Minimum Cartridge output for CAT Ultimate Preamp

Thom,

Intersting point regarding the total gain. One thing to add is that Ken Steves told me that the effective input voltage that the line stage will be from the phono stage is 200 x phono output. That means a 0.5mv cartirdge output would feed 1,000 mv, i.e., 1.0 v to the Line stage. With 26 dB in the line stages, does this seem reasonable?

CORRECTION (I need to brush up on my math):

In the above example the input the line stage section would see is 100mv (not 1,000 mv), i.e., 0.1 V. apparently this should not be compared to the output voltages of CD players since they have a different dB baseline.

Anyway, I'm hearing that 0.5mv cartirdge output should work just fine with the CAT pre. I've heard some say they are happy with 0.24mv outputs with dynamic systems.

Thanks.

I use an Ultimate and despite the measured gain, it comes up very short with my 0.6 mV Koetsus necessitating a step-up. Interestingly, the people who do enjoy lower output cartridges directly through the CAT also seem to use CAT amps so this may need to be considered.

Hi Aoliverio,

The 47 dB translates to a voltage multiplication of 223. Likely Ken was rounding for sake of simplicity.

Being too lazy to go to my calculator, I found the following calculator online:

http://www.sengpielaudio.com/calculator-db.htm

Click the radio button for the value you know.
For example, enter 47 (for dB) and click the dB button, then calculate the voltage multiplier.

You'll get the answer - 223.

I cross validated this against some known values (e.g. 1:10 is 20 dB).

Back to our .5mv cartridge. Let's look at total gain in the preamplifier, since our concern is being able to drive a power amp to full power.

With a total gain of 73 dB, our .5mv cartridge's voltage will be multiplied 4466 times - to 2.233 volts.

This is probably a touch more than you need - with an amplifier designed to deliver full power with a 2 volt input (the old standard). These days, many power amps deliver full power at less voltage - in order to anticipate people who use passive line stages fed by wimpy CD's.

Cheers,
Thom @ Galibier

Thom,

Your analysis suggests I'll be fine since the typical output voltage out of my pre at normal listening levels is ~0.5V. Therefore, there should easily be enough gain in the amplifier. Another way of saying it is that I defintely will not need to completely open the volume control.

thank you.

By the way, I am using a CAT amp and as Kleech mentions, this would be less of an issue based on the input sensisitivty and dynamics of the amp.

Thanks and Take care,