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A question of loading...

I have just replaced my aging tube preamp with a new model. When I was using my older model with tube phono stage, I would run my Lyra Kleos and other MC cartridges with a load of 750 ohms. So, I assumed that with my new tube phono stage, which also utilizes a transformer in the phono stage and is also built into my new preamp, that the same cartridge loading would apply. I listened to the Kleos for about a week with this loading, and frankly, while it was fine, I wasn’t bowled over. Tonight I decided to experiment, so the first thing I did was to run the cartridge straight in, with no loading plugs. WOW, the increase in overall musicality and soundstage width was eye opening! Lesson learned is that not all gear is going to react the same when it comes to cartridge loading, particularly if there is a transformer involved and even if you are using the same cartridge from one phono stage to the next! An eye opener, anyone else experience something like this?
128x128daveyf
daveyf's avatar
daveyf OP
2,871 posts
 
@rauliruegas   Thanks for your post and the link. I did read the link. Seems like FM believes that 20-500 ohms works best for MC cartridges. While this may be true with their preamp, it was not true with my older CAT as it sounded best loaded to 750 Ohms and NOT lower and as stated in my OP, my new model CAT sounds way better unloaded! 
fsonicsmith's avatar
fsonicsmith
950 posts
 
For my Etna, it is 50k" -  50 kohms is unloading, its higher than the standard 47k.
You are showing your ignorance Dover. 47K is not standard for a MC and not standard with the Etna Lambda, which I am listening to as I type this. 47K is the standard for MM. Not for MC. We vinyl junkies, for better or worse, refer to lower capacitance as unloading even though you are technically correct. Why is this? Because as you lower loading values, the cantilever is subject to less damping. At the end of the day it is damping and not technical numbers that counts. Someone who knows his stuff wrote this;
The loading that the owner adds is a resistor in parallel to the signal path. That means that the higher the value of that resistor, the LOWER the amount of loading. Higher loading (lower value of the resistor) tends to damp high frequency peaks. With modern cartridges, the peak is usually well into the ultrasonic range, so loading is not needed as much as was the case in the past to correct for peaks. Jonathan Carr, the designer and builder of Lyra cartridges is among those who believe that additional loading is not needed to damp such peaks and it takes away some of the extension and open and airy sound on top. However, even though the peak is outside of the normal hearing range, it can be high enough in amplitude to overload some phono stages. He believes that loading is more important for preventing such overloading than in taming the frequency response of cartridges. I tend to agree with this. I happen to have a phono stage that does not overload and I like to run my MC cartridges (Lyra Titan and Transfiguration Orpheus L) wide open.

Sometimes, loading helps to suppress RF interference. A friend had a Hovland preamp that was passing a lot of hashy noise. It turned out that the factory default loading was 100k (essentially no loading). When we increased loading, the noise went away.

There is absolutely no harm in utilizing any particular amount of loading so one can experiment. I tend to find that higher levels of loading, say any value lower than 100 ohms, makes the sound warmer, more bass prevalent and shut down on top. Also, the lower the resistor value, the lower the total output so that volume level will go down. As a very rough rule, with most cartridges, a load of about 125 to 150 works perfectly well, and no much difference is heard if a higher value resistor (lower loading) than that is used.


dover
2,243 posts
 
@fsonicsmith 
47K is the standard for MM. Not for MC.
Whats your point. Are you loading at 50k as you claim or 50 ohms ?

We vinyl junkies, for better or worse, refer to lower capacitance as unloading even though you are technically correct. 
MC's are not generally impacted by capacitance changes.
Loading generally refers to resistance with MC's.
Because as you lower loading values, the cantilever is subject to less damping. At the end of the day it is damping and not technical numbers that counts. 
Jonathan Carr, the designer of your cartridge, does not agree with this.
Your theory is old school thinking. If you search for JCarr postings on loading you will find his views elsewhere on this forum.
 


atmasphere's avatar
atmasphere
11,793 posts
 
You are showing your ignorance Dover. 47K is not standard for a MC and not standard with the Etna Lambda, which I am listening to as I type this. 47K is the standard for MM. Not for MC.
Actually 47K is the standard input impedance for all phono sections, MM or LOMC.


LOMC cartridges often seem to need lower impedances, but this is really for the benefit of the phono preamp, not the cartridge, due to the reasons Jonathan Carr has talked about, mentioned earlier on this thread.


I've been telling people this for years. If your phono section does not have troubles with the RFI caused by most LOMC cartridges (and the capacitance of the tonearm cable) then 47K will sound just fine.

An additional side benefit will be less ticks and pops, since the phono preamp will generate ticks and pops if the input section is overloaded by the RFI at its input. It is for this reason that tubes have a distinct advantage over solid state, as its easier to designed a phono section using tubes that is hard to overload.
daveyf's avatar
daveyf OP
2,871 posts
 
+ 1 Atmasphere.

OTOH, do tubes have a distinct advantage?? I would say that they do when it comes to overall SQ, plus the decreased likelihood of overload, BUT they are never 100% quiet...at least IME. There is always some minimal hiss..and this leads me to believe that their noise floor has to be higher than ss. 
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