Hey all, I just got home with my brand new Mark V head, couldn’t wait to play through it. So “Stupidly” I plugged the amp head into the wall wart, threw in a guitar jack and turned on the amp in stand-by for about 10 min. when I realized that the amp was NOT connected to the cab I immediately went into “PANIC MODE” , so instead of just turning the amp off since it was in Stand-by , I flipped the switch to ON , then in a rush tried turning it off and went straight down to spongy mode. What the F?!K. to soon after place the friggin’ switch on OFF. now my question is : Does any one now if I have done some serious damage to my new amp since I ran it for about 10 min on stand-by with no speaker load connected and soon after, for about 5 seconds on full power with no speaker load. ?!? (I did not play the guitar ) during this time. Does anyone know if I damaged anything? (internal components, Output transformer, Capacitors, tubes, whatever!!!) Please Help. Has anyone ever done such a stupid thing!!!. What are your thoughts and suggestions . I highly appreciate it. P.S. I tried the amp soon after and it seemed to work fine , but I had it on 10 watts, so I don’t know how it would react in 90 watts for an extended period of time at high volumes which I can’t try at home.… Thanks guys. Peace and Rock on… :roll: :roll:
Turned my NEW Mark V on without having a speaker load connec
- Thread starter ricorocks
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Having the amp in stand-by only runs the heaters, speaker load is not necessary. However, turning off the stand by switch send all power to the tubes. No load, well that could result in damage to the power tubes and supply if any high voltage transients were to occur. If you amp is no longer operating, the question to your answer is yes you did some damage.
Most of the parts are tolerant to some mistakes, however, most of the parts are not tolerant to back EMF that may be created by the output transformer with no load. If your amp works with the speaker connected, there may not be any issues. I have done this by accident on a few occasions, one was moving the amp while it was on and it fell over and broke off the speaker jack while I was playing at the same time. (if you have a combo on casters, do not move the amp with your foot or it may fall over).
I normally check the speaker cable on my heads (just in case the cat pulled them out) I have also done the oops after replacing tubes.
Most of the parts are tolerant to some mistakes, however, most of the parts are not tolerant to back EMF that may be created by the output transformer with no load. If your amp works with the speaker connected, there may not be any issues. I have done this by accident on a few occasions, one was moving the amp while it was on and it fell over and broke off the speaker jack while I was playing at the same time. (if you have a combo on casters, do not move the amp with your foot or it may fall over).
I normally check the speaker cable on my heads (just in case the cat pulled them out) I have also done the oops after replacing tubes.
Old BF Shred
Well-known member
I would not loose sleep over it...
Highly unlikely that any damage was done. This not an uncommon scenario. I've done it, too. :roll:
Never hurt the amp.
As long as you switch to standby, as soon as you notice a problem, you should be fine.
Highly unlikely that any damage was done. This not an uncommon scenario. I've done it, too. :roll:
Never hurt the amp.
As long as you switch to standby, as soon as you notice a problem, you should be fine.
Thanks Guys , I appreciate your great help and recommendations. bandit2013 when you say: “most of the parts are not tolerant to back EMF that may be created by the output transformer with no load” what is EMF ??? could you please explain this better. Thanks. Rock On… :wink:
cradlefish
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Thanks for the info. I was always curious about that. I couldn't find answers around the net with your amp on standby without a load. Now i know it's safe. Whew! i've had my amp turn on without a load but has always been on standby.
Good info!
Good info!
ricorocks said:
Back EMF (electromotive force) is primarily related to inductive motors, counter EMF, CEMF, in other words; counter electromotive force, which is also related to inductance (output transformer would be the case here) is a voltage that has opposite polarity to the supplying voltage, however, the voltage potential can be extremely high. A sudden change in current such as turning off the standby switch or power switch can induce a voltage that may be 10 to 100 times that which was applied at the moment of the change. Without a load or speaker connected to the output transformer, there is no means for the inducted voltage to be dissipated but thought the power supply which may result in damage to components. It is similar (but not the same) to an automotive coil and spark plug starting at 12v DC when it is switched off, there is a 10,000 to 40,000 voltage that is created by the instantaneous change in current which causes the spark to jump the gap of the plug. Your power supply operates at 480V dc. Any counter EMF if 10 times the potential could be devastating. This is why some tubes may get lightning inside them, and possibly at a cost of a grid resistor, rectifier diode, etc.... There are some protection devices in the power supply that will react quickly to thwart the induced voltages but they only can survive the energy only a few times before they fail (usually depends on level of energy needed to be shunted or shorted).
Wiki has a good definition. of counter EMF or back EMF (although they relate this to motors, all inductors will exhibit this which includes transformers, relays, chokes, etc...
Ytsejammer777
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If it makes you feel any better...I did almost the same thing a couple of months ago, except much worse.
I had had my Mark V for a couple of weeks and had purchased a mini amp gizmo for switching channels. I hooked everything up, powered up the amp... no sound. The amp was stuck on channel 3 and i couldn't change it via any method. I probably had the amp on a good 10-15 minutes trying to troubleshoot.
Well, when I was hooking up my speaker cable, my muscle memory kicked in and i plugged it into the channel 3 1/4" jack, which happened to be in the same location as the 8ohm input on my old Triamp. When i was hooking it up, the 3 looked enough like the 8 from the angle i was at, so i instinctively plugged it in there which explained why I couldn't switch channels
So long story short, had the V powered up with no speaker load for 10-15 minutes and I haven't noticed anything wrong with it and have played several shows since. The consensus from those I talked to about it, is that Mesa uses really high quality parts and can tolerate some abuse/absentmindedness from us dumb guitarists from time to time....
I had had my Mark V for a couple of weeks and had purchased a mini amp gizmo for switching channels. I hooked everything up, powered up the amp... no sound. The amp was stuck on channel 3 and i couldn't change it via any method. I probably had the amp on a good 10-15 minutes trying to troubleshoot.
Well, when I was hooking up my speaker cable, my muscle memory kicked in and i plugged it into the channel 3 1/4" jack, which happened to be in the same location as the 8ohm input on my old Triamp. When i was hooking it up, the 3 looked enough like the 8 from the angle i was at, so i instinctively plugged it in there which explained why I couldn't switch channels
So long story short, had the V powered up with no speaker load for 10-15 minutes and I haven't noticed anything wrong with it and have played several shows since. The consensus from those I talked to about it, is that Mesa uses really high quality parts and can tolerate some abuse/absentmindedness from us dumb guitarists from time to time....
kraftwerkd
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Yeah, you're fine dude. I've done it once or twice myself, but I can't remember if I had it out of stand-by at that point or not. Either way, Mesa makes some tough-as-nails equipment.
I have done the same as well. Tuned the amp on, took off standby and WTF no sound? Oh SH## is the speaker connected?
As a habit, I usually check to see if the amp is plugged in to the speaker cab (not just looking for the cable on the amp but also checking the cabinet).
I found out why I was blowing tubes in my Mark V, and had lightning in a set of Tung Sol 7581's, it was the split switch in the jack for the 8 ohm input. My cabinet is 14 years old, the Mark V was the first head I ever owned. Used the 412 with my Mark IV combo once in a while but it stayed in storage since there was no space for it. Blew out the factory Mesa tubes in two weeks of use (red plated while in 45W mode ch3 and with power switch set to variac) At first I thought the V30's were crapping out. Did not care much for them in the larger 412 so I installed EV black label. Also rewired the speaker connections and only have one jack in use for the speaker (set to permanent 8 ohm). I discovered that the switch or contact with the rubber stopper was not maintaining contact when driving the speakers with ample bass. No more of an issue now. and have not lost a power tube since. In addition, the amp runs cooler now. It used to get extremely hot. Intermittent load dropping out due to bad switch connection in the jack was the culprit. So far the amp is in great working order and no issues. I always check for speaker connection, sometimes I swap speaker cabs but usually leave the unused end of the speaker wire hanging over the amp if I am using the cab with another amp. That way I know the amp is not plugged into a load. I usually reconnect the loads when I am done, but have forgotten to connect the speaker after doing a tube roll from time to time. Mistakes do happen. Double checking even if redundant will keep you happy for the long run.
As a habit, I usually check to see if the amp is plugged in to the speaker cab (not just looking for the cable on the amp but also checking the cabinet).
I found out why I was blowing tubes in my Mark V, and had lightning in a set of Tung Sol 7581's, it was the split switch in the jack for the 8 ohm input. My cabinet is 14 years old, the Mark V was the first head I ever owned. Used the 412 with my Mark IV combo once in a while but it stayed in storage since there was no space for it. Blew out the factory Mesa tubes in two weeks of use (red plated while in 45W mode ch3 and with power switch set to variac) At first I thought the V30's were crapping out. Did not care much for them in the larger 412 so I installed EV black label. Also rewired the speaker connections and only have one jack in use for the speaker (set to permanent 8 ohm). I discovered that the switch or contact with the rubber stopper was not maintaining contact when driving the speakers with ample bass. No more of an issue now. and have not lost a power tube since. In addition, the amp runs cooler now. It used to get extremely hot. Intermittent load dropping out due to bad switch connection in the jack was the culprit. So far the amp is in great working order and no issues. I always check for speaker connection, sometimes I swap speaker cabs but usually leave the unused end of the speaker wire hanging over the amp if I am using the cab with another amp. That way I know the amp is not plugged into a load. I usually reconnect the loads when I am done, but have forgotten to connect the speaker after doing a tube roll from time to time. Mistakes do happen. Double checking even if redundant will keep you happy for the long run.
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