MC Cartridge loading for Cornet2

analog97 · « **on:** 14 Oct 2005, 09:52 pm »

Hi. I built the Cornet2 (wow, what a great product) and am still trying to maximize performance. I am using a 0.3 mv MC (Denon 103) that likes 100 ohms, a Denon step-up transformer (10x) and the Cornet2 front-end. The Denon step-up manual is all in Japanese and I am wondering if there is any way I can measure this "loading" with a DMM? I have seen MC step-ups that appear to solve this by wiring an appropriate resistor to the output terminals. Appreciate any insight to my ignorance of theory and fact.

PS: my experience with break-in seems to max-out by 50 hours or so (with Auricaps).

hagtech · « **Reply #1 on:** 14 Oct 2005, 10:43 pm »

Loading is a recommendation by the cart manufacturer. Typically for MC it is about 100 ohms. You can achieve this using 1:10 step-ups by adding a 13k resistor on the secondary.

More info at:

www.hagtech.com/equalization.html

jh

analog97 · « **Reply #2 on:** 14 Oct 2005, 11:03 pm »

Thanks, but I don't understand the concept of putting the resistor "on the secondary". I hate to take the engineer's time for a dumb question. Can anyone else help me understand, in simple terms, how to a) measure the loading with a DMM, i.e. where and how and b) where the resistor needs to be wired, i.e at which of the leads....inside the MC transformer or the Cornet2? Sorry.

hagtech · « **Reply #3 on:** 15 Oct 2005, 01:20 am »

First, try it without any loading modification. You might like it best. If too bright, then add resistance in parallel to the 47k already there in your phonostage. To get 100 ohm loading seen by the cart, then use 13k. At least with a 1:10 steo-up.

You cannot measure this loading with a DVM. It is an ac impedance.

jh

analog97 · « **Reply #4 on:** 15 Oct 2005, 02:29 am »

I am getting there. This means that I would replace the 2, 47K resistors at R200 with a value > 60K? Sorry, I'm learning.......

hagtech · « **Reply #5 on:** 15 Oct 2005, 05:18 am »

Leave the 47k installed. The new 13k in parallel gives 10k. Which then reflects by the inverse square of turns ratio (10k / 10^2) = 100. So the cart "sees" an ac loading of a little over 100 ohms.

Why a little over? Because there is dc resistance in the primary and seconday windings. Primary probably measures about 5 ohms. The true result is a loading of maybe 105 ohms. But hey, we're looking for a zipcode here, not some mythical 0.1% number.

If the sound is too dark or rolled off, check your VTA. Really. Then make loading a higher value. If still too bright and sibilant, lower it. Go in big steps. Drop from 100 down to maybe 50. Listen again. You'll converge to an optimum result quickest.

jh

analog97 · « **Reply #6 on:** 15 Oct 2005, 06:56 pm »

Thanks much. I understand now. I solder a 13k resistor to each R200 location, using the same points of contact as the 47k resistors. That puts them in parallel. I'll try my best not to trouble you again. You're a gent. Still gotta hear that Trumpet, though!!!!