Mark V Variac

244300

Formerly posted as MkIIC+
Silver Supporting Member
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1,982
I understand the amp has a Variac option on the power switch to operate on 90v instead of 120v. Ignoring just how amazingly creative and cool it is to even provide that options...

...I’m curious about two questions.

Who loves this option and why?

If wall voltage is 110-115, then is it still 90v or does it lower wall voltage 25%?
 

Hefalump

Member
Messages
8,871
Well....I found out the hard way that you have to use variac power with el34's.......
 
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Hefalump

Member
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8,871
Doesn't the bias switch on the back of the amp look after the EL 34 swap?
Apparently NOT.....they changed it in user manual AFTER I bought my amp.....Mesa never bothered contacting owners.....ended up exploding a resistor....of course a couple months after my warranty expired.....$480.00 IN SHIPPING AND REPAIR.

I am not impressed at all with the Mark V reliability.......that is a long story and I have to run.
 

conrad79

Member
Messages
307
Yea several years after the fact Mesa sort of slipped it into a manual revision that you were supposed to use variac power in addition to the EL34 bias switch.

anywho, I like variac mode and use it often. Just makes the amp a little softer. However, if the wall voltage is below 117 I use full power mode
 

244300

Formerly posted as MkIIC+
Silver Supporting Member
Messages
1,982
Apparently NOT.....they changed it in user manual AFTER I bought my amp.....Mesa never bothered contacting owners.....ended up exploding a resistor....of course a couple months after my warranty expired.....$480.00 IN SHIPPING AND REPAIR.

I am not impressed at all with the Mark V reliability.......that is a long story and I have to run.
If this was recent, consider calling Mesa to see what they say.
 




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