What loading with Pass Xono / Helikon SL?

http://www.kabusa.com/frameset.htm?/phoncart.htm

Above is a great little tool for cartridge evaluation.

Scroll down the page to: "OUTPUT LEVEL CONSIDERATIONS"

You can then use the "PHONO PREAMP PARAMETER CALCULATOR" to dial in your load settings. This little calculator is as accurate as it gets.

Best of luck, Ed.

It seems a little complicated. But the output doesn't seem to be in ohm?

Your Helikon has an output of 0.23mV. An optimum gain range would be 60-65db. The range is to allow for tonearm wiring characteristics.

Your Pass Xono provides 71dB @ 1kHz (MC) single-ended, 76dB @ 1kHz (MC) balanced. I'm assuming you're running SE?

Below is an excerpt from the same website. It is probably the most pertinent information on the whole website:

"A phono cartridge has an electrical circuit which consists of coils of wire. These coils have electrical resistance and inductance, parameters which make them sensitive to the resistive and capacitive loading created by the tonearm wiring, interconnects and internal circuitry of your preamp. Manufacturer's specify the proper load resistance and capacitance with each cartridge. The cartridge will present the flattest frequency response when the manufacturer's recommended load is observed. Improperly loaded cartridges exhibit frequency response dips and peaks and often emphasize surface noise.
To know all the pieces of this puzzle, you will need to know:

1. The capacitance per foot of your interconnects
2. The capacitance of the internal tone arm wiring
3. The load components inside your preamp

Often this information is specified but you may find that it is not optimum for your cartridge. Many designers put way too much capacitance in their preamps forgetting, it would seem, that the tonearm wiring contributes to this quantity."

Hope this helps, Ed

Buscis2, the paragraph that you quoted is incorrect regarding a low impedance cartridge like the Helikon SL, since the low source impedance of the SL means that the frequency response within the audible band will not be altered by loading values.

With low-impedance cartridges and within the audible band, the frequency response of the cartridge itself is insensitive to what value you load it at (ambient temperature has a much bigger effect on the frequency response than the loading value).

Changing the loading _can_ create variations in the frequency response at the input of the phono stage, but these will be a result of how the source impedance and inductance of the cartridge interact with the interconnect cable's capacitance (which will therefore be affected by the length as well as the structure of the cable). Since the source impedance and inductance will be quite small with a low-impedance cartridge, these frequency variations will be at frequencies in excess of 500kHz, a wee bit higher than anything that you can hear directly.

Therefore with low-impedance cartridges, loading is mainly about giving the phono stage something that it can be happy with. Not the cartridge. For a manufacturer of low-impedance cartridges, it therefore doesn't make sense to provide a precise recommended figure for loading (apart from when stepup transformers are used), since the choice of interconnect cable (including length) and what the phono stage can tolerate will have a significant influence on what is perceived to be the optimal loading value.

As a general rule of thumb, the less linear the phono stage is at RF frequencies (the regions where loading will alter the frequency response), the heavier the loading will need to be to achieve listening satisfaction.

hth and regards, jonathan carr

I have the pass xono with helicon sl on a linn ekos tonearm/linn lp12 with audioquest leopard tonearm cables and cheetah interconnects, bat 31se preamp, x250.5 amp and magnepan 20.1. believe it or not, I load the xono at its most resistive setting 5.4ohm. my speakers have great clarity in the highs but get more grainy if i set it higher. i probably am an outlier, but loading is such a personal thing, i don't think there is a correct formula for it and you have to talk to people who have exactly the same equipment and preference, otherwise it's all just talk.

"but loading is such a personal thing, i don't think there is a correct formula for it and you have to talk to people who have exactly the same equipment and preference, otherwise it's all just talk"

EXACTLY! That is the EXACT reason I put that excerpt above. There is no value that can be determined until the above information is considered. The Pass provides tremendous loading variance. The optimum loading value will be dialed in after the cumulative total above impedance, capacitance and inductance levels create the loading requirements.

Dear Shsohis: The Pass Xono is a very decent phono stage and due to the low internal helikon resistance ( 5.5 Ohms ) IMHO it will be perform very good with a load impedance of 100 Ohms.

I owned the Helikon with good success at that impedance load.
In many ways as Jcarr point out the impedance load value is system dependent and you have to set up where you hear the best natural balance music sound reproduction on recordings that you know in deep, looking too for the best extreme frequency range best reproduction ( the load impedance changes affect mainly the high frequencies on your phono stage. ).

Btw, Buscis2 post speaks about " capacitance " and this " figure affect " the response on a MM cartridge but there is no change in a very low internal resistance cartridges like your MC Helikon ( at least not at pf values that are the standard ones in a phono stage like your Pass Xono. ) so don't worry about.

Regards and enjoy the music.
Raul.

I recently found that when I shunt the gain to -4dB of the original that I can increase the loading from 5.4ohm to 9.5ohm and it sounds more open, but if I load it higher it sounds too bright at the top. It just seems a delicate balance and your best bet is to play with the loading in incremental steps in either direction to see what you prefer.