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In Reply to: MM vs MC (not Spy vs Spy) posted by tlea on August 5, 2005 at 23:41:55:
What are you hearing now from the current set up? Is it bass heavy or bass light, and what is your current loading?
Follow Ups:
The seller recommended 100 ohms.
Sounds a bit muddy in the bass, and there's a slight hum.
But the mud could be a VTA issue and the hum probably is a grounding problem. Also, the cart has not been properly run in yet.Maybe I should have posed this a theoretical question rather than giving the details. Of course I can experiment with the settings and decide on what sounds best, as another poster suggested. But in addition to that I am interested in knowing more about what are the characteristics of and differences in the impedence loading settings, in terms of sound perception or physics or both. Is there any danger in using the higher settings? Any harm in switching setings while the music is playing?
This is new territory for me. With the high output carts I've owned previously, it's just set it and forget it.
So on my preamp, I load my cartridge with a 450 ohm and a 860 ohm resistor. The value is 450 times 860 divided by 450 plus 860. This gives me great bass and all the instruments have correct timbre. I do not have a calculator with me at the time so I cannot tell you exactly what the value is. I started with 450 and 1320 ohs, then 450 and 1280, then 450 and 1150, then 450 and 980, then 450 and 860 and this is what sounds awesome!Just remember you can parallel two resistors to get this level of perfection in your loading rather than settle for a mediocre sound.
If I use a 640 and 450 ohm resistor the sound is shelved down on the highs and the timbre becomes very dark. I pick the timbral accuracy point where violins, violas, cellos, woodwinds, and brass all have the right tone. Get it? This is really easy for me to do cause I soldered in a post that connects to jumper cables. So I can switch in a dozen resistors in an hour to fine tune. Be prepared to play a bit and you can really nail it down tight.
We are here to help!
Hi Tubes,You gotta go with what sounds good to you but I would like to point out you experiment above is random and incomplete. The actual values you ended up with are the following:
332, 322, 320, 305 and the final 293. The value found to be too low was 262 ohms. What about the values between 262 and 293, there may be a better one than the one you chose, who knows?
I personally don't see this as a level of perfection since the range of resistance you left out is a large as the range you tested larger than the value you ended up with.
Is this hair splitting? Yes, of course.
My testing is only limited by my available supply of 1% resistors. I do plan on buying some nice Vishay resistors for my preamp, and I will try to find some values between these points just to check. I thought of using a trim pot, but afraid that the quality might negatively effect the sound and my ability to choose wisely.I have a few Philips records that are nasty bright. I did try the 520 ohm and 450 ohm on these albums and the sound became much more neutral.
Now I have to find some explanation why I would ever need to change the resistor value for a brand of recordings???? I may very well be insane. But these once super crisp albums are now more balanced, but still hard sounding.
Anyone else have this same problem or even care about the issue.
I have a calculator and know how to use it!!
because the two resistors are also in parallel with the 47000 ohms input of the preamp. But for all practical purposes any value 1000 or under will result in that value more or less when paralleled with 47000. For instance 1k is actually 979ohms. That's about the tolerance of the resistor.
My post show the label values, each resistor at 1%.The 47k resistor goes positive leg to ground, the cartridge loading goes from this leg to ground to the phono circuit.
So do you consider the cartridge loading as a fine tune of the 47k phono circuit?
We already discussed the fact that my brain scan confirms I have a zero ohm or dead open circuit! But my stereo sure kicks ass! Brain dead or not, I have a smile from ear to ear!
LOL
"So do you consider the cartridge loading as a fine tune of the 47k phono circuit?"Well, as I said before the circuit being changed is a combination of resistance, capacitance and inductance. These three elements in whatever combination occurs in your preamp (and practically no one knows that that actually is) create a filter. Changing the resistance changes the filter. It also changes the impedance which affects the frequency response of the cartridge.
So consider it what you will. Since the actual value of the resistance is somewhat arbitrary, there is no "correct" value for a given cartridge, the use of a 1% resistor only helps assure channel to channel sameness without actually measuring the two resistors first. I use standard 5% film resistors and actually they are more like 1-2% when a small grup are measured. But it doesn't matter unless you intend to create a given know impedance value and want to be dead on but that is different from empirical listening tests.
Sorry, my mistake three not two resistors. The calculator was not at fault, just me!Answer is 301.2048 ohms. No?
It seems to me that any proper calculator should be accurate to five significant figures. Here's the answer that my calculator provides.R = 1/(1/47000 + 1/860 + 1/450) = 293.574575917
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