Amp and Speaker Impedance Mismatch

[MJP]

Output Transfer impedance = 8 Ohm (no 16 Ohms)
My Altec Impedance = 16 Ohm.
Based on your actual listening experience (no mathematic), what is the sound will be comparing to the matching case?
Please advice.

[martyh45]

Tube amps are different than solid state.

The power will not necessarily be reduced by half if you double the load. There are allot of variables so it would be hard to know exactly what it will sound like without hooking it up. In general, the AE-25 is a type of circuit that is more forgiving of impedance mismatching than some others. Cary output transformers are generally high quality which should also help. They are a reputable company so if they say the amp will work with your speakers, I would tend to trust their judgment.

[donaldpatten]

I will guess you have an amplifier rated to deliver some ? watts ,say 100 watts into an 8 ohm speaker. Even if 8 ohms is not stated it is the standard way to test and specify power. With your ALTEC 16 ohm speaker , you will get half that power , 50 watts for example. This is a 3dB difference , and is audible if you listen at maximum power. If you do not drive your amplifier to distortion ( clipping ) ,you will not hear any thing different. Lucky you have ALTEC speakers as they are more efficient than other speakers. So your ALTECs will sound louder and cleaner than most other 8 ohm speakers.
Don

[MJP]

Thank you DON for the reply. I am going to buy Tube Amp (Audio Electronic Supply) AE-25, max output transfomer is 8 Ohms. The power is around 15-30 Watts (depend on bias adjustment). My altec is 16 Ohm impedance.
I get to worry about the sound. I thanks to your reply that describe to me and make me more understand. AES replied me that with AE-25 (by CARY) all power amp will sound excellent to the speaker imdeance range from 4-17 Ohms.

[GM]

Greets!

Hooking up a 16 ohm driver to a tube amp's 8 ohm tap will double its DF, so while its peak average power rating is lower, its voltage sensitivity will be higher, making for a better damped, more dynamic system with lower distortion due to lower thermal losses from lower current draw. Considering the in-room efficiency of a typical Altec system, it seems like a 'no-brainer' trade-off to me, but as always YMMV.

GM