Ortofon 2M Black - frequency response charts

I think there is some sense that designers of phono stages can create an advantage for themselves by creating products that meet the real-world demands of MM carts, rather than including the standard defaults and built-in high capacitance as an afterthought, assuming most critical listeners are going to use a MC.

 

Don't many MC carts have a rising top end, anyway? To me you should be striving for the sound you like and your system requires. I think for too many people who think that lps have sounded thin over the years it is that the loading was not right for their rig and cart. It is clear that a diff of 200 in Cap can make huge difference.

What is interesting is some prefer much different resisttive loading outside of 47K. It would be nice if every table manufacturer would accurately specifyseperately the cap of the tonearm wiriing and the cables they supply as that would help solve much of this and give the table owner a mathematical starting point. It is clear from this thread that it is very important.

 

You almost have to rewire your tonearm to get a fair run at it, which is what I have done. I know from conversations with Michael Yee, he was surprised that the 200pF/300pF native settings on his phono stage were high.

We also need solid inductance figures from the manufacturers. I have to work with a range because of conflicting published data.

 

Yes, I know what you mean but I think I can explain that. What I should have said is that for every chart, the software calculates the mean (average) response for all frequencies and arbitrarily calls that "zero" purely in an effort to make comparisons easier - it's not zero in real life or it would be silent! Unfortunately, if you get a bigger hump on one chart than another chart, that will change the mean and therefore you get a situation where the whole line shifts its position relative to the "zero" level, which can give a misleading impression if you don't realise what's going on. The important thing to remember is that it's the shape of the line that matters, and the amplitude of the frequencies relative to one another - the position of the line relative to the "zero" level is meaningless and can vary from chart to chart.

Oops, sorry, I missed the MC bit! But I agree with your verdict on the chart - it sounds as bad as it looks.

Thanks, Jim, much appreciated.

Like jupiterboy, I'm not sure we're any the wiser but what could be more fun than gazing at charts?

 

When digital sounds bad there is little we can do but replace the player of buy a new DAC. It is now clear by what you've done that Carts are the most tweekable and can make a serious improvement in vinyl enjoyment, yet the cart companies don't seem to bent on help customers in this regard.

I will say that the next phono stage I buy will be extremely adjustable, even if I only adjust to the sound that I prefer without the extensive work and measurements you have done. Most of us don't really know if our phono stages are actually 47K. They could be + or - ,10-20% for what we know. Great work.

 

I have been using an AT 150MLX as my primary for a couple of years, so I have been following along.

 

There is often some rise in output down at 20hz due to the main LF resonance.
If as will typically happen, you main arm cart resonance peaks say 10dB at 10hz it will still be impacting the bottom of the audible range by a couple of dB.
Assuming the phono stage isn't rolling away by then.

 

They do Jim.

There is a mechanical resonant peak in the cantilever assembly (often called the tip mass resonance) and with MM, losses in the high inductance generator act as a counterbalance to bring this down near flat.
With MC there is very little inductance but we still have a HF mechanical resonance, hence the rising top end. However, many MCs using advanced cantilevers push the resonance way above audibility and so appear flat over most of the range. A good example is the Dynavector DV17s with tiny diamond cantilever which I think has it's resonance out past 40khz and so appears dead flat at 20khz.

 

Sorry to bump up this old thread but I recently updated from a 2m blue to the 2m black and I am looking for a new phono pre to adapt better to the black. I am currently using the Pro-Ject Phonobox SE II and have set it to 120pf ( ~100pf in the Technics 1200mk2 I use)

I have been in contact with a German engineer who builds his own version of the Aikido phono pre but with FETs instead of tubes. He send me this chart and said for my tonearm (100pf) and the 2m black he would recommend a capacitance of 5pf in the pre and a resistive loading of 64k Ohm (blue curve). I would get the pre modified so I could choose 5pf, 47pf and 180pf as well as 33k Ohm, 47 k Ohm and 64 k Ohm.

Does this sound reasonable? From reading this thread I am sure the 5pf setting will be beneficial but I thought the resitive loading mentioned here was 33 k Ohm?


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The higher value for impedance has to be seen alongside the very low 5pf capacitance. That's extremely low and actually very difficult to achieve in practice as stray circuit capacitance often exceeds that value. In fact that value probably is the stray figure and there will be no loading cap. Theoretically it will give a very extended response.

 

Would you think there would be an audible difference between those proposed values (blue curve) and the capacitance (220pf @47k Ohm = red curve) I am running at the moment?

 

Anyone other ideas? I think I am going to try the phone pre.

 

Well, at a glance, I think anyone would have to say the blue curve looks a lot more attractive than the red because it pushes the hump further towards the very high frequencies where it will be less intrusive and also pushes the fall-off that follows the hump almost out of the audible range.

In very non-technical terms, lowering capacitance pushes the hump to the right (the further, the better, to get it out of harm's way) while lowering resistance squashes it down.

So, you say, why not just squash those humps flat with lower resistance and be done with it? The problem is, as you can see from your charts, the hump is followed by a big fall-off. If you squash the hump flat, the fall-off tends to happen earlier (meaning further to the left) than it otherwise would and this can have the effect of drastically rolling off the high end, which is obviously not desirable.

I'm talking in very general terms now, not about any cartridge in particular. But maybe your German engineer is recommending HIGHER resistance for the 2M in an attempt to delay the point at which the fall-off begins until it is beyond the audible range.

 

There are mathematical ideals. But, what you are saying is very true to my experience. I can load my cart at 100K, 61.5K or smaller increments downward with plugs. The issue is our speakers and amp, and how they handle the extended frequency (He said not being able to hear above 16Khz.) I have yet to order an accurate capacitance meter to test the tone arm cable manufacturer’s stated capacitance, nor have I cut the cable down to a shorter length to reduce capacitance even further. All I need is some time and the budget for some Eichmann RCA plugs.

 

I agree. I find 5pf to be silly. The phono lead itself will have at least 100pf, so you have essentially just wasted one of the setting positions as 5pf is basically 0. or (0 + 100 = 100pf total). The 47pf is also so low and so close to the 5pf range that it will be useless. I'd say the phono stage gain structure sounds interesting and if it's within your range and interests you, then I'd order it with 0pf (5pf, whatever) 100pf, and 180-200pf. That will give you three options with the phono lead contributing to what will be three real world loadings of about 100pf, 200pf, and 300pf. The resistance loading values are OK but if you only have three, I'd go a bit lower and choose 1k, 33k, and 47k.
-Bill

 

Sometimes it's quite useful not to be able to hear above 16kHz! I doubt if I can, if I were honest.

For a meter, I bought an LC200A fairly cheaply on eBay and it works well.

 

I do not know whether I can hear above 16kHz but the black has so far been responsive to the smallest changes in VTA for instance more than the 2m blue I own so I think the capacitance change will be audible as well.
I am looking forward to testing this preamp. It will be a pure MM preamp and I can test it for 14 days and see if I like it or not.

 

What do you do to make sense of frequency response with a pink noise recording? If I recorded a pink noise track from a test LP, what steps would I go through to obtain a log scale of the frequency response? I'm thinking I could get the same effect from looking at the waveform of a recorded frequency sweep. Are the results more accurate using pink noise?

 

Jumping on an old thread, I wanted to add some words regarding the 2m black. I have the DBP-Capacitance loading kit and am using the 400pf capacitor plug and it sounds best for my set up. The highs sound smoother. I am able to keep my EQ more in the middle. I am using a Marantz 2230 as the preamp, which has been upgraded and refurbished, and blue jean cables. I believe this would put my capacitance at or above 500pf. I called Ortofon and asked them about this and the tech who called me back said adjusting capacitance was of such a minor detail that it is ultimately about what you think sounds better. My Marantz is going into a modified by Tubes for HiFi Dynaco St-70 and my speakers are Dynaco A25's with the Madisound A26 wiring and tweeter, along with radio shack super tweeters and a polk sub. Both the sub and super tweeters are blended. The ortofon tech did say that making the impedance lower would go against the grain of the design more than tweeking the capacitance. That they had a panel to determine the 47k impedance and that it is not suppose to be flat in its response. There is suppose to be a glimmer and sheen on top that jumps out and if you don't want that then you should probably use a different cart. His words not mine. Hopefully this is of help to others searching threads about this fine cart.

 

Great thread. I would love to see response graphs for the Sumiko Pearl, Ortofon MC1 Turbo, Dynavector 10x5, and the Grado DJ cartridges.

 

Another bump to add thanks for this immensely helpful and informative thread; it made all the difference in fine-tuning my 2M Bronze, which has the same inductance and recommended capacitance range as the Black.

 

34K is where I've settled on this cart in my system. Wish I could get it to track better though.

 

I'm surprised you are having an issue with tracking. What arm have you got it in? Needs to be a fairly low mass one as it's quite high compliance, 22cu IIRC. I'm running mine in a SME M2-10, which is fairly light at 9.5g effective mass, so a decent match. It tracks beautifully, quiet, solid and generally unflappable with very clean tracing end-of-side.

 

SME 309. On paper should match. Resonance confirmed okay with test record.

Set up using the SME alignment protractor. Null points (63,62mm & 119,46mm) double checked using universal protractor on HiFi News test record. Azimuth set level with spirit level (accommodating for the slope on the top of the headshell). Stylus Rake Angle adjusted in increments of playing card thickness to find the best tracking (ending up tail high for least distortion). Vertical Tracking Force set at 1.70g using digital scales at same height as average record surface (scales checked with class M1 calibration weights). Both deck and tonearm base set with spirit levels.

I expected hassle setting up a Shibata stylus, just not this much.

I envy you.

 

Based on all the info in this thread I had a question. I have a Rega incognito wired tone arm. So that would be 50uF.
Im using the Ortofon 2M black. Right now Im using the Bellari VP129 but ive decided to upgrade to either the two phono preamps below. So was the final concensus that the 2M Black should be set at 33uF and 100uF ? Not sure how I would do that with these two preamps

Phenomena II phono preamp
Gain Switches (dB)
40, 44, 46, 48, 50, 51.5, 52.7, 53.7, 56, 57.5, 58.4, 59.4, 60
Input Loading Switches (Ohms)
30, 40, 50, 59, 80, 100, 121, 150, 243, 280, 380, 475, 660, 1k, 2k, 50k, 100k

chinese made "Little Bear T10-Pro 12AX7B Tube valve Phono Turntable RIAA Preamp"
RIAA phono stereo
RIAA freq response 20hz-20kHz +/- 0.5dB, S/N ratio >92dB
THD <0.05%, input sensitivity 3.0mV, gain 50dB
Output impedance 200 ohms, input 47k ohm / 220 pF