Madrigal cartridge loading?


I have an old Madrigal cartridge and I'm trying to learn the correct output voltage/cartridge loading for it.

Does anyone know the answer?

The second part of my question is- if my pre-preamp, a Tom Evans Micro Groove, is set for a 20-30 ohm loading and my Madrigal’s loading is different from that, will I be sacrificing audio quality when I run the Madrigal through the Micro Groove at the wrong loading?

Can you help me?

Thanks,
128x128shaq
You can find listings for the Madrigal Carnegie One and Carnegie Two at:

www.cartridgedb.com

There's not much info on the Two, but the One is spec'd at .28mV with a VTF = 1.5 - 1.8 gm. The load is spec'd at 30 - 47K ohms, which doesn't tell you a hell of a lot. IMO, establishing the proper load has everything to do with good sonics, and you can usually find a good (starting point) optimum load by multiplying the coil resistance of the cartridge by 25. Unfortunately, its not listed. You could measure it easily using a sensitive volt-ohm meter. Most cartridges fall somewhere between 4 - 30 ohms or so.

In the absence of the right info, I'd take an educated guess that it's around 30 ohms, because manufacturers typically use the coil resistance for the low end of the range (in this case 30 - 47K) If I'm right, a good starting point for your cartridge loading would be around 750 ohms plus or minus.

On the other hand, it could be much lower than 30 ohms since it's such a low output design and probably doesn't have many coil windings. My advice would be to start around 400 ohms and if the bass is muddy, increase the load until it's clear and defined. If it's lacking bass and the highs are glarey, the load is probably too high. Reduce it until you get good bass response.
Nsgarch

Thank you for the informed response

I have to send the Tom Evans unit back to England to have the loading setting change, so it's a big hassle. Is it worth it?

Or does anyone know a place in the U.S. that can reset the loading if need be?
If anybody could help you with local service, it would be Tom Evans. I'd write to them and ask if they could direct you to a USA service station.

I don't know any design particulars about that unit, but since all cartridges it seems have different load requirements, I feel they must have made provision for easily adding load resistors. Ask them about that too.
Shaq,
How long have you had the microgroove, and what is your opinion of it. Everything I've read about Tom Evans in 6 Moons sounds fantastic.
Thanks, Ken