Cartridge Capacitance and Eros

Bryon · 4719

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Offline Bryon

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on: December 14, 2010, 03:49:45 PM
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Offline Paul Joppa

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Reply #1 on: December 14, 2010, 05:13:40 PM
Most often, a cartridge manufacturer will specify a capacitance load that optimizes the cartridge frequency response. This will be the 'table to phono preamp cable capacitance, plus any inherent input capacitance of the preamp itself. The output cable (phono preamp to main preamp) requirements are a function of the phono preamp; for the Eros I prefer to see 1-meter cables but I think most 2-meter cables are fine unless they are especially high capacitance.

The capacitance load that gives the best sound is not always that which gives the flattest frequency response, so some experimentation is often in order. I'm just sayin' what the cartridge manufacturers can't always say ...

I looked up the specs online, and found that the standard output is 2.12mV which is just about perfect for the Eros. (The 0.6mV is at 1cm/sec rather than the standard 5cm/sec - I'm not sure why they provide that specification but it's interesting that they do.) The specified optimum load is 47K with 400pF in parallel, so you may want to experiment with some added capacitance. You can solder them in parallel with the 47K input resistor, near the input RCA jacks. I would suggest just tacking in a capacitor without wrapping the lead wire so you can try a couple different values until you settle on the value you want to stick with. Get good caps, this is an important location. Fortunately the voltage rating is not important. Be sure to let them and the cartridge break in before making any final decisions.

Paul Joppa


Offline Bryon

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Reply #2 on: December 14, 2010, 05:44:55 PM
Thanks for the quick response.

I think the standard capacitance for the voice is 100-200pf although they have a 400-600pf version available -if you read the review and saw the specs on dagogo.com, the cartridge he reviewed was the 400pf version but that was specially made for his system.

I think the one I bought is the stardard 1-200pf version - do you think I'll still need to add capacitance?

It's good to hear that the output voltage is going to work with the Eros

thanks

Bryon



Offline Doc B.

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Reply #3 on: December 15, 2010, 05:52:26 AM
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(The 0.6mV is at 1cm/sec rather than the standard 5cm/sec - I'm not sure why they provide that specification but it's interesting that they do.)

I think maybe because that is the spec EMT uses, and those of course are carts which are considered by many as legendary. It would be kinda like if everyone switched to the different distance for speaker measurements that Altec used - what was it, 10 ft. instead of 1 meter?

On the topic of EMT and good sounding cartridges - we demoed the new Bottlehead Tube Phono with a Brinkmann turntable with a Brinkmann modified EMT cartridge at RMAF this year, courtesy of Philip O'Hanlon of On a Higher Note. I think that cart is spec'd at around .2mV at 1cm/sec. Helmut Brinkmann assured me that the cart would work fine with the MQ stepup transformer we were using (at, IIRC, 1:10), and he was right. The cartridge sounded quite wonderful.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.