impedance help

[rainsong86]

jus bought my mesa single rectifier and all I got to play it through is a 16 ohm Marshall 1960A cab.. the mesa head only has one 8 ohm and 2 4 ohm output jacks.. should I run 4 ohms or 8 ohm?.. and are there any precautions I need to take when running with the 4 or 8 ohm impedance?

 

[rainsong86]

Re: impedance help

any help?

 

[marvar]

Re: impedance help

you are ok running out of the 8 ohm output-but short of getting new speakers or an attenuator, you won't be matched up properly-
I'd consider getting the correct impedence cab, or speakers to replace those you have now so that you will get the most out of your amp. You won't get the full output of your amp with a 16 ohm load.

 

[rainsong86]

Re: impedance help

thanks for the info.. but will I hurt the cab if I run my mesa head loud using 8 ohms?

 

[PFDarkside]

Re: impedance help

No, it won't hurt it, but you can have it rewired to to give you a 4 ohm load.

 

[marvar]

Re: impedance help

No, it won't hurt it, but you can have it rewired to to give you a 4 ohm load.

duh, I've gone brain-dead, I didn't even think of that! I do have a few other things on my mind.

 

[marvar]

Re: impedance help

thanks for the info.. but will I hurt the cab if I run my mesa head loud using 8 ohms?

About the only way to hurt the cab is by running too much power into them- or, a DC signal-
I suppose that is a 300 watt cab (4x75)- so crank 'er up!

 

[muttonchopsrule]

Re: impedance help

you're running a 1960 cabinet and you don't have a 4 ohm input? the 1960 should have the type of wiring that allows you to run at 4 ohms mono, 16 ohms mono, or 8 ohms stereo. if it doesn't, then it's easy to rewire the spearkers to operate at a total of 4 ohms (provided the speakers are rated at 16 ohms, which they probably are if it's a 1960). all you'd have to do is wire them all up in parallel (connect all positive spearker terminals to the poisitive terminal in the input jack, and likewise with the negative terminals).

you won't get the most out of that amp volumewise unless the impedence is matched properly. my old cabinet was wired up for 16 ohms, and i did the above and wired it for 4 ohms and it worked great.

 

[rainsong86]

Re: impedance help

the cab seems old.. it's a 1960A lead.. only has one input which is 16 ohms.. it's a friends so I don't want to modify it but thanks for the idea.. my main question now is.. will there be a dramatic volume drop due to the impedance mismatch?.. I've been testdriving this amp and it's not loud enough for band practice (the clean starts to distort at a rather low volume).. is this due to using a 16 ohm cab with a 8 ohm amp output?