Building my own amplifiers I’ve always loaded my mc cartridge according to the supplies advice (most often 100R seen by the cart throw the step up transformer).
However. Many, many years ago Allen Wright (Vaccum state) advice me not to load the cart that hard. He advised me to keep the 47K load at the phonoamp input, making a 470R load seen by the cart throw a 1:10 step up.
I didn’t follow his advice then. But now I have seen several post where others claim that to hard loading could making less than optimal conditions for the step up (Lundahl transformers in my case).
I can’t say that I can hear huge difference loading my mc (ZYX R100H) with 100R or 470R (I have old ears)
But how do you load your carts?
However. Many, many years ago Allen Wright (Vaccum state) advice me not to load the cart that hard. He advised me to keep the 47K load at the phonoamp input, making a 470R load seen by the cart throw a 1:10 step up.
I didn’t follow his advice then. But now I have seen several post where others claim that to hard loading could making less than optimal conditions for the step up (Lundahl transformers in my case).
I can’t say that I can hear huge difference loading my mc (ZYX R100H) with 100R or 470R (I have old ears)
But how do you load your carts?
I have loaded both SPU and IO as recommended, although different transformers have changed the sonic impact with the same loading.
You have to provide the loading that the transformer required, not what the cartridge requires.
I am talking about difference in sound, for transformers designed for std 47k phono inputs and turn ratio
to achieve recommended loading for the cartridges.
to achieve recommended loading for the cartridges.
So are we all, but it starts by obeying the laws of electricity. You need the loading at the preamp times the turns ratio to achieve the recommended cartridge loading. If that doesn’t answer your question, what exactly is your question?
@ejp
I’ve spoke to Per Lundahl about optimal loading of their mc step-up transformers, and they don’t specific that (Im currently using LL9206/1:10/Dynavector Carat Ruby (30R) and LL1931/1:8/ZYX R100H (8R), both carts currently see a mirrored load of 100R).
Surelly, I could try to measure/tune it by myself, but still. I wanted to hear from you, how you do it, and if you had give it a thought.
The optimal transformer loading is by the way, seldom a pure resistive one. But include a notch. a rc-link or something controlling a resonance peak. The resistive loading is not the optimal way to do it. But perhaps it’s good enough?
In my previous post I mentioned a discussion with Allen Wright. He claimed that the 100R loading, stated by the cartridge manufacturers, was picked for optimal frequency response, but that with a purelly resistive load, not the reactive load that a step up transformer with a resistive loaded secondary winding give.
He claimed that the step up transformer has some many stray components, that it would be impossible to take all into account.
I’m not saying this is a fact. But according to Allen a 47K loading (470R seen with 1:10 winding ratio) would be a better choice than the specified 10K (100R seen with 1:10 winding ratio) taking t some of he stray components in to account.
I’ve spoke to Per Lundahl about optimal loading of their mc step-up transformers, and they don’t specific that (Im currently using LL9206/1:10/Dynavector Carat Ruby (30R) and LL1931/1:8/ZYX R100H (8R), both carts currently see a mirrored load of 100R).
Surelly, I could try to measure/tune it by myself, but still. I wanted to hear from you, how you do it, and if you had give it a thought.
The optimal transformer loading is by the way, seldom a pure resistive one. But include a notch. a rc-link or something controlling a resonance peak. The resistive loading is not the optimal way to do it. But perhaps it’s good enough?
In my previous post I mentioned a discussion with Allen Wright. He claimed that the 100R loading, stated by the cartridge manufacturers, was picked for optimal frequency response, but that with a purelly resistive load, not the reactive load that a step up transformer with a resistive loaded secondary winding give.
He claimed that the step up transformer has some many stray components, that it would be impossible to take all into account.
I’m not saying this is a fact. But according to Allen a 47K loading (470R seen with 1:10 winding ratio) would be a better choice than the specified 10K (100R seen with 1:10 winding ratio) taking t some of he stray components in to account.
I’ve already said how I would do it. I don’t own an MC cartridge, and don’t really believe in them. Or in Allen Wright either 🙂
I have made some of this stuff some years ago
Three gain
Trafo custom by Brian Sowter ( now I have a clone for the future)
24 position of resistors in parallel to MM input.
The best way is to have the MM set at 100kohm ( as my phono)
In this case the range of optimization is almost perfect
Walter
I don't buy this reasoning. At the frequency extremes (<40 Hz, >10 kHz), perhaps.
I just load my DL-103 with a 1:16 Lundahl and 47 k on the secondary, that is about 180 R on the primary. I am happy with it.
A properly loaded s.u transformer presents a resistive value to the primary, not reactive.
Jan
Yes sure, that’s obvious.
But what is a “properly loaded s.u transformer”?
I would say it depends on how close you look. All winded devices has inductance, wich means they are all reactive devices.
If “properly loaded” means zero reactance, all inductive- and capacitive- components must fully be compensated for to fully be a resistive device.
Yes. You can tame ringing (resonance) with a resistive loading. But it’s that to say that it is “properly loaded”?
It might be good enough for this application. But what Allen ment, was that a trasformer is not just a winding ratio, it has several stray components that will influence just as much as the resistive loading.
I meant loaded with the right resistor value to get the desired primary resistance value.
In any case, the primary will see a resistor, not a reactance, except at the extremes of the specified bandwidth.
Depending on the transformer the impedance seen at the primary side may turn reactive at say below 20Hz and say above 18kHz.
Jan
In any case, the primary will see a resistor, not a reactance, except at the extremes of the specified bandwidth.
Depending on the transformer the impedance seen at the primary side may turn reactive at say below 20Hz and say above 18kHz.
Jan