Chervokas, one of the problems with RF is it can be rectified by elements of the preamp circuit itself. Tubes often tend to be a little less susceptible on account of transistor junctions can rectify the RF energy fairly efficiently if not properly set up. Tubes don't do that nearly so easily. Mechanical connections can also be a problem.
If the RF can get in at sufficient level, non-linearities caused by overloading the circuit can drive any preamp into conniptions, so the trick to do things that limit that; shielding at RF frequencies (aluminum is often better than steel for this), correct use of 'RF beads' that limit how much RF can enter the input connectors, proper 'grid stop' resistors in tube circuits ('gate stop' resistors in solid state gear), layout and grounding all play a role.
IOW its all in the design and the designer's attention/awareness of this as an issue. |
Right, I get that, it's an RLC circuit and the capacitance is tuning the resonant frequency, and the lower the capacitance the higher the frequency (and the R is damping it).
So what does it take in terms of good design for the phono stage to be stage be be stable at RFs or to RFs -- I assume there's some kind of RC filter at the input of the phono stage that's a low pass filter typically, to reject RF generally, no? Just trying to understand. Thanks for your help. |
Chervokas, As far as an undamped LOMC goes, there is no effect whatsoever in the audio band, other than the voltage output- with no load its output will be a little higher, not much.
The issue is that the coils in the cartridge have so little inductance that the ringing issues that often affect inductive devices do not come into play until you are at very high frequencies, well into the MHz region. It is this ringing that supplies energy for the tuned circuit that results from the cartridge and the interconnect cable. Note that the capacitance of the cable always plays a role, the lower it is the higher the frequency of the resulting tuned circuit. So its rare that this can be solved by reducing the capacitance of the cable!
What is paramount, IOW, is that the phono section be stable with RF at its input. |
Thanks, yeah, that's what I'm trying to get a grip on, if we're talking about a resonant peak way up above the audio band....maybe 600 khz a the low end or even pushing 2 Mhz at the high end; where presumably it's far enough above the audio band also to have limited if any impact on the phase performance of the audio signal, and even if it's basically undamped or at least certainly underdamped by the cartridge impedance loading (in many instances it seems like even 100 ohm loading would leave the ultrasonic peak underdamped), what precisely is the expected impact in the audio band?
I also realize that these aren't just electrical devices but also mechanical ones and the actual in-use performance isn't always perfectly predicted from trying to model the performance based on a circuit model of the device. |
Chervokas, to be clear: if you load the cartridge with a lower resistance than your 10:1 or 11:1 ratio, all that happens at audio frequencies is you may reduce the output voltage of the cartridge. Its bandwidth will be unchanged.
So in theory you would want to load it as lightly as possible such that the RF issues are managed. The RF issues *can and do* act like changes in tonality. I admit that its confusing, but if you study this stuff on the test bench the fact of it comes out in spades. |
05-21-12: Chervokas
I just installed an AT33EV at home and noted that the specs supplied in the manual were pretty thorough on those scores -- 10 ohms impedance at 1 khz; 22 uH inductance at 1khz -- but I gather that's not always the case. Yes, those specs are unusually well defined. What I don't quite understand is what, if any, disadvantages there are to lightly loading the cartridge. Like what are the problems that arise when loading a low impedance MC with a high impedance? Why would you want to load it down? The one reason I am aware of (although I'm not completely certain that there are no other reasons) is the one Ralph (Atmasphere) described. Heavier loading will reduce the magnitude of the ultrasonic resonant peak you referred to, which as you realize is caused by the interaction of the inductance of the cartridge and the capacitance of the cabling plus the input capacitance of the phono stage. The greater the magnitude of that resonant peak, the greater the amplitude boost that will occur, relative to other frequencies, of frequency components that may enter the phono stage that are near the frequency of that resonant peak. Depending on the design of the phono stage, that may increase the likelihood that intermodulation or other effects caused by those ultrasonic frequencies will affect audible frequencies. Extraneous ultrasonic or RF energy may be present as a result of tics and pops, ultrasonic musical information that is on the record, RFI pickup, etc. Some references that may be of interest: http://www.hagtech.com/loading.htmlAnd the post dated 8-14-10 by JCarr (Lyra cartridge designer) in this threadBest regards, -- Al |
Al, thanks for the clarifications. I just installed an AT33EV at home and noted that the specs supplied in the manual were pretty thorough on those scores -- 10 ohms impedance at 1 khz; 22 uH inductance at 1khz -- but I gather that's not always the case.
I'm trying to learn the tech of cartridge loading so it's less trial and error. I get impedance matching and insertion loss. I get how you have to manage the resonant frequency of the RLC circuit with higher inductance pickups by being careful about capacitance loading (that resonant frequency never seems to get close to the audio range with low inductance pickups and any amount of real world capacitance you run into). I get the need to watch out for the cutoff frequency of low pass filters formed by output impedances and cable capacitances, though again that seems to be a rare real world problem. I'm not sure what other tech stuff comes into play. I guess the need for an RC network at the front of the phono stage with a cutoff frequency sufficiently low enough to reject RF noise but not too low to affect audio signal. What I don't quite understand is what, if any, disadvantages there are to lightly loading the cartridge. Like what are the problems that arise when loading a low impedance MC with a high impedance? Why would you want to load it down? |
05-20-12: Chervokas
The load impedance of a device should be at least 10X the source impedance of the device driving it to minimize insertion loss. Even at 10:1 you have a 1/10th loss of voltage IIRC. That's close. It's actually 1/11th, assuming that both impedances are essentially resistive at the frequencies being considered. Now if you plugged a mid output Benz with a 24 ohm output impedance and 0.8 mV output into the 100 ohm phono stage I think you'd have around 0.5 mV insertion loss (if I'm remembering the math correctly) Assuming both impedances are essentially resistive at the frequencies being considered, you would lose: 0.8 x 24/(24 + 100) = 0.15 mv Resulting in (0.8 - 0.15) = 0.65 mv appearing at the input of the phono stage. Which can be calculated a little more directly as: 0.8 x 100/(24 + 100) = 0.65 mv All of which brings to mind a pet peeve of mine. When the specs for a cartridge indicate "impedance," what are they talking about? Impedance at zero Hz (i.e., DC resistance), impedance at 1 kHz? 20 kHz? Other? For many and perhaps most LOMC's it won't make much difference, because of their low inductance. But it would certainly be nice if DC resistance and inductance were separately and explicitly specified (which they sometimes are, but all too infrequently), so we don't have to make assumptions and guesses. Regards, -- Al |
Odd that Boulder would suggest 100 ohms generically for all moving coils. Chervokas, read my posts above and you will see why this is not odd at all. Actusreus, the Atma-Sphere preamps are intended as stand-alone phono reproducers. People ask us all the time why we don't have a separate phono section; the reason has to do with interconnect cables. The idea behind our preamps is to reduce the signature of the interconnect cable between the amp and preamp. Without special circuity this cannot be done. It is included in our preamps. This allows the phono section to be more neutral. |
Jmcgrogan2,
Thank you very much for the info; it is greatly appreciated.
Dover,
I concur. |
Actusreus,
As far as I know the input impedance of an amplifier will have ramifications in the first gain stage with regard to bandwidth, gain etc. Therefore the chosen input impedances provided by any particular phono stage may have as much to do with the design of the succeeding gain stage as it does as with the designers choice of cartridge. No doubt many designers are trying to second guess what customers are going to buy and their preferences for loading.
It can be a chicken and egg - which comes first, cartridge or phono.
Mostly what we are buying in an analogue front end, including the phono stage, are a cocktail of complementary colorations. |
Actusreus, Mehran at SORAsound carries Klyne, though I don't know about his auditioning policies. Klyne preamps are very rare and hard to find. Stan Klyne builds and repairs them all by hand. He could easily grow bigger, but he doesn't care to. Hence, no, if you're looking for auditions, dealers, flavors of the month, a Klyne is not for you. They show up so rarely on the used market because once one attains a Klyne, they rarely sell them. The Klyne 7PX 5.0 is the best phono stage that I have ever heard, tube or solid state. |
Odd that Boulder would suggest 100 ohms generically for all moving coils.
The load impedance of a device should be at least 10X the source impedance of the device driving it to minimize insertion loss. Even at 10:1 you have a 1/10th loss of voltage IIRC. So a 0.3 mV, 10 ohm output impedance cartridge would lose 0.03 mV at the front of the phono stage with 100 ohm input impedance.
Now if you plugged a mid output Benz with a 24 ohm output impedance and 0.8 mV output into the 100 ohm phono stage I think you'd have around 0.5 mV insertion loss (if I'm remembering the math correctly), which is starting to get considerable, now it's like you have a .3 mV cart -- so you crank the gain to make up for the signal loss and you wind up with a higher noise to signal ratio than before. That's why Benz recommends greater than 200 ohms loading -- 250 ohms, 470 ohms, 1000 ohms, 47kohms even. 200 ohms is the minimum recommendation; not the preferred loading.
I know people like to load down their phono cartridges as a way of shaping the tone. I never quite got that. I'd rather just get flat frequency response and as little voltage loss as possible with as few resistors inline to add thermal noise. Greater than 10X source impedance is the starting point for me. There shouldn't be a magic number at which to load one kind of cartridge or another. It really depends on the cartridge's specs.
With MM and high output moving coils, there are other considerations. The higher inductance of those carts means you have to be careful about the capacitance loading or you'll change the frequency response of the system, but that has to do with the RLC circuit formed by the cart's inductance, the capacitance in line, and the phono stage's input impedance. That's a whole different calculation. But the impedance loading still should be at least 10X the source impedance. The source impedance is just typically much higher so the load impedance has to be much higher. You wouldn't want to load your 660 ohm output impedance Clearaudio Virtuoso at 1000 ohms. |
Sorry, the Boulder's retail price is actually $36,000, not $26,000. Chump change. |
Syntax,
That's a pretty bold statement that only those four phono preamps got it right given the many reputable brands out there. How many different units have your actually heard to make such a definitive finding? I'm by no means being critical of your statement, but simply curious how you reached it.
Speaking of the preamps you mentioned, do you know who distributes Klyne or how one can get more information about where you can audition one? The Klyne website has no contact or dealer information, which I find rather disappointing and unprofessional considering the target market.
Regarding the Atma-Sphere preamp, it appears there is no a stand-alone phono unit, but it's a built-in phono stage in one of the preamplifiers. Is that correct?
I'm also curious whether you heard the JC-3 preamp, which was compared favorably to the Vendetta by I believe Art Dudley in Stereophile not a long while ago. Your (and others') comments regarding the 47k ohm load also compel me to ask if this is purely a function of how good the preamp is, why do designers refer to the cartridge's design as the determinative factor, or flat out state something diametrically different? Here is a quote from the JC-3's description:
"MM 47 k ohm, MC 100 ohm or MC 47 k ohm; (MC 47 k ohm is ideal for high-end Grado moving iron cartridges)."
From the $26,000 Boulder 2008's manual:
"In the MC position, the maximum input resistance is 1,000Ω without additional components installed on the card. All four of the cards are shipped with a resistor to bring the impedance down to 100Ω, which is recommended for MC."
Are you saying Boulder claims their unit runs best at 100Ω because "they can't do it better"? |
My experience is as per Lewm's and Syntax. I run MC's into 47k tube preamp, Marantz 7 modded, which although it is only 60db TOTAL gain, can easily handle MC's 0.3mv up with no noise. I also had a Klyne 7 which seems to emulate tube pre's in that it is designed to run mostly 47k and use very high frequency contour filters to handle the resonances. I found 47k plus filters at around 50k plus were the go.
The Klyne has been despatched as it was easily outperformed by both the Marantz and my tweaked Theta tube preamp from the 80's.
I have generally found that the MC's with very low internal impedance such as Koetsu's ( 3 ohm ) etc run fine into 47k but have occasionally had issues with MC's with higher internal impedances such as Denon 103D ( 40ohms ) and Benz ( 40 ohms ).
I have a gut feel that the lower impedance MC's in general will do better into 47k. |
If the Chinook is anything like the Steelhead, it will benefit immensely by
upgrading the tubes. In the Steelhead, I found the NOS tele to sound the
best in the 6922 slot. Try rolling the 7044's also, they aren't as expensive, i
think a pair of good raytheons were 95 bucks a pair. (Not sure if the
chinook uses the same tube complement as the Steelhead).
I've used tube preamps, line stages and amps since 1973- more modern
tube stuff is not the lush sounding stuff that most people associate with
tubes. Indeed, the Steelhead doesn't really sound like a tube unit at least
with the stock tubes (again assuming the Chinook has a similar character).
I am temporarily using a Joule line stage while I wait for my Lamm hybrid
line stage to get repaired and the Joule is reminescent of older style tube
preamps, very romantic, but suprisingly robust bass. It is a little too lush for
my taste with SET amps, but part of it, as you recognize by your question,
is system matching.
enjoy the chinook. Eva Manley is a stand up woman.
PS, again, not sure the Chinook is the same as the Steelhead in this
respect but I liked going into the MM input at 47k rather than through the
autoformers with both a Lyra Titan i and my Airtight PC1. Interestingly, my
new phono stage, an Allnic H 3000 is all about the step up transformers,
and there, the Airtight is sounding great. FWIW, when I ran the Steelhead, I
liked it just as a phono stage, with a separate line stage, and not 'straight
in'- it sounded a little too hi-fi straight in, and adding the line stage gave it
more dimension and palpability. Maybe just adding more distortion, I did
discuss this with Eva Manley at one point, who advocated a 'less is better'
approach, but to my ears, and extropolating my experience with the
Steelhead to the Chinook (FWIW), adding the line stage gave me more of
what my system needed to fully appreciate the Steelhead's strengths.
Have fun.
That, in the end, should be what it's about (although you'll catch me cursing
like a longshoreman sometimes when things go wrong with the system) :) |
To run a complete tube fronted is no problem, it depends on the quality (as
usual). There are differences.
Cartridge loading discussions were endless, are endless and will be endless...
To make it short, to dampen a cartridge means, you reduce their headroom,
47kΩ is 'open', you can hear the cart purest, the way it was made, when
your System is not up to the task to handle that (and most can't), you can
dampen it down (some say it has to be done based on high frequency
distortions but that is wrong). With one of the better Phono Stages you can hear
it easily when you step down from 47kΩ it always becomes more slow
and dull (but honestly a lot of Systems need that, the wonder word is:
Compensation, with Cables you can do the same)
To design a Phonostage which is silent, not sensitive to hum or other
influences, probably with higher gain (62dB and more) AND finally has to sound
like music and not dead and lifeless (most do) ---> this is VERY difficult to do ,
the Designer really needs knowledge about that chapter. In the last 15 years I
only heard 3 Phonostages which were able to solve that
- Klyne Phono 7
- Atma-Sphere
- J. Curl Vendetta
All the other countless designers will find endless reasons why their units run
best with 100Ω or 125Ω or 165,37Ω or 358.5Ω -:) but at
the end of the day, they can't do it better. It is the way it is.
Marketing can replace knowledge [and does of course and when it is repeated
countless times, it becomes ---> A Fact :-)]
Years ago a lot of cartridge manufacturers wrote in their datas: recommended
loading 47kOhm (Benz for example)....with the result, that the customers
tortured their dealers that their Phonostages were not able to run with
47kΩ (or they sounded simply awful with this setting, Levinson, XONO and
so on), and they didn't buy the cartridge.
No deal is the worst deal for a 'Dealer'
Now we have in the manuals: Recommended loading 100Ω -47kΩ
The problem is solved now.
That's High End :-) |
Actusreus, if Fremer is not 'full of it', he was hearing those differences due to issues with the **phono section(s)** rather than the cartridges. 47K, 100 ohms, the cartridge does not care. I run my cartridges (Transfiguration Orpheus, ZYX Universe) at 47k with no worries, can't really tell the difference if I use 100 ohms. But our stuff is stable in the presence of Radio Frequency energy, which is in fact what this is about.
Jonathan Carr's comments can be trusted regardless of the LOMC.
You are partially correct with your summary in your last post. The entire summary should read: "So to summarize, it depends on the preamp." |
So we have support for loading at 100 ohms and 47k ohms, and possibly everything in between. So to summarize, it depends... :-) |
The late Allen Wright was also among those reputable designers who advocated "no load", or 47K ohms in other words, for use with LOMC cartridges. I am sometimes astounded to read what some listeners prefer in terms of phono load resistors, often so low in value as to significantly drain off signal voltage to ground, i.e., where the load R is much less than 10X the internal resistance of the cartridge. |
I believe Jonathan Carr, the designer of the Lyra cartridges, has stated that modern cartridges do not need loading to tame ringing and a response peak because those phenomena occur at ultrasonic frequencies; but, loading may be beneficial with phonostages that are prone to overloading from such peaks. Where overloading is not a problem, he preferred the wide open sound of using very little loading (e.g., 47k ohms).
I don't think Fremer is "full of it." One can quite readily hear the effects of increased loading. Loading acts like a form of tone control--reducing high frequencies. For my taste, with my phonostages, I prefer much less loading than is usually recommended; too much loading (i.e., a lower numeric value for the resistor) causes a significant loss of "air" on top. |
Thank you, Atmasphere. This does help with understanding the issue. I don't want to keep dragging this topic, but I must ask: if Fremer (or anyone else for that matter) hears clearly definable differences in the quality of the sound, not the noise, with different resistive loads when using an MC cartridge, is he full of it?
Jtwrace,
The Andros is a beauty and everyone raves about it, but it is also nearly twice the price of the Chinook, so they are really not in the same league. If you can afford the Andros, it seems it's an easy choice, at least on paper. elast |
Actusreus, (in case its not clear from Al's comments) the reason some preamps offer more loading settings, and that they are audible has to do with the fact that such preamps are not 'graceful', as Al put it, when dealing with RF energy. IOW, the RF energy affects the way those preamps sound.
All we ever found with loading (our preamps have a loading strip above the phono connectors so you can put anything there you want) is there is a slight change in the noise floor.
If you have a moving magnet cartridge, the loading can affect the sound of it directly, IOW the effects are occurring at audio frequencies. |
I took a look at the KAB Gain Calculator. First, it clearly states in its introduction that: The optimum gain is based on achieving 325mV rms output at 5 cm/s. For the current crop of CD recorders, 300mV is required for 0dB recording level with the recorder's level control set at max. Aiming for 325mV gives a little margin. 325 mv is not close to being enough to drive most power amps to full power, so clearly the answer provided by the calculator applies just to the phono stage, and not to the combination of phono stage and line stage. All the gain calculator is doing is dividing the cartridge's rated output in mv into 325 mv, and converting that ratio into db based on the standard conversion formula 20log(V1/V2), where V1 and V2 are two voltages, and "log" means the base-10 logarithm. That is very simplistic at best. Not only does it not take into account line stage gain, but it also does not take into account power amp gain, speaker sensitivity or efficiency, listening distance, and speaker type (volume falls off more rapidly with increasing distance for box-type speakers than for planar speakers, for example). All of those factors will influence the position at which the volume control will be set. And perhaps most significantly, it does not take into account the signal-to-noise ratio of the phono stage, as I discussed earlier. One phono stage providing a given amount of gain may result in an acceptable level of background hiss, while another phono stage providing the same amount of gain may not, even though both phono stages will cause the volume control to be used at the same setting. That is especially a concern if the cartridge has a particularly low output. In other words, the calculator should be considered as providing at best a rough rule of thumb guideline. Nothing more. Best regards, -- Al |
Jmcgrogan2,
That has certainly not been my experience. My current phono preamp came with a factory preset gain of 29 dB for MM cartridges and it was not enough to drive my temporary Shure M97-xE that outputs 4 mV. It simply didn't have enough volume even though I could not go past 12 o'clock when I played CDs. I then had the manufacturer up the gain to 39 dB and it solved the problem. As an experiment, I also ran the cartridge using the built-in phono stage in my then-amp, Rogue Cronus Magnum, that had a gain of 35 dB in the phono stage before the line preamplification and the difference was tremendous. According to the KAB calculator, an optimal gain for the Shure was 38 dB...
I experienced a similar problem with my original cartridge, Soundsmith Aida, which had an output of 2.12 mV, when I used it with the built-in phono stage in the Cronus. When I switched to a separate phono preamp (Soundsmith MMP3) with 43 dB of gain, the volume was much higher and just sufficient, which obviously points to the low gain in the phono stage as the problem. Well, the KAB calc is 44 dB for an output of 2.1 mV so, in my opinion and experience, it provides a pretty good estimate of an optimal gain for a given cartridge in the phono stage independent of the line stage. How differences in line stages would affect that calculation, I frankly do not know. |
The KAB calculator considers preamp gain period. That's phono preamp + preamp gain. So the calculator said I needed 63 db and I had 66 + 22 = 88db of gain. Way more than enough. I probably could have gotten by with a phono stage with a 50-54 db of gain for my 0.24 mV output cartridge. Maybe I could have turned the volume knob up to 1 or 2 o'clock instead of 9 or 10 o'clock. |
Jmcgrogan2,
I'm not sure, but as I mentioned in one of my posts above, my preamp has five gain settings so it certainly does have gain. I might be wrong, but I believe the KAB calculator only considers the gain of the phono stage. It's possible that an assumption is made as to the base line preamp gain. You can read more about this at www.kabusa.com
Btw, for a cart with an output of 0.24 mV, you apparently need 63 dB of gain so it makes sense that you found 66 dB to be more than enough. I just experienced the opposite a few times, so I am always very careful about matching the phono preamp gain with the cartridge output. |
Thank you Al. I've always been interested in the interplay, for lack of a better word, between volume and gain. I understand they are obviously not the same thing, but certainly more gain at a given volume = louder sound. So with variable gain settings gain can also be used as volume control, even though in a more dramatic way.
As a correction to my post regarding resistive loading in the JC-3, it actually has two settings, not one, for MC cartridges: 100 Ohm and 47k Ohm. |
Actusreus, how much gain does your preamp have? As Layyi mentioned, his preamp has 13 db of gain, mine has 22 db of gain. Either when combined with a 60db phono stage would be more than enough for most any cartridge I can imagine.
I just sold a phono stage with 66 db of gain while using a cartridge with a 0.24 mV output. Combined with my 22 db of gain from the line preamp, I never turned the volume knob much past 10 o'clock. Together that combo provided 88 db of gain, I'm sure I could have gotten by on 82 db of gain very easily. While doing your KAB number crunching, don't forget to add in your line stage's gain, unless of course your line stage has no gain. |
05-16-12: Actusreus
... are audiophiles unnecessarily obsessed about resistive loading, and manufacturers simply cater to that obsession? As always, I am sure the answer is more complicated than that.
Hi Marek, Not necessarily. As Ralph indicated, it can be presumed (or at least suspected) that JC's phono stage design can handle frequency response peaks in the ultrasonic and RF region with relative grace (i.e., with minimal interaction with audible frequencies). But it is probably safe to assume that many other designs will not be able to, which would make the choice of resistive loading more critical in those cases. And I'm personally not sure if the effect Ralph described is the only means by which differences in resistive loading may affect sonic results when LOMC's are being used. But it is certainly a major one. It is still unclear to me why, but increasing the volume at a certain gain level will not render the same results as upping the gain at a given volume level. IOW, the sound is much better at a higher gain setting and lower volume, than lower gain and higher volume. There are a great many variables, many of them unpredictable, that can influence that tradeoff. Some of them are the signal-to-noise characteristics of the phono stage and the preamp; the distortion performance of the two components at various signal levels; side-effects of the preamp's volume control mechanism, that may worsen as the amount of attenuation is increased; ground loop issues that may exist between the two components, whose significance may be lessened if the signal level is greater at the interface between them, etc., etc. Best regards, -- Al |
Al, Thank you for linking to this article. I believe I actually have seen it before as it looks familiar. Interestingly, the author posits that a loading value of 100 ohms might indeed be suitable for MC cartridges in general. If so, are audiophiles unnecessarily obsessed about resistive loading, and manufacturers simply cater to that obsession? As always, I am sure the answer is more complicated than that.
Great point about the noise issue that's tied to increased gain. My line preamp has five gain settings and definitely noise increases as the gain is increased, so I try to find a setting that will provide an optimal balance of (low) noise and the weight, presence, and immediacy of the sound. It is still unclear to me why, but increasing the volume at a certain gain level will not render the same results as upping the gain at a given volume level. IOW, the sound is much better at a higher gain setting and lower volume, than lower gain and higher volume. The sound just lacks the heft and presence that it has at a higher gain. Perhaps that is why I am so focused on gain when it comes to phono stages... |
Good point by Ralph (Atmasphere) about resistive loading. Marek (Actusreus), although this reference is somewhat technical, it may help to clarify what Ralph is saying. Concerning gain, it should be kept in mind that all 60 db gains are not created equal. In a given system and with a given low output cartridge, some 60 db phono stages will be adequately quiet and some will not. What makes the difference is signal-to-noise ratio. A general purpose gain calculator will not be able to take that into account. Along the lines of some of the earlier comments, as long as the gains and sensitivities of the downstream components are not particularly low, chances are that with most low output cartridges 60 db of phono stage gain will be adequate to avoid running out of range on the volume control, or having to turn the volume control up to levels that will cause preamp-generated noise to become objectionable. But the key question is how much noise the phono stage itself generates. It is easy to design a phono stage that can provide high gain, and even sell at a low price point, if noise performance is compromised. Assessing s/n performance from specs can be difficult, because different manufacturers tend to specify that parameter based on different reference levels and with different frequency weightings. And in a lot of cases they don't even indicate what those reference levels or weightings are. Fortunately the s/n specs for the Chinook are presented in a meaningful manner. For the 60 db gain setting the spec is: Noise Floor at 60dB gain setting with shorted input: -75 dBu, A-weighted Based on some quick calculations that spec strikes me as encouraging, with respect to use with cartridges having rated outputs significantly less than 0.5 mv. But of course the only way to know for sure is empirically. Best regards, -- Al |
Lewm
Dear Actusreus, If what you say is true about the JC3 load resistor for MC, I share your chagrin, but one might always open the chassis, find said 100R load resistor, remove it, and replace it with a resistor of the desired value. I do agree that the task is tedious, if one wants to play with a variety of cartridges and/or experiment with different load values. I'm usually reluctant to mess with a product that is designed in a specific way. I always think there was a reason why a designer made his choices the way he did. I'd think that someone like John Curl knew exactly what he was doing when he fixed the impedance at 100 ohms, even though it is rather curious given other phono preamps in this price range. Atmasphere
This is almost as frustrating as John Curl's JC-3 phono preamp offering only one impedance setting of 100 Ohms for MC. That one I'll never understand.
The reason is if the preamp is resistant to RF at its input, the load on the LOMC is not critical. Its only there to reduce RF caused by the inductance of the cartridge interacting with the capacitance of the interconnect cable, which can form a tuned RF circuit. The resistor destroys the 'Q' of the circuit. IOW if the preamp works right, the value of the resistor is not important since it only works at RF frequencies. Atmasphere, I have to admit I don't fully understand your explanation as I don't have a technical background and my understanding of technical intricacies involved in designing playback equipment is rather limited. This particular aspect of the JC-3's design baffled me as the great majority of phono preamps in this price range (and certainly above) offer adjustable impedance settings for MC cartridges. It was also my understanding that it is so because impedance always mattered with MC carts, just like capacitance with MM carts; a mismatch can result in a less than optimal sound that the cartridge is capable of (usually expressed as too harsh on top or too mushy at the bottom). Admittedly, I played with load impedance settings in my friend's setup once with his remotely controlled Aesthetix phono preamp so any effect should have been immediately audible, but the differences were very subtle, if any. However, we both preferred his Dyna XV-1s at about the same setting, and we reached that conclusion independently. Fluke? Perhaps. Jmcgrogan2
Actusreus, I would think that 60 db of gain from a phono stage would be enough for any cartridge, unless possibly if you are considering running through a passive controller instead of an active preamp. Most will run the Chinook through an active line stage preamp (as the OP is here) which will add more than enough gain for any cartridge. If you use the KAB calculator, 60 dB of gain is optimal for MC cartridges with an output of 0.4 mV or higher. If that's true, the Chinook does not have enough gain for most Dynavectors, just to mention one popular manufacturer. The KAB calculator does not seem to take the gain of the line stage into consideration. From my experience, I certainly had phono preamps that simply did not have enough gain to produce a sufficient volume level with the cartridge I used (in this particular case a MM), even though the same amplification produced more than adequate volume levels for CDs. Doing the math, the KAB calculator seemed to be pretty spot on. My current phono stage has 55 dB of gain in the MC setting and I feel anything less would not be sufficient for my Lyra Delos's 0.6 mV despite the fact that my line stage has a variable gain. It appears that having the optimal gain at the phono stage level is more crucial than having enough gain downstream. At least in my less than expert opinion... |
If your linestage has reasonable gain, 60 db of phonostage gain may be enough for some pretty low output cartridges. My phonostage has 60 db of gain, my linestage delivers 13 db of gain, and I use the combination with a .30 mV cartridge with no noise or other problems.
I also agree that a fixed loading of 100 ohms is not that big of a problem--that will work with a vast majority of MC cartridges. Linn did the same thing with its Linto phonostage (fixed at 125 ohms), claiming that the switches to allow for more options would degrade the sound while 125 ohms would work with most cartridges. |
Actusreus, I would think that 60 db of gain from a phono stage would be enough for any cartridge, unless possibly if you are considering running through a passive controller instead of an active preamp. Most will run the Chinook through an active line stage preamp (as the OP is here) which will add more than enough gain for any cartridge. |
This is almost as frustrating as John Curl's JC-3 phono preamp offering only one impedance setting of 100 Ohms for MC. That one I'll never understand. The reason is if the preamp is resistant to RF at its input, the load on the LOMC is not critical. Its only there to reduce RF caused by the inductance of the cartridge interacting with the capacitance of the interconnect cable, which can form a tuned RF circuit. The resistor destroys the 'Q' of the circuit. IOW if the preamp works right, the value of the resistor is not important since it only works at RF frequencies. This says to me that Mr. Curl's preamp must be pretty resistant to RF issues. |
I'm between the Chinook and Zesto Andros. |
Dear Actusreus, If what you say is true about the JC3 load resistor for MC, I share your chagrin, but one might always open the chassis, find said 100R load resistor, remove it, and replace it with a resistor of the desired value. I do agree that the task is tedious, if one wants to play with a variety of cartridges and/or experiment with different load values. |
I'm also looking at the Chinook as a potential upgrade to my current phono stage. It's got everything I'm looking for, except one thing: a relatively low gain of 60 dB for MC. This would suggest that it's not adequate for MC cartridges with an output below 0.5 mV, which eliminates a lot of great cartridges. This is almost as frustrating as John Curl's JC-3 phono preamp offering only one impedance setting of 100 Ohms for MC. That one I'll never understand. |
Glad to hear that. I"m looking pretty hard at the Chinook. A friend of mine just got a Zesto Andros....now I'm wondering if I should really stretch. Yikes! |
Hello. Thanks for the message. Yes, I'm very happy with the Chinook. I'm amazed it sounds as good as it does using the stock Russian tubes. Prior to this purchase, I really ran the gambit - I tried the Nova Phonomena II, Cambridge Audio Azur 640p, Clearaudio Smartphono, and Ray Samuels Audio Nighthawk. Both the Phonomena II and RSA Nighthawk leaked DC and were returned. It's true what they say - you get a huge improvement in sound quality when you go beyond the $1,000 threshold (when it comes to phono stages, at least). I really think Manley Labs has a solid hit with the Chinook. It's well built, looks good, and performs flawlessly out of the box. I couldn't be happier! |
I have a tubed Joule Electra LA Mk 2 pre-amp and a tubed Fosgate Signature phono pre-amp. The reason its not overkill in my system is the solid state Belles 350A amp and Dynavector 20XH cartridge, so system synergy is very important as others have stated many a time. Your choice of the other components, cables, and interconnects as well as things like footers and room treatments as well as speaker placement can make all the difference in keeping a tubed pre-amp and tubes phono amp together from tipping the sound into the overly warm and mushy. Obviously if you feel the two together might be too much, then your other components need to have a character thats more clear and detailed and leaning slightly toward the bright side of the audio spectrum. |
Still happy with the Chinook? What else did you consider? |
Hello everyone. Again, thanks for the responses. I appreciate your thoughts on the topic. The Manley Chinook arrived this evening. I hooked everything up according to the manual and commenced the audition. The MM gain was preset at 45db at the factory. The phono inputs were preset at 47k ohms by Manley. The only dip switches I had to adjust on the back of the unit were the load capacitance settings which I dialed in at 200pF (using a formula provided by Manley in the equipment manual). The power up sequence commenced, and liftoff occurred! Based on initial impressions with a variety of music styles, Manley has a solid winner with the Chinook. As I summarized my initial thoughts for a good friend about one hour ago, I provide same for your consideration:
- very tight bass response I like what I hear bass response is very good (bordering on exceptional after two hours of listening)
- good channel separation
- very quiet operation - I don't hear a thing between songs or when the stylus is elevated (dead quiet)
- very nice sound-stage overall plenty of depth across the spectrum
- I can hear each of the instruments in isolation very cool when they all come together to make the sound
- Advents sounding incredible (Im so glad I never sold them)
- comes equipped with Electro Harmonix stock tubes
- first album on the turntable is Steely Dan AJA 180g pressing
- initial impressions tell me this is a keeper I think Manley has a solid winner with this unit
- stock number #046
I like what I hear very much clean, sharp sound with incredible depth and precision. Exploring the possibility, after the testing phase is complete, of replacing the stock tubes with NOS 7308 E188CC tubes - that should set me back some serious bucks. But, I hear they're the best for sound and low microphonics in phono stages (if they're still available).
Pony up boys - this unit is slick. By the way, the Manley logo on the front is dim lit while in standby mode; when you engage the power switch, the soft-circuit takes over and you wait 45 seconds until the Manley logo becomes brighter - way cool!
Feel free to ask any questions and I'll try to answer them as best I can. |
Love my CAT, 10 tubes total, 5 for phono stage and 5 for line stage. And I also use a tube amp for mid/hi with a SS amp for bass(<250Hz).
One can roll tubes for any balance of sound one desires, from fat and slow to lean/mean speedy machine, and any mixture between the two. |
Well now it seems that I agree with Larryi. :)
Lot's of folks ask for advice, and if they know what they want you can kind of guide them in a general direction. However, there is absolutely no substitute for listening in your own system/room, with your own ears.
That Chinook looks very interesting Steve, very flexible, let us know what you think. Do you have some NOS 6DJ8 variant tubes to play with? |
I do try to attain a particular sonic result and that obviously means trying to balance tonal qualities and balance and manage tradeoffs. I was merely cautioning against assuming that one can determine the intrinsic qualities of one component (e.g.this amp is warm but sluggish) which means it can be matched with another component of somewhat opposite character (this component is fast and detailed) to attain a medium ground or the best of both--the results are largely unpredictable. Everything requires a trial. The results are particularly unpredictable, and often disappointing, when someone mixes and matches tube and solid state amplification.
I have often been taken completely by surprise by nice sounding systems that sounded completely different from what I expected given what I've heard from these components in a completely different system.
Yes, I do have certain general preferences and I tend to like and dislike certain types of gear, but, there are often exceptions to such generalizations--either exceptional implementation of a design, or system matching with surprising results. An example of the former, for me, involves ceramic driver speakers--I generally don't like them--but I heard Tidal speakers that I thought were promising. The example of great system matching involved a system built around Spectral electronics that sounded nothing like other systems I've heard using that gear.
The point is: it is all about system balancing and matching, but, that requires experimentation and not reading reviews or going on reputation or relying too heavily even on what one heard from a component in a different system. This necessarily involves home trial (good relationship with dealers is a must) and an open mind. |
Hello everyone. So, I purchased the Manley Chinook on Monday. Can't wait to set it up. I have high expectations for the sound quality. Hopefully, I won't be disappointed. Given all the hype to date about this new item from Manley, I expect it will deliver as advertised. Once I've had a chance to test drive it, I'll let you know my thoughts. Again, thanks for all of the replies. |
Well it appears as if Larryi and myself are in complete disagreement. That's ok, that's why they make so many different flavors.
I do have to say that I don't agree that "balancing" rarely works out as planned. In fact, I believe that we all balance our systems. In the "more than one way to skin a cat" category, I find that many audiophiles argue over which preamp, amp, cartridge, etc is better, when the answer lies within their own systems and rooms.
For example, I tend to enjoy warm, musical speakers, soft dome tweeter type. Now I like to pair them with revealing electronics like Audio Research or VAC gear. I've found that C-J and Cary gear put me to sleep. Now I know many people love C-J and Cary, and when I look at their systems, I usually see them using more revealing speakers, cables, etc. Koetsu cartridges don't work in my system. Now maybe if I buy more revealing speakers and cables (Nordost?) I'd like the Koetsu with a C-J preamp, who knows? Now how about the room? Is it a dead room? A lively room?
From my experiences, it's ALL about balancing. ALL warm equipment will lull me to sleep. ALL thin equipment will have me running from the room pulling my hair out. I think the sound that we all enjoy is more similar than many people realize. There are just many different ways to arrive at the same destination. As always, YMMV. |
