Switches on Aleph Ono with Grado

[Netlist]

Currently, I only have the MM part of the Ono soldered but plan to populate the MC section as well and give the Grado Statement a try.
http://www.gradolabs.com/product_pages/statement.htm

The Ono can be set for a variable impedance of 10 to 1000 ohm but the cartridge needs an input load of 47k.

I’m a bit confused on how to set the switches or do I solder a 47k resistor in?
Perhaps I don’t need the MC input at all, given the high gain of the Ono in MM mode.
I found a post that might indicate that the previous is valid:
http://www.diyaudio.com/forums/showt...7218#post27218

Also, are there any particular tweaks possible to perfectly mate the Statement to the Ono?

/Hugo

[Nelson Pass]

The Statement is my favorite cartridge. I am running it with the
X-ono MC input with 47 Kohm, and it's perfect.

To get 47 Kohm, simply disable all other load values - 47 Kohm
is the default.

[Netlist]

Of course I overlooked R31, 47k.
Saves me a switch.
Does the input stage benefit from matched FETs?
I have the -BL on the shelve.

/Hugo

[Netlist]

Ignore.
Manual says 'Matched'.

/Hugo

[Nelson Pass]

It says that, but in point of fact it is only necessary to confirm
Idss numbers.

[Netlist]

It appears they are all from the same lot so i guess they will do fine without matching then.
Is there any advantage in paralleling even more devices?
I happen to see Sansui using six in a row in the AU-919 MC section.
In other words, what determines the amount of FETs?

/Hugo

[GRollins]

More gain, less noise.

Grey

[Tarasque]

There has been an article about the noise cancellation when using parallel input devices.
In theory the noise halved every time the number is doubled, in real life it is a little less, about 5,4dB
If I remember correctly, the conclusion was that 4 in parallel has optimum efficiency (cost) 8 in parallel make sense.
Going beond like 16 or 32 would only add very little to noise cancellation.

I can send you the article if you are interested.

[Netlist]

Thanks Grey.

Tarasque, I'm interested. Or you could try posting it here for all to read.
hugorx . hotmail

/Hugo

[wuffwaff]

Hi Hugo,

when using the BL version you can´t use the highest gain setting. Be sure to disable that.
The cause is the Idss that is too high causing a voltage drop higher as the cascode voltage.

It is no problem as such. Mine also runs with BL´s.
Matching them is no big deal and I would do this because they do vary quite a lot. I´ve measured Idss and Vp and drew the (theoretical) Vgs/Id lines. Then used the ones that matched best.

William