Importance of impedance matching cartridge with phono stage?


Hi,

I just received my new Gryphon Diablo 300 integrated (which I absolutely love), and my dealer sold me a barely used demo Gryphon phono board for it which I installed into my new amp.  When I checked Gryphon’s site, I realized the board they sold me was Gryphon’s PS2 model, and not the latest revision, which is the PS2-S.  The only change with the new revision appears to be that it now supports a variety of impedance load settings for MC cartridges, including 20/100/200/499/806 Ohms and even custom loads using resistive jumpers applied to the board.  In comparison, my version only supports 20 and 100 Ohm settings for MC cartridges.

My question is, how much should I care that my Gryphon phono board does not have these expanded  load settings?

If it matters, the dealer gave me the board for over 50% off retail value.

I know relatively little about analog (the last turntable I owned I got when I was 5) and am looking for some informed advice here.  I could ask my dealer or Gryphon but I think their response may be biased considering they will likely want me to keep the board.  Not to mention I don’t think the dealer was supposed to sell me the demo board; Gryphon seems to care about such things.

Thanks




nyev
A whole lot of low-output MC’s like to be loaded 100 ohms or less in conjunction with many active MC phono stages. If you get one of those, the new additional settings at 200+ won’t help you anyways. Of course there are exceptions, e.g. Benz Ruby. And if you go with medium/high output MC’s, the 100 ohms will probably be very sub-optimal. For the most part you should be good with MC’s in the output range of say 0.4 mV and lower, depending on the gain and signal/noise of your card (the higher these are, the lower you can go, down to say 0.2 mV or less). And this range is generally considered to be the highest quality for MC carts (lower output is better as long as you don’t need the extra signal). For example, all Koetsus and upper-range Ortofons (Cadenza and up) should be an excellent match at 100 ohms.

If your phono card has an MM mode you can additionally consider using a Step-Up Transformer in conjunction with a low-output MC, at which point the cartridge/SUT pairing is the important one to match.
Hi. The quick response is that most people aren't even aware of this little detail (i.e.getting the loading correct) and live their lives complaining about the mediocre sound.The second point is that most cartridges play reasonably well @~100ohms  (capacitance???), hopefully so does yours.
The third point is that getting the loading correct is of primordial importance: you finally get to hear what your TT system is capable of...
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There are many threads on this subject in these archives. Try doing a search. Personally, I’d say 20 ohms is useless with all but a very few very low output cartridges. So you’re basically stuck with 100 ohms, which is ok for most but not all LOMCs. Bad for any other types.
You should mention the gain of the phono and line sections and what cartridges you use.
A whole lot of low-output MC’s like to be loaded 100 ohms or less in conjunction with many active MC phono stages.
This statement is false (and a very common myth). The reason for the 'loading' has nothing to do with the cartridge and everything to do with the preamp's ability to deal with RFI.

The correct term for the resistor is its a 'detuning' resistor. Here's why:http://www.hagtech.com/loading.html

As you can see (from the link), the peak is a good 30dB more than the signal itself; if your phono section isn't good with that sort of RFI at its input, it won't sound right and by detuning the tank circuit at the input of the phono section relieves the preamp of the RFI so it can perform properly.


But there's more- the detuning resistor forces the cartridge to do more work and that energy has to come from somewhere- which means that the cantilever becomes stiffer and less able to trace high frequencies.


You are far better off if your phono section can deal with the RFI. A side benefit of this is you will likely get less ticks and pops, since overload margin at RF frequencies plays a role as well (IOW many ticks and pops are caused by overload, not the LP itself).


Many phono preamp designers simply don't realize that a good phono section is more than enough gain, proper EQ and low noise. It also has to have good overload margin, be resistant to RFI and otherwise be stable (and FWIW feedback or passive EQ has nothing to do with it). 


If the preamp itself has options for loading its a good bet the designer hasn't thought this through.

Thanks for the responses.  The phonostage was added for a turntable/cartridge I will get in the future, and as such I don’t know what cartridge I will get yet.  It will be my next addition to my system, and why I cannot do a test with how it sounds now.  That is why my question is whether I should care that my version of the phono board supports only 20 and 100 Ohm loads, and not the higher impedance loads of the new revision of the board.

From the responses so far, it sounds like I should be okay with this board based on the fact that 1) most MC cartridges should be fine with the 100 Ohm setting so there are lots of options, and 2) I can simply make sure I don’t get a cartridge that isn’t okay with this setting, by ensuring the cartridge has a less than 0.4mv output.

Right?  Thanks!
Dear @nyev : I know very good Gryphon electronics and are really good. Like other gentlemans posted you don't have to be worried about impedance for your future cartridge, 100 ohms can works very good with.

""  I know relatively little about analog .... """

when you receive the cartridge try that your makes the cartridge/tonearm set up for you and that you can learn about, very important this subject as it's too that you give the cartridge at least 50 hours of playing time to fine tune that set up and for the cartridge can shows its real quality level performance.


Regards and enjoy the MUSIC NOT DISTORTIONS,
R.


From the responses so far, it sounds like I should be okay with this board based on the fact that 1) most MC cartridges should be fine with the 100 Ohm setting so there are lots of options, and 2) I can simply make sure I don’t get a cartridge that isn’t okay with this setting, by ensuring the cartridge has a less than 0.4mv output. 


Yes you will be okay. But no, its nothing to do with output. Different MC cartridges sound better with different loading, but it has nothing to do with their output level. Where you care about output is if the cart is very low output, making sure you have enough gain.

The reason you don't care about the loading is its so easy to get whatever you want. Buy resistor. Swap resistor. Listen. Repeat. A little extra hassle, well worth it for the savings I would think.
Certainly listen with no resistor at all first.


Why i suggested you search the archives.
The original suggestion that cartridges with output below 0.4 would work with 100 ohm load was probably based on the assumption that such cartridges typically have an internal resistance at or below about 10 ohms.  You want a ratio of about 1:10 or >10 between those two values. However there are exceptions. Denon for example; their DL103 has a high internal resistance yet low output and would not be well suited to your Gryphon. And finally you need to know that your phono section has sufficient gain for these low output MCs. Don’t buy a high output MC for this setup.
Okay, thanks All.  I think that answers the question sufficiently and the 10:1 or greater ratio makes sense.