Helikon LOADING

Dear Gmorris: +++++ " the optimal loading value is indeed system dependent " +++++

Maybe there are something that I missed about because I still can't understand your statement.

For me, for a cartridge perform flat ( frequency response ), exist a precise load impedance that is not system dependent because we have to set it through a resistor change or through a variable resistor or through a impedance switch. What have we to take in count for we can have the right resistor value ( this one is the input impedance of the phonopreamp )?: the manufacturer load impedance value and the sum of the impedance of the tonearm internal wires with the impedance of the tonearm interconnect cable. These impedances sum has to be added to the resistor value for to find the precise resistor value for the cartridge can " see " the right load impedance value where it performs flat.
Sorry, I can't see your " system dependent ".

Regards and enjoy the music.
Raul.

Jeff, re: mechanical damping affecting total load impedance, I suppose it does contribute by a small factor (you are talking about a reactance-type current in the coils damping the cantilever movement, right?)

Anyway, the effect on the freq. response curve would be small I should think, compared to the deviation from flat that would be caused by a load change of even 20 or 30 ohms.

It's one of those factors like VTA, where a less than optimum configuration will only yield 4th (or was it 8th) order distortions which are essentially inaudible. Whereas even a slight mis-adjustment of SRA is quite audible. It's sort of like that I think.

Nsgarch - Right.
All - Thanks!

After reading this thread I went home to experiment with the loading on my Helikon which I had been using at 47K. My phono is currently set up for 100, 200, 1K, and 47K.

The 25 x output impedance suggests 137.5 ohms.

I tried 200 and there was a little more bass but the sound was uninvolving, no punch or energy. I tried 1K and that brought back the energy quite a bit. However, at that setting, it seemed that some records sounded great and others didn't. The ones that didn't had an almost "out of phase" kind of sound. The music didn't project out into the listening room the way I thought it should.

I will continue to experiment but color me confused by the results so far.

Loading affects the frequency balance -- LESS loading (higher value like 1k or 47k) means a more prominent peak in the treble response, but, it also means that the peak and fall off after the peak occurs at a higher frequency. Therefor, it is hard to say which setting has an objectively flatter response.

I tend to like the cartridge running more wide open and extended on top (47k for my Lyra Titan). But, I do somewhat compensate for the tendency of this setting to be a bit sibilant by having the vertical tracking angle set low (cartridge very slightly "tail down"). I tend to treat VTA and loading as complementary, so both have to be fiddled with to find the best combination. Both factors affect tonal balance, as well as other performance characteristics.