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Reply with quote  #1 

I am new to the forum. I am considering buying these mono blocks to power my Magnepan 3.6R. They are 150 watts per channel, so just wondering if they would be a good match. The Maggies are 87 Db efficient.

Reply with quote  #2 
STEREOPHILE auditioned your Maggies back in the day; and had this to say...

"The Magnepan's estimated voltage sensitivity was on the low side, at 83.5dB(B)/2.83V/m.
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"The speaker's impedance (fig.1) approximates a resistive load of around 4 ohms over much of the audioband. However, there is a slight magnitude peak centered at 1.6kHz, due to the crossover between the ribbon and the midrange diaphragm. The minimum value is 3.3 ohms at 10kHz, which is not going to be problem for any good amplifier to drive, while the increasingly positive electrical phase angle at the top of the audioband is, I assume, due to the residual inductance of the ribbon driver. There is a small wrinkle in the trace between 50Hz and 60Hz, which is probably due to the tuning of the woofer diaphragm."

The lowest impedance dip of the Maggies is around 3.3 ohms.  This will have an impact on the driving ability of an OTL like the TS Monoblocks you mention.

Also, STEREOPHILE measures the Sensitivity as 83.5dB at 2.83v.

But all is not lost...

I would assume that the lowish impedance might halve the amps effective output, and base my calculations on that assumption. so, the question then becomes: -

Can 75w drive 83dB with adequate power and reserve to deliver satisfying bass - and without risk of clipping.

My thinking and rationale:

My 12w LEBEN (12w into 4, 6 or 8 ohm loads) drives 90dB/4-ohm speakers with absolute ease.  So I am using this as my starting point and my (known) reference point.

On this basis then: - 

12w driving 90dB
24w driving 87dB
48w driving 84dB
85w driving 81dB

With amp and speaker matches, nothing compares to trying the real thing.  However, most of us need to make a theoretical call at some point.

My call would be:  It should be a good match, if you listen at same listening levels.

My only disclaimer would be if you were looking to rock the house with heavy ELECTRONICA/ROCK/ORCHESTRAL WAR-HORSES at party levels.

If you listen at moderate levels, I think you will be handsomely rewarded.

Others may disagree.

Reply with quote  #3 
TYPO:  I meant to say "sane listening levels" above.  [Not "same"...]
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