Switching from Class A to Simul Class on Mk IV

[Thors Twins]

Hello,

1st post, tried searching the above topic but cannot get a defined return on the query. The manual doesn't really specify.

Based on the subject, what I'm trying to achieve is using a simple remote footswitch to change between both of those power modes for the purpose of making the amp louder, or "boosting" during solos, then reverting back to Class A afterwards.

Is this a safe method to work with, or is it not recommended to switch between power levels.

Thnx in advance for your input.

 

[sduck]

There's not a way to do this without customizing the amp. And it's probably not the best idea, as you'd be switching on (probably not the correct technical term) 2 of the power tubes on the fly. There are lots of other, non-invasive, safe ways to get a lead volume boost - investigating those is probably your best course.

Edit: I'm completely wrong of course. ^Ignore all of this^. I'd forgotten about the jack for a simple switch to switch between the 2 modes. And I'd suspect that if the designers saw fit to include this, it's probably safe to use on the fly.

 

[bgh]

Perhaps I don't understand the question. But, my Mark IV has a rocker switch to allow switching between Class A and Simul-Class at any time. Also, there is a jack in the back where you can plug in a foot-switch for switch between the two modes. But, like I said, I may be missing the question.

 

[Markedman]

I'm not a tech, but I switch on the fly for leads - by hand. At a lot of the open mics I play, players want to have a pissing contest with the amps. I practically all but disappear, no, actually sometimes I do shut the sound off completely and pretend I'm playing if there is another rhythm player, trying to keep the sound level down. I have found that kicking it up from class a to simul the best way to cut through the complete clutter that is playing. The tubes are ready. It's not like they need to warm up or anything. Maybe a lesser amp would die, I'm not a tech so I can't say really. I think Mesa would've put something in the manual if this was wrong, and in all my years of playing I've never had someone say, "I messed my amp up switching between class a and simul too fast."

 

[HBob]

I've wondered the same thing. Would it hurt the amp to footswitch between Simulclass and Class A, back and forth, maybe even several time during a song? Dozens of times during a set? Is the amp designed to handle that?

 

[tony777]

If you look a the schematics for the amp (do a google search) only thing you do is that you lift the middle tubes (V6 & V7) from ground, and it shouldn't harm anything.

EDIT: When you switch from simul to class A, is just as switching the middle tubes to standby. It's exactly the same as playing a note on the guitar in stanby mode and turn on the amp.

 

[Chief Brody]

Mind blown...

After all these years I've only switched between A & Simul while in Standby. The above discussion never even occurred to me. And now there's yet another amp/guitar variable to mess with at Friday's rehearsal. The bass player and drummer will love it. Thanks. :lol:

 

[Thors Twins]

I've owned the Mk IV since Feb2000, played on and off over the years, never really dialed it in for anything specific, never really tinkered with anything. it's a great amp, and I've really never explored its capabilities. I've dusted it off after 4 yrs of idleness, starting fresh, dialing in some great tones.

Don't know much about overdrive/distortion/boost pedals - basically never needed with this amp. however, just thought a bit louder when solos would be nice, and thought switching between power levels may be the way to go.

I am going to take a chance with this - Chief "we're gonna need a bigger boat" Brady, let's try it out and see how thing go~~~

Thnx to all for the input

 

[Chief Brody]

Oh wait, where am I?

I'm a Mark III guy. How did I get here and who is that sharing my pillow?

Though I must say before I go, between R1, R2, Lead, EQ, guitar volume and a pedal or two the last thing I need is yet another option for more volume (every band mate I've ever had are now choking on their spit And with the IV you have even more, no? Still an interesting idea and I'm sure I'll be manually flipping that switch out of curiosity soon.

Cheers,

Chief "it's only an island if you look at it from the water" Brody