New Lyra Delos Cartridge

Dear Nrenter:

>Does the diagram out on AudioNord accurately imply the your front magnet structure is larger (stonger) than in the typical MC cartridge, and therefore allows for less mass in your coils & iron core) for a similar output?

A typical MC cartridge doesn't have a front magnet (or a rear magnet). With the exception of yokeless designs, most MC's have a single magnet which is mounted asymmetrically relative to the gap. The asymmetrical mounting of this magnet makes it unlikely that the flux across the gap can be made symmetrical. Years ago, I analyzed this by building traditional, single-magnet prototype cartridges with 4 independent signal coils, placing one coil in each quadrant of the gap. In such a prototype, if the cantilever is driven with a mono LP, the signal output from each coil should be identical. Observation showed that this doesn't happen. What happens is that the outputs of the coils farther away from the magnet are reduced in level but lower in distortion, while the output of the coils closer to the magnet are increased in level and have higher distortion. In a yokeless design (which includes all present Lyras with the exception of the Olympos), the differences in individual coil outputs are notably reduced. When I introduced our first yokeless cartridge (Clavis DC), tracking performance improved as well as distortion, and we were able to reduce our recommended tracking weight. This was because the dual-magnet yokeless design made the flux forces more consistent across the entire coil former.

The Delos' unique damper, suspension and body design achieve better orientation of the coil former, which achieves a further improvement in consistency of flux forces across the entire coil former. Once again, for the same vertical tracking force, the tracking performance that can be obtained improves.

Although I admit that less moving mass in the coils and coil former is worthwhile, it doesn't mean so much if inadequate magnet circuit design or improper coil former orientation results in uneven flux forces pulling the coil former more in certain directions than others. Greater output levels and less moving mass are desirable attributes, but the reduction of distortion is a higher priority (for me).

kind regards

Jfrech, thanks for your comments and thanks for your continued support.

Tokyo is now under 10 degrees centigrade maximum daytime temperature, and gets down to around freezing (or below) at night. I am using a tallish gooseneck incandescent lamp in front of the turntable. Faster and cheaper than bumping up the temperature setting on the heater (smile).

In my experience, an audio designer needs to be able to identify and eliminate (or at least mitigate) significant sources of errors in order to make real forward progress. However, once a major error source has been removed, it becomes easier to hear the other errors that still remain. So it is with the Delos and things like tracking forces vs. ambient temperatures, and I think that the same is true for loading.

If I get the time, I would like to put up a page on the Lyra website that discusses loading and illustrates how things like frequency response change as a function of loading (some of the numbers and trends may be easier to understand if they are accompanied by response graphs). Although the loading values will change depending on the design of the cartridge and how much capacitance is in the tonearm cable (and how much of an RF or high-frequency spike your phono stage can tolerate), the thinking should be valid for the majority of magnetic cartridges.

I have been experimenting with an alternative means of loading, and if I have some spare time to generate and collate sufficient data, I will put up a page for that, too.

In your particular case, Jfrech, I will note that both the Skala and Delos are quite dynamic cartridges, and if you load them down excessively you will compromise this energy somewhat, so I would suggest not loading them down any more than you find necessary (unless you prefer listening to concerts from Row M rather than Row C or the conductor's podium).

>When can you commment on other changes in your line up?

Not yet, but there is a chance that we may be able to show a prototype of the next step up from the Delos at the upcoming CES in January.

FWIW, I'd say that the Delos already surpasses the Helikon in terms of performance.

cheers

Old post I know but I'd appreciate hearing from anyone here who has now used a Delos. Anyone run one of these in a VPI JMW9 (mounted to a Scout?). Great post--thanks Jcarr for your thorough commentary.

Hi Jonathan,

do you have any recommendations for step-ups for the Delos? The Delos internal impedance is somewhat higher than other Lyra cartridges and you seem to recommend 5-15 Ohm where 5 Ohm is even below the internal impedance of the Delos. Would you recommend a 1:10 or 1:20 step with resistor loading (primary or secondary)?

Thanks for the help!

Rene

Hi Rene: Normally I wouldn't recommend a step-up transformer with the Delos unless your phono either has low gain or good overload margin.

The 0.6mV output from the Delos is high enough that it caused clipping when we matched it up with a Nagra BPS, which (according to Stereophile) has 51dB gain in fixed-coil mode and 62dB with the built-in stepup transformer in the circuit. Jumpering out the transformer cleared up the situation. I presume that the 9V power supply of the BPS is to blame, and that using a different phono stage with a higher power supply voltage would avoid the problem.

If you use a transformer, I suggest 1:10 ratio, loading at the secondary, and very short, very low-capacitance cable connecting the transformer to the phono stage.

Boosting the output from a Delos with a 1:10 ratio will present your phono stage with a 6mV input, which should be quite comfortable for all MM and MI-level phono stages.

If your phono stage has 60dB gain or more, you won't need a transformer (unless you have very low preamp/power amp gain, or very inefficient speakers). If your phono stage gain is in the 40-some dB range, you will probably need a headamp or stepup transformer. Again, your results will be affected by preamp/power amp gain and speaker efficiency, but likely not enough to let you get by without the extra gain stage.

The situation is more unclear with phono stages in the 50-some dB range. Here I don't have any firm recommendations, other than suggesting that you compare with and without a transformer or headamp. Perhaps you could first find a vintage unit of low price and the right properties, then change to a higher-quality unit once you've verified that things work.

FWIW, we also make the Erodion (http://www.lyraconnoisseur.com/Products/Products_Analog/Erodion/erodion.html), which is a stepup device, but this has a 1:20 ratio, so I wouldn't recommend it for the Delos unless your phono stage gain is in the low 40-some dB range.

hth, jonathan