After reading about other TBers using their Mesa Walkabouts at 2 Ohms without any problems I picked up a local Scout combo with the intent of running a 4 Ohm extension cab I already have. Once I got the combo I couldn't help myself and had to remove the amp from the combo just for kicks. I was quite surprised that buried in the combos chassis was a handle attached to the head for when the head is removed. Nice touch Mesa!
What surprised me and what I didn't like was the lable seen below:
Here's what it looks like with the cover on:
Invalid Link Removed
And here's with the cover off:
That's a lot of venting they are covering up with that back cover!! After I ran the amp at 2 Ohms carefully for a practice, I monitored how the heat is dissipated throughout the amp. I know from my electronics background that you can squeeze a little more head room out of SS amps if you keep them cooler. I found a few flaws in the Scouts design IMO. The stock fan Mesa choose is capable of moving much more air flow than the exposed vents can vent. I believe there is a slight positive pressure buildup of air in the amp because of this and thusly makes the fan a little noisier than it has to be. Those of you who installed a quieter lower volume fan will most likely still achieve the same cooling of the stock fan despite the lower volume rating of the new quieter fan due to the limited vent holes.
The heat sink side of the amp is equipped with much vent holes on the side of the amp as well. With the cover in place the heat dissipated by the air moving out the of the side of the amp is directed on a long natural heat opposing down direction to be dispersed right at the fan intake, recirculating heated air for cooling. Heat rises.... This could have been designed a little better by Mesa.
Perhaps some side vents at the top back of the combo would better vent this heat out of the combo away from the amp.
I read about the preamp tubes sounding a little more dirty when they get heated up on a long gig. I have devised a cheap solution to these heat related problems that probably only show up when the combo is ran below 4 Ohms. It will ensure an even longer life of the Walkabout amp while spending it's life mounted in the Scout combo as any reduction in heat absorbed by the internal components will allow a longer service life.
It started with a trip to the Home Depot where I bout a 8' piece of U channel for $5 and some door weather striping for another $3. 1 Hour later I had made 3 of these up:
My plan was to use these to hold the amp in place instead of the vent covering wood. I wish I could have found the silver aluminum U channel but the Gold was all they had in stock. The gold aluminum is actually lighter than the wood cover so I actually reduced my Scouts weight as well!
Here's the installed pics:
I haven't used it on a gig yet but I can tell you there is much more air movement and all the heat is dissipated out of the amp and away from it. The real benefit here is allowing the heat sink side vents to vent vertically out the top of the combo and not out the bottom to be pulled back in by the fan. I believe this will give me a much longer service life of my Walkabout amp as opposed to having the cover installed.
What surprised me and what I didn't like was the lable seen below:
Here's what it looks like with the cover on:
Invalid Link Removed
And here's with the cover off:
That's a lot of venting they are covering up with that back cover!! After I ran the amp at 2 Ohms carefully for a practice, I monitored how the heat is dissipated throughout the amp. I know from my electronics background that you can squeeze a little more head room out of SS amps if you keep them cooler. I found a few flaws in the Scouts design IMO. The stock fan Mesa choose is capable of moving much more air flow than the exposed vents can vent. I believe there is a slight positive pressure buildup of air in the amp because of this and thusly makes the fan a little noisier than it has to be. Those of you who installed a quieter lower volume fan will most likely still achieve the same cooling of the stock fan despite the lower volume rating of the new quieter fan due to the limited vent holes.
The heat sink side of the amp is equipped with much vent holes on the side of the amp as well. With the cover in place the heat dissipated by the air moving out the of the side of the amp is directed on a long natural heat opposing down direction to be dispersed right at the fan intake, recirculating heated air for cooling. Heat rises.... This could have been designed a little better by Mesa.
Perhaps some side vents at the top back of the combo would better vent this heat out of the combo away from the amp.I read about the preamp tubes sounding a little more dirty when they get heated up on a long gig. I have devised a cheap solution to these heat related problems that probably only show up when the combo is ran below 4 Ohms. It will ensure an even longer life of the Walkabout amp while spending it's life mounted in the Scout combo as any reduction in heat absorbed by the internal components will allow a longer service life.
It started with a trip to the Home Depot where I bout a 8' piece of U channel for $5 and some door weather striping for another $3. 1 Hour later I had made 3 of these up:
My plan was to use these to hold the amp in place instead of the vent covering wood. I wish I could have found the silver aluminum U channel but the Gold was all they had in stock. The gold aluminum is actually lighter than the wood cover so I actually reduced my Scouts weight as well!
Here's the installed pics:
I haven't used it on a gig yet but I can tell you there is much more air movement and all the heat is dissipated out of the amp and away from it. The real benefit here is allowing the heat sink side vents to vent vertically out the top of the combo and not out the bottom to be pulled back in by the fan. I believe this will give me a much longer service life of my Walkabout amp as opposed to having the cover installed.
