2 30W speakers in parallel - how many watts total?

[markmalin]

Probably a silly question.  I searched the site and found a thread refering to Duncan's spreadsheet, which I downloaded, but my question isn't how many ohms total, I'm wondering about the power rating of the speakers.  For example, do 2 30W speakers in series or parallel total a 60W rating?

Humbly...
Mark

[FYL]

Yes. Ditto for a series connection.

[markmalin]

thanks

[tubeswell]

But the power will be distributed according to the impedance of each speaker. If you have a 4r speaker and and 8R speaker, both each rated at 30W, then the 4R will 'see' twice as much power as the 8R.

[fud]

But the power will be distributed according to the impedance of each speaker. If you have a 4r speaker and and 8R speaker, both each rated at 30W, then the 4R will 'see' twice as much power as the 8R.

That's interesting.  So, in theory, you could balance the outputs of a high and low sensitivity speaker via impedance?  Like mixing an 8-ohm Greenback and a 16-ohm Vintage 30?  Obviously impedance matching with the OT would get tricky...

[jcm-jmp]

yes but the 8 ohm greenback is going to draw 2x the power from the OT as the 16ohm creamback will, meaning that the 8 ohm speaker will be consuming most of the power and doing most of the work. it will work 2x as hard as the other. the empedence will not be 8 or 16 ohms. It will set in the middle so the load reflected back to the power tubes on the primary side of the OT will not match the OT's rated primary empedence.

[tubeswell]

yes but the 8 ohm greenback is going to draw 2x the power from the OT as the 16ohm creamback will, meaning that the 8 ohm speaker will be consuming most of the power and doing most of the work. it will work 2x as hard as the other. the empedence will not be 8 or 16 ohms. It will set in the middle so the load reflected back to the power tubes on the primary side of the OT will not match the OT's rated primary empedence.

Yup in the 4R||8R example the total impedance is 5.3R. Mind you with a 1000:1 reflected load on your typical 6V6 or EL84 OT, a 5k load is quite a nice load, esp for fixed bias amps. I did a 5G9 with a OT 5K PrZ and a plate voltage of about 370 in fixed bias - sounds real nice.