Running Extension Cab -Blue Angel

[Natman]

Hey guys, I feel a bit dumb but I can't can't figure this out:

I want to run my 1x12 BA combo + a 2x10 extension cab.

Right now my 12" speaker is 16 ohms and the manual says to use the lower impedance jack when using 6V6's (which I use most of the time), so it gets plugged into the 8 ohm jack.
I do switch it back to the correct jack if I go up to EL84's or Simul Class FWIW.

Now I understand how output transformers work but only to an extent. As far as I can tell, the secondary just needs to "see" the correct load, no matter where it is coming from. So hypothetically:
16 ohm speaker + 16 ohm cab (2 x 8 ohm speakers in series) would probably have the jacks in parallel I'm guessing? then I would have an 8 ohm load and I should plug it into the 4 ohm jack when using 6V6?

You can see where it gets complicated real quick.
Thanks for your input (pun intended)

 

[elvis]

You're probably right, but I would check with an Ohm meter. Best to be sure, especially with old iron.

 

[hugsy41]

Natman,

It can get confusing sometimes, especially under your current set-up circumstances! However, you are correct in all your assumptions (a. the secondary sees only total combined load, and b. you have an 8 ohm load in your current setup).

It's often convenient to break it down into blocks:

Blue Angel --> Cab

The Cab here consists of (2) 16 ohm loads in parallel, hence any amp will see a total 8 ohms in resistance.

Hence,

For normal use:
Blue Angel (8ohm) --> internal 16-ohm speaker
Blue Angel (8ohm) --> external 16-ohm cab.

For 6v6 use:
Blue Angel (4ohm) --> internal 16-ohm speaker
Blue Angel (4ohm) --> external 16-ohm cab.


Hope that helps.

Chris

 

[Natman]

Awesome, thanks Chris!

 

[Natman]

Hey all, just bumping this to share a bit. I tried the arrangement mentioned above, using the 2x10 cab I built (Weber alnico P10R and Silver Ten) and the combo's 12" (Mojo Greyhound). To my surprise, there was a volume drop when using all 3 speakers and it didn't really sound that hot. Either the cab or the single 12 on their own sounded better. There was definite farting from the P10R if I pushed it too much. Shortly after trying these, my RCA Blackplate 6V6s died . Waiting for some new glass to arrive and will keep testing, but early indications are that it's not as awesome as I had hoped. The 2x10 on its own did limit volume as I was planning however and bass loss was minimal.

 

[elvis]

You might check the polarity of the cabs. If they are out of phase they will sound terrible together.

 

[Authorized Boogie]

You might check the polarity of the cabs. If they are out of phase they will sound terrible together.

+1!!

 

[green_henry]

I have a 2x10 combo with 8 Ohm speakers in parallel and I use the 16 Ohm jack.

I'm a little confused by the advice in the owner's manual about using the 4 Ohm jack when using the 6V6s. Is that true regardless of the speaker impedance?

Am I going to have problems if I forget to change jacks when I switch over to the EL84s?

And what do you use when using the 6V6s and the EL84s together?

So confusing

That said, it sounds great to me as-is with the 16 Ohm jack (at least at bedroom volumes)