SUT - electrical theory and practical experience

@rauliruegas 

My point about the specified impedance along with the output voltage was to make the necessary gain calculations easier.  In your Lyra example, using a 10 Ohm load with a 7 Ohm impedance cart will drop the output level by 4.6dB, which could be significant.  The output level will only be insensitive to the load if the load is 10x the cart impedance or higher.

My point about conjugating the imaginary (reactive) impedance of the cart is to cancel out any inductive or capacitive reactance so the cart sees a purely resistive load which will give the flatest frequency response with no peaking at high frequencies.  If the complex impedance of the cart could be measured or calculated, then the proper termination could be easily determined instead of guessing or by changing loads and listening for a difference.

For some years in my system the active high gain phono stage came with a 100 ohm input resistor and through all those years I had not any single trouble ( that I been aware of. ) with several and different LOMC cartridges that I owned and own.

If you never tried any load other than 100 ohm, then you cannot know if there was a problem due to loading at 100 ohm .

My point about conjugating the imaginary (reactive) impedance of the cart is to cancel out any inductive or capacitive reactance so the cart sees a purely resistive load which will give the flatest frequency response with no peaking at high frequencies. 

@phoenixengr 

Flattest frequency response or best square wave ? Are these codependent ?

With Jensen SUT's that are designed to be used with a zobel network  they suggest  adjusting the network to the source load by scoping a square wave.

phoenixengr 

Flattest frequency response or best square wave ? Are these codependent ?

With Jensen SUT's that are designed to be used with a zobel network  they suggest  adjusting the network to the source load by scoping a square wave

@dover ^thanks!^

I suppose I should ask where does one get the square wave track from?

Does Jenson say to do this after the phono stage, or directly after the SUT?
Or is there a link?

Ah! I forgot about being shown a Square Wave by the EE producing the Phon'.

From recollection this Scope Reading was shown in conjunction with the 'mv' output per channel as a valuable reading to be assessed.

I don't get too bogged down in such a presentation, I am trusting in the EE and their abilities, if they are claiming there is something present that is impressive and of value to the electronic function of the device, who am I to nit-pick at their explanation.

The follow up listening has always been where I do my evaluations, and decide how much monies are to be removed from one's account, to achieve the experience permanently.