A case building question about the aksa 100

Freeflyer · « **on:** 21 Apr 2004, 04:00 am »

Hi, just found this forum after viewing the aska website. I'm considering building the aksa 100 and have been looking into case options.

I'd like to have the heatsinks on the outside of the case to facilitate cooling, but haven't found any regular style cases (such as parmetal) that allow this and maintain around a 19" width (I'm not rack mounting, but a rack might be in the future)

I have thought of making my own wooden case that uses the heatsinks as the sides and make wooden base, top, back and front. However I couldn't see from the photos on the website if there was a way to attatch the heatsinks in this configuration.

So, two questions now:

1. can the heatsinks make this sort of attachment.
2. are there any advantages/disadvantages to using wood over metal.

Thanks,

J.

andyr · « **Reply #1 on:** 21 Apr 2004, 04:31 am »

Hi, Freeflyer,

I expect you'll get diametrically opposed replies on "wood vs. metal" but, as far as I am concerned, a metal case is better. Yes, wood is easier to work with for most people (me included) but if you go through the AKSA Forum posts, you'll find quite a few about hum problems that people have experienced from not having an earthed metal case surrounding everything.

When I built my AKSAs, I faced the same issue re. wanting the heatsinks on the outside ... so I got a local metalshop to bend approx 2mm mild steel to form the back, base and front of a case. They also produced a top so I bolted a heatsink on each side, to finish the case, and the top is bolted down to the heatsinks. Then I got the metal power-coated black ... looks good and very sturdy!

With the heatsinks on the outside, they rarely get even warm ... let alone hot (although I certainly keep the amp out of direct sunlight).

Regards,

Andy

AKSA · « **Reply #2 on:** 21 Apr 2004, 07:47 am »

Freeflyer,

Yes, the heatsinks can indeed be machined to form the sides of the box.

You need a U-shaped base to permit vertical attachment at the base of each heatsink using 3 x M6 studs from the inside. The metal of the base should be at least 1/8" thick to form a rigid box since the leverage of the heatsinks is considerable.

Top cover is secured with Umbrako M4 mushroom head studs into threaded holes in the base of the heatsinks; very strong. The heatsinks are machined so that from the top only the fins are visible; the base of the heatsink is completely obscured by the top cover which is 2mm (0.079") thick.

The front and rear panels are secured to the first and last fins of the heatsinks, which are thicker and stronger than the usual fins.

Here's the top view:

And here's the bottom view:

I'm having some of these made; if demand is strong I may offer some for sale, but there's a lot of precision fitting in them, and they will be quite expensive. All laser cut, powder coated, of course.

Cheers,

Hugh

Grumpy_Git · « **Reply #3 on:** 21 Apr 2004, 09:17 am »

Hugh

I must say those cases look very good and a far more elegant solution than my own attempts at hammering the heatsink into a case.

I will definitely keep an eye in and maybe I'll be able to get that double 55 setup i really want.

Nick

elektratig · « **Reply #4 on:** 22 Apr 2004, 12:47 am »

Freeflyer,

I'm not at home so I can't measure how wide my case is, but what I did was to cut slots in the sides of a standard Par-Metal case (using a drill and then jig saw), then bolt the supplied heatsinks to the case sides from the outside. The pictures in the AKSA folder at http://photos.yahoo.com/elektratig will hopefully give you the drift.

Tempest and Pi Construction Pix: http://www.audiocircle.com/index.php?action=gallery;area=browse;album=130

Martin · « **Reply #5 on:** 22 Apr 2004, 12:56 am »

Hi Freeflyer
I put my 100 watt nirvana Aksa amp & TLP in wooden cases.
I fitted a metal back and that seemed to be a plus. Easier to attach RCA's.
The pictures are posted in the gallery. I had hum in my TLP which
was resolved with some additional grounding. The amp is dead quiet.
I am really pleased!!!

Martin

Martin · « **Reply #6 on:** 22 Apr 2004, 01:04 am »

Freeflyer
The dimensions of my case are 16" wide (including heat sinks),
20" deep and 5" high.
My amp & pre are on almost all the time now and rarely get warm.

Martin

Seano · « **Reply #7 on:** 22 Apr 2004, 04:45 am »

Hey there
My case is made in a similar fashion to Andy's. Except heavier!!

3mm steel plate bent up into a C section shape to form the front, base and side with a seperate 3mm plate on top ($40). The whole amp assembly sits on 10mm thick sheet of MDF ($5 offcut) with the heatsinks connected to the MDF via 15mmX15mm aluminium angle ($6). This way the amp assembly can slide sideways in and out of the case for mods, repairs and general fiddling. Heatsinks were drilled and tapped to receive M8 bolts both top and bottom. Another piece of alloy angle is bolted to the top of each heatsink. This angle carries the steel plate top and also the outer corners of the C section case making for one solid block of case. For decoration, there's a slab of oiled blue gum out front and the metal is painted in matt black Killrust.

The whole collection weighs about 30kgs and is solid as a rock. Not only that but the metal to metal connection betwwen the heatsinks and the case gives extra cooling ability even with the heatsinks externally mounted.

And it didn't cost much!!

Bert · « **Reply #8 on:** 23 Apr 2004, 08:59 am »

Hi there,

I have used 19" cases and this is the result:

http://users.pandora.be/bertmahieu/index.htm

AKSA · « **Reply #9 on:** 23 Apr 2004, 09:22 am »

Bert,

Every time I look at your work I marvel at your skills; very, very professional. There are many AKSAphiles who do exquisite work; you are one of them, Monsieur!!

Thanks for sharing it with us.........

Sean, I'm most impressed with your Rover; wonderful work on the panels, how do you do it?

Cheers,

Hugh

SamL · « **Reply #10 on:** 24 Apr 2004, 09:23 am »

Quote from: AKSA

Freeflyer,

Yes, the heatsinks can indeed be machined to form the sides of the box.

You need a U-shaped base to permit vertical attachment at the base of each heatsink using 3 x M6 studs from the inside. The metal of the base should be at least 1/8" thick to form a rigid box since the leverage of the heatsinks is considerable.

Top cover is secured with Umbrako M4 mushroom head studs into threaded holes in the base of the heatsinks; very strong. The heatsinks are machined so that from the top only ...

Hi Hugh,
Not sure if I will get the metal base and cover as I prefer a slighly bigger case for ease of working around. However, I will be more than happy to pay a bit more to have the heatsink to come with predrill hole for M6 and M4 screw as you stated.

Sam

dayneger · « **Reply #11 on:** 24 Apr 2004, 10:17 am »

Some people work with wood and then line the interior with thin sheets of aluminum or copper sheeting, which is easily cut with metal snips. This combines the ease of woodworking with the benefits of shielding. I haven't done this myself yet, but would certainly consider it for new projects.

Cheers,

Dayne

SamL · « **Reply #12 on:** 25 Apr 2004, 09:54 pm »

Quote from: dayneger

Some people work with wood and then line the interior with thin sheets of aluminum or copper sheeting, which is easily cut with metal snips. This combines the ease of woodworking with the benefits of shielding. I haven't done this myself yet, but would certainly consider it for new projects.

Cheers,

Dayne

Did anyone tried aluminium foil - the normal type used in kitchen?
It will be easy to work with.

Just a though,
Sam

Propstuff · « **Reply #13 on:** 26 Apr 2004, 06:39 am »

Quote

Did anyone tried aluminium foil - the normal type used in kitchen?

Yes Dayne,
but it has to be OXYGEN FREE cooking foil. :o

cheers,
N.

PSP · « **Reply #14 on:** 27 Apr 2004, 05:40 pm »

You will need to ground your shielding and aluminum foil is very difficult to solder... it also is prone to tearing if you try to drive a screw through it for mounting.

I have used thicker aluminum (like really thick foil) used for cheap single use serving trays that you might use for a party. This is thick enough so it doesn't tear when you put a wood screw through it. I used this stuff to line the wood base of my Foreplay preamp. I mounted it with a few screws and significant amounts of contact cement. I used one continuous aluminum sheet so I didn't have to worry about slightly differing potentials and possible resulting hum. In one corner I mounted a toothed solder lug and soldered the mains ground to it.

If you can find a cheap aluminum baking sheet (or cookie sheet) that would even be better... thicker (more shielding), easier to work with, and still way less than ten bucks.

Good luck,
Peter