Guitar amp/match speakers

I have a Blackstar HT5 (5 watt) head. I use it on a Eminence 1 by 12 cabinet and I like the sound. My question is what other speakers/set ups can I play the head with? I read on line people are using the HT5 with 4 by 12s and other configurations. Can I damage the amp or the speakers? I know enough that I do not want to use the amp with speakers that will not handle the wattage (with 5 watts that is not usually a problem). The amp on the back has the following speaker connections: 1 by 16 ohms 2 by 16 " 1 by 8 " Thanks, Wayne

Thanks, got to plug into a nice Marshall 4 by 12 very nice and loud. Actually like the sound of my Eminence speaker as well as the Marshall cab. Wayne

Cactus Music, Good information, I am of course interested in the sound and trying different cabinets. By the way it is a tube amp. Very important to me is if I will damage the amp or speakers by trying it out on different cabinets. Do you have any opinion on that aspect? Thanks, Wayne

Tube amps are more forgiving of impedance mismatching than solid state amps tend to be. 

With a solid state power section you most certainly want to follow the nameplate load ratings and never connect a load that is LESS then the minimum recommended load. It will cause damage to the power amp output transistors.

A tube section is less likely to be damaged in that way. I have run tube amps most of my musical life and have never destroyed one by running it unloaded or overloaded. It is best to match as closely to the recommended loads since that allows the amp to run in it's most efficient mode and deliver the best power and tone. 

Speakers: interesting topic.... since speakers come in all sorts of sizes, power ratings, impedances, and efficiencies.  It's best to match the power and impedances to the amp. Having said that, you can get tonal variations by mixing and matching. I would still keep multiple speakers the same mfg..... etc. 

there are no hard and fast rules.  But for a low powered amp I would be looking for the most efficient speaker since it will give the most sound volume with a given wattage applied to it. Efficient speakers just tend to sound better too.... Back in the day EV's were among the most efficient and they sounded good. I've used them in all sorts of things. 

match power to the speaker ratings according to the impedance. If the amp is 50w into 8 ohms... and you have a speaker setup to match, all is good.  

If you try to drive a large power rated speaker with an under-powered amp and are running it wide open, into distortion, you can actually damage the speaker thinking all is good and fine. In distortion... from the amp... the signal is clipped at the power amp (as opposed to the pre-gain stages)..this is true distortion. When that is occurring, the speaker cone has moved out as far as the signal has pushed it and now reaches the flat "clipped" part of the wave....and so it stops moving and sets still while current continues to flow in the voice coil.... this causes heat. As long as the cone is moving, the heat dissipates with air movement, but when the cone is still, no air, not heat dissipation and the coil can heat to the point of warping or burn out. 

In an opposite situation, that does not occur, with a 50w amp and a 30w speaker for example.... the amp has sufficient power to keep the cone moving with plenty of head room.... but the amp can blow the speaker from it's sheer power delivery capability. I have, however, run this sort of set up on stage in my various rigs, actually preferring it, and never had a problem blowing speakers. A little bit of common sense running this sort of rig and the speakers will last a very long time and sound good.

I had 2 cabinets....each had 4  30w speakers wired to 16 ohms, and powered by a 400w per channel stereo amp. (carvin DCA-800) while my Boogie was 22w with a factory speaker and pushing a cheap fender cab w/ 1 15"  (Jensen?) in it as a floor monitor at the mic stand. The boog was mismatched (tube section) and underpowered, but never run more than 4 or 5 on the master.... it was all pre-stage distortion, or clean guitar (country band) and the DCA-800 was solid state well above the minimum loads and the amp sides were dialed down no higher than 50%... the amp barely got warm. 

All that to say watch the numbers but experiment to see what works best. With a 5 watt amp, none of this is super critical. Find the tone you want and like and don't worry. 

There is no set of circumstances that suggest that having lower than rated impedance speaker cabs connected to any amp is anything like ok.