Is this safe to do?

I've had my Mark V for months now and I love it. I am however confused by a design feature. And that would be the power/variac switch. It's made to seem like you could switch between the two without turning off the amp. But the "off" is in the middle.

I've been told this is ok to do. However there is no info about this in the manual. I was hoping someone could explain if it's really alright to switch between variac/full power with the amp on, and possibly even when the amp isn't in standby? I don't really understand the technology behind this or why Mesa Boogie wouldn't make a note of it in the manual.

Any guidance or explanation would be appreciated

The amp is being disconnected from power in the middle of the switch and some argue that guitar amps don't even need standby switches. Some devices can be harmed by turning them on and off rapidly but I don't think it'll hurt an amp other than arcing on the switch. If you're concerned, just move the switch slowly.

Yes there is the "Off" position between "Full Power" and "Variac" but the "Standby" is recomended when turning the amp off to let the tubes warm up before playing and cool off after playing so by default you are turning the amp "Off" to switch from one to the other. So I use and recomend using the "Standby" when switching from "Variac Power" to "Full Power" or the other way. But for me as I have been playing for a bit the amp is warmed up so I just give it a few seconds in "Standby" when switching between the two. Better safe than opening your wallet for new tubes earlier than you could have.

In the store while I was testing the amp the salesman said "Check this out" and he switched it. He did switch into "Standby" mode and then from "Full Power" to "Variac" and then out of "Standby". I believe that coming out of standby applies the power to the power section smoothly as to not shock the power tubes. Going from one to the other may not hurt the amp but it may abruptly hit the power tube. I always use the "Standby" when switching. My thought is even if it's not required I may be saving tube life and that is always a good thing. The salesman did point out that running the amp in "Variac" mode does give you longer tube life as the tubes are "Cruising" when you are not playing and the power is applied as more of a push instead of hits. I like the sound and feel of "Full" power but when I'm not at a gig I use "Variac". I change my tubes all at the same time. I have a tube tester (I'm spoiled, I know) then I test each tube after I change out a set. I only keep the ones that test "perfect" as spares. I love the sound and feel of new tubes.

In the variac mode the power section is just cruising and only ramps up while you are playing. If you really pay attention you can feel the delay of your guitar after switching from the "Full Power" to the "Variac Power".

A set of tubes is expensive so I baby them.

OldTelecasterMan said:

Yes there is the "Off" position between "Full Power" and "Variac" but the "Standby" is recomended when turning the amp off to let the tubes warm up before playing and cool off after playing so by default you are turning the amp "Off" to switch from one to the other. So I use and recomend using the "Standby" when switching from "Variac Power" to "Full Power" or the other way. But for me as I have been playing for a bit the amp is warmed up so I just give it a few seconds in "Standby" when switching between the two. Better safe than opening your wallet for new tubes earlier than you could have.

In the store while I was testing the amp the salesman said "Check this out" and he switched it. He did switch into "Standby" mode and then from "Full Power" to "Variac" and then out of "Standby". I believe that coming out of standby applies the power to the power section smoothly as to not shock the power tubes. Going from one to the other may not hurt the amp but it may abruptly hit the power tube. I always use the "Standby" when switching. My thought is even if it's not required I may be saving tube life and that is always a good thing. The salesman did point out that running the amp in "Variac" mode does give you longer tube life as the tubes are "Cruising" when you are not playing and the power is applied as more of a push instead of hits. I like the sound and feel of "Full" power but when I'm not at a gig I use "Variac". I change my tubes all at the same time. I have a tube tester (I'm spoiled, I know) then I test each tube after I change out a set. I only keep the ones that test "perfect" as spares. I love the sound and feel of new tubes.

In the variac mode the power section is just cruising and only ramps up while you are playing. If you really pay attention you can feel the delay of your guitar after switching from the "Full Power" to the "Variac Power".

A set of tubes is expensive so I baby them.

Click to expand...

Wow. Thank you for this very detailed response. It sounds like what I thought, and what other people have said, which is that it's fine to do. Just to be safe I'll switch to standby if I ever want to switch from full to variac really quickly (which honestly is very rare). Sounds like worst case scenario is going through tubes just a little fast.

I like that you can put in new tubes without having to bias the amp. Where do you get your tubes? And what exactly do you mean by some tubes being perfect? I'm not super knowledgeable on the technical side of tube technology. I'd like to learn more, and possibly have some spare tubes of my own lying around.

Thank you!

Yes. Tubes being perfect. I have a Tube tester just like the one in the link below. I'll test a brand new tube and get the reading, when I test my used tubes, if they are not pretty darn close to the new tube reading I don't keep them. I got extreemly lucky and worked for an electronics Engineer who happened to have a tube tester and gave it to me on a perminant loan.

As for where I purchase my tubes. I purchase them from Boogie. Many people purchase tubes from other outlets, I just choose not to. Yes they are more expensive but Tubes actually last quite a long time. In my case, when I was playing nearly every weekend I changed them once a year. I have taken a break from gigs for the last few years (my wife was very sick) so tubes last years when they are used less and not pushed at all.

When I decide to start working again I will change the set that is in the amp. I don't remember what the last set cost me but I think it is somewhere around $220. It might be $160 but it was about 4 or 5 years ago and I can't remember. Is having your own tube tester overkill? If you own one you won't think so. I was gigging a lot and just because I wanted to go for a drive on a Sunday I went to Hollywood and stopped in the the Boogie store and picked up a set of tubes. When I got home I pulled all my tubes and tested them. Some were almost to the "Replace" mark on the tube tester. Gigging so much I didn't notice the slow loss of life. I replaced all the tubes and it was a brand new amp crisp and warm. I have never had to replace a Mesa tube at a gig but I have them, used ones that test good (almost perfect). I carry a full set. I never mix new tubes and used tubes.

http://www.indianaradios.com/Precision%20Electronamic%20Tube%20Master%2010-12%20Tube%20Tester.htm

Here is one on eBay
https://www.ebay.ca/itm/NICE-WORKING-PRECISION-TUBE-MASTER-SERIES-10-15-TUBE-BATTERY-TESTER/391307737863?hash=item5b1bc23b07:g:XxcAAOSw5VFWJmo7