cartridge output level


Hi all,
This is Marco from Italy, I have a question about how a cart output level relates to volume knob position.

Let me explain: my VdH colibri is rated .45mv@5.7cm/sec, it goes into the mc phono stage of an hovland hp100 tube preamp, no complaints for the sound but the preamp volume knob is often in the 3 o'clock position, and anything below 12 is not enough.

Now this preamp phono stage is quiet enough up to 1 o'clock, above that the tube noise is audible, not to a level to ruin the listening pleasure, but is there.

I would like to be able to play with the volume knob between 10 and 2, the question is, if i could get a new cart, how do I know the correct output level to achieve that goal? I wouldn't want to end up not being able to go beyond 9 o'clock either.

Also, is there a difference in output level at 5.7cm/sec as per VdH spec compared to 5cm/sec of other manufacturers?

I know the simple answer is to try other carts in my setup, but unfortunately that is not an option here.

Any advice for a suitable cart is very much appreciated, I listen to jazz 60%, classical 30%, pop/rock 10%, I like lively dynamic sound with huge soundstage but not dry or too bright.

Thank you all,
Marco
128x128cptaz
The overall gain of your system is what is really most important. With a 0.45 mV cartridge output, I don't think your 46 dB phono and 14 dB linestage gain are enough. You also need to know the voltage gain of your power amp and the voltage sensitivity of your speakers. You can actually figure out how much overall gain you need since most power amps need about 2 volts input to drive them to full power. Each 20 dB of voltage gain multiplies the voltage by a factor of 10. So if your overall phono and preamp gain is 60 db, you are multiplying your 0.45 mV by 1000 to give you 0.45 volts, not enough to drive your power amp IMO. Changing the impedance load won't affect the gain much if at all. I would see what Hovland has to say--if they cannot increase the phono stage gain I would look for an outboard unit. My Aesthetix Rhea has all-tube gain and goes up to 75 dB but I run mine at 62 dB. Again, you have a great cartridge, so I would be a lot more inclined to find a way to increase gain rather than changing cartridges.
Post removed 
Rlawry, thank you, I think I understand your point, but I have to do some more homework to fully grasp the overall gain concept.
I now realize anyway, that I didn't previously make clear that the total gain of the unit is 77 dB, phono 63 dB, line 14 dB, as you can see in the Hovland web site http://www.hovlandcompany.com/products/electronics/hp100/specs.html.
That probably doesn't change the substance, and I agree that increasing gain would be a good solution, I'm now waiting for a reply from Hovland.
Yes, I now understand that you have 77 dB of gain prior to your power amp. That should be enough gain (77 db gain of 0.45 mV is a gain factor of almost 8,000, so your preamp output should be close to 3.2 V) which should be way enough gain for your power amp. Unless, of course, your power amp has low voltage gain, which I doubt, and/or your speakers have low voltage sensitivity. To get the dB from input and output voltages (output/input=gain) you use the formula dB=20 log (Vout/Vin). In your example your dB is 77, Vin is 0.45mV. If you solve for Vout you get 3.2 volts. This should be plenty of voltage to run your power amp to full power assuming it has a normal gain of 20-30 dB. Something does not add up here so maybe Hovland can shed some light on your problem. Let us know what they say. Again, I think you said it right, you probably have a voltage gain problem, not a cartridge output problem.
As an aside from the current discussion:
The Thor Cantantus has a fixed resistor that you can specify, is best for cartridges at .65mVolts but my Sumiko Celebration at .5mVolts works fine. My preamp lacks a phono preamp so it was necessary to get a separte piece.
Check and see if the SUT is in, a voltage reading should tell Hovland that info, let them instruct you just in case, working with live units is for people trained to do so.
As a former electronic tech, better safe than sorry