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Mesa M9 Carbine Mod? Possible?

Pbassmanca

Pbassmanca

In the pocket n' thumpy. So woody, so greasy...
Jul 6, 2014
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Oshawa, Ontario, Canada
#1
Being the kind of guy that really doesn't have a lot of knowledge about the inner workings of bass guitar amplifiers, I suddenly had a thought that occurred to me. I wonder if it's possible to have my Mesa M9 carbine modified so that it will send the 600 watts to 8 ohms instead of 4? I'm not sure whether this is even possible or how it would work, whether it would just be internally done or whether there will be another switch added? (The amp is past its 5 year warranty and I'm aware that such mods usually void all warranties)The reason I am interested in doing this is because I really like the amplifier but I would like the option of sending the most Watts from it to an 8 ohm cabinet of my choice. For example, there are lots of 410 cabinets out there used for a great price that will handle 600 - 800 Watts, but they're usually 8ohm cabs. Thoughts anyone?
 
#3
I play my Carbines (M3, 6 and 9) through 8 Ohm Mesa PH cabs, the 212 and 410 which are rated for around 600 Watts IIRC. I'm not sure there would be a noticeable difference if I could feed either of those cabs more than the Carbine's 8 Ohm rated output. If I had less efficient cabs, it might make a difference.

When I need more volume, I use two PH212's. Of course at that point they are each getting a little less power than they do when driven individually by the same amp. It's the additional speaker area that gets me the big bump in volume even with the slight loss in power I can feed each cab.

As an aside, Mesa modded my M9 to the newer 600 Watt configuration - down from the 900 Watt configuration I bought it in. I couldn't tell the 300 Watts were missing when I got it back and to this day still think the head is more than powerful enough to damage, or at least severely punish most cabs/speakers.
 
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#4
Al Kraft said:
I play my Carbines (M3, 6 and 9) through 8 Ohm Mesa PH cabs, the 212 and 410 which are rated for around 600 Watts IIRC. I'm not sure there would be a noticeable difference if I could feed either of those cabs more than the Carbine's 8 Ohm rated output. If I had less efficient cabs, it might make a difference.

When I need more volume, I use two PH212's. Of course at that point they are each getting a little less power than they do when driven individually by the same amp. It's the additional speaker area that gets me the big bump in volume even with the slight loss in power I can feed each cab.

As an aside, Mesa modded my M9 to the newer 600 Watt configuration - down from the 900 Watt configuration I bought it in. I couldn't tell the 300 Watts were missing when I got it back and to this day still think the head is more than powerful enough to damage, or at least severely punish most cabs/speakers.
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I wonder if the M9 has enough of an internal cooling fan to handle 2 ohms on a regular and extended basis? I was looking at one cab by Barefaced Audio their 410 actually,
that only comes in 8 ohm and 2 ohm configuration. I regularly use the M9 with a 2 ohm load and it doesn't complain but it does feel fairly hot by the end of the night. I wonder if an extra cooling fan around the back blowing on it would help?
 
#5
I wonder if 2 Subway 210's or a Subway 210+115 would perform on the same level as the barefaced 410? I've tried Subway Cabs and they sound great, but I've never tried Barefaced or actually any of the other so-called super cabs so I don't really have any way to compare.
 
#6
Pbassmanca said:
I wonder if the M9 has enough of an internal cooling fan to handle 2 ohms on a regular and extended basis? I was looking at one cab by Barefaced Audio their 410 actually,
that only comes in 8 ohm and 2 ohm configuration. I regularly use the M9 with a 2 ohm load and it doesn't complain but it does feel fairly hot by the end of the night. I wonder if an extra cooling fan around the back blowing on it would help?
Click to expand...
I'll let Mesa give the authoritative answer, but in my experience, Mesa heads will deliver their rated power reliably in appropriate environmental conditions night after night. As with any piece of electronic equipment, some additional air flow (if you don't mind the breeze and/or noise) is usually beneficial and IME never hurts.

That said, if your M9 is in the latest configuration and racked according to Mesa recommendations, I don't think additional cooling is a necessity.

EDIT: Just be careful when providing additional cooling flow that you don't work against the cooling fans and flow paths designed into the head. A lot of thermal management science, best practice, and calculations go into designing the head. If you're unsure on something like this, always call the factory and ask for their advice...they know how they designed the head and whether your "cooling help" will actually be helpful. They can also tell you where to provide additional airflow/movement so that it will be of the greatest benefit.
 
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#7
Pbassmanca said:
I wonder if 2 Subway 210's or a Subway 210+115 would perform on the same level as the barefaced 410? I've tried Subway Cabs and they sound great, but I've never tried Barefaced or actually any of the other so-called super cabs so I don't really have any way to compare.
Click to expand...

I think the voicing will most likely be different, but in terms of volume and efficiency I suspect you'll be in very close territory. While not usually considered "super cabs", I think the Mesa Subway series is a lot closer to that category than it is to typical high production, off-the-shelf products.

Some may disagree and I'll admit the Barefaced One 10 is the only cab of that brand I've ever played/heard...and it was impressive, so 4 of them in one box should be equally so. FWIW, I've yet to find any weakness in my Subway cabs (112 and 115) compared to my Berg, GK and Mesa PH cabs, or any other bass cabs I've owned or played in the last 40+ years.
 
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#8
Pbassmanca said:
I wonder if the M9 has enough of an internal cooling fan to handle 2 ohms on a regular and extended basis? I was looking at one cab by Barefaced Audio their 410 actually,
that only comes in 8 ohm and 2 ohm configuration. I regularly use the M9 with a 2 ohm load and it doesn't complain but it does feel fairly hot by the end of the night. I wonder if an extra cooling fan around the back blowing on it would help?
Click to expand...
I wouldn't recommend it.
 
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#11
He's definitely an invaluable resource and unimpeachable source for technical insight when it comes to Mesa gear...for everything else related to the electronics world,...well it turns out he's pretty much the same thing,...so there you have it!
 
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#13
Al Kraft said:
I'll let Mesa give the authoritative answer, but in my experience, Mesa heads will deliver their rated power reliably in appropriate environmental conditions night after night. As with any piece of electronic equipment, some additional air flow (if you don't mind the breeze and/or noise) is usually beneficial and IME never hurts.

That said, if your M9 is in the latest configuration and racked according to Mesa recommendations, I don't think additional cooling is a necessity.

EDIT: Just be careful when providing additional cooling flow that you don't work against the cooling fans and flow paths designed into the head. A lot of thermal management science, best practice, and calculations go into designing the head. If you're unsure on something like this, always call the factory and ask for their advice...they know how they designed the head and whether your "cooling help" will actually be helpful. They can also tell you where to provide additional airflow/movement so that it will be of the greatest benefit.
Click to expand...
Some very good points!
 
#14
Al Kraft said:
I think the voicing will most likely be different, but in terms of volume and efficiency I suspect you'll be in very close territory. While not usually considered "super cabs", I think the Mesa Subway series is a lot closer to that category than it is to typical high production, off-the-shelf products.

Some may disagree and I'll admit the Barefaced One 10 is the only cab of that brand I've ever played/heard...and it was impressive, so 4 of them in one box should be equally so. FWIW, I've yet to find any weakness in my Subway cabs (112 and 115) compared to my Berg, GK and Mesa PH cabs, or any other bass cabs I've owned or played in the last 40+ years.
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I use a Powerhouse 600 watt 4ohm 210 and frankly it really puts out a loud fat tone. It does have its limits however, and sometimes an extra cab under it helps fill out my volume/air movement needs. It's just the weight of all this that gets a little much after the gig at 2 am, so I'm trying to look into what are my best options for a lightweight cab or cabs. Actually that's why I posted this thread about the M9 carbine, it was more about my cab needs than anything! In terms of the ability to put out a good level of volume and fat low end and Clarity of sound across the stage how do you find the subway cabs in the 12 and 15 configuration stacked?
 
#15
Pbassmanca said:
I use a Powerhouse 600 watt 4ohm 210 and frankly it really puts out a loud fat tone. It does have its limits however, and sometimes an extra cab under it helps fill out my volume/air movement needs. It's just the weight of all this that gets a little much after the gig at 2 am, so I'm trying to look into what are my best options for a lightweight cab or cabs. Actually that's why I posted this thread about the M9 carbine, it was more about my cab needs than anything! In terms of the ability to put out a good level of volume and fat low end and Clarity of sound across the stage how do you find the subway cabs in the 12 and 15 configuration stacked?
Click to expand...
They are surprising in terms of their performance. Personally I think the 115 is an absolute stand-out among all the cabs I've owned or heard over the years. Two or three of them would likely carry any venue I could ever imagine playing without FOH support and would be more than sufficient as monitors on any outdoor stage I've ever played.

The Subways are not inexpensive, but high quality, well designed gear rarely is. Given their performance and high quality components I consider them very fairly priced. I own a 112 and 115. I was concerned that two 115's might be a little too much at times and really like the projection, full rich mids and deep lows I get with the combination.

With what I now know from using the cabs for a while I think I could buy an additional 115, sell my two PH212's and PH410 and never miss those big cabs at all. As a Mesa user yourself, I'm sure you recognize what that says about the Subway cabs.
 
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#16
Pbassmanca said:
Do you mean you wouldn't recommend running a 2ohm load regularly or using an extra fan?
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I suspect, given the rear panel design of the enclosure and the upgrades Mesa has done relative to thermal management since the amp was originally released, he means he would not recommend forcing external air on or into the unit.

By forcing air into a set of vents in one location you would likely disrupt the internal flows the existing fans are set up to provide. This could theoretically cause hot spots on components and/or the heat-sink and actually create a problem. Thermal management design has a number of variables factored in and together they offer a balanced approach to managing heat and noise via various cooling methods/modalities. This is why Mesa and other amp manufacturers tend to be very specific about the clearance needed around an amp. Cooling is accomplished via both active and passive methods and techniques that can involve conduction, radiation, convection and/or any combination.

If you had an amp with only passive cooling using large external heat-sinks on the back of the unit, moving air across them might be useful, but that's not the case with this design. And even with designs using large external heat sinks, good designers take all operating conditions into account so that additional cooling is not required in normal environmental conditions.
 
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#17
Pbassmanca said:
Do you mean you wouldn't recommend running a 2ohm load regularly or using an extra fan?
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Running at 2 ohms. An extra fan isn't going to help much either, the best way to deal with it is to be sure it has the most recent updates.
 
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#20
agedhorse said:
Running at 2 ohms. An extra fan isn't going to help much either, the best way to deal with it is to be sure it has the most recent updates.
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I haven't done it often, but with the latest upgrades and switch set to 2 Ohms I haven't had any problems with mine Andy. I wouldn't push it like that on 100 degree plus day outdoors with the head sitting directly in the sunlight for hours on end, but is a fully modified M9 really running that close to the edge?
 

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