As you all know, Mesa uses a fixed bias. That means you just have to put in new tubes and voilá: you're ready to rock. In some amps, like mine rect-o-verb it has even a switch for if you want to use EL34 or 6L6's, zet the switch, put in tubes, rock.
Now the following: the proper bias voltages for EL34's and 6L6's are different, but that is what we have the switch for. But even within the same type and even the same brand there are differenences of proper bias voltage per tube. Pick two 6L6's out of a box of hundred of the same brand or factory, and they won't have the same bias voltages.That's why variable bias settings are in existance with other amps like Marshall.
Mssa has solved this by catogorizing its tubes. The taken the whole range of possible bias voltage for a tube, let's say the 6L6 and divided that in (I thought six groups) and given every group a name of a colour, red, yellow, etc. Now your Mesa amp has a set/fixed bias and that is set to a certain tube with a certain colour code in the factory. Thus if you want to change tubes you have to change it with a tube with the same mesa color code or you have to know with what voltage interval your tube with its specific colour code belongs to.
Now, my question. This story, is this true and complete? I probably think so, so my second question:
I read alot about chaning tubes, about brands en what more, but according to my story it is not possible to just stick in any new pair of tubes, but you have to get some tubes with the same values as your old set.
Now how is this done by you guys ? You just use mesa tubes, or measure your amp settings and pick tubes of any brand you wish ? (how is this done?) Or you just heard this for the first time and you just replaced new tubes ignorantly or you modded it with a potmeter ? or ...?
Now the following: the proper bias voltages for EL34's and 6L6's are different, but that is what we have the switch for. But even within the same type and even the same brand there are differenences of proper bias voltage per tube. Pick two 6L6's out of a box of hundred of the same brand or factory, and they won't have the same bias voltages.That's why variable bias settings are in existance with other amps like Marshall.
Mssa has solved this by catogorizing its tubes. The taken the whole range of possible bias voltage for a tube, let's say the 6L6 and divided that in (I thought six groups) and given every group a name of a colour, red, yellow, etc. Now your Mesa amp has a set/fixed bias and that is set to a certain tube with a certain colour code in the factory. Thus if you want to change tubes you have to change it with a tube with the same mesa color code or you have to know with what voltage interval your tube with its specific colour code belongs to.
Now, my question. This story, is this true and complete? I probably think so, so my second question:
I read alot about chaning tubes, about brands en what more, but according to my story it is not possible to just stick in any new pair of tubes, but you have to get some tubes with the same values as your old set.
Now how is this done by you guys ? You just use mesa tubes, or measure your amp settings and pick tubes of any brand you wish ? (how is this done?) Or you just heard this for the first time and you just replaced new tubes ignorantly or you modded it with a potmeter ? or ...?