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8 ohm Head with 16 ohm Cabinet
Old 23rd December 2010
  #1
Gear Addict
 

8 ohm Head with 16 ohm Cabinet

I have a 8 ohm Ampeg Head and a Marshall 16 ohm 4x12 cabinet.

Is it ok to hook them up?

Is there any power loss etc.
Old 23rd December 2010
  #2
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Flying_Dutchman's Avatar
 

ja, but you cant burn the amp
just do it
amp 16 to 8 cabinet is a risk but the other way works
Old 23rd December 2010
  #3
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Chris Parsons's Avatar
 

You may not achieve max power output but I don't believe you are at risk to hurt your amp. However, never run an amplifier into a lower impedance than it is rated for, that will do some damage.

-Chris
Old 23rd December 2010
  #4
Gear Addict
 

Thanks!

I have a ampeg SS150h head. It says it's 150 watts. Even if it's not, it is extremely loud. So I don't mind a little power loss.
Will I loose any tone from the 8 ohm head/ 16 ohm cab set up?
Old 23rd December 2010
  #5
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Colonel Blues's Avatar
Quote:
Originally Posted by greenfields View Post
Thanks!

I have a ampeg SS150h head. It says it's 150 watts. Even if it's not, it is extremely loud. So I don't mind a little power loss.
Will I loose any tone from the 8 ohm head/ 16 ohm cab set up?
No… Compared to cab brand/model & HP brand/model & guitar brand/model & player skillness, impedance is nothing about your tone !
Old 23rd December 2010
  #6
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AnthonyRochester's Avatar
 

I wonder if you can rewire the speaker configuration for the right impedance?
Old 23rd December 2010
  #7
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softwareguy's Avatar
 

If you pull two power tubes (outside pair or inside pair) you will lower the wattage by 1/2 and the impedance will actually match.
Old 23rd December 2010
  #8
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Colonel Blues's Avatar
Quote:
Originally Posted by beebay007 View Post
I wonder if you can rewire the speaker configuration for the right impedance?
Unfortunately not… Marshall cab's are made with 4x16 ohms speakers to have :

4 Ohms mono on 4 speakers
16 ohms mono on 4 speakers
or
2 x 8ohms, on 2 x 2 speakers, to have two 8 ohms heads in the same cab, sharing 2 speakers each…

Old 23rd December 2010
  #9
Gear Nut
 

I would try to rewire the cab to 8 ohms. Which marshall cab? Many are switchable between 4 and 16 ohms, and 8 ohms stereo. Last time (and only time) I plugged in a head that had a lower impedance than my cab, I had to buy 4 new speakers. The amp has less resistance (lower ohms) so the signal is stronger than what the cab is wired to accept, potentially damaging your speakers.
Old 24th December 2010
  #10
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Colonel Blues's Avatar
Quote:
Originally Posted by softwareguy View Post
If you pull two power tubes (outside pair or inside pair) you will lower the wattage by 1/2 and the impedance will actually match.
Lowering the wattage, ok… but matching the impedance… are you sure ?
Old 24th December 2010
  #11
Gear Addict
 

More Info about my Haed/Cabinet.


On the back of my Head it says:

Speakers
150 Watts RMS @ 8 Ohms
4 Ohms Min Total
Load Impedance


My cabinet is a Marshall 1960A 4x12 16 ohm.
Old 24th December 2010
  #12
Gear Addict
 

It also has two 1/4 inch outputs on the back. One says "INT" and the other says "EXT"

I'm guessing the "EXT" is for the speaker Cable but what is "INT" for?
Old 24th December 2010
  #13
Gear Addict
 

As posted earlier:


4 Ohms mono on 4 speakers
16 ohms mono on 4 speakers
or
2 x 8ohms, on 2 x 2 speakers, to have two 8 ohms heads in the same cab, sharing 2 speakers each…

....................................................................................................

SO
If the "INT" and "EXT" are both speaker Jacks and are both 8 ohm loads.


Could I plug Both speaker outputs into each side of the (2x8 ohms, on 2x2 speakers) marshall cab?
Old 24th December 2010
  #14
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Colonel Blues's Avatar
Quote:
Originally Posted by greenfields View Post
It also has two 1/4 inch outputs on the back. One says "INT" and the other says "EXT"

I'm guessing the "EXT" is for the speaker Cable but what is "INT" for?
This on your amp head, ok ?

I suppose it's because this head should have been also sold as a combo version…
INT was to plug the internal spk / EXT for plugging an additionnal spk

Do you have a pic of the back of this head ?
Old 24th December 2010
  #15
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Colonel Blues's Avatar
Quote:
Originally Posted by greenfields View Post
SO
If the "INT" and "EXT" are both speaker Jacks and are both 8 ohm loads.
Are you sure there isn't any mention "total load with both : xx ohms" somewhere ?

Quote:
Could I plug Both speaker outputs into each side of the (2x8 ohms, on 2x2 speakers) marshall cab?
Depends on the answer to my question just above… and if yes, be sure to switch the cab on "stereo" mode !!!
Old 24th December 2010
  #16
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Colonel Blues's Avatar
Quote:
Originally Posted by greenfields View Post
More Info about my Haed/Cabinet.


On the back of my Head it says:

Speakers
150 Watts RMS @ 8 Ohms
4 Ohms Min Total
Load Impedance


My cabinet is a Marshall 1960A 4x12 16 ohm.
Hey ! I haven't seen that post !!!

150W RMS @ 8 Ohms means : if you plug an 8 Ohms spk system to your head, it must handle at least 150 Ohms


4 Ohms Min Total Load Impedance means : your head can handle a system in 4 Ohms, but not less (2 ohms, for example…)

So, the final solution is there :

Plug your head, from its "INT" output (because this jack is supposed to be the first in the parallell row of outputs) to the "4 Ohms" jack of your 1960-A, switched on "mono" ! That's all !!!
Old 24th December 2010
  #17
Gear Addict
 

Thanks So Much!!!!!!
Old 24th December 2010
  #18
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Colonel Blues's Avatar
Quote:
Originally Posted by greenfields View Post
Thanks So Much!!!!!!
You're welcome !
Happy Xmas to you & yours !!!
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