Mesa Walkabout Megathread!

[tombowlus]

Actually, Tom, if you've got a few minutes, could you hook up the Walkabout with your EA VL2x10 and tell me how you think it sounds. I've got a line on one locally from a fellow TB-er and I'd love your opinion. I'm going to try my setup out with it soon too, but your pallette is much more...er...exercised than mine, I'd appreciate your opinion

Jason

I have done this in the past, and to be honest, the VL-210 likes more headroom than the Walkabout has to offer. Even the VL-208 and VL-110 really like more power.

Tom.

 

[JJBluegrasser]

Thanks for the feedback guys. I'll be running at 2.62 ohms out of the Scout (4 for the internal speaker and 8 for the 2x10). Maybe this isn't my best option...

Jason

 

[Vic]

Thanks for the feedback guys. I'll be running at 2.62 ohms out of the Scout (4 for the internal speaker and 8 for the 2x10). Maybe this isn't my best option...

Jason

Yeah, I'd imagine you'd barely hear the VL. An NL would be significantly louder than the VL, but not sure if it'd be good enough for the investment or not. Ddunno what deal you've been offered on the VL you're talking about, but the VL's are still very popular, so you generally don't find them super cheap, and the cheapest I've seen an NL is prolly close to 700 used (650+ship).

 

[Smallequestrian]

Well, the Walkabout that I picked up at GC for a steal on Clearance had some problems. Major farting issues, and was going in and out. No problem, thats what 5 year warranties are for right. I am not sure when I will get it back, but I am not in a big hurry. I think it is one of the older models so I will have them do the fixes while they are at it as well.

As far as a cab to go with it, I think I am strongly leaning towards an Epifani UL110 for my aparment and then later possibly pairing it with another UL110 or a UL112. In Tom's mini cab shootout he posted something about this cab that sounded perfect for my use.

the Epi really shines at lower to mid volumes

Since a lot of my playing will be done at lower to mid volumes I think this sounds like a great match for the amp and my needs with my matching Fretted and Fretless Single H Bongos.

Any thoughts?

 

[KJung]

Well, the Walkabout that I picked up at GC for a steal on Clearance had some problems. Major farting issues, and was going in and out. No problem, thats what 5 year warranties are for right. I am not sure when I will get it back, but I am not in a big hurry. I think it is one of the older models so I will have them do the fixes while they are at it as well.

As far as a cab to go with it, I think I am strongly leaning towards an Epifani UL110 for my aparment and then later possibly pairing it with another UL110 or a UL112. In Tom's mini cab shootout he posted something about this cab that sounded perfect for my use.



Since a lot of my playing will be done at lower to mid volumes I think this sounds like a great match for the amp and my needs with my matching Fretted and Fretless Single H Bongos.

Any thoughts?

Two Epi110's aren't going to get you much bass extension, but a 110 and 112UL should be wonderful.

 

[tombowlus]

Actually, one of my favorite amp/cab combinations is the Walkabout driving a T-110UL/T-112. BTW, the T-110UL is now the UL110. I think that a UL110/UL112 would also sound very good with the Walkabout, and I agree with Ken that this combination gives you much more low frequency extension (compared to two UL110's).

Another favorite of mine with the Walkabout is to drive two EA Wizzy's. But this is a 2 ohm load, and I would understand if someone wanted to shy away from that (although it's never given my Walkabout any problems).

Tom.

 

[jvtwin]

Getting back to Fan noise and Tubes..

Is the fan noise everyone's talking about relate to the older amps or is it apparent in the new ones as well? I have 2005 model and haven't really notice any fan noise.

Also are the tube upgrades making that big of difference in tone/volume?

 

[JJBluegrasser]

I have new Walkabout and I still switched the fan out.

Yes, tubes make a difference, and Tom has done a terrific job earlier in this thread to discuss the differences. I've said it before in the thread, but I prefer my GT 12ax7Ms.

Jason

 

[JJBluegrasser]

Okay, speaking of running at 2 ohms...

I called Mesa again today to see how the 'torture test' of the Walkabout at 2 ohms was going. The guy I spoke with was very nice, but he told me no way no how, don't run it below 4 ohms.

So, I'm an electrical engineer, and I discussed this was some of friends here at work and here is the concensus:

If you're running your amp at max master volume, then it will get twice as hot as it would with 2 ohms as with 4 ohms. For every 9 degrees C you increase the temp, the lifetime of the semiconductors will be halved. Semi lifetime is very long, but how long is hard to say. Worst case? You run it wide open 8 hours a day, one of the transistors dies and takes a few supporting parts with it. It would suck, but our guess is that it's nothing a soldering iron and Digikey can't fix. (actually worst case is it melts a trace on the PCB, but that's not real likely).

More realistic case? The few times I've run mine with my 2 Cxl 1x12s attached (2 ohms total) it doesn't seem to have gotten as hot as the same playing situation with just the Scout. Why is this? Because I don't turn the master volume up as loud since I have more speaker area. If they volume is at half with 2 ohms, but all the way with 4 ohms, then the heat generated is equivalent (it's not really exactly linear, but you get the idea).

What's the point? If you keep an eye on the temperature and it doesn't get hotter than normal under the lower load, then you shouldn't be causing damage. If it's a little hotter, then maybe your amp will only work for 20 years instead of 40. Or, I'm wrong and it will jack your stuff up immediately I make no gaurantees...

 

[tombowlus]

More realistic case? The few times I've run mine with my 2 Cxl 1x12s attached (2 ohms total) it doesn't seem to have gotten as hot as the same playing situation with just the Scout.

This mirror's my experience. My Walkabout has never felt unusually warm running a 2 ohm load, due in part to the fact that it gets really loud without me having to crank the Gain or Master too high. The only time that it did run hot (and it was quite hot to the touch) was when I was driving an 8 ohm load (T-112) and I had to crank the Gain and Master both pretty high to keep my volume up to where I could hear it a practice.

Also, FWIW, when I spoke to Mesa's techincal support experts, they told me that the worst case scenario running a 2 ohm load was that the thermal protection circuit(s) would kick in and cut off the signal until they had cooled down, but that I basically could not damage anything by running a 2 ohm load.

Tom.

 

[KJung]

This mirror's my experience. My Walkabout has never felt unusually warm running a 2 ohm load, due in part to the fact that it gets really loud without me having to crank the Gain or Master too high. The only time that it did run hot (and it was quite hot to the touch) was when I was driving an 8 ohm load (T-112) and I had to crank the Gain and Master both pretty high to keep my volume up to where I could hear it a practice.

Also, FWIW, when I spoke to Mesa's techincal support experts, they told me that the worst case scenario running a 2 ohm load was that the thermal protection circuit(s) would kick in and cut off the signal until they had cooled down, but that I basically could not damage anything by running a 2 ohm load.

Tom.

Actually, if I understand things correctly... a 2ohm load will 'allow' the amp to put out a lot of power... not require it to do so. If you are running two cabs (4ohm, 8ohm... i.e. total impedance of 2 or 4 ohms), you might not actually be generating as much power from the amp as having to really push a single cab (in your case an 8ohm 12) to get up to the volume needed for the gig, due to cone area, coupling, efficiency, etc. So, the amp might actually run cooler. I may be wrong about that, but that's my understanding of the way it works.

We are probably saying the same thing in different ways!

 

[tombowlus]

We are probably saying the same thing in different ways!

Quite possibly! At least it sounds like we are on the same page.

 

[KJung]

Quite possibly! At least it sounds like we are on the same page.

How the heck are ya! Hey, check out the 'custom cab' thread.... the originator is asking about various 2x8, etc. designs from Don. I put in my 2 cents.... he's looking for more input.

Vic... sorry for the thread hijack... back to the wonderful Walkabout!

 

[Vic]

Actually, if I understand things correctly... a 2ohm load will 'allow' the amp to put out a lot of power... not require it to do so. ...

Actually, there's a big thread about this, but this is oversimplified. Yes, actually it will be "required" to do so.

In the virtual equivalent of the circuit (either thevenin (sp) or norton), the circtuit can be viewed as a sine wave generater and a series resistor (the amp (or battery)), and the speakers are in series with that.

The key is the "internal resistance" of the amp. For "optimum power transfer" you want to MATCH the internal and external. Even batteries can be viewed as having an internal resistance, which is why they get hot when shorted thru a very small load.

What this means is, if you lower the speaker resistor too much, the amp has to put out MORE current to maintain the same voltages across the voice coil (load), which determines cone movement, and of course, a given SPL.

The downside is, when you raise the current thru a resistor, more voltage is dropped, and the more heat is generated.

SO... to get the same voltage dropped across a 2 ohm load, you'll have to get TWICE that voltage dropped on the (internal) 4 ohm load, which raises the heat generated inside the amp.

In the case of the single higher impedence cab config, in a simplified model, you're basically dropping twice the voltage over one speaker, because it's trying to do the job of two, so you're still generating a lot more current out of the amp, and still heating it up internally.

Heat does two bad things... yeah it shortens the life of components, but it also can potentially alter your tone as well as lose "headroom" since the amp is basically out of reserve current.

It's all about matching... not under or over driving... if you want the "most" in output and reliability from an amp.

IMHO, anyway...

 

[slombovia]

I believe that'll be the standard effects/input jacks fix.

If you don't want to send it in for the FX loop fix simply put a short patch cable from send to receive and it won't cut out anymore.

 

[slombovia]

Actually, there's a big thread about this, but this is oversimplified. Yes, actually it will be "required" to do so.

In the virtual equivalent of the circuit (either thevenin (sp) or norton), the circtuit can be viewed as a sine wave generater and a series resistor (the amp (or battery)), and the speakers are in series with that.

The key is the "internal resistance" of the amp. For "optimum power transfer" you want to MATCH the internal and external. Even batteries can be viewed as having an internal resistance, which is why they get hot when shorted thru a very small load.

What this means is, if you lower the speaker resistor too much, the amp has to put out MORE current to maintain the same voltages across the voice coil (load), which determines cone movement, and of course, a given SPL.

The downside is, when you raise the current thru a resistor, more voltage is dropped, and the more heat is generated.

SO... to get the same voltage dropped across a 2 ohm load, you'll have to get TWICE that voltage dropped on the (internal) 4 ohm load, which raises the heat generated inside the amp.

In the case of the single higher impedence cab config, in a simplified model, you're basically dropping twice the voltage over one speaker, because it's trying to do the job of two, so you're still generating a lot more current out of the amp, and still heating it up internally.

Heat does two bad things... yeah it shortens the life of components, but it also can potentially alter your tone as well as lose "headroom" since the amp is basically out of reserve current.

It's all about matching... not under or over driving... if you want the "most" in output and reliability from an amp.

IMHO, anyway...

I understand this point but if you don't turn it up it WON'T put out more wattage. And with an extra speaker you are less likely to have to turn it up more. By adding a second 4 ohm cab to my WalkAbout I was actually able to turn down quite a bit in most situations.

So if by "power", KJung meant wattage, he was right in that 2 ohms allows more power (wattage) but does not require it. Turn the master volume down = less wattage no matter what resistance.

 

[JJBluegrasser]

Actually, there's a big thread about this, but this is oversimplified. Yes, actually it will be "required" to do so.

In the virtual equivalent of the circuit (either thevenin (sp) or norton), the circtuit can be viewed as a sine wave generater and a series resistor (the amp (or battery)), and the speakers are in series with that.

The key is the "internal resistance" of the amp. For "optimum power transfer" you want to MATCH the internal and external. Even batteries can be viewed as having an internal resistance, which is why they get hot when shorted thru a very small load.

What this means is, if you lower the speaker resistor too much, the amp has to put out MORE current to maintain the same voltages across the voice coil (load), which determines cone movement, and of course, a given SPL.

The downside is, when you raise the current thru a resistor, more voltage is dropped, and the more heat is generated.

SO... to get the same voltage dropped across a 2 ohm load, you'll have to get TWICE that voltage dropped on the (internal) 4 ohm load, which raises the heat generated inside the amp.

In the case of the single higher impedence cab config, in a simplified model, you're basically dropping twice the voltage over one speaker, because it's trying to do the job of two, so you're still generating a lot more current out of the amp, and still heating it up internally.

Heat does two bad things... yeah it shortens the life of components, but it also can potentially alter your tone as well as lose "headroom" since the amp is basically out of reserve current.

It's all about matching... not under or over driving... if you want the "most" in output and reliability from an amp.

IMHO, anyway...

I'll buy that. I guess the point is, if you want a lot more volume out of the Walkabout, then get a new amp because you can't just run 600W out of it into 2 ohms and crank like you're an SVT.

If the bump in speaker area adds enough percieved volume at a lower Master Volume setting, then 2 ohms may be the way to go.

If you want to crank it at 2 ohms don't. It is a combo here folks Let's not go too crazy... I believe I'm going to try it more often.

Jason

 

[Vic]

I understand this point but if you don't turn it up it WON'T put out more wattage. And with an extra speaker you are less likely to have to turn it up more. By adding a second 4 ohm cab to my WalkAbout I was actually able to turn down quite a bit in most situations.

So if by "power", KJung meant wattage, he was right in that 2 ohms allows more power (wattage) but does not require it. Turn the master volume down = less wattage no matter what resistance.

Well, IMHO, there's no free lunches. I think this still does not considering everything properly.

So if what you're talking about is that 2 8 ohm speakers will move more air at a given power level than a single 4 ohm speaker, or a 2 ohm speaker run at a lower power level, yeah, that's a whole new ball-o-wax.

I was trying to just focus on what happens to an amp when you "underdrive" it's output, which is what I thought was being asked about. However, in re-reading KJung's post I see what you and he are suggesting. He's basically saying make the speaker more efficient per watt by adding radiating space, so you can actually turn the amp down and still have a comparable SPL. I'm not sure it really works that way, tho, as you still have to push all that extra mass as well.

Hey, it's not a linear world, but again, there's also no free lunches, either...

Thing is, I still believe that, by the time you did ALL the math, the amp would still be putting out more juice. Bill Fitzmaurice needs to step in at this point. I bet he'd know.

 

[KJung]

I understand this point but if you don't turn it up it WON'T put out more wattage. And with an extra speaker you are less likely to have to turn it up more. By adding a second 4 ohm cab to my WalkAbout I was actually able to turn down quite a bit in most situations.

So if by "power", KJung meant wattage, he was right in that 2 ohms allows more power (wattage) but does not require it. Turn the master volume down = less wattage no matter what resistance.

That's the way I was seeing it.... but I've been wrong so many times before

K

 

[Vic]

By the way, I should point out that every speaker and amp have ranges of optimum efficiency -- down too low and they don't work too well -- up too high, and they don't work too well -- somewhere in the middle -- juuust right.

In other words, again, when Tom was pushing the tar out of that one speaker config, he was basically "over"pushing that cab to get the SPL he wanted, so I think he was beyond the efficiency range of that config, so he was really demanding a lot of both the amp and speaker cab, which is why the amp got so hot.

...again, tho... admittedly IMHO...