Minimum Cartridge output for CAT Ultimate Preamp

I am not sure if the CAT Ultimate has the same output on the phono stage as the CAT SL1 MKII (an older model with 47 db on it's phono stage). I find that 1.0mv to 2.0 mv cart. would give you best results. My Benz with 0.8mv barely gave me the volume I wanted, and I listen to jazz.

Yes, I think the Ultimate also has 47dB of gain.

I used to own the CAT SL-1 Mk. III with the built-in phono stage, and I ran the 0.65mV van den Hul Frog with no problem.

I have an Ultimate II and have no problems using low output (0.2 - 0.3mv) cartridges. But....I use an Audio Note step up in front of the CAT.

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

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?

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

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.

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.

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,

You're on your way!

Cheers,
Thom @ Galibier