Ampeg V4.com

Yes, you can recone them with a different impedance.  I've done that before.

I think you are comparing apples to oranges. The V4 is a tube amp with a transformer than has a 2 ohm tap. 2 ohms is perfectly fine. I've run mine that way with 2 x 4-ohm cabinets. For some perspective, Fender Super Reverbs have a 2-ohm load and people have been torturing those things for decades just fine.

The Colliseum is a high wattage (for the time) solidstate head and they are probably suggesting that you go 4-ohms instead to put less stress on those old transistors.

Maybe I don't understand your application. Is your Sunn cab an 8-ohm? You won't realy get a different sound out of the VT-22 with an 8 ohm cabinet vs a 2-ohm cabinet (assuming you have the impedance switch appropriately set).

Would you be using the VT022's speakers simultaneously as the Sunn cab? You are just asking for trouble hooking up a 2 ohm cabinet along with the 8-ohm load of the VT-22's speaker pair.

I really don't think you'll notice any difference. I have 2 identical cabs loaded with identical speakers albeit one is 4 ohms, the other is 8 ohms. I notice no difference in tone between the 2 when the output transformer is switched to its corresponding correct load.

Who knows though...

"to try and milk a little extra headroom out of the amp. (for bass guitar) Am I out in left field on that?"

Yes, I am out in left field. You are correct.

Thanks again for your input!

hangman wrote:

I have known marshall guys that swear up and down that their amp sounds better through the 16ohm out.   
They could never give me a articulate answer for why they felt that way,  and I could never hear a difference.

That's funny. On Scott Henderson's forum, he swears that everything other than 8 ohms sounds like...I think, all else being equal, difference of parallel or series wiring will be more significant, if anything.

hangman wrote:

one thing is for sure,  you wont get more headroom.   using more cabinets you might push a little more air...  which could translate into the bass being a little more present.

Definitely.  If you want more headroom, get a cabinet with speakers that have higher sensitivity.  Increasing 3 db of speaker sensitivity with the same amp, can make as much volume difference as would doubling your amps wattage, on paper.  6db increased sensitivity is pretty significant, like going from a 25 watt amp to 100 watts.