Ohmage

[Acesulfame]

I'm not 100% on this, but I've always been told that you are doing the right thing as long as you send less ohms from the amp to the cab than the cab is designed to take. For example, if the cab is designed to take up to 8 ohms, it's ok to use either 4 or 8 ohms from the amp... I usually use a Mesa Triple Rec into a Mesa Rec oversize cab and I've always just gone with 8 ohms just to be sure I don't blow anything. I'm recording with a Peavey cab this time and only want to go into one side (just two speakers out of the four). A friend of mine tells me that when doing this, it is better to use 16 ohms rather than 8..? I'm confused! Surely if you're using just two speakers in one side you should go for less ohms...

Can anyone shed some light on this topic please?

 

[006]

Go by what the connector plate says you should do.

 

[Trevoire520]

I think you're actually getting mixed up here man and talking about wattage. A 50 watt head will be fine into a 100 watt cab, but a 100 watt head will blow a 50 watt cab!



When dealing with ohm's your head should match your cab:

4 ohm cab = 4 ohms on the head
8 ohm cab = 8 ohms on the head
16 ohm cab = 16 ohms on the head

If your using 2 cabs simultaneously you need to divide the ohmage rather than multiply it, so:

2 x 8 ohm cabs = 4 ohms on the head
2 x 16 ohm cabs = 8 ohms on the head

I know most solid state heads normally give a minimum load (i.e. 4 ohm minimum) so for these amps its ok to use say a 8 ohm or 16 ohm cab, but for valve heads mismatching ohms can destroy your output transformer and take the cab with it! Dont risk it!

 

[006]

+1 pretty much. However, MESA recommends (in their manuals) that you experiment with the OHMs, using 4ohm output on the head and 8ohm input on cab, etc. As long as the tranny is good then they can generally handle it.

 

[John_C]

a 100 watt head will blow a 50 watt cab!

a 100W head CAN blow a 50W cab. Keep the volume down and it'd be fine

 

[Metaltastic]

For the love of god, a 100 watt head will not invariably blow a 50-watt cab, think about what you're saying people - if you've got a 100 watt Crate solid state head and a 50 watt Marshall JMP, take a guess which is louder (hint: it's NOT the one you'd be worried about plugging into the cab if you went by wattage alone ) Wattage for power handling is a load of shit, it's volume that does the damage, so just do it and stop only if you hear the speakers farting out or otherwise giving audible signs of being strained! (I ran my 300 watt HD147 into my 120-watt 2x12 cab with no problems for multiple band practices, because all that power is just there for clean headroom)