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Okay, I ditched my high output cart (Sumiko BPS) in favor of an MC with .48mV output (ZYX R20h). So now I'm trying to figure out this whole impedence loading thing. My phono stage has switchable settings for 100, 500, 1K, and 47k ohms. I'd appreciate some advice as to what setting I should start with and what I should listen for in terms of optimizing it. In other words, what are the benefits and tradeoffs of lower impedence settings.
Turntable is Rega P3 w/RB300 Incognito rewired (by me).
Phono stage is PS Audio PCA-2 preamp w/built-in phono card - gain is adjustable from 52 - 67 dB in MC mode.
I looked at the Cartridge Database with those cool calculators, but what do they mean ???
Follow Ups:
What transformer is it?As the load impedance goes above source impedance the power is decreased. with the load impedance lower than the source current flow will be greatly impeded.
That and the fact the load impedance is a combination of resistance and reluctance (capacitance and/or inductance) which basically define a filter, like in a speaker crossover, and may now with the low resistance create an impedance at a certain low frequency casuing it to sound bright because those frequencies are missing.
My theory but in any case "don't do that!"
Yeah, I'm using a Denon AU-320, which has settings for 3 and 40 Ohms. The 3 Ohm setting sounds so much more dynamic and punchier, with a more forward high-end. I wouldn't say that bass was lacking at that setting, either tho.I've tried loading the 103R at 15 and 7 Ohms with resitors on the primary, but it still sounds better at 3.
How did you know you were loading it at 15 and 7 ohms? Did you open it up and see what values of resistors are being paralleled with the secondary when the 3/40 ohms switch is activated?You put those resistors on the primary, i.e. input side of the transformeer? I suppose an additional resistor could be put in parallel with the 40 ohm load to reduce it. Is that what you did?
I just know that "audiophile" values are to avoid the bright treble and prominent bass for a more subdued sound. Which is what it was like at the 40 Ohm setting.Yes, I paralleled the resistor with the 40 ohm load to reduce it to the other values.
Has anyone else played music? Am I the only one who cares about timbral accuracy?A brass instrument should BLAT out the sound. It is not smooth and refined. An Oboe will quiver. Smooth and refined makes it sound like a constipated Clarinet. Dulling the sound makes the first and second Violin lines congeal together. Violas sound like upper register Cellos.
Please!!! A true audiophile should be someone trying to somewhat reproduce true high fidelity sound. They would want a 4 ohm resistor. The so called audiophiles that want homogenized sound should save their money, their time, and their energy for other pursuits.
Make sure the soul is communicated in your music and you will always find satisfaction.
I generally with the above except for the condescending tone.Hey, this is a hobby and the reasons one occupies his time with it varies. Some like to hear the toot of a horn and others like to toot their horn.
Sorry for the tone.I really have it out for those that want the sound like syrupy mollasas (spelling error most definitely.)
Power transfer is maximized when transformer input impedance is equal to cartridge output impedance.Current from a cartridge is maximized when its load is zero-ohms.
Reluctance is a term that deals with magnetism and has absolutely nothing to do with resistance.
Please, Garth, try to control yourself in the future.
Garth, I am reluctant and resistant to put in my two cents worth on this. The magnetic flux of the purist tonality is pushing the extremes of my linearity and I am afraid the warp core will rupture and the positive matter and anti matter will end our hapless universe.John is right when he asks me to shut up. I am sorry he is picking on you. Perhaps we should both duck and hide a while while John is on the prowl.....
John I said and I quote myself here:"As the load impedance goes above source impedance the power is decreased."
Ok, you can turn it around and say as the load impedance decreases power is maximized. But as it goes below the source impedance it is no longer optimized.Read more carefully and try to control yourself in the future.
BW - reluctance is the term used when capacitance and inductance make impedance. Impedance is not just resitance but also reluctance in the form of some capacitance and inductance.
I'm sorry (for you) but I believe I used the term correctly and in context.
So, you don't want to troll anymore on the Schröder arm? Ok by me.
That is what my brain scan has confirmed. If anyone sees a brain running around somewhere in cyberland, it is probably mine.This same resistance, reluctance, capacitance, and inductance is what makes cable reviews so fun to poke at. Transparent Audio builds networks just to make their stupid copper cable sound like silver. I can build silver cable for 1/1000th the cost and it still wipes a network speaker cable.
Heck my friends are experimenting all the time with better quality teflon CAT 5 and are getting pretty respectable results.
The truth in all audio reproduction is that each little piece has an important contribution to the junk or the magic we hear.
I just wish my brain showed some resistance. It might help end my reluctance and induce me to capacitate a bit more.
But otherwise...
> > Of course I can experiment with the settings and decide on what sounds best, as another poster suggested.Yep
> > 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.
Impedance is the resistance of a circuit to the flow of AC, and it is frequency dependent. Therefore, changing the impedance of a phono circuit changes the frequency response curve of the circuit.
Lowering the impedance allows lower frequencies to flow more easily and impairs higher frequencies. Raising the impedance does the opposite. Your ears will confirm this if you simply try a few different settings.
The effects vary on a logarithmic scale (I think, help me out here John). At any rate, a change from (say) 100 to 200 ohms would be much more audible than a change from (say) 1,000 to 1,100 ohms. A change from 47,000 to 47,100 ohms would almost certainly be inaudible. This is why your phono stage's impedance options are spaced as they are.
> > Is there any danger in using the higher settings?
No.
> > Any harm in switching setings while the music is playing?
If it's an external switch, no problem. If it's an internal dip switch or requires resistor swapping, I'd power down first.
__________
"Do not meddle in the affairs of wizards, for they are subtle and quick to anger." - JRRT
NT
That the higher settings will yield a brighter sound, and the lower settings a darker sound, all else being equal. So by all means, do what sounds best to you. My Benz L2 Wood likes 1000 Ohms best, as does my Denon DL103. Or at least I like them best at 1000 ohms :-}
Rob
Set the load switch for the best sound. That's all that matters.
So many vinyl circuits are "massaged" one way or the other, experimenting is the best and only way to know you have nailed down the best sound.But please listen for timbral accuracy, and not for boom and sizzle. If the sound is right, the smiles will follow.
What are you hearing now from the current set up? Is it bass heavy or bass light, and what is your current loading?
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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