Unmatched Impedance on my Studio .22+?

[tidymilk]

Hello all. I picked up a mid 80's Studio .22+ today at my local music store. I played it at the store and really enjoyed the tones, and took it home for a good deal. Upon reading about some of the various issues that these amps are prone to, I decided to take a look closer at the amp to see if anything was out of place/ looked off.

And then I noticed, this thing has a f****** 16ohm celestion in it! How does this thing still work? Shouldn't the output transformer be close to failing with a load like that? Im very new to tube amps. Should I immediately switch out the speaker on the inside? For reference, it appears to be a very old celestion g12-65 speaker.

 

[Markedman]

Not a problem at all. The other way around would be a possible problem at high volume. 8 ohms into 16 actually is kind of good for tube life. The Mark IIB owner's manual recommends using the 4 ohm jack into an 8 ohm speaker.

From the Mark IIB manual - "With 60 watts models, plug the single 8 ohm speaker into the 8 ohm jack for the most power and clarity. If two 8 ohm, speakers are used, plug each one into a 4 ohm jack for proper balance. But you may also try other combinations if you want one speaker slightly louder or happen to prefer the tone caused by a slight mismatch; it will do no harm to the amplifier. With 100/60 watt models we recommend that when you run a single 8 ohm speaker you use the 60 watt position and plug into a 4 ohm jack. This will give the strongest possible output without damaging the speaker. You may get more clean power by switching to 100 watts, and still more by also plugging into the 8 ohm jack but remember to avoid lead tone distortion as it increases power dramatically (though not so much the apparent loudness) and may cause speaker damage."

 

[Don]

The Mark IIB owner's manual recommends using the 4 ohm jack into an 8 ohm speaker.

The Mark IIB manual recommends using the 4 ohm jack with an 8 ohm speaker when using the 60 watt position because you're then using 2 power tubes instead of 4 and the 4 ohm jack becomes a correct match for the 8 ohm speaker.

In any case, using the 8 ohm jack with a 16 ohm speaker is probably okay for the Studio .22+ and the old Celestion G12-65 is an awesome sounding speaker!