This can be an amplifier problem as well. With many amplifiers, the distortion goes down as the output power is reduced- but only to a point. Below that point the distortion starts to go back up.
This occurs at different points with different amplifier designs and also with different power capabilities- the more power the amp can make, the higher the point where the distortion 'turns around' and goes back up.
For example with many amplifiers of about 120-150 watts this point might be at about 5-7 watts- just the point you are using at lower power levels.
With increased distortion comes less detail and a less musical presentation. |
Broadstone, that is true to a certain extent but should not be held as gospel! Generally speaking though, Martin Logan speakers are tricky for any tube amp due to the low impedances of less than 1 ohm at high frequencies. Quite often though they can be solved with a set of ZEROs ( http://www.zeroimpedance.com). |
Broadstone, from the sound of it all you have to do to confirm or deny my theory is to hook up your integrated amp. With less power, you will be pushing it harder and likely not using it in the lower power region. Try it and see if your low level detail is restored. If not then we need to look at other possibilities. |
Well, you may not have enough power at higher volume levels... |
You are quite welcome.
Should I point out that tubes have a reputation of doing low level detail better than transistors? The more resolution you have (and ESLs have a lot) the easier it is to hear this.
However since you have Martin Logans, in order to get a tube amp to play them right, a set of ZEROs (www.zeroimpedance) is advised. This will allow a tube amp to deal with the near-short impedance that occurs at high frequencies in the Martin Logans. |
^^ No. I don't know of an output transformer that is designed to handle a 0.5 ohm load!
Fortunately this impedance occurs at about 20KHz, so there is not a lot of energy involved. But if you are using a 4 ohm tap on the amp to drive the speaker, the feedback needed to cause the amp to give flat frequency response might be insufficient. The ZERO solves that. |
^^It might be, but when you use the 4 ohm tap of most tube amplifiers, the output transformer often has a loss of bandwidth at both extremes and some are better than others. The ZEROs take care of that problem by allowing you to use a higher impedance tap where the transformer is more efficient and the amp makes less distortion.
While fundamentals of instruments don't go that high, harmonics of them certainly do. |
We do have customers that have had Martin Logans and our amps for extended periods- one guy still has the same speakers (CLS2s) and a set of MA-1s built in 1990. So you can use OTLs.
Paul Speltz, who makes the ZEROs, has a letter from Steve McCormick that states that his solid state amps sound better driving 4 ohms through the ZEROs than they do direct, and Steve's amps drive 4 ohms without difficulty.
IOW even solid state amps make more distortion when driving lower impedance loads (this can be seen in the specs of any solid state amp), so the ZEROs can be used to reduce that distortion. Since the ear translates distortion into tonality, the result should be smoother sound. |
Listening is the best means. The use of the ZEROs should not represent a compromise to the tonality of the system. |
Since you have a solid state amp that does OK on the speaker right now my first inclination would be to simply go with the 2X multiplier tap, IOW 4 ohms. |
Broadstone, according to what I have heard, it should also sound generally smoother without loosing any detail. |
A super tweeter is one that operates at about 10KHz and above. A regular tweeter might only roll in at about 2KHz or so. |
Piezo tweeters usually don't need a crossover- you can just hook them up. Check with the manufacturer to be sure.
You may need some kind of level control to tame its output. |
Phase is tricky! We can't hear phase on simple tones like a sine wave, but we can hear it in a spectrum of frequencies. Our ears use phase to construct the sound stage. If phase is altered, it can also be interpreted as tonality.
I had this demonstrated in spades years ago when I was trying to find why a phono section was sounding bright. It turned out that the manufacturer had abandoned the RIAA curve at frequencies above 50KHZ- well above human hearing- but the phase shift that resulted sounded like brightness. The fix was to restore the RIAA curve even though the preamp hardly had much bandwidth above that!
An EQ unit between me an the source would be one of the things I would look at eliminating if low level detail in the system seemed to be lacking. There are often other ways of dealing with hearing loss. |
Adding a super tweeter would be another method. |
Hi Atmashphere, Electrostats that are not direct driven already have a transformer to step up the voltage built in. Would it not be better to replace the transformer in the speaker with one that raises the impedance, than to add a set of Zero's? Certainly- if it can be done. Broadstone, just in case- air molecules cannot be 'charged' at GHz frequencies... actually that sounds kind of dangerous, like being in a microwave oven. |
