Head and Cab Impedance match. Please help this confused soul.

[Audix99]

 

Hi all,

 

Just got a used head (H&K Warp 7, 100W head).

On the speaker output, it reads "100 Watts 4 - 8 ohms" and there are TWO output jacks.

So I assume that the minimum cab ohms acceptable for this head is at 4 ohms.

BUT, the way the manual is written is really confusing to me.

It reads, "Designed to connect to the included 4x12" cabinet and another auxiliary cabinet with a rating of at least 8 ohms. The minimum permissible impedance is 4 ohms."

 

Moreover, the spec on the website shows, "Impedance Mono: 8 Ohms"

(here. http://www.hughes-and-kettner.com/products.php5?id=39&prod=WARP%207%20Halfstack )

So---, do these mean that when only ONE cab is in use, it will have to be minimum 8 ohms???

 

Or, is it okay to run ONE cab at 4 ohms???

The reason for asking is that the cab I want to use with his head is rated at 100W, 4 ohms.

Will it be okay to run this 100W 4 ohms cab with his head?

Your help will be REALLY appreciated.

Thanks!!!

 

 

[jimash]

Yes it will be ok to run your one 4 ohm cab.

Watch the heat.

Don't plug in anything else .

 

[tlbonehead]

well, that would be 4 ohms, correct?

[Audix99]

Thank you for your replies.

 

So when they say, "Mono Impendance: 8 ohms," that doesn't mean 8 ohms is the minimum cab impedance when running ONLY one cab, correct?

That line,"Mono Impendance: 8 ohms," was what got me confused.

So it seems that I can run one cab of 4 ohms with this head without any problem per your responses.

Thanks again!!!

 

[Mogwix]

---

Audix99 wrote:

 

It reads, "Designed to connect to the included 4x12" cabinet and another auxiliary cabinet with a rating of at least 8 ohms.

The minimum permissible impedance is 4 ohms.

"

---

 

The important bit is bold. This phrase means that you can plug in any combination of cabinets, so long as the total impedance is greater than 4 ohms. When you connect cabinets in paralell, the total impedance goes down.

 

16 + 16 = 8 ohms

8 + 8 = 4 ohms

4 + 4 = 2 ohms

 

For solid state amps such as yours, the total load must be greater than the minimum rated impedance of the amplifier. For tube amps, the total load must match the selected impedance of the amplifier.