[alfa] Re: Overheating Spider amplifier

["Ray Manners" <rmanners@xxxxxxxxxxxxx>]

Thanks for the input Sonny
Actually, I had thought of everything you mentioned. My top priorities were
to mount it right side up somewhere, and to have it aesthetically pleasing
without eliminating storage space unnecessarily- but the amp I chose is
physically gigantic- approximate size 19x10x3 inches. No way to put it under
a seat, and mounting it right side up in the trunk would make a large
percentage of the trunk unusable. In my first '87 Spider- I had an older amp
with less power that I was able to shoehorn in the trunk shelf (under the
vapor canister) but that's not an option with this monster. Another solution
would be to mount it exposed on the shelf behind the seats- but that's too
exposed (to the elements and prying eyes), and I do like to use that area
for occasional storage of light items. That left making a new, higher shelf
in the original location- with some room for ventilation. I probably should
have made the shelf about 1/2 to 1 inch higher than I did- my new shelf only
has about a 1/4 inch clearance above the heat sinks.
I knew that heat would be a problem- especially here in Miami- but my
ventilation system does help a bit. If I keep the volume at reasonable
levels (about 75% of max) I can run it all day even if it's 95F outside.
When I crank up the volume for the highway and top-down road-warrior songs
for extended periods (over 30 minutes) then the amp will drop-out
occasionally until I lower the volume and the heat comes down. At that
point- the amp is too hot to touch, and the vent system exhaust is
noticeably warmer than ambient.
As far as MDF- since I have 2 speakers and a sub-woofer mounted in it- I
think it's better than the acoustic abilities of marine ply- but I agree
100% that it makes more sense in the typical humid environment of a South
Florida convertible. BTW- no warping so far, despite being caught in
occasional thunderstorms and the usual high humidity here. I think you might
have MDF confused with particleboard. MDF is very stable and is frequently
used in high quality furniture where the intent is to use an exotic wood
veneer (or other material) over a dimensionally stable platform.
Particleboard is just plain junk- at least for this application.
At this point, unless I can find an amp that is very tolerant to lack of
proper ventilation, or make drastic steps to improve cooling (maybe pump
Freon to the package shelf! No- not at this time!) I'll just live with the
current setup. When you get down to it- it's only a minor inconvenience- and
even then- probably only about 5% of the time.
One of my biggest worries though is longevity. I know running the amp at the
high end of its' thermal limit is either abuse or just short of it- but in
any case- I know it's my fault and not Nakamichi's. The system has worked
admirably for about 3 years- so I can't complain!
One last comment for other Spider owners out there who are thinking of other
solutions - this amp is too big to put next to the ECU under the shelf
without relocating the ECU and its bracket, and possibly the seatbelt
retractor on the driver's side. For smaller amps- that is probably a good
alternative- but do think about some ventilation here in any case. I'm 6'-1"
so the seat is all the way back, with no room to mount the amp on the front
vertical portion of the package shelf- and that would put the heat sinks in
poor alignment to work properly anyway. If you don't have the heat sinks
looking at the sky, you should have the fins aligned vertically so the heat
will not just sit there between the fins. At 19" long- it just won't work.
Good luck audiophiles!

Best Regards,
Ray Manners
1987 Alfa Spider Veloce
1983 Pininfarina (Fiat) Spider
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