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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
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cptaz OP
29 posts
 
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.
rlawry
484 posts
 
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.
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uru975
684 posts
 
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
gregm
3,407 posts
 
Rlawry, according to Marco's reports, he's getting ~0,9v at the output with the SUT in the circuit (63dB) -- before even hitting the active pre... and that's the reported overload ceiling of the phono.
Strange, as you & Marty note.
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