SA90

Having checked my current setup, the head I am currently using is also rated at 4ohms, going into my 8ohm cab.

This amp is only 300W...so going into a 8ohm cab, it's only transferring 150W?

The 900W amp should, in that case, give the cab a far better run for its money.

Thanks for all the info...I had actually figured out eventually that the new amp I am looking into will be fine, but wanted to know more but impedance anyway!

4 ohm rated (solid state) amp > 8 ohm speaker is fine. Though as Pete says, you will not get all of the power your amp is capable of providing. That does not make it a bad thing though, as your amp is having an easy time.

 

Add a second 8 ohm speaker (in parallel) and the amp "sees" 4 ohms which is good. Now you're getting all the power the amp was designed to give. Each speaker only gets to use half of that power though.

 

Add a third 8 ohm speaker, and the amp now "sees" about 2.7 ohms which is bad. You're now trying to get more power out of the amp than it was designed to handle, so it will probably distort - even at very low volume, get too hot, and may let the smoke out. Or, if you're lucky, it may have some self protection built in and shut itself down.

This particular amp (Darkglass Microtubes 900) also has a 2ohm setting, so I'm guessing it should be fine whatever the load? (providing impedance doesnt drop below 2...which it never will in my case!)

The amp is rated to 900W 4ohm, and the cabs is 450W RMS 8Ohm...

So would that mean that essentially, the amp (at full whack) will be delivering 450W at 8ohms???

4ohm bass amplifier...

 

Valve with transformer output or solid-state?

Solid state

Morning all,

I've been sprawling the web and asking friends for an answer, but they are always differing.

4ohm bass amplifier into 8ohm bass cabinet...bad or ok?

And why?

Impedance has always confused me...is there a simple explanation out there?

Thanks