Tone Control (or lack of it)

Written by Bill Leebens

I’ve previously mourned the death of tone in modern audio gear, and written about wood in audio gear. As far as I’m concerned, we’re talking about two sides of the same coin.

There was a time when every radio and preamp had some type of tone control that could be used to compensate for deficiencies in recordings, or to a certain extent, the room. -Or, even, adjust the sound to match personal taste, or just to crank up the bass when the thunder-sheets are going in the Ring cycle, or for Jack Bruce’s intro to “Badge”. When you look at the much-loved Audio Research SP-3 shown above, what do you see?

Tone controls. Not just the usual treble and bass, but a contour control which altered the slope of the bass and treble controls. They were useful. Not every recording is perfect—in fact,very few are— and those tone controls were particularly useful in the ear-bleeding days of early CDs and certain moving-coil cartridges.

So: where did they go?

As is often the case in the history of high-end audio, credit and/or blame can be ascribed to Harry Pearson. Amidst the numerous pieces he wrote about the SP-3 and its multitude of alphanumeric variants, HP commented that the sound was notably better with the tone controls switched out of the circuit (one of the five push-buttons at the bottom of the faceplate switched out the tone controls). And so it was, largely due to a decrease in noise. If memory serves (and increasingly these days, it does not) one of the changes wrought by the Paoli mod of the SP-3a-1-et al was to eliminate the tone control circuit entirely. Snip-snip.

From that point, the deficiencies of one circuit in one particular preamp were transformed into a philosophical movement of sorts, one whose rallying cry was “a straight wire with gain!!”

The first product from Mark Levinson Audio Systems that I was aware of was the decidedly pro-looking LNP-2 (Low-Noise Preamplifier), designed by pro-side engineer Dick Burwen, complete with not two but three tone controls. (Side note: the LNP-2’s $1750 price tag in 1973 was almost three times the price of the SP-3, and equates to more than $10,000 today.)

But the Levinson product  that broke through in the audiophile world, again courtesy of HP, was the minimalist JC-2 preamp designed by John Curl. See the difference? No tone controls, and the pitch is even based upon that straight line thing. Note that there was no way to alter frequency response, but gain could be adjusted independently for each channel, in 1 dB steps, no less. While channel-matching in volume pots is sometimes inexact, dual volume controls are a pain to live with.–Yes, I digress. Sorry.

By the time Audio Research came out with the SP-6 (the real heir to the SP-3, not the contentious SP-4 and SP-5), tone controls were nowhere to be found. Sniff.


And yet, and yet: as Mark Levinson moved on to found Cello, he apparently saw the need for an ultra-sophisticated tone control (or more likely, sensed the market for one). The Cello Audio Palette was more complex and versatile than anything seen since the ancient Altec Acousta-Voicette, the granddaddy of all graphic equalizers. The Audio Palette replaced the grotty sliders of the Altec with  precision rotary controls. Despite the 12 knobs on the unit, only the bottom six altered frequency response—the top six were rather extensive preamp controls.

Like the LNP-2, the Audio Palette was the work of Dick Burwen. In terms of raw geekiness and gadget-lust, the Palette is pretty much the ultimate. I’ve never seen anyone able to walk past one without clicking at least one of the stepped rotary controls.

So: here we are, in an era in which frequency response can be contoured in zillionths of a dB in the digital mode (horrors!). Does anyone do that? Aside from digital crossovers and room-correction devices like those from DEQX, mostly no. One exception: yep, Dick Burwen is still around, and offers Audio Splendor, software-based tone controls and ambience generation. Despite my Luddite resistance to complex mucking about with frequency response—especially through a computer—knowing Dick, I’d bet that it works, and works well.

One problem…there aren’t any knobs!

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