Yellow jacket EL84 adapter in a MkIV?

[tubeydude]

Has anyone done this?
Did you like the tonal change?
Was it reliable?
Was it worth doing?
Does the adapter and the EL84 fit in a small head?

Thanks

 

[gonzo]

i use groove tubes substitubes in my mark2b.
works like a charm.
dig the blend of el84 chime, with the boogie preamp....

 

[jutsin]

I just got the THD yellowjackets to use in my MK IV and 50 cal +, but i haven't had a chance to plug them in yet. yes they will work, and yes they are safe. i've heard of some people having issues with the Groove Tubes variant (can't turn volume up past 4-5 or it fries resistors) but haven't heard any issues with the THD. to make it fit into a head, you'll need to make sure you get the short versions.