Singapore....

anyway, onto the point in question. My AKSA 100 is totally sealed using plexiglass/perspex/acrylic sheet for the top, front and rear. This stuff softens at about 65 degrees, but even in tropical Singapore the lid and the heatsinks don't even get luke warm. I feel there is little need for extra vents just like everyone else

See my sig file or the gallery (sticky on the first page) for other options...

AKSA · « **Reply #5 on:** 23 Jun 2004, 11:01 pm »

I pretty much agree with this commentary on heat for the 100W AKSA, Matt, but as I designed the AKSAs to survive rock concerts in the open air in central Australia at mid-afternoon, I have actually gone to the trouble of laser cutting ventilation slots directly above the driver heatsinks (the copper thingies on the brass whatsies).

The ensures the amp will survive in all weather conditions, something I was keen on for obvious reliability reasons. It also means that at higher output, thermal tracking of quiescent by the Vbe mulitiplier is more accurate, which holds bias more constant and keeps sonics right on song. I have generally found that someone, somewhere, sometime will always take a product to the limit, and I'm just trying to second guess.........

Cheers,

Hugh

SamL · « **Reply #6 on:** 23 Jun 2004, 11:08 pm »

My first stainless steel case for my aksa100n was a disaster due to my own error. To make life easy for myself, I plan to conceal the hole unit including the heat sink inside the new case with a few ventilation hole at the top and bottom. When I was doing the bias setting the aksa hardly feel warm and that set me to this direction. I hope it will be fine.

Sam

MattCassidy · « **Reply #7 on:** 23 Jun 2004, 11:35 pm »

You are all most helpful. For now what I have decided is to go with unventilated, I am putting largish rubber feet to give some air-flow around the bottom and the amp will always be on the top of the pile of elctronics. It is in a cabinet and see's no sun inside a pretty cool house. I will monitor it for the first few weeks (no doubt including some loud playing sessions). If it shows any signs of getting warm then I will get some holes drill in the top. I like the idea of keeping the inside nice and clean too.

The dissociatives were good, although Daniel had the flu and had lost his voice and I wish someone with a little more finesse would have done the mixing, I think some of those roadies are a bit deaf...Good show but.