2. analog
  3. 1261350841

Convert cartridge output voltage to db gain

Happy holidays everyone. I hope that you may help me with a problem. I have re-configured my system, preamp and amp gone, I'm now using a integrated amp. I still have my phono stage and cartridge. My cartridge has a 0.24mV output, my phono stage has 66 db of gain. This used to sound fine, but now I notice that the noise floor is too high for me. So I'm debating on whether to look for a higher gain phono stage, or more likely, a higher output cartridge.

So now my question, how much more output would give me how much more gain? Should I be looking at a 0.5, 1.0 or 2.0+ mV output cartridge? I think I need at least 10 db more gain, and there are not many 76db+ phono stages out there. So what do you analog experts think? Is there any table out there that can show me how to convert voltage output to gain increase? TIA.

Cheers,
John
128x128jmcgrogan2

Showing 2 responses by dougdeacon

dougdeacon
3,338 posts
 
A cartridge with 2.0mv output will need a higher input impedance than your .24mv cartridge, typically something from 10K-47K ohms. Can your phono stage provide that *without* switching to the MM inputs and reducing the gain you're trying to increase?

Even if you can get a suitable impedance without losing gain, I'm not sure I'd replace the cartridge. The higher noise floor is in the new line stage, not the phono stage or cartridge, so address that.

Your old (seperate) line stage had an acceptable noise floor with phono, the new (integrated) line stage does not. It's not really a gain issue, as already discussed. Any decent line stage should play with a similar noise floor at both 10 o'clock and 2 o'clock. Those are not extreme settings.

It's worth trying different tubes. Which will work best depends on the circuit of course, but FWIW the best new production JJ 12AX7 and 12AU7 both have a low noise floor in my preamp, and they won't break the bank.

If that doesn't help, the quality of the line stage circuit and/or the power supplies in this new integrated begin to become suspect.

You haven't described just what this higher noise floor sounds like. That might help...
dougdeacon
3,338 posts
 
John,

You should be aware that ZYX's output specs for their MC's is not based on the industry standard test record. I lost the reference (I think Nsgarch posted it here once), but from memory you need to multiply ZYX's stated output by ~1.4 to get a spec that's comparable to most other cartridge brands.

For a .24mv UNIverse, the actual output using the industry standard test record would be around .35mv.

FWIW...
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