Ultimately It's Marantz--Go For It.
Marantz goes beyond THD to lower TIM (transient intermodulation distortion)
Because TIM doesn't show up on conventional amplifier testing equipment, most manufacturers and their engineers aren't even aware that it exists in their amplifiers. Even if they were, they probably wouldn't know what to do about it.
But because Marantz builds for the music and not just the specs we know how destructive TIM can be to pure sound reproduction.
And we've developed a revolutionary new circuit design to eliminate it.
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ABOVE: Spectral analysis demonstrates that Marantz conquers TIM distortion.
Test signal (sine and square waves mixed).
Competitive amplifier's output. Note the added distortion products.
Marantz 1180 DC's output is identical to the input test signal.
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The reduction of TIM can be the single most important element in making an amplifier sound better. For instance, two amplifiers with identical total harmonic distortion (THD) specifications should sound the same when compared ... but the one with low TIM will sound audibly better! That's because TIM adds an unnatural harshness to the music. It's not only detrimental to pure sound reproduction, but it can have an emotional effect that you experience as "listening fatigue:' TIM is caused by an improper design of "negative feedback circuitry" by other manufacturers.
Every modern amplifier uses it to lower THD. But excessive negative feedback coupled with an insufficient slew rate* can lead to gross internal overloads under the constantly changing transient and sound levels of music.
That distortion is TIM. The gentle slopes of continuous sine wave test signals normally used to test an amplifier simply cannot detect TIM distortion. It requires the type of extremely sophisticated spectrum analysis equipment developed by the space industry to analyze radio frequencies.
Our answer to TIM is a circuit design that ensures the widest bandwidth and the lowest obtainable THD before negative feedback is applied. The Marantz 170DC Stereo Power Amplifier (the 1152DC, 1180DC and 1122DC also use this circuitry), for instance, needs only 1/100th (-40 dB) the amount of negative feedback commonly required by other amplifiers to yield the same low total harmonic distortion figures.
Incredibly, Marantz amplifiers with low TIM design can deliver flat frequency response from 0 Hz to 20 kHz without the use of negative feedback. And this same circuit design provides the optimum slew rate for minimum TIM and maximum reliability.
Result: Marantz reduces TIM to an inaudible level, which means you get clear, clean sound from all your records and tapes. Think of Marantz with low TIM as a window to the original performance.
If you truly want the best reproduction of musical sound available anywhere-and are willing to spend a little more to get it-then go for it.
Go for Marantz.
(Source: Audio magazine, Apr. 1978)
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