Classic 9 amp consideration: Sanders vs Anthem

[Tmort]

I have an Anthem MCA 225 mk2 amp running my classic 9’s in a bi-wire configuration. Sounds pretty damn sweet honestly, but you know how it is…
The Sanders Magtech amp claims to be the end-all of solid state amps for our beloved electrostatics, anyone have any experience comparing these two power sources? They seem to be available out there at a somewhat reasonable price.

 

[Rehan Azim Hashmi]

I have an Anthem MCA 225 mk2 amp running my classic 9’s in a bi-wire configuration. Sounds pretty damn sweet honestly, but you know how it is…
The Sanders Magtech amp claims to be the end-all of solid state amps for our beloved electrostatics, anyone have any experience comparing these two power sources? They seem to be available out there at a somewhat reasonable price.

A very useful concept or idea put forward by Leporello. I will explain with an example.

Anthem MCA 225, if you read the manual, max power output single channel driven is 550 watts @ 2 ohms. If we consider both channels driven simultaneously this measure is lower, namely, 370 watts @ 2 ohms.

After firmware upgrade, numerically STR integrated volume ranges from -96 dB to +7 dB. In my medium sized room listen to Audirvana radio at -17db, Max amp volume is 7 db. If we consider the net reduction in volume in dB is 24 db. Then power output of power amp is reduced by half 8 times. 24/ 3 = 8.

In stereo watts this is

360, 180, 90, 45, 22.5, 11.25, 5.5, 2.75, 1.4 watts @ 2 ohm.

7, 4, 1, -2, -5, -8, -11, -14, -17db.

While listening through CLS, amp volume level is -17 dB or 79 dB ( Audirvana radio). Power in watts required from Anthem STR and nearly identical power amp section of MCA 225 to listen at moderate intensity is 1.4 watt @ 2 ohm (Audirvana radio.)

A very surprising conclusion if my calculation is accurate. What counts is quality watts not quantity for CLS original and further less watts for Classic ELS 9. Original CLS is 85 dB sensitive. ELS 9 is 91 dB sensitive. Above measurements for CLS. A true 30 watts RMS @ 8 ohms class A amp like one from Pass Labs should be greater than adequate for CLS Original and 9's.

Roberto and BIg Dog RJ accurate when mention amplifier needs to be stable when dealing with speaker impedance changes. Greater important than just high-power output in watts.

 

[Tmort]

A very useful concept or idea put forward by Leoprello. I will explain with an example.

Anthem MCA 225, if you read the manual, max power output single channel driven is 550 watts @ 2 ohms. If we consider both channels driven simultaneously this measure is lower, namely, 370 watts @ 2 ohms.

In my medium sized room i listen at -26db, Max volume is 7 db. If we consider the net reduction in volume in db is 33 db. Then power output of power amp is halved 11 times. 33/ 3 = 11.

In stereo watts this is 360, 180, 90, 45, 22.5, 11.25, 5.5, 2.75, 1.4, 0.8, 0.4 and finally 0.2 watts at -26 db
7, 4, 1, -2, -5, -8, -11, -14, -17, -20, -23, - 26db.

0.1 watts at 4 ohms. This is all the power i need from MCA 225 to listen at moderate intensity or 96 - 26 = 70db in my medium sized room.

A very surprising conclusion if my calculation is accurate. What counts is quality watts not quantity for Classic ELS 9. A true 30 watts RMS @ 8 ohms class A amp should be more than adequate.

Thank you for the reply, I didn’t mean to suggest that I think I need more power, the Sanders amp delivers its power in a manner that’s supposedly better suited to electrostatics than other SS amps.

 

[john65b]

Sanders' opinion is to have an amp that has all the power needed for any music peaks not to clip.

I have the Sanders Kaya amp - converted to full range. I only use it for very difficult ESL loads, like my Acoustats.

 

[Tmort]

Sanders Magtech amp is in and hands down a marked improvement in clarity and soundstage. Going to try bi-amping with anthem in the bottom end.

 

[Rehan Azim Hashmi]

Sanders Magtech amp is in and hands down a marked improvement in clarity and soundstage. Going to try bi-amping with anthem in the bottom end.

Do not bi-amp. Danger of frying panel power supply circuit.

 

[JonFo]

Do not bi-amp. Danger of frying panel power supply circuit.

Huh?
Please explain in detail; that does not make sense on a passive XO setup.

Reminder: the Classic 9 uses a passive XO for the low-end and can be safely driven by a separate amp in a bi-amp scenario. Just remember to remove the bridging straps on the speaker terminals.

Bi-amping a model with its own bass amp and an active low-pass XO makes no sense and should not be tried. Most people know that.

 

[JonFo]

Sanders Magtech amp is in and hands down a marked improvement in clarity and soundstage. Going to try bi-amping with anthem in the bottom end.

Congratulations!
I read your glowing feedback in the other thread. Glad it delivered a significant improvement.

 

[Tmort]

Do not bi-amp. Danger of frying panel power supply circuit.

These speakers were designed to be bi-amped, so I don’t get your concern here.

 

[Rehan Azim Hashmi]

I do not remember precisely which Quest model suffered from molten circuitry when overdriven. I came across this information from the website of an electrostatic speaker repair outlet in Europe. Located either in Germany or Austria.

Based on this information I made the assertion that with the ultra-powerful ELS amp if unintentionally increase pre-amplifier volume too much Classic 9 internal circuits may heat up and burn.

If I am not mistaken, acoustics in a medium or small size room may for a given amp volume level cause loudness not to be perceived to the same extent in intensity like in a large room. Ergo the danger of overdriving speakers.

Glad to know Sander's amp has synergy with Classic 9. Useful information for me. Though I intend to sell my ELS 9 after I replace two circuits with one burnt component each and install two new electrostatic power supply circuits.