Phono cartridge noise calculator

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I've posted a little Excel-based calculator for intrinsic phono cartridge noise, both flat and with RIAA equalization weighting. Input cartridge nominal output voltage, DCR and inductance, then preamp load resistance and capacitance. The noise voltages assume a unity gain ideal (noiseless) preamp- this sets the noise floor so you can determine what an acceptable preamp noise is for your cartridge. It also allows you to compare the intrinsic S/N of different cartridges.

SYclotron Audio RIAA Noise Calculator
 
I'm surprised others haven't done it before. As I was putting together my MM phono stage and reading about the stunningly low noise of some other preamps, I wondered, "What do I really need? Is there a reason to increase complexity and heat to get an extra 6dB in the preamp?"

It should be pretty easy to add a noise figure function as well. I'll do that at some point...
 
I had noticed the intrinsic phono cartridge noise calculation result in your article for HMV here at diyaudio and I thought to myself at the time how tedious it must have been to come up with that number slice by slice.

Nothing quite like Excel to simplify the task. Thank you, very worthwhile.
 
Hi,

I'm surprised others haven't done it before.

I have used a spreadsheet like this for years, except I also had input fields for Ein from Datasheets and for other resistances in the circuit, so if you got Ein right for your complete circuit (easy for Op-Amp's, less so for tubes) it would tell you you output noise.

I have a rummage around to see where it is. I't probably in Excel 2003 or earlier though.

Ciao T
 
Perhaps we could characterise groove noise (with a particular stylus) by giving a noise temperature in record reviews? How about cryogenics - not for treating components but cooling preamps and cartridges. Barmy, I know, but someone has probably tried it. As we know, some audiophiles have hearing as good as a radio telescope.

Many years ago I remember reading an article on FM tuners in which the author showed the plausible theoretical limit for sensitivity for a room temperature solid-state circuit, which curiously was worse than some manufacturers seemed to claim for their tuners.
 
I make phono stage as low noise as i can. Groove noise dominates mostly but some customers go to the speakers and simple put an ear on them. If they hear noise, they complain, even when the record is not spinning.
If a super low noise stage sounds better then one with a little more is hard to tell.
Talking of the noise spectrum, there are big differences for sure. Tubes and Fets have a quite soft treble but there is more noise in the deeper regions starting at 1kHz or so. BJT´s are much better there. Burkhard Vogel went so far that he does not recommend Fets for lowest noise MC phonos. Subjectively i can not second that. The ear is less sensitive for noise in the bass so psycho acoustics help out a bit here.
 
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And they turn up the volume to its fullest also while sticking an ear to the tweeter I suppose. To win that over a horn system with high gain line preamp would be the coolest party trick. To no avail, but go figure. Its a system grounding thing to have no trace of hum also in such conditions plus the chain being up to scratch and balanced XLR though.
 
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