@mijostyn +1: A 7 watt SET amp has a really limited dynamic range unless you have Klipschorns (100db sensitivity). To hear an appreciable increase in loudness with the Sabrina's an amplifier of at least 70wpc is required. 10 x the wpc = twice the perceived loudness.
300B SET Amp driving Wilson Sabrinas
Interesting experience to share.
In my home system I have a pair of Wilson Sabrina speakers normally driven by a Modwright KWA 150SE (Special Edition). On a lark, I replaced the Modwright with an Elekit 8600S 300B amp (Lundahl output transformers and Mundorf Supreme output capacitors) I had in another system.
The surprise, not only did the Elekit drive the Sabrinas very well (improved clarity and tonality), but at the same volume with the same input level as the Modwright! Using a passive preamp, when I set the volume knob on the preamp to the same point for both the Modwright and the Elekit it results in essentially the same volume from the speakers.
Admittedly I listen at moderate levels (SPL rarely exceeds 70dBA), but the sensitivity of the Sabrinas is only 88 dB. Who would have thought!!
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Most people that say that won’t work have never hooked up SET to non efficient speakers. I have hooked up my Magnepans to my 807 monoblocks at 13 watts and because the Maggies are a stable 4 ohms for some reason it just works. Right now I’ve loaned my 807’s to a friend that has very inefficient Ryan speakers. He has several higher powered amps and the 807’s have not left his system. |
This is another good example of how a mismatched amplifier and speaker "will work" and even sound OK but you are not hearing the speaker sound the way the designer intended. Looking at the impedance curve (thanks @vonhelmholtz ) the Sabrina is a very difficult speaker to drive. It is a classic example of a speaker that needs a robust amplifier to sound its best. It should be driven by an amp that can double its output with each halving of the impedance - a feat that your 300B amp cannot do. The result of this mismatch is that the speaker will sound weak in the bass. In other words, you are introducing an unintended tone control into your system. Your Modwright isn't specified into 2 ohms but it does provide good power into 4 ohms. However, it doesn't look like it was designed to power a difficult speaker like the Sabrina. BTW, you never see a pair of Wilsons at an audio show being driven by a low wattage tube amp. Most often it's a D'Agostino amp that puts out huge current at low impedances. Apparently this setup sounds OK to you and the altered frequency response may be a better fit for your room acoustics or perhaps it better conforms with your taste in sound. If possible I would recommend that you try an amp that is rated to 2 ohms (something like a Krell, Pass, or Levinson) and see what it sounds like. Maybe you won't like it but at least you could hear your speakers sound the way the designer voiced them. |
It's baffling that in this hobby so few people understand what speaker sensitivity actually means. They just take what's fed to them by reviewers or other opinions and regurgitate it when talking about speakers and how sensitive they are or are not. Someone once said something along the lines of, better to keep your mouth shut and be thought the fool than to open it and confirm the thought. Then again, those that continue to spread the nonsense, think they're right. |
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