Ohms? ...what do they mean and how do you match?

[arjun]

I was looking at some used Marshall heads and cabs on the net, and in the specs it always says the wattage of the head @ certain ohms, and for cabs it says the power handling with ohms.. now what do I need to know about ohms to make a conscious purchase of an amp head and a separate cab? For example, if I got a head that put out 100 watts @ 4 ohms, could I hook it up to a cab that can handle 120 watts and 8 ohms?? I'm really confused about this ohm thing, and any clarity is needed.

Thanks!

 

[M.Brane]

All tube Marshalls have an impedence selector on the back. This must be matched to the speaker load or you can and likely will smoke the amp. Anytime you have two cabinets of equal load hooked in parallel you half the ohm rating.

It works like this:

1 16 ohm cab- amp set to 16

2 16 ohm cabs- amp set to 8

Likewise:

1 8 ohm cabinet- amp set to 8

2 8 ohm cabs- amp set to 4

It's not wise to mismatch impedence on tube amps. Transistor amps don't care what the load is as long as it doesn't go above or below the range the amp is designed to work within.

Hope this helps.

 

[arjun]

alright.. i'm still a little confused though. so you're saying it doesn't matter if the amp isn't a tube amp? well the head i was looking at is a Marshall Valvestate VS100 head.. it's 100watts @ 4 ohms. so what kind of cabs can i hook it up to? only a 4ohms cab? or can i hook it up to a cab that handles up to 8ohms?

thanks

edit: oh and, the valvestate series is NOT tube, am i correct?

 

[M.Brane]

well the head i was looking at is a Marshall Valvestate VS100 head.. it's 100watts @ 4 ohms. so what kind of cabs can i hook it up to? only a 4ohms cab? or can i hook it up to a cab that handles up to 8ohms?

If the amp puts out 100 @ 4 then it would do roughly 50 @ 8. You should be safe at 8. You probably wouldn't want to try 16 though and definately not 2. It depends on how the amp's circuit is designed. You might try to find some info on exactly what the amp can handle at Marhsall's web site. If it's not on the site try e-mailing their tech support.

oh and, the valvestate series is NOT tube, am i correct?

Yes, the Valvestate series are solid-state (transistor) amps. While I don't care for 'em personally (I'm spoiled ) I've heard some players get good tones from 'em.

 

[arjun]

ah, thanks for all your help. you cleared it all up for me. the marshall head is on ebay anywho... i put my max bid at $80, and currently i'm the highest bidder. 6 days left though, we'll see what happens

thanks again
*arjun

 

[guhlenn]

at 80 dollars be prepared to lose... dude, eaby auctions always start out low... but in the last day it usauallyu climbes.. even I would buy it for 80 dollars...

Guhlenn

 

[arjun]

yeah i know, i'm just messin around on the auction. i'm guaranteed to lose but oh well, you never know, someone might not spot it..