Buying used Martin Logan Theos?

[allisone]

Hi all, first time posting. I am finally in a place (life-wise and home-wise) to start putting together a home stereo system and am looking for some triple-checking of my math/specs to make sure what I'm doing will work.

The short version is that I heard a pair of ML electrostatic speakers about 10 years ago in a showroom and was floored by the imaging and clarity. Now that I'm ready to invest in a system, I've found a pair of used Theos speakers on Craigslist (original owner, had them for ~10 years, purchased from Stereo Exchange in NYC). I'm going to go listen to them this weekend, see if they match my memory. I am also buying a Sony STR-DA777ES receiver (circa 1999) from a friend. I won't be able to take the receiver to the speakers to test it all together before I buy, but the Sony *should* be beefy enough to power the ML's, I believe. The Sony puts out 120W at 8 ohms, 100W at 4 ohms. The ML spec is...

Recommended Amplifier Power	20‒400 watts per channel
Impedance	4 Ohms, 0.8 at 20kHz. Compatible with 4, 6, or 8 Ohm rated amplifiers.

Seems like the Sony lands in the right range, right? There's no different between, say, a 100W tube monoblock and 100W solid-state from the Sony. 100W is 100W, right? (not talking quality, simply compatibility).

I read on the ML owners forum that it's important to pick an amp that can handle the fluctuations in impedance load, and that the sign of a good amp is a doubling of wattage at the lower impedance... which the Sony does NOT demonstrate. However, Google seems to suggests (below) that the massive power supply of the Sony and it's protect mode would protect it from blowing up if I play dynamic music too loudly...?

The "Audiophile Approach": Because the build quality is so substantial, many enthusiasts run complex or varying impedance speakers on the 8 Ω switch position anyway, provided the room is well-ventilated. Leaving it at 8Ω allows the amplifier to leverage its massive power reserves to drive impedance drops seamlessly. However, if you listen at high volumes for prolonged periods and the receiver triggers its PROTECT mode, you should back the switch down to the 4Ω position. [1, 2, 3]

Any caveats/thoughts/suggestions are very welcome! Thanks in advance,

Alex

 

[Mikado463]

First off if the Sony receiver you stated actually boosts those specs it's a poor match for Stats. Rated power into 4 ohms less than 8 ohms ? As a general rule with stats and planners, is that a good amp has the ability to 'dbl down' (4ohm rating would be dbl that of the 8ohm rating) An electrostatic speaker is seen in a very capacitance load to an amplifier and I wouldn't be surprised if it could send that Sony into oscillation. I know you read all this in the ML forum but I needed to reiterate.

With regards to the Theos, 10 year old panels, if not properly cared for could very well be in need of replacement, not cheap, even though the Theos is an entry level hybrid stat.

Good luck, keep us posted !@

 

[allisone]

Thanks for this, Dave. Yeah, seems like I'm pushing the compatability of these two items a bit...

From what I've read, re: panel care, it's the high-end that goes first if not properly dusted and cared for, correct? Are there visual signs I can look for to determine how well they've been cared for, or is it just listening to them?

 

[Mikado463]

other than 'obvious' visual damage one of the first things you'll notice is the high frequency become 'muddled' and 'soft' as you so mentioned. If everything checks out, Imo you would be best to have knowledge of their replacement cost and work that into your negotiating play. Truth be told a well cared for and if they were in a good environment, 10 years is not 'that bad'

perhaps Brad will chime in as well. He's a long time Logan guy that he and I go back many years on the M/L forum together.

Also, 'JonFo' on the M/L forum is one of the most knowledgeable stat guys around, don't be afraid to reach out to him as well, a real gentlemen !

 

[Mr Peabody]

Keep in mind the 4 ohms is nombinal that will swing up and down with programming. The speaker you are looking is said to dip to 1 ohm or lower. If it didn't kill the Sony it would be in protection most of the time. At a minimum look at the Parasound INT 6 which is one of the more affordable options. Maybe a used Krell integrated if you can find one. One of the Pass integrated would sound beautiful, IMO and do the job. The amp will need to deliver a lot of current when called on. As mentioned the rating at 4 ohms should be double the 8 ohm rating and stable into 2 ohms.