Using a 6v6 OT for EL84's

[John Fisher]

Hello!

I was just wondering if there was a way to use an OT made for 2 6v6's for 2 el84's.
Correct me if I am wrong but I think the primary impedance of the 6V6's is about 8k while the el84's are about 5 k.
Would it still work or can I possibly adjust the impedance differences by selecting a different tap on the speaker output?
Thanks for you comments

[Albert Kreuzer]

5k is for EL84 SE. For PP 8k is just about right

[tedmich]

2x EL84 PP amps are usually between 6k-8k, with higher being more common and lower expected to push the PA harder toward breakup.

All you can usually get by swapping speakers is a 2-fold difference; a 8Ohm speaker on a 4Ohm tap doubles the primary imp. 6k->12k. There are common 6 ohm speakers that give 6k->9k on a 4ohm tap.

[John Fisher]

So would it simply be practical to use a 0t for 2 6v6's with 2 el84's ?

[Wombaticus]

2x EL84 PP amps are usually between 6k-8k, with higher being more common and lower expected to push the PA harder toward breakup.

All you can usually get by swapping speakers is a 2-fold difference; a 8Ohm speaker on a 4Ohm tap doubles the primary imp. 6k->12k. There are common 6 ohm speakers that give 6k->9k on a 4ohm tap.

.....and, if you're using a 2xwhatever cab, you can presumably also parallel an 8 Ohm and 16 Ohm speaker for a total of 5.33 Ohms. 5.33 Ohms into the 4 Ohm tap will then give you 5K->6.6K or 6K->8K

[Albert Kreuzer]

So would it simply be practical to use a 0t for 2 6v6's with 2 el84's ?

Yes.

[NorCalTuna]

Fwiw, I built a 4x84 voxxy thing for a friend with an enormous Hammond 6.6k tranny I bought for a 6l6 thing I never built. I set it up (iirc) for an 8 ohm speaker on the 16 ohm tap (again iirc) and it RIPS. Wedding gift!

It's cathode bias, of course.... He gigs pretty routinely with it and it's quiet enough for his studio (I won't drop names but he works for a very, very high end mic manufacturer) so it's likely an ok build. El84 is a really good sounding, forgiving tube for what we're doin'.

Also, a great thing to have, which I have in my mini 18w jcm800, is a multitap tranny like Hammond sells- they do a 15w one that rocks both 84s and 6v6s and is overall an awesome go to part. It saturated well with around 90ma of power tranny. Multitaps... That way you can pretty much hook up anything!
And, you will!

[mooreamps]

So would it simply be practical to use a 0t for 2 6v6's with 2 el84's ?

yes.