Calculating the correct gain for your MC (Moving Coil) or MM (Moving Magnet) cartridge

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There is a lack of information when it comes to phono stages and and more specifically the ones that support MC cartridges, in my experience the majority of them do not deliver sufficient gain for the cartridge to deliver its potential.
I am making this video to help out anyone that has questions on the subject, the information shared is based on this article: web.archive.or...
I hope you find this helpful

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16 сен 2024

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Комментарии : 6

@davidatrakchi2707 Месяц назад

Thanks for bringing this up. If you look carefully into the specifications of phono stages that have adjustable gain you can clearly see that once you go above 50dB of gain their signal to noise ratio drops This can be noticed by using ear phones, cranking all the volume knobs up.... Out of curiosity, I installed the SUT to add 20dB of gain to the 0.5mV output of my Sumiko. This enabled me to lower the gain of my phono stage to 40dB which brought a significant reduction in that annoying background noise which is typical to vinyl, I like the results and the SUT’s are going to stay in the setup. I used Transformers I bought from Lundahl, rest was diy ( packing, resistance matching, in/out connections, screening) One thing to be aware of: SUT’s have a tendency to pick up magnetic interference from transformers and motors,the turntable motor is a good example. Double screening and placing the SUT away from electromagnetic sources do the job

@sonicmainliner Месяц назад

Cheers, basically if you don't have enough gain you get noise, and if you have too much, you get distortion. It needs to be balanced, but in most cases, such as yours, the gain is too low and things sound "dead" and noisy. The 1v output target is not exact, but if Rega is using a similar approximation I think that will help you see if it is sufficient for your situation (which seems to be from what you are saying). Also, I didn't know there were issues with picking up interference, I thought it was just the annoyance of buying extra cables that was the problem to an otherwise legit solution.

@silvershield2342 3 месяца назад

You did a very nice job in explaining calculation - you were more explicit than many other videos I've watched and articles I've read. As I am researching this myself (looking to buy a pre-Amp), I was under the impression that the Gain should 2-3 times (and no higher than this) your Amp's Input Sensitivity. In my case my Denon AVR Input Sensitivity is 200mV (0.2V). So at PreAmp Gain of 40dB my 3mv (0.003) MM cartridge calculates to be 1.5x the 0.2V Input Sensitivity which is below this 2-3 times rule of thumb. The 1V you were talking about seems pretty high for an Amp Input Sensitivity amount - perhaps that is the Amp's analog device output figure? The rule of thumb range I actually got from two AI sources - ChatGPT and from Schiit Audio's chat (which is quite amazing). No one actually speaks of range but usually say your PreAmp output to the Amp should be more than the Amp's Input Sensitivity. Ultimately, it usually comes down to how things sound at the various Gains and to pick the one that sound best. Hope this helps in your research and understanding.

@sonicmainliner 3 месяца назад

Hi, thanks for your feedback, I find that the input sensitivity that you quote is exceptionally low, most line inputs are around 2v, even in the 70s amplifier inputs were rated at 1v. Since the 80s, with the proliferation of CDs a 2.15v input sensitivity is the norm pretty much. You mention your machine is an AVR, so I am not sure if this plays a role as the expectation is that the inputs will be predominantly digital (Coax, Toslink, HDMI) and analogue line level inputs are designed to work with TVs, not sure, but still sounds way low. Regarding Pre Amp to Amp, to my knowledge the most important thing to watch out for is Power Amp impedence matching with the Pre Amp, which should be 40 times (don't quote me on that) or some large difference, otherwise the Pre will not be able to drive the Power amp to its full potential. Either way, not related to Phono stages where these values generally are within a very specific range.

@silvershield2342 3 месяца назад

@@sonicmainliner Funny, I think its the terminology that is confusing (my) issue...it seems that Denon specs refer to analog input as "rated output" which is 1.2V. This is in-line with your Input figure. It makes more sense (and practical) to me to dial in your pre-amp gain in order to come close to the 1V or so receiver requirement than to use a ratio (the 2-3x range that quoted in the community) calc based on Input Sensitivity. Back in the day, you just plugged your turntable to the Phono Input and things were fine. Didn't have concerns about MM cartridge voltage output, etc. Hey, I guess that's what makes this "hobby" interesting and fun. But sometimes, I just want to enjoy the music rather than worry about whether the gain is correct, the cables are of pure enough quality, etc.