Minimum Cartridge output for CAT Ultimate Preamp

Greetings,

You need to consider your complete system gain structure.

I took a look at the following review of an SL1 Ultimate:

http://www.gcaudio.com/products/reviews/infocat.html

It claims:

Phono gain: 47 dB (less than I'd expect)
Line Stage Gain:26 dB (this is HUGE)
-----------------------------------------------
Total Gain: 73 dB

I'd expect to see more gain in the phono section and less in the line section. The good news is that the combined gain is over 70 dB.

If the above stated gain is correct, you'll be fine with a cartridge in the .2 to .3 mv range.

Because of how the gain is distributed (more in the line stage and less in the phono), you'll notice that you're turning down your volume control when listening to line level sources like CD.

I wouldn't stress out over this, but mention it anecdotally.

When I popped the lid on a later CAT, I noticed that the attenuator is a series type, rather than a ladder type so the lower your volume setting, the more resistors and solder joints your signal is passing through.

Cheers,
Thom @ Galibier

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

You're on your way!

Cheers,
Thom @ Galibier