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Using tube amp with electrostatic speakers.

Moons ago I started similar discussions and thought I had been given enough good advice not to approach the subject again. Here goes anyway. I've used Martin Logan electrostats for well over 30 years with quite a few different amps but have recently switched to a tube amp and dynamic speakers with which I am very satisfied.  It consists of the Cary Rocket 88R amp and Serie Reference 3 speakers. 

My brother was visiting last week and was so impressed with the sound that he decided that he might want to try a tube amp also (probably the same one as mine).  However, he is using a pair of SL3's that I gave him years ago and I'm concerned primarily about the current requirements of the Martin Logans as well as other concerns that I'm not thinking of.  I don't want him spending money on something that may not bring him improved sound so would appreciate more advice to pass on to him.  He currently uses a Rogue Audio SS amp with his SL3 speakers and, to me, it sounds very good. 
jimbreit
atmasphere's avatar
atmasphere
11,849 posts
 
@lewm 

Yes, the tricky bit is that the transformer impedance increases as frequency goes down. So with a given capacitance with increasing impedance, the crossover point moves lower- there is no set crossover point! This is why the resistor is there, so that the crossover point is not a moving target- the resistor dominates the formula of the -3db point. Removing it theoretically would open the transformer up to saturation caused by too much bass, but in practice I've not heard of that happening.

At any rate Dr. West seems to have it sorted with the newer Toroidal 2 version, and thanks goes to you for pointing out the problem with his simulation from years earlier.
gwho
47 posts
 
atmasphere

Thank you for this explanation as it gets to the heart of the matter.  I just want to make sure I understand this correctly.  What occurs to the sound of the speaker when the transformer saturates or begins to saturate?  Is transformer saturation a voltage or current issue?

Are you saying:
1. That the resistor is not needed for either the Toroid l or Toroid ll?
2. That the concern of transformer saturation does not occur (at higher input signals) because:
     a) at higher frequencies the music power requirements are typically not high (so the Toroid will not/does not saturate); and    
     b) the Toroid impedance increases at lower frequencies to a level that the Toroid cannot saturate even with a higher voltage signal (in other words the Toroid by it's impedance nature is self-limiting to prevent saturation?).

Regards,
Gary
atmasphere's avatar
atmasphere
11,849 posts
 
What occurs to the sound of the speaker when the transformer saturates or begins to saturate? Is transformer saturation a voltage or current issue?
Distortion- Its pretty obvious. Its a power issue- both current and voltage (of which neither can exist without the other).

Are you saying:
1. That the resistor is not needed for either the Toroid l or Toroid ll?
Not needed for the Toroid 1, needed for Toroid II

2. That the concern of transformer saturation does not occur (at higher input signals) because:
    a) at higher frequencies the music power requirements are typically not high (so the Toroid will not/does not saturate); and    
    b) the Toroid impedance increases at lower frequencies to a level that the Toroid cannot saturate even with a higher voltage signal (in other words the Toroid by it's impedance nature is self-limiting to prevent saturation?).

We're talking here mainly about the Toroid 1:

Bass energy can saturate the core of the part, because it was built with intention to optimize higher frequency performance. In practice it does not saturate with low frequency energy simply because its impedance is so high at lower frequencies (and there is a capacitor in series with its input) that most amps can't make any power at those impedances.

The Toroid II:

The crossover of the resistor and capacitor prevent lows from entering the input of the transformer; otherwise it too would saturate because its core is too small just like the Toroid 1.
gwho
47 posts
 
Atmasphere,

Thank you very much for that explanation.

Best Regards,
Gary
milt808
4 posts
 

HELP?

In your opinions, would a pair of Balanced Audio Technology (BAT) Rex II mono blocks be powerful enough to make the Martin Logan Neoliths sing?

I'm currently using a pair of Krell 575 mono blocks, which is powerful enough, but I'd like a warmer sound with more harmonics. I mostly listen to old standard jazz LPs from 50's to 70's (at night club sound level) and smooth jazz CDs (at concert levels).

BAT: 

 

Neolith: 

 

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