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  #1  
Old 09-08-2017, 09:12 PM
Robes Robes is offline
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Thumbs up How to set cartridge loading on Yamaha C-85?

Wow! Last post in 2010?
Hoping to find someone at home here......it's hard to find those in the know on 80's Yamaha Pre amps. I am original owner of a C-85 & M-65 both bought new in 1988. Neither have ever given me a problem-nothing.

NOTE: I have attached specs to my amps

I'm here because I'm upgrading to a VPI Prime turntable and need a cartridge for it. To find a good match it has lead me into the realm of understanding the pre amp I have, the C-85. Through my internet surfing I see that I have indeed bought a good product but, I need to know more about it & I can't find answers to my questions, electronics are not my forte.

I notice that some of the present day "phono stages" (not that I want to get one at this point) available on the market have selectable gain & loading levels, eg. several levels of gain anywhere from 40 - 70+ dB as well as several selections for ohms like 100 - 47K ohms. This is what made me look at what selections I have.

It looks like I have two choices of gain, per the RED BUTTON on the rear Pre amp panel. That being, #1, whatever "normal" dB is on the RED BUTTON and #2, the ("normal" dB) - 10dB, by selecting -10 dB.

My question is, what is the "normal dB"? Knowing the normal dB and - 10dB would then tell me what the value for my 2nd dB level would be. I assume it would be good to know those two dB values when trying to select a good match in cartridge for my system. So, is it correct that I only have 2 choices in dB level on the C-85, and those I don't know?

I also have a problem understanding the line level association. I was told the line level for this unit is 150mV. For example, if a cartridge has a 2.5 mV output voltage you need to multiply it by 60mV to reach line level at 150mV, which then goes to the power amp (M-65). I can understand that. So, if 150mV can be converted to dB is that the value of the "normal" gain on rear panel red button? Then that value - 10dB is the 2nd dB value I could select?

Looking at the front panel Phono switch, I'm only selecting the ohms right? Some carts give recommended ohm loads so that I just pick the closest on that selector right? I also found this: A good rule of thumb (i.e. place to start) is 25 times the coil resistance of the cartridge. That generally winds up somewhere between 100 - 1000 ohms as most moving coils have an internal resistance between 4 and 40 ohms. Then you can vary it up or down 50% (from the 25 times number) until you get the best results.

Bottom line. I've read that the carts with low output voltage eg. 0.25 have to be multiplied far more then higher output voltage carts eg. 2.5 to reach line level value and therefore will then be more of a dirty signal. So are the higher voltage output carts as a rule, the best choice for cleaner signal? Seems more MM carts are higher output over MC carts, but would high MC be best or at least at par with MM of similar output?

So, if I had carts of different output voltages say: .23, .8 & 5.0mV does the pre amp know that voltage and automatically, specifically multiply each to reach/equal the line voltage of the system at 150mV? Because I don't see that I have any control over that aspect.

Well, I'm sure you can see I don't know what I'm talking. Maybe you can suggest something to help me understand some of this so I can buy a good matching cart to optimize my C-85.

Well, lets see if the dead can be resurrected......

Robes
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  #2  
Old 09-08-2017, 09:49 PM
john from seattle john from seattle is offline
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The best way to know is what is considered "normal" for Ohms is 47K, but not all cart follow that so a selection is provided to better match the cart to the phono preamp.

I run my SHURE M97xE at an Ohm other than 47K, I forget what now, I have to open it up and document what I have mine set to, it's the Muffsy PP3, that is heavily based on the Audio Karma CNC design from several years ago.

I found that by running it either at 63 Ohms or 53Ohms gave me a better top end extension, but it is still on the soft side, but that's without inducing too much of an upper mid bump in the process. Capacitance loading will solve that, but I need the pins necessary to swap out the caps to achieve that, but the space for them is provided if you needed them.

Most phono stages that are not adjustable default to 47K in the first place.

I hope this gives you a starting point when it comes to your cart/phono pre combo.
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my system Kenwood KD12-RB turntable, SHURE M97xE cart, Muffsy PP3 phono pre, Receiver: Sherwood RX4030R, TEAC A4300SX R2R, Denon DCM-370 CD changer, Speakers: sansui SP1700 and in testing/restoration phase, Sansui SP-3000, eMachines PC for multimedia use and recently got a Nakamichi BX100 cassette deck
  #3  
Old 09-08-2017, 10:30 PM
Robes Robes is offline
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Hi John, thanks for your input-

In conclusion, from multiple replies on several post on different forums it seems I usually get answers that completely overwhelm me and to which I don't have a clue what they said as well as not answering a specific question of the many I usually ask.

But, what seems to be the final answer is everyone seems to agree my Pre amp will run practically any present day cart I would buy. And, that outside of what manufacturer & audiophiles suggests for loading criteria it really don't matter much, maybe select the MC/MM choices, but in the end switch between all your options till it sounds good.

I still think, it must be possible for someone to look at the Pre and say go with an MM with xmV output and select best sound from your Phone selector and Gain selector, MC go with Highest or lowest mV output and again, select as MM.
I guess I'm left to think just buy something and turn knobs till it sounds best. Yet, if I didn't supply all the specs everyone would say "How can we suggest anything when you don't supply us with the vital specs of your components"
Robes-
  #4  
Old 09-08-2017, 10:55 PM
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GeneL GeneL is offline
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Ok, it's not a Yamaha, but I thought I'd throw up a pic of my 70's Paragon 12A pre....

BTW, I am a Yamaha lover,my favorite right now is my KX-1200U cassette deck.
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  #5  
Old 09-09-2017, 09:53 AM
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Mark J Mark J is offline
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Quote:
Originally Posted by Robes View Post
Hi John, thanks for your input-

In conclusion, from multiple replies on several post on different forums it seems I usually get answers that completely overwhelm me and to which I don't have a clue what they said as well as not answering a specific question of the many I usually ask.


Robes-
This is because you are trying to understand the minutia of the issue instead of asking the pertinent question..."I've got tt x with tonearm y (for mechanically matching the cartridge) and a budget of $$$$ and a yamaha c-85 preamp, the only item concerned with electrically 'matching' the cartridge. What cartridge will work well with this combo? I like the sound to be full of ...(describe the sound you like, zingy highs, gut punching lows, sweet midrange or whatever) and I listen to mostly...(describe the music you like). You might mention speakers, too so folks don't get you too crisp with the horn speaker and an AT high frequency peak for example. You will get answers you need to help select a cartridge.


A VPI should have a fine Moving Coil cartridge of low output. Since most of these today have an output of 0.4-0.9mV or 400-900V they will work perfectly with the 100V minimum input for the preamp.

You are trying to learn too much in one step to allow you to select a cartridge.
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Last edited by Mark J; 09-09-2017 at 09:57 AM.
  #6  
Old 09-09-2017, 11:01 AM
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kcbluesman kcbluesman is online now
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Quote:
Originally Posted by Robes View Post
Well, I'm sure you can see I don't know what I'm talking. Maybe you can suggest something to help me understand some of this so I can buy a good matching cart to optimize my C-85.

Well, lets see if the dead can be resurrected......

Robes

The job of the preamp is to optimize the performance of the cartridge, not the other way round.

Optimal performance from a particular cartridge may require a particular impedance or capacitance loading. Your Yamaha preamp has limited choices in this regard - 47K impedance for moving magnet carts, with either 220 or 330 pf of added capacitance, 100 ohm impedance for high-output moving coil carts (using the moving magnet 100 ohm setting), and a choice of 100 or 1000 ohms for low-output moving coil carts.

For optimal performance, you will want to assure that the recommended loadings of the cartridge you choose can be accommodated by the C-85. Most can.

VPI provides recommendations regarding appropriate cartridges for the Prime TT; see here:

http://www.vpiindustries.com/prime

While most recommendations for a table of that caliber will be for moving coil cartridges - the great majority of which the C-85 preamp can accommodate quite nicely - there are certainly some moving magnet carts also capable of doing it justice.

Among them would be the AudioTechnica 150MLX, the Ortofon 2M Black or Bronze and the Nagaoka MP-500. And if your record collection is less than pristine, or your budget is highly restricted, you might consider something with a slightly less-refined stylus...such as the Ortofon 2M Blue or the AT VM540ML.

Finally, don't get overly hung up on cartridge loading or specific voltage gains. If your preamp/phono amp has both MC and MM capabilities, you don't really need to know much more than that as regards gain. Use MM for moving magnet carts and high-output moving coils, and MC for all other moving coils. For impedance loading, close (+/-20%) willl generally be good enough.

If you are the type of person who must have it 100% perfect (vs 99%), you will need to invest in a stand-alone phono amp with a broad array of loading options. Alternatively, if you want to play with impedance loading, you can make up some loading plugs fairly easily....see this link:

http://daveyw.edsstuff.org/vinyl/loading/

Final thought...the 10dB gain button is only there for situations in which the voltage from your cartridge is so high that your volume control becomes overly sensitive (in other words, has only a very small range between very soft and very loud). Dropping the voltage (which is what this button does) would give you back a wider control range. This has very little to do with sound quality, and I would advise that you don't make cartridge output a consideration in your cartridge decision, given that your preamp can accommodate both high and low output carts.

Last edited by kcbluesman; 09-09-2017 at 11:11 PM. Reason: Added info re loading plugs
  #7  
Old 09-09-2017, 11:38 AM
john from seattle john from seattle is offline
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What KCbluesman said,

I did look inside my phono preamp, and I had the gain set to 40dB and the impedance at 47K, or where I had left it with the SHURE M97xE cart, though I think it should be at 53K Ohm to extend the top end a bit and I may need to adjust the capacitance at some point as the SHURE rolls off the top end by attenuating rather sharply at about 8K or so, with increased impedance, the top end extends, but with a risk of a bump in the 5-8K range, but with the right capacitance, I can extend it with a relatively flat response to roughly 15K with a much slower drop off of the top end after that if memory serves.

This is the function of a good phono preamp, to best mate up with the cart, and get the most out of it in general.

So I'm currently running, as an experiment to see if my older Ortofon Super OM-10 is as bright as I seem to recall and thus was tiresome to listen to. Even at 47K, it was not as bad as I remember, and even now with some better speakers with a horn based super tweeter and a horn midrange included with the cone midrange driver for an even more detailed and open top end than my previous speakers.

That all said, I switched the impedance on my preamp to 53K and the cart suddenly went TOO bright, so dropped it back to 47K, but decided to try it at 36K and it attenuated a little the top end, taming it a bit and I'm going to leave it there and see if I like that as the OM series carts tend to extend the top end to about 23K, and in some systems may be too much of a good thing vocally speaking.

I hope this helps you to better understand how this all works and interrelate to each other and the rest of the system.
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my system Kenwood KD12-RB turntable, SHURE M97xE cart, Muffsy PP3 phono pre, Receiver: Sherwood RX4030R, TEAC A4300SX R2R, Denon DCM-370 CD changer, Speakers: sansui SP1700 and in testing/restoration phase, Sansui SP-3000, eMachines PC for multimedia use and recently got a Nakamichi BX100 cassette deck
  #8  
Old 09-09-2017, 12:43 PM
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Mark J Mark J is offline
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From a pioneer SA-8800 owners manual:



Let us know if you have questions about this as that is the starting point for understanding what the changes in capacitance and resistance will do for the MM cartridges. The MC cartridges are a whole nother conversation with the capacitance having little effect and the resistance being a completely different range compared to MM which want in the tens of thousands of ohms. MC usually in the 10-1000 range. HOMC is another discussion, again.

Way too much learning for the simple task of selecting a cartridge.
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  #9  
Old 09-10-2017, 02:25 PM
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Nakdoc Nakdoc is offline
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I have an AKG MC cartridge that I use with my C-85. You have an option (which IS the point of having front controls) of running a MC cartridge at the 47k ohm MM setting or using one of the MC inputs. You should try to match the cartridge's impedance if using MC input. Note that there will be a volume difference when switching from MM to MC - don't blow your speakers!
MCs are not affected by capacitance. Older magnetics like Shure M91 and Empire 999 sound best with 330pf. Audio Technicas sound best with no extra capacitance. I use the MC stage with my cartridge because it is a bit quieter.
  #10  
Old 09-10-2017, 03:03 PM
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NEMOaudio NEMOaudio is offline
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Quote:
Originally Posted by Nakdoc View Post
.... Note that there will be a volume difference when switching from MM to MC - don't blow your speakers!....
Which is probably why there is that switch at the back for NORMAL or -10dB gain.
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  #11  
Old 09-10-2017, 03:17 PM
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Quote:
Originally Posted by Nakdoc View Post
I have an AKG MC cartridge that I use with my C-85. You have an option (which IS the point of having front controls) of running a MC cartridge at the 47k ohm MM setting or using one of the MC inputs. You should try to match the cartridge's impedance if using MC input. Note that there will be a volume difference when switching from MM to MC - don't blow your speakers!
MCs are not affected by capacitance. Older magnetics like Shure M91 and Empire 999 sound best with 330pf. Audio Technicas sound best with no extra capacitance. I use the MC stage with my cartridge because it is a bit quieter.
I don't know of any MC carts that would be suited to 47K. However, doesn't the C-85 have a MM setting with 100ohm loading?

Last edited by kcbluesman; 09-10-2017 at 11:06 PM.
  #12  
Old 09-10-2017, 04:31 PM
john from seattle john from seattle is offline
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What about high output MC's as they use the same phono stage as the MM carts do? Not saying 47K being ideal always or anything but wouldn't some of them use 47K?

Now I know LOMC's have different parameters that has capacitance being more critical than resistance like is found on MM carts and thus it's more likely that 47K is good enough for many.
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my system Kenwood KD12-RB turntable, SHURE M97xE cart, Muffsy PP3 phono pre, Receiver: Sherwood RX4030R, TEAC A4300SX R2R, Denon DCM-370 CD changer, Speakers: sansui SP1700 and in testing/restoration phase, Sansui SP-3000, eMachines PC for multimedia use and recently got a Nakamichi BX100 cassette deck
  #13  
Old 09-10-2017, 05:20 PM
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Those with which I am familiar have much lower impedances than MMs, so need a lower load. The coils cannot be so heavily wound in a moving coil cart. There may well be HOMC carts with a manufacturer's recommended loading of 47K...I'm just not familiar with them.

EDIT: By the way, I think you got the relationship of capacitance to inductance wrong....capacitance becomes of less significance as inductance is reduced. So, moving coil carts - with their dramatically lower inductance - are relatively unaffected by loading capacitance. At least that's my understanding!

Last edited by kcbluesman; 09-10-2017 at 11:34 PM.
  #14  
Old 09-11-2017, 09:32 AM
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In the early days of MC Absolute Sound published reviews comparing MC head amps and transformers to a standard 47k ohm magnetic preamp input. In most cases, they preferred the 47k. If you have a quiet preamp, you ought to try it.
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Old 09-11-2017, 09:42 AM
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In the early days of MC Absolute Sound published reviews comparing MC head amps and transformers to a standard 47k ohm magnetic preamp input. In most cases, they preferred the 47k. If you have a quiet preamp, you ought to try it.
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Old 09-11-2017, 11:48 AM
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Assuming your preamp is stable at ultrasonic frequencies and very quiet, there is no technical reason not to use 47K...it this case, it is much more of a subjective issue. In my limited use of MC carts, I've found they perform better with more loading than 47K.
  #17  
Old 09-11-2017, 12:45 PM
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The ARC SP-9 has an input sensitivity of 1mV and I don't know if that is with the 6dB of gain, in the line stage, engage or not using an internal soldered jumper. This makes the phono input usable for many cartridges, MC included. But one needs to crank up the volume when using some of the 0.4mV output MCs. Good thing it is a high quality quiet preamp.
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Old 09-11-2017, 12:47 PM
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Wonder if Robes is on to picking a cartridge, wonder what he got or what made his short list.
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  #19  
Old 09-11-2017, 03:17 PM
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Based on his questions, I expect that he is still agonizing over the details. He has a nice preamp and is acquiring a very nice table...all of the carts recommended by VPI for that table will provide wonderful performance in his system, as will the better moving magnet carts I mentioned.

Cartridges are hard to evaluate....unlike speakers and other components, which you can often trial before buying (or at least return after buying), you must make a fairly significant financial commitment to find out if you like the sound of a particular cart in your particular system. That risk is hard to avoid. Reviews (both professional and from regular users) can help give an idea of the characteristics of a particular cart, but their usefullness is limited by their inherent subjectivity...what one person finds "detailed", another may find "strident".

But I hope that he doesn't let the more esoteric details keep him from just making a decision and moving forward.
  #20  
Old 09-11-2017, 03:58 PM
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True about not getting much chance to hear a cartridge. Fortunately, there are a number of us that get together and we have a range or cartridges and experiences to discuss.
Koetsu Black (vintage
Ortofon MC-20
ZYX Yatra
AT 33something
Dynavector 23R
Dynavector 20x2
ZYX Omega
others that have been here, Shelter 501 II, Ortofon MC30 Super, Benz Ace, AT 15Sa, Shure V15, Grace F9/Soundsmithed and a few more.

Usually a couple of them can be heard back to back and discussed.

I asked at the local stereo emporium how they handle letting their customers hear different cartridges. They discuss with them what they want and recommend then check back and if it works great, if not they will swap it out. Has to be done early on and the it doesn't work needs to be described so the next selection will work. Hard for a store to have more than 2 or 3 $2000-$10000 cartridges on display for comparison.
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