It appears that the Rega P3 is normally fitted with a Rega RB300 tonearm, which according to the listing at Vinylengine.com has an effective mass of 11.5 grams. Also, since the cartridge is made in Japan its dynamic compliance is probably specified on the basis of 100 Hz, rather than on the 10 Hz basis that is usually used by the calculators, such as this one. I would expect that its compliance at 10 Hz is **probably** in the rough vicinity of 10 or so. Plugging a compliance of 10 into that calculator in combination with a tonearm effective mass + cartridge weight of 11.5 + 6.5 = 18 grams results in a calculated resonant frequency of 11.86 Hz, which is within the 8 to 12 Hz range that is often considered to be ideal. But note the word "probably" in my statement. It’s hard to say for sure. Good luck. Regards, -- Al |
The crazy thing is this was a brand new P3 and I’ve used it without any trouble for a few months, then all of the sudden rumble from nowhere, so I moved the whole setup thinking the speaker was too close to the TT only to make the TT too far away from the Marantz and still rumble and now hum when the phono input is selected, and the TT isn’t even powered on! I have tried two different amps as well and the hum is still there, and I have a hum X on the amp power line plugged directly into the outlet in the wall.
In your current thread about power conditioners I noticed the following statement: I have a Sony OLED TV, Marantz preamp processor, Atoll amp, cable box, nighthawk router, Xbox, Rega P3 TT, and powered 12” subwoofer with 2 stereo speakers. I have 2 Monster JP 800 surge protectors if nothing else to plug everything into. My suggestion is that to isolate the causes of the rumble and hum problems you start by simplifying the setup as much as possible. Disconnect and unplug everything except what is needed for phono operation (turntable, prepro, amp, main speakers but not the sub). Remove the two Monster Cable surge protectors (some surge protectors can do funny things with grounds) and plug the prepro, turntable, and amp directly into a wall outlet. See if the problems are still present. If not, reconnect the remaining items one by one. Also, just a thought but cable boxes have been known to cause hum in audio systems, especially if something is amiss with the ground connection of the cable outside the house. Good luck. Regards, -- Al |
... as far as I understand, capacitance does not matter if you use a Moving Coil(MC) cartridge. The OP’s cartridge in this case is a moving magnet type. But regarding this point, generally speaking load capacitance is much less important in the case of a **low output** moving coil cartridge. But it can still matter, to a greater or lesser degree depending on the particular phono stage that is used, and generally speaking the less capacitance the better in the case of an LOMC. Lyra cartridge designer Jonathan Carr explained it as follows, in a post dated 8-14-2010 this thread: I should now debunk another myth regarding loading, which is that low-impedance MC cartridges are insensitive to capacitive loading. OK, the MC cartridges themselves aren’t particularly sensitive to capacitance, but the inductance of the cartridge coils will resonate with the distributed capacitance of the coils and the capacitance of the tonearm cable to create a high-frequency spike, and this spike certainly is sensitive to capacitance. In general, the less the capacitance the better. Having more capacitance (across the plus and minus cartridge outputs) will increase the magnitude of the high-frequency spike and lower its frequency, neither of which is good news for phono stage stability or phase response.
Generally speaking, the greater the capacitance across the plus and minus cartridge outputs, the heavier the resistive loading needs to be to control the resulting high-frequency spike. Conversely, less capacitance allows the resistive load on the cartridge to be reduced, which will benefit dynamic range, resolution and transient impact.
From the above we can deduce that tonearm cables for low-impedance MCs should have low capacitance. As a test, some time ago I built some 5-pin low-capacitance tonearm cables of 1.2m length (configured for use with a Graham Phantom). Including 5-pin and RCA connectors, the smallest-capacitance versions got down to 32pF, there was an intermediate version at 42pF, and the highest-capacitance version had 50pF. I felt that these low-capacitance tonearm cables resulted in greater flexibility in loading, a more natural tonal balance with better dynamics and resolution, and were a worthwhile upgrade. Regards, -- Al |
I wish I understood how that all worked. Impede sounds like it’s resisting something. So if the Marantz has low impedance then why would a tube amp have a hard time with it? So would I also want to make sure the operating ohms of a tube amp is on the higher end and closer to 30-40k? Yes, resistance is a form of impedance. For further explanation of the difference between impedance and resistance see my first post in the following thread: https://forum.audiogon.com/discussions/the-difference-between-impedance-and-resistance A tube power amplifier is very unlikely to have a problem with the Marantz. What I was referring to that **might** result in a less than optimal impedance match is driving the Marantz with the output of some tube-based phono stages. It’s important to distinguish between how output impedances and input impedances relate to the component providing the signal. From the perspective of the component providing the signal the input impedance it is driving appears in parallel. Thus the higher the input impedance the lighter the load it presents to the component providing the signal. While output impedances can be thought of as being in series with the connection, and thus the higher the output impedance the more the signal will be affected by the interaction of output impedance and input impedance. Which tends to be especially problematical if output impedance is high AND input impedance is low AND either impedance varies significantly as a function of frequency, in which case frequency response and/or phase response anomalies can result. And components employing tube-based output stages often have coupling capacitors at their outputs. The impedance presented by a capacitor increases as frequency decreases, which often results in the output impedance of a component employing a tube-based output stage being much higher at deep bass frequencies than the specified output impedance, which is usually based on a mid-range frequency such as 1 kHz. For further comments regarding impedance matching of line-level interfaces, see my first post in the following thread: https://forum.audiogon.com/discussions/amp-preamp-impedance-matching-can-anyone-explain Regards, -- Al |
I found a report that the cartridge capacitance for the MP-110 is either 100 or 300. As I said, "various anecdotal reports I found regarding what capacitance may be optimal for it are inconsistent and inconclusive." Those are very different numbers :-) Also, 100 pf is too low to be achievable with many phono stages in many setups. Is the goal to get the capacitance of the tone arm, phono cable, and input capacitance of the preamp to match the recommended total capacitance of the cartridge? Yes, for a moving magnet cartridge ideally the sum of the capacitances of the tonearm cable, the phono cable, and the input capacitance of the phono stage should fall within the range of load capacitance recommended by the manufacturer of the cartridge, assuming the manufacturer provides a recommendation. And they should provide a recommendation, but as in this case they sometimes don’t. What are your thoughts on tube preamp vs solid state. I have no experience with phono stages in the price range you appear likely to be interested in. But I’ll mention that some tube-based phono stages may have problems driving line-level inputs having low input impedances. (An input designated as being for connection of a CD player, for example, is a line-level input). And the input impedance of the line-level inputs of the AV7704 is not specified. So if you want to consider a tube-based phono stage it would be best to first ask Marantz what that number is. If it is say 30K or 40K (30,000 or 40,000 ohms) or higher there won’t be a problem with almost any phono stage. But if it is much lower than that some tube-based phono stages might have a problem. Good luck. Regards, -- Al |
Can somebody teach me how the capacitance works for matching to my Nagaoka MP-110? Unfortunately it appears that the manufacturer does not provide a load capacitance recommendation. And various anecdotal reports I found regarding what capacitance may be optimal for it are inconsistent and inconclusive. I did find mention of a measurement someone performed of the cartridge’s inductance, the result being 810 mH (milliHenries). That is a very high number, and suggests to me that relatively low load capacitance is more likely than not to be optimal. However that can’t be said with certainty, and in any event we don’t know what the input capacitance of the phono stage in the Marantz is. And of course capacitances vary widely among different cables, as well as being proportional to cable length for a given cable type. So it comes down to guesswork and trial and error at this point. If you do purchase a separate phono stage, though, it would be best to choose one which provides a choice of several different load capacitance settings. Regards, -- Al |
How much of a problem the capacitance of an RCA extension would cause, if any, depends on the particular cartridge. Let us know what that is. Hopefully its manufacturer provides a recommended load capacitance range.
Also, the input capacitance of the phono stage in your AV7704 adds to the load capacitance that is seen by the cartridge. Unfortunately the documentation on the AV7704 doesn’t specify what that input capacitance is. You might want to contact Marantz and see if they can provide you with that information.
Without having a load capacitance recommendation for the particular cartridge, and without having some idea of the input capacitance of the phono stage of the AV7704, unfortunately the answer to your question has no predictability. And for all we know, depending on those variables the added capacitance of an extension might actually improve sonics, rather than compromising them.
Regards,
-- Al
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