an 8ohm out and a 16ohm out. how to add an xtra cab?

[tom skool]

hi all
I have got an old valve amp which has got one 8ohm output and one 16ohm output.
Is there any way i can attach more than one cab for a bit more oomph?
I'm guessing putting an 8 ohm cab to the 8ohm out and a 16 ohm cab to the other wouldn't be right for some reason.

[josh3184]

[quote name='tom skool' post='756829' date='Feb 25 2010, 10:12 AM']hi all
I have got an old valve amp which has got one 8ohm output and one 16ohm output.
Is there any way i can attach more than one cab for a bit more oomph?
I'm guessing putting an 8 ohm cab to the 8ohm out and a 16 ohm cab to the other wouldn't be right for some reason.[/quote]
I too think this would be bad juju. How would the wattage balance for one? Will let more techy people fill in the details though

[chris_b]

I believe this is telling you that the amp has a maximum output of 8 ohms, ie 1 8 ohm or 2 16 ohm cabs. That was pretty good back then!

Edit: What amp is it? What does Google say?

Edited February 25, 2010 by chris_b

[Bill Fitzmaurice]

[quote name='tom skool' post='756829' date='Feb 25 2010, 05:12 AM']hi all
I have got an old valve amp which has got one 8ohm output and one 16ohm output.
Is there any way i can attach more than one cab for a bit more oomph?
I'm guessing putting an 8 ohm cab to the 8ohm out and a 16 ohm cab to the other wouldn't be right for some reason.[/quote]
The taps on a valve amp represent the maximum load that should be used with them, the opposite of SS amps. You can daisy chain cabs no problem, just make sure both cabs have the same impedance. A pair of 8 ohm cabs daisy chained is 4 ohms, so run them off the 8 ohm tap. The 16 ohm tap is pretty much of no value, as 16 ohm and higher cabs are no longer to be found.

[tom skool]

[quote name='Bill Fitzmaurice' post='757058' date='Feb 25 2010, 01:48 PM']The taps on a valve amp represent the maximum load that should be used with them, the opposite of SS amps. You can daisy chain cabs no problem, just make sure both cabs have the same impedance. A pair of 8 ohm cabs daisy chained is 4 ohms, so run them off the 8 ohm tap. The 16 ohm tap is pretty much of no value, as 16 ohm and higher cabs are no longer to be found.[/quote]
Ah yes i daisy chaining them would work, although both cabs i have access to atm have only got a lead and a jack plug to attach to. I would need a cab with two sockets on.
I do have a splitter box ( wired for either series or paralell) Could i use that somehow? have both cabs plug into the box and then run a lead from the box to the amp?

[chris_b]

I don't recall "daisy chaining" being offered on "old" cabs so I would check that you can run a 4 ohm load out of a socket that says 8 ohm! If you get this wrong the valves and biasing will take a hit and you could burn out all sorts of other internal bits.

[Bill Fitzmaurice]

[quote name='tom skool' post='757243' date='Feb 25 2010, 11:27 AM']I do have a splitter box ( wired for either series or paralell) Could i use that somehow? have both cabs plug into the box and then run a lead from the box to the amp?[/quote]
That should work fine. You could also try it with the cabs in series into the 16 ohm tap, you never know. Cabs in series tend not to work all that well, but it's worth a shot.

[tom skool]

ok not sure if i want to risk putting a 4ohm load into an 8ohm out. Does any one else know if this is ok on valve amp (its a selmer t&
And why does running cabs in series sometimes not work so well?

[chris_b]

This guy looks like he could know the answer:

[url="http://www.chambonino.com/"]http://www.chambonino.com/[/url]

[url="http://www.chambonino.com/work/selmer/selm8.html"]http://www.chambonino.com/work/selmer/selm8.html[/url]

Edited February 26, 2010 by chris_b

[Pentode]

I have a 50W Ampeg B25 which has 8ohm and a 16ohm outputs.

I've been running two 8ohm cabs from the 16ohm output using a series cable made up by our very own OBBM.

Not had any problems and sounds soooo good I sometimes have a little sex wee just listening to it! ^_^

[Clarky72]

This is always my bible for hooking up amps and cabs, it shows you the formula at the bottom of the page for mixed hook-ups.
[url="http://www.tunemybass.com/bass_amps/how_to_hook_up_heads_and_cabinets.html"]Click[/url]

[oldslapper]

[quote name='Clarky72' post='758085' date='Feb 26 2010, 12:14 PM']This is always my bible for hooking up amps and cabs, it shows you the formula at the bottom of the page for mixed hook-ups.
[url="http://www.tunemybass.com/bass_amps/how_to_hook_up_heads_and_cabinets.html"]Click[/url][/quote]

Very helpful thread.

I think I've got it!

I've been offered a cab that switches from 4-16 ohm.

I could use my amp rated at 500 watt @ 4ohm and get the full 500 watts when the cab is switched to 4 ohm.

I could use another non "switchable" 8 ohm cab by itself and get 350 watts from the amp.

Or...I could pair the 2 cabs together, switch one cab to 16 ohm and get slightly less than 500 watts @ 5.3333333 ohm impedance/resistance/........thingy.

Nes pas????

Wonder what I'd get from the amp if used with the one cab switched to 16 ohms? 200 watts??