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Mesa M9 Carbine problem

Monotheist

Monotheist

Nov 24, 2010
433
18
56
Ottawa, Canada
#1
Good morning guys, I need your help.

Last night I hooked up my newly purchased Peavey 810TX 4ohm to my M9 Carbine, of which I already have a Fender 215Pro 4ohm going through it. I played for roughly 5 minutes when I realised I had forgotten to switch my amp to 2ohm. Everything is sounding great still. I switch it to 2ohm and all is great, sounds awesome. I try out a bunch of different settings on my Sansamp BDDI since it’s a new toy and I want to see what I can get out of it. Still, everything is going great at this point.

I turn off the head for about 10 minutes or so and when I turned it back on it sounded like total crap. Both cabs were farting like crazy and the signal was very weak, the master was at 7 O’clock which was crazy loud before I turned off the amp. At that point I’m thinking that the 810 has faulted so I unhook it to see what it sounded like with my 215 on it’s own. Same thing is happening. So I re-hooked the 810 to the amp and try running the Sansamp from the back of the head as opposed to the front. I’m thinking that something might have gone wrong with the preamp in the M9. It sounds better, the cabs aren’t farting out as much anymore but I’m not getting the tone I was at the beginning.

I unplugged the Sansamp and plug it into the front of the amp again to see what is happening. It’s farting a little less but I’m not getting the tone I was getting when I started. The tone is very muddy even though I haven’t touched the settings on the head nor the Sansamp.

In the past with my 215 on it’s own I had the master volume at 7 O’clock and my bass volume about half and it was very loud but after everything went wrong last night, I had the Master at noon and my bass at max volume and it wasn’t nearly as loud. I was getting drowned out by the 2 guitar players that weren’t even at their usual playing volume.

I’m might not be explaining it wright so I hope you guys can understand what I’m trying to explain. Is it possible that I “broke” something in the amp because I didn’t set it at 2ohms from the beginning? What do you guys think is wrong?
Thanx in advance.
 
#3
There's no way for us to be sure, but it IS possible that running it at 2 Ohms without the switch engaged damaged it in some way. Easiest troubleshoot is to open it and change the preamp tube. If that doesn't fix it-you need an amp tech, preferrably at a Mesa service site or ideally at Mesa. Obviously you should change cables, basses, etc as well.
 
#4
lomo said:
There's no way for us to be sure, but it IS possible that running it at 2 Ohms without the switch engaged damaged it in some way. Easiest troubleshoot is to open it and change the preamp tube. If that doesn't fix it-you need an amp tech, preferrably at a Mesa service site or ideally at Mesa. Obviously you should change cables, basses, etc as well.
Click to expand...


cables and basses...How about shoes? ;-)

How do I know if the tube needs to be replaced and how difficult is it to change? I've never changed a tube before.
 
#5
Monotheist said:
cables and basses...How about shoes? ;-)

How do I know if the tube needs to be replaced and how difficult is it to change? I've never changed a tube before.
Click to expand...

Easy as pie. 1st UNPLUG the head, then remopve all screws holding the top in place and locate the tube (easy to see. Grip it with your clean, dry fingers; ease it upward and back and forth-it will come loose. You'll need another 12ax7 to replace it with. They are cheap and available online or at many electronics shops. 10 bucks online. Only way to know for sure it's bad (without a tube tester) is to try another one. If your bass is active, try it with another rig (combo maybe), another cable or a new battery.
 
#8
lomo said:
Easy as pie. 1st UNPLUG the head, then remopve all screws holding the top in place and locate the tube (easy to see. Grip it with your clean, dry fingers; ease it upward and back and forth-it will come loose. You'll need another 12ax7 to replace it with. They are cheap and available online or at many electronics shops. 10 bucks online. Only way to know for sure it's bad (without a tube tester) is to try another one. If your bass is active, try it with another rig (combo maybe), another cable or a new battery.
Click to expand...

Thanx for your help my friend. I replaced the batteries in my bass as I thought that could be the issue. Sadly it wasn't.
 
#10
KrisWarrington said:
Why would you run 2ohms out of a 4ohm cab. Bad judgement.
Click to expand...

He hooked up a second 4ohm cab to the M9 and forgot to switch the amp to '2 ohm mode'.

I would be surprised if that would do any harm. If it did, that is a poorly designed amp. The 2ohm switch, as far as I understand it, is kind of a limiting circuit on the power supply to keep the amp at 4ohm power levels so there aren't heat issues, etc. The worst that should happen is that you hit the power amp limiting/head shutdown.

Lots of issues with this amp model though, might need a trip back the Mesa. Their support is very good.

However, to the OP per the above comments, make sure it isn't just chance that the amp has an issue after you did this. Make sure your bass and cables are OK. The next step would be to buy a 12ax7 tube and just replace the tube that is in there. If none of that helps, back it goes.
 
#11
KJung said:
He hooked up a second 4ohm cab to the M9 and forgot to switch the amp to '2 ohm mode'.

I would be surprised if that would do any harm. If it did, that is a poorly designed amp. The 2ohm switch, as far as I understand it, is kind of a limiting circuit on the power supply to keep the amp at 4ohm power levels so there aren't heat issues, etc. The worst that should happen is that you hit the power amp limiting/head shutdown.

Lots of issues with this amp model though, might need a trip back the Mesa. Their support is very good.

However, to the OP per the above comments, make sure it isn't just chance that the amp has an issue after you did this. Make sure your bass and cables are OK. The next step would be to buy a 12ax7 tube and just replace the tube that is in there. If none of that helps, back it goes.
Click to expand...


Thanx. I will try another bass and cable tonight and will replace the tube as well. I'm keeping my fingers crossed. :D
 
#12
Monotheist said:
Thanx. I will try another bass and cable tonight and will replace the tube as well. I'm keeping my fingers crossed. :D
Click to expand...

Hey,

What is the Serial # of the amp and where/when did you buy it?

If you bought it at L&M, or the original purchaser did, I can give you some advice as I just went through this.

I doubt the 2/4ohm issue is going to fry your amp. Expecially after only 5 minutes.

Bottom line... Mesa has a transferrable 5 year warranty (includes the tube) and the M9 has not been around for 5 years... so you have warranty no matter what. This is good as the older M9's can be absolute garbage and generally need a complete factory overhaul.

IM me for more info or just bring it to L&M and tell them to send it to Mesa (not to their Pickering "Mesa Authorized" techs, but to California) to be fixed.

P.S. Read through some of the M9 Mega Threads. M9s that are older or not upgraded can be complete disasters. If it is acting up a bit now, be very careful. When these die on gigs, they will ruin your night.

P.P.S. The upgraded and/or newer versions of the M9 seem rock solid.
 
#13
2nd and 3rd'ed to the "running at 4 ohms" thing being the issue. That AFAIK is just a thermal-shutdown prevention issue from overheating and frying the amp. However, weirder stuff has happened with all kinds of amps... Even at loud volumes for just a few minutes, it shouldn't have done that.

Are you sure you didn't fry your cabs though, or did something to them? Do you have another amp that you can try those out with? That may be another place to look.
 
#14
rockstarbassist said:
2nd and 3rd'ed to the "running at 4 ohms" thing being the issue. That AFAIK is just a thermal-shutdown prevention issue from overheating and frying the amp. However, weirder stuff has happened with all kinds of amps... Even at loud volumes for just a few minutes, it shouldn't have done that.

Are you sure you didn't fry your cabs though, or did something to them? Do you have another amp that you can try those out with? That may be another place to look.
Click to expand...


I don't think I did. I don't have another bass amp but I tried a guitar amp with a guitar with low tuning and they both seamed fine.

The 215 is 1600 watt program and the 810 is 800 watt program and I didn't push them hard at all. Unless there's another factor I don't know. I bought a new 12ax7 and will put it in tonight to see if it helps.
 
#19
KrisWarrington said:
Just noticed that... I skim read so I miss things. I just saw a post about an M9 going to crap and kinda thought to myself on it. Never been a big fan of any of those amps.
Click to expand...

I hear you. I own one and have been through a couple of returns to Mesa.

However, my M9 is my favorite, even though I have a Crest CA6 with a couple of pre-amps in a rack sporting ~1500 watts bridged and 600 watts stereo (@ 4 ohms ), and a sweet little 600 watt GB Shuttle 6.0.
 

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