highly recommended, ext. cab for classic 30

i had a pair of older 12 inch 16 ohms speakers leftover
from an old twin.
some of you gave me the idea to use one to build an
ext. cab for my classic 30.
i`m a professional carpenter so it took me 2 hours to build a plywood cab, closed back, same size as amp.

i liked my classic 30 before, but the combination with the cabinet makes it sound huge.
i did a few gigs with it already and ev`rybody made
compliments how great my esquire sounds with it.

all you classic 30 users give it a try you won`t regret it!

Are you using the cab by itself or with the internal speaker? If you are using the internal speaker, the extension cab needs to be 16 Ohms. The extension jack will switch the transformer to the 8 Ohm tap and you will be running a total of 8 ohms between the internal speaker (16 Ohms) and the extension (which should also be 16 Ohms).

If you have the cab wired up for 8 Ohms you can disconect the internal speaker wires and tape them so they don't short. Then, when you plug into the extension jack, that taps the transformer to 8 Ohms and you'll be ok with your 8 Ohm cab.

i don`t have much knowledge about electronics.
i use the cab with the 16 ohms speaker plugged in the
speaker jack on the backside of the amp.
i didn`t disconnect the built in amp-speaker, so both
speakers work.
i hope that`s not hurting the amp, but like i said i used
the combination for quite a while and had no problems yet.

Doh! My bad! After re-reading your post, I see you used only one of those speakers in your cab. You are perfectly fine running the internal and external speaker together. Sorry!

hi merlin, i think it was you who gave me the advice
with the speaker originally.
i`m very happy with this rig so i want to thank you again!

Hello,
I have a Peavey Classic 30 with a matching Peavey 112E cabinet.
In the combo I use a Celestion G 12 H 30 speaker (8 ohm) and in the cabinet a Celestion Vintage 30 (8 Ohm).
Usually I plug the cabinet into the "external speaker out" and use the combo's internal speaker as well. Never had any problems.
Klaus

Klaus, basically what you're doing is running the amp with a 4 Ohm load when 8 should be the minimum. You may get by with it for a while, but you'll go through tubes faster plus you're overheating the transformer which can lead to it's premature failure.

If you hook up your speakers in series and run them off of the main speaker connection you'll be back to 16 Ohms and be OK, but it will look a little funny.

I should say that I'm not a tech, I'm just regugritating what I've learned from techs, so I can't give you the whys and wherefores.