Can a tube be added?

I have been reading where tubes, usually a 6V6 onto a EL84 circuit, have been added. How would that be done? Just curious at this point, but it sounds cool!

Typically you would replace EL84s with 6V6s if you were looking for the rounder 6V6 tone. They're electrically compatible, so all you have to do is change the socket, connect the wires, insert the tubes, and rebias.

There's a Rivera amp with both EL84s and 6V6s. That's not a practical solution for most amps--no room, not enough power for the filaments.

ADDING a tube to an existing circuit is typically pretty dicey. Trannies are engineered to run a certain set of tubes and might not be able to handle having another tube added, at least not another power tube. A preamp tube might be possible. Swapping a 6V6GT for an EL84 is, as noted by Billm, a complex exercise in simplicity by comparison.

Then there are the physical limitations...is there room in the chassis for it to fit? Are you capable/inclined to cut a hole in your amp to make it fit? Not recommended in high-value vintage stuff, but hey, they were all new amps once.

Are you able to work on amps without electrocuting yourself?

Thanks Bill and Marshman!

I believe there is space, but I think Bill's idea is a better option. AS it stands I have a bunch of 6V6's around and a couple of extra sockets to, so I think that is the direction I will go. Should be fun as I have never swapped tube sockets or had occasion to re-bias tubes, but I have been looking for a chance to learn!!.

I'll throw the ol' disclaimer in here.

If you've never had the occasion to rebias tubes, then I feel the need to suggest that you make absolutely sure you know how to properly discharge your filter caps. Failure to do this can kill you dead. This is not something you can skip if you're working on your amp.

Of course, when you're rebiasing the amp, you've got to have it running, so be doubly sure you know which parts contain the nasty shocks - and when the amp is on, that's almost all of them.

Also, make sure you're familiar with the pinouts of the tubes you're swapping. The 6v6s are octal, and the EL84s noval, so at very least you're looking at a different number of connections. I honestly wouldn't classify this as a beginner project.

I do wish you luck though. Enjoy!

I'll throw the ol' disclaimer in here.

If you've never had the occasion to rebias tubes, then I feel the need to suggest that you make absolutely sure you know how to properly discharge your filter caps. Failure to do this can kill you dead. This is not something you can skip if you're working on your amp.

Of course, when you're rebiasing the amp, you've got to have it running, so be doubly sure you know which parts contain the nasty shocks - and when the amp is on, that's almost all of them.

Also, make sure you're familiar with the pinouts of the tubes you're swapping. The 6v6s are octal, and the EL84s noval, so at very least you're looking at a different number of connections. I honestly wouldn't classify this as a beginner project.

I do wish you luck though. Enjoy!

Yeah, I definitely know about the hair straightening potential of amps. I actually was just reacquainting myself with the noval's. I always kinda felt any project is a beginners project if you prepare properly and have good instructions.