NAD M25 will it power ESL Reserve?

[snyderkv]

MLO,

Sorry if this is another "can this amp power that" thread, but I'm just purchasing an M25 on Audiogon and realized that nobody on MLO is using these to power their electrostats from what I can search.

I'm looking at buying Montis or Ethos. I thought since the manufacture website said 100-200 and into 2 ohms, that I was safe but everything I see in the amp section of this forum has Krell or something double the price or watts.

I thought they were more efficient than say a Theos since they have powered subs.

Please give advice on whether or not the NAD M25 will power these ESL Reserve series electrostats with overhead.

 

[JonFo]

That NAD will have the 'nads necessary to power a Theos or Montis with decent authority.

Since those models have their own bass amps, the NAD channels would only be powering the panels. So the load will be reasonable.

I still prefer an amp that can double it's 8 ohm rating into 4 ohms, but the NAD has always had decent power reserves and serve up good amperage into low impeadance loads like our ML ESLs.

 

[edwinr]

Be careful using later NAD products at the moment. While the manufacturer rates their amps into very low impedance loads, there seems to be a problem when they're asked to drive electrostatics. I've tried a couple of NAD amps recently and they all want to shut down even when listening at moderate levels. There even seems to be a problem with the C275BEE power amp!

My issues have been referred to NAD in England who are currently testing their amplifiers with Martin Logan speakers to see what the problem is - early thoughts were that there might be an issue with the protection circuitry design.

In saying the above, the NAD amplifiers I have tried have fabulous sound quality. I'm sure NAD and ML will be a great match when they sort the problem out.

 

[snyderkv]

Edwin,

Thanks for the response, both of you. But I want to ask when you say "later" models, does that include the Master series? Is the M25 the one you had trouble with specifically?

I ask because I have a buy order in place for one and only a day left to place the order. Is it possible that the circuitry can be updated via firmware updates or would we have to wait for a new model? I'd hate to drop the buy order form this guy. it's kinda rude.

 

[snyderkv]

I just registered with NAD and posted the question on their support page. The M25 has been out for years, surely someone would have had said something a long time ago.

 

[JordanD]

Hmmm I dont have any useful info, but maybe talk to NAD directly and see what they think? Also I am sure if you talk to your seller for the NAD and let him know that youre trying to sort this out first he may be willing to give you a little bit of time to figure it out.

 

[edwinr]

snyderkv, you're right about the Master series. Any problems driving difficult speakers would surely have become apparent by now. I believe NAD's current amplifier models like the C275BEE and the new T series of receivers are based on the more expensive Master series designs. Perhaps something was lost in the translation when NAD introduced the new receivers.

 

[snyderkv]

I wonder if the issue can temperarily be solved by enabling the soft clipping feature? This prevents dynamic spikes. Ofcourse the system won't be as dynamic but wonder what the actual human audiable difference would be?

Anyways, just baught the M25 and deciding on purchasing a pair of Ethos. I guess I'll be the one answering my question. I'll update this thread eventually

 

[snyderkv]

I received an answer from NAD. In a nutshell, the M25 will handle ML Electrostats and are stable to .5 Ohms by design but I'm sticking with the Ethos due to the smaller load .8 Ohms.

re: M25 can it power ML Electrostats?
Dear K,

The problem with electrostatics is that they have a very low impedance (caused by high capacitance – the bigger the panel the higher the capacitance and lower the impedance) at very high frequency.

Montis = 0.52 Ohms @ 20kHz
Ethos = 0.8 Ohms @ 20kHz.

All NAD amplifiers are stable to ½ Ohm by design.

And fortunately there is very little musical energy at 20kHz so there is not much power draw.

Things to watch out for:

Using speaker cable that also has high capacitance – coaxially braided cables often exhibit this characteristic. Add this in series with the speaker and the impedance will be even lower.

Using source components with poor digital filtering that could have significant HF output of the sampling frequency. This isn’t an issue with properly designed products, but some high end designs do goofy things with filters trying to get different results.

The C 275BEE was either a) arcing the electrostatic element because volume was too high (very bad for speaker, you want the amp to protect) or b) being run in bridged mode. In bridged mode 0.5 Ohms would trip the protection.

I also think grounding of the entire system could be critical. You want to keep ground for all components as close to 0 Ohms as possible. Plugging the ML’s stator supplies into the same circuit as the M25 would be a good start. The ML supplies draw very little current (but the M25 is another story!) The powered subwoofers are another potential problem as they use Class D amplifiers which typically generate a lot of noise back into the AC circuit. Using high quality AC Power Conditioners can be beneficial. Be sure the model you choose does not float the ground, you want a ground path to earth (via the grounding pin of the AC receptacle).

I hope this information is help with your purchasing decision.

 

[rubyrod]

Didn't work for me

I have a pair of martin Logan aerius and stopped using my nad m25 because it would constantly shut down listening at moderate levels. Swapped my Aragon 2004 and never happened again.

 

[snyderkv]

I have a pair of martin Logan aerius and stopped using my nad m25 because it would constantly shut down listening at moderate levels. Swapped my Aragon 2004 and never happened again.

This is such an old thread that I've learned a lot since I wrote this. I'm now powering my Martin Logans with integrated AVRs with no problems.

The expensive and powerful amp requirement is a common bandwagon fallacy or consensus fallacy. Martin Logan even states you can drive these with 8 Ohm amplifiers if not driven beyond their capabilities.

http://www.youtube.com/watch?feature=player_embedded&v=eWCI4GqjVf8#t=127

Your M25 was probably defective. I had no issues with either the lower 975 model, Emotiva and even NAD and Onkyo 4 Ohm integrated. I switched between all of these and sound quality is indistinguishable. I have now lowered my electric bill big time by going integrated as well as cleaned up the place aesthetically.

 

[TomDac]

Driving a pair of older ML's such as the Aerius the previous poster mentioned is WAAAY different than driving a pair of newer ones.. There is no fallacy... Newer ML's are much MUCH easier to drive - plain and simple.