Audio Research and Martin Logan Montis
I would be wary of any tube amp with these speakers to make them perform at their absolute best. As at 4khz they give a nasty 3ohms and -55 degree phase angle. Which would be more like a 1-2ohm load as seen by the amp. An amp that "almost" doubles it's wattage for each halving of load impedance down to 2ohm would be the amp to look for. EG: 8ohms - 100watt 4ohms - 200watt 2ohms - 400watt http://www.stereophile.com/content/martinlogan-montis-loudspeaker-measurements Cheers george |
All I can say to that is, "why do all equipment manufactures strive for a flat response?" And give +-db frequency response measurements points in their specifications? If they wanted to have it altered all over the audio spectrum because of external loads, they wouldn't be bothered to list those specs to start with. Need to look at the graphs closer, as the Montis is the harder load as it's bad phase/load point is at 4-5khz (the presence region), the Prodigy is up much higher at 7-10khz, as for the rest of it down low, it is a benign 4-6ohm load, with no - phase shifts to add to it. Cheers George |
03-06-15: Zd542 Well your not listening to a flat frequency response, it like having a fix tone control embedded, + - 4db from 20hz to 20khz As for the Prodigy, it too has an evil load, of -55 degrees with 3ohms, but it's further up around 7khz. http://www.stereophile.com/content/martinlogan-prodigy-loudspeaker-measurements As for Bfin3 Spire's there is no load v phase angle graph done on these, so who knows. Cheers George |
Zd542 This is the kind of non linear frequency response that may happen with a tube amp at 4.5khz with the Montis, -2db!!! because of it's -55 degree phase shift and combined 3ohms load, because the amp can't deliver current. It has nothing to do with wattage! It's all about current. Not very flat is it? http://www.stereophile.com/images/archivesart/A88FIG01.jpg Cheers George |
Zd542 The Montis is a harder load at 4khz. than most other ML's I'm not saying good tube amps won't drive them Zd, and they may sound very good. But if you want to get 100% drive capability and sound out of them then tubes will struggle a little at the presence region of 4khz as I outlined above. Frequency (Hz) Octave Description 2048hz to 8192hz 8th to 9th octave. Gives presence to speech/music, where labial and fricative sounds lie. Cheers George |
Bfin3 It may sound very good with your 80w tube. But with this statement for the measured Stereophile tests, it maybe not at it's "best" with tubes. "Stereophile: Either way, that this speaker is a difficult load for the partnering amplifier to drive is compounded by the high electrical phase angle. The shape of the impedance trace will result in the Montis's top octaves shelving down when the speaker is driven by a tube amplifier having a high source impedance." Cheers George |
