Marshall 72410 - Ohm rating on the speakers?

[Cohacq]

I recently bought a second hand Marshall 72410 (as in, I just got it into my apartment) and I noticed there are 2 speaker connectors on the back of the "head" part. But what ohm rating does the "cab" part run on?

 

[BassmanPaul]

I was about to say that its impedance should be on the connector plate BUT thinking back, a long time, I can't remember any of the Marshall cabs I've used having such information. I guess back then, in the UK, all cabinets were 16Ω so perhaps it was not needed.

You could measure the DC resistance and extrapolate the impedance from that.

 

[Cohacq]

I cant check the connector plate, as the plate is INSIDE the cab, as it is a combo amp.

 

[BassmanPaul]

In that case it's most likely 4Ω as most combo amps are designed to give their maximum output into the internal speakers.

 

[BassmanPaul]

Correction: After doing a google search I found this: Link Removed

The amp has a minimum impedance of 4Ω. The copy says that an extension can be added. It would seem reasonable that both the 1x15 and 4x10 would be 8Ω. That would allow a second 8Ω cabinet to be added to meet the 4Ω minimum of the amp.

 

[Cohacq]

Nice to know, thanks!

 

[BassmanPaul]

Just don't add a single 15 to the equation.