MC Output Voltage - Impact on Noise


Question; how does the output voltage of a moving coil cartridge affect/interact with the phono with regards to overall noise in a system? For example, the Dynavector DTR XV-1s has a very low output of .3mv; a Transfiguration Orpheus has a higher output of .48mv... is that a 'significant' difference in output voltage? Also, if you use these cartridges in rig that utilizes super sensitive horn loudspeakers would one be inherently quieter than the other?
stickman451
0.48 mv compared with 0.3 mv is a difference of about 4.1 db, calculated as 20 times the logarithm (base 10) of the two voltages.

Which means that for equal volume levels you will turn up the volume control on your preamp to a point that provides 4.1db more gain with the 0.3mv cartridge than the setting you would use with the 0.48 mv cartridge. Which in turn will, in the case of the lower output cartridge, boost the noise/hiss levels that are generated at the front end of the system (primarily by the phono stage) by 4.1 db, relative to what they would be with the higher output cartridge.

That is a significant difference but not a huge one. Although if your phono stage (whether separate or in your preamp) has noise/hiss levels that are marginal for use with low output cartridges, it might mean the difference between acceptable and unacceptable hiss levels.

However, I see in your system description that you are presently using a 20XL, which also has a 0.3mv output. So going to a 0.48mv cartridge would result in your setting the volume control 4db lower, rather than higher. That would REDUCE front-end generated noise or hiss, which is usually the predominant source of noise or hiss in a system because any noise generated there is amplified by everything that follows.

The concerns resulting from using extremely efficient speakers would be:

1)That you don't want the overall system gain, and the output voltage from the cartridge, to be such that you end up using the volume control near the bottom of its range. If you are not presently approaching that situation with your 0.3mv cartridge, you should still be ok with a 0.48mv cartridge.

2)That noise or hiss generated by what follows the volume control (i.e., the power amplifier) is acceptably low when reproduced by the speakers. Which is a separate issue that is unrelated to the cartridge and the phono stage.

Hope that helps,
-- Al
Correction: The first sentence of my preceding post should have read "0.48 mv compared with 0.3 mv is a difference of about 4.1 db, calculated as 20 times the logarithm (base 10) of the RATIO OF THE two voltages."

-- Al
With my Hovland HP-100 at average phono listening levels I am typically at the noon to 2 o'clock position on the volume control, so moving to a .48mv output from a .30mv would move the control back to a typical range of 10 to straitht-up...correct? The volume control works in 2db increments.
Since the control works in 2db increments, going to a cartridge that has a 4db higher output would move it down by two increments. I suspect that would be a difference that is somewhat smaller than 2 "hours" if the setting is considered in terms of a clock-face.

Regards,
-- Al
Noise is a particular concern in high efficiency horn systems. If you now have an issue with noise when phono is your source, you would have substantially less noise going to the Orpheus -- a signal that is 4 db further above an audible noise floor (assuming the phono chain is the source of noise) is a meaningful improvement.

I don't know if this applies to the Hovland HP-100, but, a friend's HP-200's built in phono stage seemed quite noisy (sounded like RFI noise). It turned out that the factory setting for loading was 100k ohms (essentially unloaded) and when this was changed, noise was substantially reduced. Some disassembly of the outer case was needed to access the switches that change the loading.
I thought that the default factory loading for the HP-100 was 500?
The Hovland website says, 530
If its 500-530 that is a reasonable default (not completely unloaded, but not too heavily loaded down either). The HP-200 that my friend had allowed for something like five different loading options, with the factory setting at 100k. Actually, we didn't even realize the unit allowed for different loading (who reads a manual?). It was only when the owner switched cartridges that we noted the noise problem and investigated by opening up the unit.
I am using a Denon DL-S1 on my VPI Scout. The output is 0.15mv and they recommend a load of 100 ohms. But at that load I find the sound a bit thin, so I tried it at 1K ohms and 47K ohms. It does sound louder with the 47K ohms setting, but the 1K ohms setting suites me better. I was told that it would be noisy at the higher load, but I was not able to detect any hissing or noise while I play some records. At one point I turned up the volume without a record playing and I heard a lot of noise at about 90% of the volume setting. It turned out that the TT ground and Phono amp ground wire was causing most of that noise. I am using a Modwright tube phono stage, my amps and pre amps are tube, except my McIntosh MC402 amp that I am using in a bi-amp configuration to drive the woofers in the Legacy Audio Focus 20/20. I was also using a Dynavector 20XH and that is much louder than the Denon. Now I listen with the volume set at about 20 to 25% and that enough form my room and I don't hear any noise or hissing. Now I am considering a Dynavector 20XL, used if I can find one.
I am using a Denon DL-S1 on my VPI Scout. The output is 0.15mv and they recommend a load of 100 ohms. But at that load I find the sound a bit thin, so I tried it at 1K ohms and 47K ohms. It does sound louder with the 47K ohms setting, but the 1K ohms setting suites me better. I was told that it would be noisy at the higher load, but I was not able to detect any hissing or noise while I play some records. At one point I turned up the volume without a record playing and I heard a lot of noise at about 90% of the volume setting. It turned out that the TT ground and Phono amp ground wire was causing most of that noise. I am using a Modwright tube phono stage, my amps and pre amps are tube, except my McIntosh MC402 amp that I am using in a bi-amp configuration to drive the woofers in the Legacy Audio Focus 20/20. I was also using a Dynavector 20XH and that is much louder than the Denon. Now I listen with the volume set at about 20 to 25% and that enough form my room and I don't hear any noise or hissing. Now I am considering a Dynavector 20XL, used if I can find one. To see my System: go to the system tab and Type "mando system" on audiogon.
Here is the link:
http://forum.audiogon.com/cgi-bin/fr.pl?vstrt&1234251690&read&keyw&zzmando