Magnepan 20.7's & Tube Amp

I Just spoke to Wendell Diller at Magnepan and reducing the speaker cables has zero affect unless your running 15-20ft of cable. I don't know why we get all this misinformation on Maggies.

We've built short speaker cables for a number of our customers who are really happy with the results. I would not want to cut an $8000 cable either!

But the difference was not trivial- shorter cables really help if you are running tube amps.

Ralph, is the need for the very short speaker cable unique to the planar/OTL combination or long cable inherently causes low frequency roll-off? I didn't think the cable length should be that detrimental given a 1.75 ohm output impedance on the MA-2.

The issue is that tube amps generally speaking have a higher output impedance than solid state. When you add a long speaker cable, the cable is a series resistance added to that of the output impedance of the amp. It may not seem like much, but fairly small resistances like that can have a big effect when the impedance of the speaker is already pretty low.

(This is one big disadvantage of 4 ohm speakers- the cable becomes really critical! You also have to make sure your connections are good and tight.)

So the simple solution is to keep the speaker cable short. I really don't think it makes a difference what tube amp is used (as long as it make a satisfying amount of power)- the speaker cable should be as short as it possibly can to make the connection. I think a foot is about as long as you want. I've heard this make a profound difference in the bass impact on several different Tympanis, MG3s, 20.1 and 20.7.

We use 10Gauge copper OFC speaker cable, using both conductors joined together at both ends by a single heavy speaker lug.  So we have to build up four such jumpers but it really pays off.

A Big high current solid state amplifier would have much better grip, control On the Panels.

I don't find this to be the case. What seems to be happening is that the lower output impedance of higher powered solid state amps allows more leeway with the series resistance of the speaker cable. We've been running fairly high output impedance amps on Maggies for decades and they seem to 'control' the panel just fine with plenty of bass impact. So I regard this as a common myth, caused by a misunderstanding of how critical the speaker cables become when you run 4 ohms and use tubes. Put another way,  if you compare a tube and solid state amp on the Maggies and you also have longer speaker cables, its likely the solid state amp will have more impact. But if you use really short cables the differences between the amps will be less profound. 

Ralph, wouldn't a set of Zero Autoformers be of help?

The MA-2s don't care, but on a lot of amps, yes. We are in Magnaplanar's back yard up here in the frozen wasteland, so we have a good number of local customers running M-60s on some of the smaller Maggies, and the ZEROs are how they do it.

Paul Speltz has a letter from Steve McCormick in which Steve states that although his amps have no problem doubling power into lower impedances, that they actually sound better if they are driving 4 ohms through Paul's autoformers (the ZERO). So the ZERO's help with a lot more than just our amps.

which one has more amps into 4 ohms?

This is a bit of a trick question.

The amount of current will depend entirely on how much power the amp makes into 4 ohms. If 200 watts, the current will be 7.07 amps regardless of the amplifier involved, tube or solid state.

Wendell Diller always made a point of telling me that the best he every heard that speaker was at Johnathan Valin's house using a set of our MA-2s. What we found with Maggies in general is that if you want to play the speaker with tubes, keep the speaker cables between the amp and speaker really short- over a foot is too long! Place the amp with the speaker terminals facing the speaker's terminals and install the really short speaker cables.

This is a really good place to have monoblocks :)

Anyway, this gets you the best bass. Don't worry about vibration from the speaker; the amp will see very little. Maggie owners know what I'm talking about.