McIntosh & Wilson: 4 or 8 ohm taps?
 

Question for those of you that have powered Wilson speakers with McIntosh amps. What autoformer taps do you use? 4 or maybe 8? On paper, 4 is the obvious choice, but I’ve always felt the 4 ohm taps never sounded correct.

Sashas are what I’m experimenting with.

Wilson and mcintosh (and audio research for that matter) all recommend 8 ohm.

I drove my Sasha 2’s from the 8ohm tap of my 601s when I had those amps and that sounded the most correct to me.

George

8 ohm tap gives a little more top end focus and punch.

4 ohm tap is fuller with better overall balance.


IMHO

I used the 4 ohm tap on 601’s and 2301’s with my Sophia 2’s.

Keep in mind when changing taps from 8 to 4 ohms you have to up the gain in your preamp 3 dB to get close to the same level. If you don’t do that the 4 ohm tap will sound dull and lifeless.
Tom

I think it's important to match the tap to the impedance of the speaker listed in the specifications. This is what McIntosh recommends. Most amps are built around one "tap". Some amps have no 2 ohm specification for output. It's all about current and stress on the amp caused by the amps inability to supply the necessary current to produce the watts. Asking an amp to supply current for which it cannot easily supply places stress on the amp and the sound quality will suffer. No two Mac amps are the same in this regard. The smaller the Mac amp the more you need to pay attention to careful impedance matching.

Were speakers actually 2, 4, or 8 ohms this would be a good rule of thumb. However, since we are talking impedance, not simple resistance, and since loudspeakers vary in impedance with frequency, you cannot count on the speakers manufacturer's stated impedance to be the best tap choice. The tube configuration/transformer windings are not the same amp model to amp model, amp manufacturer to amp manufacturer. So some speakers end up on different taps than "spec sheets" would suggest because those "wrong" settings are actually the correct settings, both technically and sonically.

VAC has a nice technical paper ( Can I link a white paper Ivan?) that helps to explain to the layman why the "which tap" answer is variable and not so cut and dried.

+1
Great explanation Bill.

Agree. But I do think that what I said is a good place to start. And I think your amp must always have sufficient current to easily supply the needed watts. One thing is sure: it is amplifier stress that degrades sound. I don't ever want my amp stressing to supply current. I personally heard a Mac integrated (8 ohm tap) connected to an Alexia version 1. The bass was bloated and uncontrolled. Dealer corrected it and bass went from poor to excellent. It also helps very much to know the impedance vs frequency response.

Great info everyone, thank you. Given that Sashas are a popular speaker and newer McIntosh amps are also very common, is there a recommended starting point from Wilson? For example, B&W says to start with the McIntosh 8ohm taps for their 800 series speakers.