08 September, 2011

Vinyl Talk: K&K LL1678 + Audio Note Kit Phono amp, Part II

Vinyl Talk: K&K LL1678 + Audio Note Kit Phono amp, Part II

For Part I, click here

Round 6, comparing K&K gain options
Previously, f
or the LL1678 I chose the 24db gain option (others are 18 and 30db). The impedance ratio thus is spec'ed at 256 and so the loading of the MC would be roughly 183 ohm, theoretically therefore likely more optimal for Denon than my Ortofon's.

And listening revealed it to be so. While the Denon DL-103 sounded fine, the Ortofon Kontrapunkt C (weight 10 gm; compliance 12; output 0.47; internal resistance 5 ohm; loading recommendation 20-200) mounted on the Kuzma was comparatively lackluster with this phonoamp. In my experience, Ortofon cartridges sound better when loaded at low value.

Minor Surgery: I looked at the K&K spec's for the 30 db gain option. With turn ratio of 32, the impedance ratio is 1024, which makes the loading 45.9 ohm, this time theoretically likely more suitable for the Ortofon than the Denon. I studied the connection diagram. All I have to do is bridge two links and move another, not insurmountable. Half an hour later I was done with the conversion.

Immediately it became clear the sound of the Ortofon improved. But what about the Denon? Well, at the unusually low loading it surprisingly sounded quite well! Perhaps a little less airy and rich, but I think most of the magic is preserved.

While the load impedance is one thing, there are caveats. Calculating according to the info available at The Analog Dept, the Ortofon is likely overloading. Resonance figures are unlikely to be optimal for both cartridges (one high on low in compliance) with either turntable (one high mass arm, one medium). Well, I don't hear much wrong. Let me run this in for further comments.

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