Cartridge loading explained

the thin end of the wedge
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SuperDaveKzoo
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Loading a 103R, DIN wiring from tonearm

Post by SuperDaveKzoo » 04 Feb 2009 15:35

Thanks for the information John and " ". I was looking for an inductance value to plug into the formula from the "Haggerman" site. I will try your recommendations. I will not be using a step up trans. My Perreaux preamp has "load" RCA jacks next to the MM and MC inputs where you can install non-wired jacks with resistors soldered across. I will solder some together with different values and listen.
On another note, my Oracle Alexandria wiring from the tonearm DIN plug to the RCA input jack has been damaged, by a mouse of all things. The little b'stard even ate through all the motor wiring. Would it be worth purchasing a new DIN wiring harness that runs direcly from the tonearm DIN jack to the preamp inputs, or should I just re-solder the damaged originals? Not sure if it matters but, the tonearm is a Fidelity Research FR64fx.

Thanks in advance, Dave

SuperDaveKzoo
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Tonearm wiring

Post by SuperDaveKzoo » 05 Feb 2009 16:07

Thanks for the info. You confirm my suspicions, less conections the better.
Do you think it would be worth it to purchase a DIN tonearm cable with silver wiring or would copper do the trick? I do remember from chemistry, a bazillion years ago, that silver is the best conductor in the known universe.........

Thanks, Dave

SuperDaveKzoo
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Tonearm wiring

Post by SuperDaveKzoo » 06 Feb 2009 20:19

Thanks for your input. I would be very interested to hear from you after you get a chance to audition your new cable. I am going to continue to research this topic further before I plunk down any cash.
I recieved an e-mail from my uncle, who has an electrical engineering degree from MIT. This is what he said in relation to this subject. "With respect to "high quality" cables, I've not found that they make a detectable audible difference. There are maybe three parameters that make a difference in cable performance. First, as mentioned above, the connectors should be gold plated. Second is the frequency response of the shielded cable, but even the cheapest cable you can find will pass signals at 1,000 times higher frequency that you are listening to. Third, you don't want cable that has "triboelectric" response, e.g. generates electrical signal in response to vibration or noise. For some medical applications for example, you need to use special cable to ignore flexing and motion. But I've never seen audio cable that is specified as "low triboelectric response", no matter how expensive it is. So I'm not convinced that the expensive cables do anything. Same is true with silver wire or "low oxygen" copper wire. I've never heard any difference in sound, and I'm unaware of any theoretical rationale of why they should sound different. There are so many other things that do affect sound quality, and that are measurable and audible, that I don't mess around with the "ethereal" stuff".

Good to hear other view points...........

Thanks again, Dave.

carlosfm
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Re: Tonearm wiring

Post by carlosfm » 06 Feb 2009 22:23

SuperDaveKzoo wrote:Third, you don't want cable that has "triboelectric" response, e.g. generates electrical signal in response to vibration or noise. For some medical applications for example, you need to use special cable to ignore flexing and motion. But I've never seen audio cable that is specified as "low triboelectric response", no matter how expensive it is.
Well get some half decent balanced microphone cable and there you have it.

MuZak

Post by MuZak » 06 Feb 2009 23:02

Now THIS thread IS worthy of a sticky!!

XTRProf
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Post by XTRProf » 08 Feb 2009 03:30

MuZak wrote:Now THIS thread IS worthy of a sticky!!


Yes, Excellent. X2. :D

SuperDaveKzoo
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Post by SuperDaveKzoo » 09 Feb 2009 15:32

Indeed ........X3!

SuperDaveKzoo
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Post by SuperDaveKzoo » 12 Feb 2009 14:24

Thanks for your input . I had a feeling that my uncle's opinion on this might rub some people the wrong way. Everbody has an opinion, especially when it comes to audio............as you know. Personally, I am trying to gain as much information and input on this subject as I can. My previous HOMC, a Denon DL-160, that I ran into the std. 47 kohms, sounded so bright, I taped napkins over the tweeters just to make it listenable. I recently loaded it with 1kohm resistors based on some forum recommendations..........it is still not right, it sounds a little less bright, I THINK but, that may just be wishfull thinking. With my "new" setup i.e. Oracle, Zu DL-160R, Fidelity Research, I would like it to be "correct" when its all put together. I am willing to spend the money to make it work, and I appreciate you and others helping me on this quest. I think I am going to invest in a cable that runs from the tone arm directly to the preamp. It seems you can obtain a half copper half silver cable for around $ 100.00 or so, which seems to be a fair price. If you or anybody else has any further input or recommendations for me, I would appreciate it more than you can imagine. Thank goodness for forums like this one...........I have learned a lot. Regards, Dave

carlosfm
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Post by carlosfm » 12 Feb 2009 17:22

The Denon DL-160 simulates well at 1K, with 100pF total capacitance.
160 Ohms impedance, 490uH inductance.
It produces a gentle falling curve, with -1.3db at 20Khz and -1.47db at 100Khz.

The 100Khz figure is just so that have an idea of FR curve.

Keeping the 1K loading, if I change the 100pF capacitance to 300pF, the falling curve turns into a rising curve. It is still at -1.28db at 20Khz, but very gently rising - when it hits 100K it is at -1.23db.

This looks insignificant but it may still be enough to produce a "bright" character.

I think that a good compromise would be something around 1K (probably even a little lower - like 680 ~ 820 ohms), keeping capacitance to a minimum - 100pF, wiring included.

I hope this info is useful for you and take it as a starting point.
Some feedback on results would be nice. :mrgreen:

carlosfm
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Post by carlosfm » 12 Feb 2009 22:16

The capacitance has a big impact...
If 1K loading still sounds too bright, I suspect that the overall capacitance (wire + cap on the input of the preamp) was too high.

SuperDaveKzoo
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Cartridge Loading

Post by SuperDaveKzoo » 13 Feb 2009 12:33

Thanks for the information gentlemen. As I mentioned in an earlier post, my pre amp has "load" RCA input jacks next to the MC and MM RCA inputs that you can install blank RCA jacks with resistors or capacitors soldered across the leads. Is there any way to solder in resistors AND capacitors to obtain the required "loading"? Or, would it be better to install a shorter, better cable. The DL160 is installed on an old Pioneer unit from the 70s. Cant remember the model off the top of my head. Its a pretty stout unit. I havent taken it apart but, I assume it has the standard RCA leads "hard wired" in. This Pioneer TT will sit next to my Oracle and will be used for vinyl that is not in "premium" condition. I am going to send the Oracle back to the manufacturer today. Motor still will not run after I soldered all the wires back together that the mouse ate through. They said there is "no guarantee" that they can fix it. I have read on other posts that the original Pabst motor is no longer available. If they cant install a motor assembly that they use in their current models into my "old" Oracle, I wonder what my options are. I seem to recall some posts where individuals have installed after market motors / controls in their units. Any ideas on this? Also, I assume Vdh stands for Vandenhull. Is that correct?

Thanks, Dave

rayr0683
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Resistor Quality Question???

Post by rayr0683 » 27 Feb 2009 14:51

Hello All,

All that seems to be readily available at local electronic supply stores in the Philadelphia,PA area are NTE Flameproof Resistors, in 1/4 and 1/2 watt values. They dont specify what type that they are....so I emailed NTE and asked them...they told me that NTE Flameproof resistors are Metal Film resistors, and Len at Audio Research Company says to use only Metal Film Resistors for Loading in SP9 and SP11 Preamps, etc..

Ray :?:




The quality of the resistor does have effect on the sound.
I use carbon composite , preferably Allen Bradley , but Philips will do allmost as good. Metal film sounds too harsch in my opinion.
It's depending on personal taste.
When tuning your cartridge loading you have to consider component quality in the entiry chain as well.

regards

Ron[/quote]

Reticuli
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Post by Reticuli » 20 Mar 2009 20:39

I reread the entire thread last night and slept on it.

I think there's something fundamentally flawed with the math and line of thinking involved somewhere.

You guys are saying you want the capacitance load for a moving magnet or moving iron cart to be as low as possible, then you simply adjust the impedance it sees.

However, every MM and MI cart in the world is "voiced" at 47kohm. My understanding was you raised the capacitance to match the inductance in order to diminish the electrical (as opposed to mechanical) resonance, but that does not necessarily dictate where the high frequencies roll off.

The 680 series has always worked best for me at 330pF+cables.

The Nagaoka mp-11 says in both the lit and online reviews you need well over 500pF to get it perfectly flat.

Audio Technica recommends about 275pF total to get the response they show in their cart manuals that have 500-600mH inductance.

And on and on. It seems like a pretty simple thing to say keep the capacitance as low as possible. So use short shielded coax phono cables and little or no loading caps on the phono stage. Then just have a 100kohm pot on the phono preamp inputs.

It's so simple if that's all it was it probably would have become the standard decades ago. I don't think it's that easy, though. Why has 47kohm become the input resistance standard and capacitance matching specs are necessary?

Why hasn't instead just near-zero capacitance become the standard and continuously adjustable impedance for boosting or quieting the extreme high end like a tone knob proliferated? There has to be a reason more than just "it's a lost art".

There are empirical examples of lowering capacitance yanking out a big chunk of the midrange in this thread. And there are plenty of instances where cartridge manufacturer recommendations for cap loading is dead on. All at 47kohm.

I think this is further exacerbated by the overuse of these math internet programs. The difference between the Hagerman and other methods’ theoretical solutions alone are often 10-20kohms...that's indicative there’s a major discrepancy in the theory. If the various functions cannot give a consistent answer, then one or both is wrong.

I am also troubled by the lack of real-world frequency response plots in this thread after the first few pages. Most of the original poster's tests exclusively involved the extreme high treble. There is no chance any of you can hear the cartridge's response changes in the 18-50khz range, assuming dynamic linearity stays the same (i.e. response of multiple amplitudes at once).

The early example given of the Grado Prestige, a 45mH cart, was within 1dB of flat at 20khz no matter what was done. And still this was shown as a primary example of impedance matching. Unless some of you are dogs, the Grado's ultrasonic response is essentially pointless to worry about. Indeed, go back to that early post and no listening tests are even mentioned in this case.

Now, if the inductance and capacitance are wildly mismatched for the given impedance seen -- say, running a 680 at 200pF total into 47kohms -- and the frequency is in the lower audible range, then I can certainly believe you're hearing an adverse change. The resonance effects cause massive compression when you get a peak in a filter state like that.

But as for the rest, I'm very skeptical of all this. It seems in an effort to get flawless high treble and ultrasonic response you may be ignoring the lower bands that your ears are more sensitive to in the first place. Most music information is found in the midrange, with the low treble and upper bass coming in second.

Please, convince me that impedance matching is the way to go and leave capacitance low on all MM & MI carts. Dissuade me from years of believing capacitance matching was the method cart manufacturers used with a fixed 47kohm.

I want to believe.

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Post by Reticuli » 21 Mar 2009 01:32

Well then the math is WAY off (internal resistance ignored or not), because Hagerman's page says at 47kohm you should be running the 440ML at 220pF total capacitance, or at 100pF total you should be running over TWICE the 32Kohm you're running now. Maybe you just don't like the 440ML's highs and you're essentially using the impedance as a treble control to tame them.

That said, if hypothetically you guys are in fact on to something, I highly recommend you take a look at the TCC phono preamps with volume pots. The 220pF caps are clearly marked and can be easily removed. Ditto with the 47U/25 resistors that I assume are in the circles right next to the row of transistors for each channel, right? Not much of an electronics person, so that’s a guess.

The volume pots are already stereo 100Kohm stepped attenuators, so I would think all you'd need to do is pull the caps and resistors (I don't know if you need to put blank loops in their places), solder out the pot, and wire it to the phono input...right? I’m not sure how you anchor the pot that way, but all the components seem in it already. The TCCs are dirt cheap, discrete components, and sound amazing.

I sent my two TCC-750LC's to a local tech to have the 221pF caps changed out to 100pF, but I'm wondering if maybe I should call him and see if he'll attempt that. What do you think? I know that at 100pF it will flatten the highs compared to right now with the Shure Whitelabels (15MR bodies), Ortofon OM, and ATP-2, but this won't extend the treble up to spec if this jive is correct.

TCC-750 (non-LC version) ...doesn't have the pot.

3870

rayr0683
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440ML and Loading

Post by rayr0683 » 21 Mar 2009 01:58

Hello,
Im using a 440ML right now, that is borrowed from a friend. I have a ZETA Vandenhul Silver Wired Tonearm. My Preamp is an Audio Research SP9....there is 560pf of capacitance at the phono inputs of the SP9, and I do not know the Capacitance of my ZETA Tonearm. I started out leaving the 560pf capacitance as is, and used the 47K Loading from factory on SP9. The 440ML sounded a bit bright, and thin....but very detailed, punchy and tight. So, after everyone telling me to take the 560pf of capacitance out of the SP9, and just use the Capacitance from my ZETA Tonearm, and the 47K resistive loading....so I did this. Now I am thinking that it may have sounded better with the 560pf capacitance in the circuit, along with my ZETA Arm capacitance. I didn't mess with the 47K resistor load, because Audio Research told me that I would not be able to hear a difference between the 47K and 32K Ohm Loads....so I just took their word on that. I think that the 440ML does sound detailed and nice...but im feeling that compared to the Grado Signature TLZ or the AT-OC9 it is outclassed. Unless im doing something wrong. Thanks, Ray
Reticuli wrote:Well then the math is WAY off (internal resistance ignored or not), because Hagerman's page says at 47kohm you should be running the 440ML at 220pF total capacitance, or at 100pF total you should be running over TWICE the 32Kohm you're running now. Maybe you just don't like the 440ML's highs and you're essentially using the impedance as a treble control to tame them.

That said, if hypothetically you guys are in fact on to something, I highly recommend you take a look at the TCC phono preamps with volume pots. The 220pF caps are clearly marked and can be easily removed. Ditto with the 47U/25 resistors that I assume are in the circles right next to the row of transistors for each channel, right? Not much of an electronics person, so that’s a guess.

The volume pots are already stereo 100Kohm stepped attenuators, so I would think all you'd need to do is pull the caps and resistors (I don't know if you need to put blank loops in their places), solder out the pot, and wire it to the phono input...right? I’m not sure how you anchor the pot that way, but all the components seem in it already. The TCCs are dirt cheap, discrete components, and sound amazing.

I sent my two TCC-750LC's to a local tech to have the 221pF caps changed out to 100pF, but I'm wondering if maybe I should call him and see if he'll attempt that. What do you think? I know that at 100pF it will flatten the highs compared to right now with the Shure Whitelabels (15MR bodies), Ortofon OM, and ATP-2, but this won't extend the treble up to spec if this jive is correct.

TCC-750 (non-LC version) ...doesn't have the pot.

3870

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