Hi Pani, I'm not sure what to make of Mr. Qvortrup's statement. After looking at the descriptions of the various SUTs listed at the Audio Note UK site it does appear that his reference to "primary impedance" refers to something other than the reflected load impedance. The descriptions appear to imply that his various SUTs have "primary impedances" ranging from 1 to 64 ohms. But I have no idea whether that means DC resistance, impedance at some frequency when some resistance is placed across the secondary, or what. Also, those listings all state that: It is important to appreciate the utmost importance of getting the impedance
matching between the cartridge coil and the primary of the transformer as
close as possible.
But what constitutes an optimal match is not stated. The ART9 has a specified DC resistance and a specified 1 kHz impedance of 12 ohms. (The two numbers are the same because the impedance presented by the cartridge's inductance at 1 kHz is very small). So his 30 to 40 ohm recommendation is about 3 times that value. I have no idea what his basis for recommending that ratio may be. Finally, my impression is that whatever he may mean by "primary impedance" is not specified in the case of most other SUTs. In any event, after reviewing the detailed specs on the Jensen SUT I see no technical issues that would arise using it with the ART9. And FWIW, as you may be aware the Jensen line-level audio transformers are used with fine results by many audiophiles, and I believe are also used internally in some well regarded high end components. Good luck. Regards, -- Al |
J_Damon, while a number of members here have reported excellent transactions with 2Juki, including purchases of the ART9, if you are in the USA you may want to consider LP Gear. They are currently offering it at a special price ("subject to allocated stock") that is only $59 higher than 2Juki's current price, but which would get you a USA warranty. Re your Mac C2200 preamp, it provides about 15 db of gain for its line-level inputs, which is plenty for a line stage. So while you may find yourself using the volume control in the upper part of its range (depending on power amp gain, speaker sensitivity, preferred listening volume, and the dynamic range of particular recordings), that in itself is not a problem and the issues I mentioned in my previous post that might arise in a few systems will not arise in your case. Oregonpapa 1-6-2017
... the ART-9 doesn't seem to have a rising top end built into the design. I
believe this is one of the major things that contributes to the natural
sound of the cartridge. Maybe someone with more technical knowledge
than I would like to comment on this.
That has been my perception as well. The cartridge is very well balanced and accurate throughout the spectrum, and does not over-emphasize or under-emphasize any particular part of it. I can't shed any light on why that may be so, even though extensive technical specs and descriptive information are published for the ART9 (kudos to Audio Technica for that). But it's interesting that it is able to display that sonic character regardless of whether it is loaded with 100 ohms (as in your case, with the ARC PH-8), or with a nearly infinite number of ohms (as in my case and that of two or three others who have posted in this thread, with the Herron VTPH-2). Regards, -- Al |
J_Damon, based on the many reports we’ve seen here from purchasers of the ART-9 it would seem that while there have been a few isolated cases of misoriented cantilevers the odds are heavily in your favor that a replacement would not have that problem.
Regarding compatibility with the associated equipment you mentioned, I have no knowledge of the technical characteristics of the arm on the VPI Super Scoutmaster. But I would point out that the relevant technical specs on your ARC PH-6 are identical to those of Oregonpapa’s PH-8. And as you’ve most likely seen his results with the cartridge have been fabulous. The only conceivable technical issue I can envision is that in the very unlikely situation where the combination of preamp gain, power amp gain, and speaker sensitivity is unusually low the 58 db of gain provided by the PH-6 (and PH-8) might on some recordings result in having to turn the volume control on the preamp so high that you would risk running out of range. Or if preamp gain and power amp sensitivity are both very low (meaning that power amp sensitivity is numerically high) you might not be able to turn the volume control high enough to drive the amp to full power, should you ever want to do so. But those issues would only arise in system configurations that are unusual, and if you’ve already used some other LOMC in the system you would almost certainly have noticed any such issue already.
Good luck. Regards,
-- Al
P.S: Frank (Oregonpapa), thanks very much for the nice words in your last post.
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Avanti, no the RF issue I referred to would have no relation to a hum problem. Not sure what to suggest in that regard, given that you haven't had that issue with other LOMCs. FWIW I had no such problem.
Good luck. Regards,
-- Al
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Avanti1960 1-2-2017
I have the loading at 100 ohms.... the dynamics are not as good as i thought they would be though compared to my dynavector 20X2L. I would try a much higher value than 100 ohms. The need for heavy resistive loading is driven primarily by the sensitivity of the particular phono stage to radio frequencies, that can be introduced as a result of the resonant peak in frequency response that occurs at RF with LOMCs due to the interaction of cartridge inductance and load capacitance (load capacitance referring to the sum of the capacitances of the phono cable and tonearm wiring, and the input capacitance of the particular phono stage). Several experts, including Keith Herron and Lyra cartridge designer Jonathan Carr, have stated that loading a LOMC with a lower resistance value than necessary can compromise dynamics. I’m running my ART9 with a Herron VTPH-2 phono stage using its "infinite loading" provision (which presents the cartridge with a load resistance value that is MUCH higher than even 47K), which draws essentially zero current from the cartridge, and just responds to the voltage it is putting out. Dynamics have been great! Frank (Oregonpapa) has found 100 ohms to provide great results, but I note that his phono stage (the ARC PH-8) has a specified 3 db bandwidth of 400 kHz, which I believe to be exceptionally wide for a phono stage. The result very conceivably being that in the absence of that heavy load the phono stage and/or components further downstream may be exposed to greater amounts of energy in the RF region than would usually be the case. So depending on what phono stage you are using his results stand a good chance of not being applicable to your system. Regards, -- Al |
I'd like to extend my thanks to Pani and to all of the other posters who have provided comments on their experiences with the ART9. I recently purchased one, largely because of those comments, and although it is not yet close to being broken in I am already completely thrilled with it.
It replaces a Soundsmith-retipped Grace F-9E Ruby moving magnet cartridge I have used for the last few years. And although I have been sufficiently pleased over the years with the Grace F-9E series that I have used it in various incarnations for the majority of the past 35
years, I would have to say that the ART9 is in a different league altogether. Most notable among the numerous improvements it has already provided are considerably increased detail and better
definition in the treble region, cleaner and more accurate response to fast transients, and improved dynamics. All of which it accomplishes without a hint of excess brightness.
I purchased it, btw, from Japan-Select-Shop, the seller to whom Oregonpapa linked just above. The transaction was speedy and perfect. As is the cartridge, on both counts :-)
Regards,
-- Al
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Hi Lew,
My re-tipped F9E Ruby is Mr. Ledermann’s CL version, not the OCL version you have.
Since I purchased my Herron VTPH-2 phono stage a few months ago I too was running it at 47K, with load capacitance being the Herron’s MM input capacitance of 100 pf plus the unknown capacitances of my approximately 5 foot phono cable and the tonearm wiring.
Of course an additional variable in the mix is that the input stage of the Herron that is used for the two cartridges is different. Although I suspect that the difference essentially just involves insertion of the Herron’s FET-based LOMC stage into the signal path for LOMC’s, with the rest of its signal path probably being the same for both types of cartridges.
I would speculate, also, that given the age of the Grace cartridges there is likely to be significant sample-to-sample variation in performance among them, even when re-tipped in the same manner.
I’ll mention also, btw, that I’ve been running the AT-ART9 essentially unloaded, into the near-infinite input impedance the VTPH-2 has on its LOMC inputs if no termination resistors are plugged into the connectors it has on its rear panel for that purpose. Keith Herron suggests that with his particular design that is likely to be optimal for many or most LOMC cartridges. After the cartridge is broken in I’ll probably try the 47K and 1K loading plugs I ordered with the VTPH-2. But I see no reason to doubt the comments that have been made in the past by Atmasphere, Jonathan Carr, and others to the effect that the need for relatively heavy resistive loading of an LOMC, where necessary, is driven primarily by the need to control the degree to which a particular phono stage is exposed to ultrasonic or RF energy resulting from the resonance between cartridge inductance and load capacitance, rather than by the needs of the cartridge itself. And it would seem that the sonics of the Herron are less likely to be affected by that energy than in the case of most other phono stages.
Paul (Ps68), thanks very much for your comment.
Best regards,
-- Al
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Thanks very much, Pani. I'm using the ART9 with a Magnepan Unitrac tonearm, which is a generally well regarded vintage arm from the 1980s that is suitable for use with cartridges having light to medium weight and medium to high compliance.
Best regards,
-- Al
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Thanks very much, Bill. I’ll definitely keep your suggestion in mind. And thanks also for your long-standing advocacy of the VTPH-2, which significantly contributed to my decision to purchase it a few months ago. In addition to its great sonics, btw, I am continually amazed at how absolutely quiet it is. Lew, I’ve never seen a load capacitance recommendation for the F-9E Ruby. FWIW, though, as you’ve probably seen the datasheet for the original non-Ruby version, while not explicitly stating a recommended load capacitance, indicates that the specified 45 kHz bandwidth (necessary for reproduction of some quadraphonic formats) is based on "operating conditions" of 80 pf in parallel with 100K. (Although elsewhere in the datasheet resistive loading of 47K is indicated). Regarding the impedance of the Herron’s LOMC input, yes I too would expect that some resistance would be incorporated between the gate of the FET and ground. But even if that is so, based on the following statement in the VTPH-2’s description I’d imagine that it would be in the millions of ohms, which in the context of cartridge loading is essentially infinite: The VTPH-2 will not load the cartridge at all if no loading resistors are plugged into the MC loading inputs. This is because the moving coil input stage of the VTPH-2 utilizes the electric field generated by the cartridge to amplify the voltage and no current is drawn from the cartridge (there is no load on the cartridge). This can give an extended sense of dynamic freedom and sound stage as it reduces the work done by the cartridge and cartridge/groove interaction. Note B: Some cartridges will need loading in order to reduce their inherent rise in high frequency response....
... We recommend trying the VTPH-2 in the no-load configuration as the unit is supplied for most moving coil cartridges. 47,000 (47k) ohm RCA load plugs are supplied with the unit for optional use. Additional user specified loading plugs can also be purchased with the unit.
Regarding Soundsmith’s CL vs. OCL, one of the main reasons I chose the CL (in addition to favorable commentary here some years ago by very knowledgeable members such as Mofimadness) was that I had some concern that with the OCL version SRA/VTA might be more critical than I would prefer to deal with (even though the Unitrac arm provides on-the-fly SRA/VTA adjustment). That concern being raised in my mind by the fact that the OCL is described as having a "diamond shape [that] closely resembles the actual cutting stylus that is used to create the master record." Best regards, --Al |
