4 ohm speakers with amp rated for 8 ohms?

if you use a 8 ohms instead of a 4 ohms, the output power will go down .... 88.88%if you use a 4 ohms instead of a 8 ohms, the output power will go down .... 88.88%the speaker should stand the amplifier power otherwise turning up the volume will fry the speaker.

Personally, I would keep using the Dynaco equipment. 

It's still very good stuff. 

(I own a 120.) 

As long as you don't crank the volume too high, 

using 4 ohm speakers should cause no problems. 

In case you didn't know or forgot, the optimum load for the Stereo 120 is 8 ohms. 

I would find it hard to believe your 4 ohm speakers have hurt it over the years. 

I let my son use my AR-3A speakers with a cheap amp.  Burned out the tweeters.  Amps that are are compatible with 4 ohm speakers will say so in their specs.  They tend to be a bit pricy.

You should use at least 8 ohm speakers. The manual wouldn't say that if 4 ohm speakers were okay.

Yes, you could damage the receiver. How likely it is that damage occurs is impossible to say.

You will probably get away with it.  Especially at modest volumes.

If you play it loud, you might trigger the protection circuits.