Hey everyone. I just picked up a Marshall 4x12 1960a cab. I want to use a RD210 100 watt with it. If it sounds good I'll probably build a head cabinet for it. My question is, how to I push the marshall cab at 4 ohms with this head. The musicman says switch to 4 ohms when using the ext. Speaker jack, but then it also says ext speaker load must be 8 ohms only. Kinda confusing. The marshall will do 4 or 16 ohms mono, but only 8ohms stereo. Does this mean I need to patch both the speaker outs to the marshall and run it as stereo 8 ohm?
Wed, 11/02/2016 - 12:12
#1
AndrewLarson
Anyone?
Anyone?
Anyone?
Anyone?
If you want to use the cab,
If you want to use the cab, use it in 4 ohm mode and set switch to 4 ohms and DON'T use any other speaker. The RD's are in parallel on the external jack so the impedance will halve. You could use the 16 ohm cab with it set to 4 if you want but the max sound will NOT be directed at the 4x12. What are the ohms of the 2-10's in the amp and are they in series or parallel? I am not familiar with the rd's but MM USUALLY used 2-8's in parallel to get a 4 ohm load.(generally). Mike.
The RD 10s are 8 ohms
The RD has 2 8ohms 10" speakers. So I should use the ext. Speaker jack and unplug the MM speakers from the jack and switch to 4ohms, correct? Why does the amp say ext. Speaker must be 8 ohms?
NO! Unplug the MAIN speaker
NO! Unplug the MAIN speaker and plug the cabinet in there, NOT the extension jack. They really mean they want it to be a MINIMUM of 8 ohms as if you put a four ohm speaker in parallel with a four ohm load, you will have a two ohm load. Not the best way to have it. If you plugged a TWO ohm load in you'd get 1.33 ohms. REALLY unhealthy. Mike.
Don't tell the wife about this way
The best way is of course to get an RD-100 head to run your Marshall cab with. Set the switch to 4 ohms and run either two wires to the cab in stereo mode or one wire in mono (six of one, half dozen of the other).
Now, if I suggested that to my better half - it would also be unhealthy :)
Have you seen that poor RD-100 on Fleabay? Painted red and all.. - would be tempting if the Canadian dinar wasn't so weak these days.
Cheers,
Lars Verholt