Quote:
Originally Posted by Bombadil
I was hopeful of getting a bit more information.
There is no way a SE tube amp can deliver the same amount of power from 2 ohms to 20 ohms. Nor will it be as linear over such a wide range of impedance.
This is why many tube amps provide multiple taps.
Look at Stereophile tube amp measurements. They vary wildly into different loads. For example they tested the Cary CAD-805RS single-ended amp with 845 tubes. At 3% THD they measured a max of 13 wpc into a 4 ohm load and 31 wpc into an 8 ohm load, both of these were measured with 10db of feedback.
When set to no feedback, they measured 10 watts max power into 4 ohms.
Note that Cary advertised the CAD-805RS as being a 27wpc amp.
So this Cary SE amp produced more than double the power into 8 ohms. They recommended using the amp with high impedance, high efficiency speakers.
|
From Dennis just now, "To answer the output impedance question …. Nominal output matching impedance design center is 9 ohms on most Inspire amplifiers."