Tube vs SS for Tannoy Prestige Dual Concentric speakers

[Arkless Electronics]

Radford are indeed one of the best valve amps technically and on measurements. They are one of the few valve amps with truly adequate DF, along with some EAR amps. The Mullard 520 design also has good DF for a valve amp if done right.
A SS amp will easily beat any of the above for DF though. DF's in the 1000's are possible, if irrelevant. Some SS amps, notably Naim, put a resistor at the output which in the case of most Naim amps means a maximum DF of 16 with a 4 Ohm speaker.....

[User211]

Post 48 of this thread shows the practical effect of changes in amp DF on planar magnetic headphones.

Good post and goes a very long way towards explaining why I heard close to zilsch difference I reckon.

This seems a good post too, found on an Apogee forum from years ago.

"With planar loudspeakers, the mass of the drivers are equally as important as the mass of cone drivers, but that is just one small part of a larger equation that holds the siginificance. Along with the mass of the drivers comes the strength of the field or the magnets that becomes the damping factor to the planar speaker.

When you place even the most ideal acoustic suspension dynamic speaker into a real room you change the frequency response of the whole design dramatically so all of the 'perfect' calculations are thrown off. But whether you change for the betterment of sound or worse, you're not stopping the back wave. You are simply damping the drivers' movement both outward and inward at a known pace to control how hard they work. With a planar speaker, you're not controlling the damping with air. The air offers a known quantity of resistance but you're not loading an enclosure to use air in this manner. Rather, you're controlling the field where the panel resides, or the level of magnetism for a ribbon, etc.

This is similar to changing gear ratios in a car. Should you have a standard gear box, this is like multiple taps on your amplifiers' output transformers. Changing the ratios will also offer an effect similar to changing the apparent volume of a dynamic enclosure, or increasing or decreasing the voltage of a field or the Oersted flux of the magnets you use in a ribbon design."

[User211]

BTW I did PM Jerry. Mind you, I asked him about it before and not much interest was shown.

[Macca]

Radford are indeed one of the best valve amps technically and on measurements. ...

And one of the best sounding valve amps too. What a coincidence!

[Radford Revival]