KEF R700s and the VTL ST-85

To Doug Schneider,

I am keen on getting the KEF R700 speakers. However, I am not sure of what amplifier to use with it.

May I know if the VTL TL-2.5 preamplifier and ST-85 power amplifier will be suitable and compatible with the KEF R700? Do you have a better recommendation? Please advise.

Thanks and best regards,

I’m not familiar with VTL’s ST-85, but I did look it up on the company’s website to get more information. They rate it to deliver 60Wpc into a 5-ohm load in tetrode mode, but only 30Wpc into the same load in triode mode. I’ve never seen a power rating specified into a 5-ohm load (usually it's 8 ohms), so I found that odd. But odd or not, I wouldn’t be surprised if the R700s presented that kind of load based on our measurements of the R500. Nevertheless, the ST-85 isn’t a powerhouse, particularly in triode mode, so speaker matching is something to be concerned about because you don't want to drive the amplifier into clipping.

Whether or not the ST-85 will be powerful enough for the R700s will depend on your room size, how far you’re seated from the speakers, and how loud you like to play your music. It only takes a few watts to get appreciable output from speakers, but it takes much, much more to play very, very loud -- and even more than that if you’re in a larger-than-average room. I don’t know how any of this applies to you, so it's hard to give you a definite answer, but I will say that if you’re in a modest-sized room and like to listen at moderate volume levels, the ST-85 will likely be okay. But if you’re in a very large room and/or you like to really crank the volume up, you might find that the ST-85 isn’t powerful enough and you might have to look at something else. . . . Doug Schneider