SET amp recommendation

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Yet another thread with too little information.......

You had a 50 watt SET so I'm thinking a 1 Watt SET might not work well for you but just a guess with so little info.

What speakers do you have, how efficient are they, what kind of music do you listen to, how loudly do you listen?

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You don't really have an SET friendly set up at least for your typical 2.5 watt 2A3 or 8 watt 300B amp. Doesn't your speaker manufacturer recommend at least 50 watts?

If your speakers are 91 dB 4 ohm and you multiplied it up to 12 ohms the trade off is you get less power delivered to the speaker. The maximum voltage output of the amp is what it is but the autoformer divides this down so less gets to the speaker.

Fine if you have power to spare but starting with a low power amp and a medium sensitivity speaker you do not. I don't see any advantage to the autoformer if you choose a tube amp that has a 4 ohm tap.

Certainly no harm in trying.

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If the 12 ohm load of the zeroformers remains relatively flat a 300b amp would love this load.

As long as you can live with the loss of power. I believe these calculations are correct.

from 12 to 4 ohms is 3:1 for the impedance ratio

take the square root of 3 to get the voltage ratio = 1.7

If you have an 8W 300B amp you have 8V at the 8 Ohm tap (8V squared divided by 8 ohms = 8W)

divide that 8V by 1.7 to get 4.6V which will get you a little over 5W max.

maybe, but that's not a lot to drive a speaker with a recommended power of 50W.

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