My Main Bass Head

[davey]

I posted this earlier at TB.

FWIW

It wasn't the nicest day, but I was off work, and my amp was home instead of the studio.



I love the way this amp sounds, I just think there's a better way of cooling it off. I've had issues in the past about the amp overheating.

This view is from the front. Air is passively drawn in through the grate at the top center. The two large rectangles are the heat sinks, and the fan is just to the right. The air is blown from the inside of the amp to the left and ostensibly out the grate on the left side of the amp.


My main problems are:
First, there's a space between the end of the heat sink and the ventilation grate. That's a lot of hot air that will get circulated back into the amp, even if most of the air gets pushed out. You'll notice there is no fan to force air in nor draw air out of the amp. In fact, there is not a ventillation grate in the cover of the amp.

Secondly, the amp is designed and expected to be placed in a rack. There's less than an inch between the side of the amp and the wall of the rack. That doesn't leave a lot of space for air to get passively pushed out of the amp and leaves nowhere for the hot air to go. Except into the rack and get drawn back into the amp.

Thanks to suggestions and ideas from people at Talk Bass, I was able to mount a fan ($15 fan from Radio Shack and a $2 plug for the end) to the upper rail of the rack to pull the hot air out of the amp. This has worked like a charm! But notice I still carry spare fuses taped to the left wall of the amp!


And a Close up of the fan.


For anyone that's had overheating problems in a rack mounted unit- seriously, it's less than $30 total and maybe an hours worth of your time to install a fan. You need a drill, a bit, 2 screws and 2 nuts, the fan and a plug to connect the power wires to. (I also taped the power wires to the ceiling of the rack) I'm not too concerned about noise, as I'm in a rock band, but I'm sure there are smaller or quieter fans than the cheap one I got.

That took a really, really long time to get these pictures taken... ;)

And the whole big gig rig:

(yes I was too lazy to drag the cab onto the deck ;) )

[Rhian Batson]

Cool rig, and nice way of fixing an overheating issue. :bwa

[chuckocaster]

shit man, just drill some holes in the front and call it a day...

nice pics. gonna post my new "secret weapon" when it arrives.

[davey]

Oooh- Secret weapon!

Sounds like fun!

[davey]

Here's an old pic of the components of my previous main rig-


Those Seymour Duncan heads completely rock. They're 300x300w or 600w bridged. The main head is the lower one- I still use that as my primary backup and the Triad cab is part of my rig at the rehearsal studio. The 4x10 and the top head with the chicken knobs sit in our basement waiting to be called upon...

[Bongolation]

I think my #1 peeve about gear is the utter lack of cooling that's typically designed in. It just drives me nuts.

It's not like these underventilated amps don't have overheating problems, either, particularly when they're being run hard at the lowest rated impedance.

I just don't know what these builders are thinking of. It's not that hard to rig up something, but I really and truly think that they operate on the premise that the gear will probably never leave the garage anyway, and anyone who's really playing out is going to over-amp to be extra-macho, so they can save $3.11 by leaving out a cheap fan and some more holes in the case. Everyone gets a bigger Christmas bonus on the savings.

When I get a 4-Ohm Goliath III extension for my Black Beauty, it'll be running at the rated 2 Ohms, but the power transistors are outside the case on a heatsink that's thermally bonded to the chassis. I can hang a clip-on fan over the heatsink and I think I'd be all right under any forseeable situation, but I've seen cheap power amps that just looked like downright fire hazards.

[Winston]

Cool Stuff Davey!!

Hey Bongo, not trying to spam here but I've got a real clean 4ohm GIII that I'd like to move. Shipping could be a challenge. Where are you located? Let me know if you are interested, if not that's cool too.

[Bongolation]

Where are you located?

Greater Sacramento, like about 35% of TTFers. Shipping costs would be...uh...prohibitive.

Yeah, for some reason, it's tough to find a 4-Ohm G-III. The Black Beauty and most of the SWR Professional Series combos are native 4-Ohm and are rated (contrary to popular misconception) for 4-Ohms to 2-Ohms net impedance. The 4-Ohm G-III is the factory recommended extension for the Black Beauty.

[EEEEW! SWR just got an ugly new website. Looks like generic Fender. Brad's work?]

[Bongolation]

Those Seymour Duncan heads completely rock. They're 300x300w or 600w bridged.

Funny, I've never seen those before. Looked on eBay and saw none either. What's in 'em? They look large enough to be well-ventilated, anyhow!

Impressive setup.

[davey]

These are the only 600w ones I've seen. In the 1988 guitar buyers guide I saw the 800w (400x400) models, and I've heard reference to them, but never actually seen one.

These weigh around 36 pounds, and will push a 2.67 ohm load bridged. The one with the chicken head knobs was wired to go to 2 ohms bridged and not run two channels. In any case, there's a 6" reverseable fan on the side forcing air over the transformers and it also has fins on the back that the air exits the amp through.

I really haven't had much in the range of problems with the more "stock" of the two. If it's on for a few hours straight, it seems to "sag" kind of like a tube rectifier. The chicken head one is pretty fragile because it's just been worked on and over a few too many times, and sat on top of too many vibrating cabinets.

I'll try to get pics of the Chicken tonite.