running the 3ch dual rec in 50 watts

[metal_man12]

in order to do this exactly which of the power tubes should i pull?
thanks

 

[jgventura]

You've got 4 power tubes and 2 recto tubes right? If so, (i have the tremoverb verb which is esentially a DR) pull either the 2 outside or inside power tubes and one rec tube. I had to do this a month or so back dude to a broken power tube (the 4th one) so i was told to remove the matching one as well (which would be the 1st in my case) and one rec tube to run at 50 watts.

 

[MesallicA]

the ohm's change aswell though, i cant exactly rember if they half or double. I havnt done it in a while.

 

[4Draw]

the ohm's change aswell though, i cant exactly rember if they half or double. I havnt done it in a while.

Nope.

You don't have to do anything to your ohms, just keep them regularly matched.

 

[boogieslide]

I have to disagree that the impedance does not change.
This is based off of an article with a tech from Mesa who likes to do this to the Tverb. He states that the tubes are in pairs of the inner two or outer two so you can pull either pair and one rectifier (doesn't matter which rectifier), but then the impedance of the outputs is doubled. The 8ohm tap becomes 16 and 4 becomes 8. If it was the other way around it would be a safe mismatch, but by doubling....if you normally connect an 8ohm cab to the 8ohm tap you would be creating an unsafe mismatch where the amp really needs to see a 16ohm load and only has 8.
I would be happy to email the article to anyone that wants to PM me an email address.

 

[zakkfaerum]

The Mesa Users manual for these amps states to pull the 2 inner tubes and 1 Rectifier tube. It doesn't state anything about changing your ohm input.

This is what I have been doing lately!!!

 

[Elpelotero]

I called Mesa and they told me to HALF the impedance from 8ohms down to 4ohms. It seems there are disagreements within the employees themselves!?

Would anyone know the technical wizardry to explain which is correct?

 

[shack]

You do have to half the impedence.

So if for instance you have an 8 ohm cab, you would plug it into the 4 ohm jack on your head.

 

[Areola]

so running an 8ohm cab from the 8 ohm output WITH tubes pulled is a safe mis-match?

It seemed to me that with the extra tubes that the amp was more than twice as loud.

 

[kawalski]

is there a final word to how this should be set up? cut the ohms in half? double them? or do nothing? and to add more to the question... everyone seemed to agree on taking out a rectifier tube. what about running the silicon diodes? thanks to anyone in advance.

 

[fredster]

is there a final word to how this should be set up? cut the ohms in half? double them? or do nothing? and to add more to the question... everyone seemed to agree on taking out a rectifier tube. what about running the silicon diodes? thanks to anyone in advance.

I don't know how final this is but...

I talked to Mesa about this - you've got to remove a rectifier tube if you take out a pair (inside or outside). Diode mode would be unaffected. About the ohms - I asked the same question and was told running a 8ohm cab at 4ohms would be more correct, but it could be run either at 4 or 8ohms with no problems

 

[soundpurist]

IHMO You sould not take chances, so if your goal is not too play loud keep matched tubes and connect the 4ohms output in the 8ohms of the cabinet. Like this there's no way to worry .