The best passive preamp


How good is one of the best passive preamp, how the transistor based bent audio or the placette or the swiss made Audio Consultant, or audio teknè, in comparision with the very best active line stage? beside the costs, is a pure quality question, for me.
alexismaster
The purpose of the transformer is to step up the voltage, not to attenuate. The 10k potentiometer or series stepped switch does the attenuating.
I've heard a few passives, but all had a reduced sense of dynamic swing...I much prefer an active preamp.
What does stepping up the voltage mean? What is the benefit? That has nothing to do with gain, right?
Actually it does have something to do with voltage gain. Depending on the ratio selected, assuming your source was 2V output, voltage gain could be stepped up to 4, 8, or 16V. Then you would attenuate the signal from there.

The circuit design loads the signal source op-amp letting it operate at its maximum ability. It is a completely passive design (no active circuitry, no power supply, or power cord), but unlike other passive pre-amplifiers, the MLA delivers a higher voltage at its output than it receives from the input. One benefit over other passive designs is the output impedance remains fixed which means that the frequency response does not change as the volume is changed.

The whole concept works due to the nature of how the hand built nickel core transformers are wound and operate. These are essentially op-amp loading transformers that cause op-amps to deliver current into an essentially pure impedance primary. The secondary then produces the equivalent voltage into hard termination which is now usable for the next stage of amplification.

So, like an active preamp it offers its own version of gain, but at much greater transparency and lower distortion levels. It does not use buffers. Call it an in-active preamp if you would. It is best used with digital sources under 600 ohms, but I have a high impedance (10K) input as well for use with tube and other sources requiring it. I also have used it with my phono stage, but it uses AD-797 op-amps for the output so it matches up better than other phono stages might. I'm working on a balanced version that will sit between my Otari Mx-5050 BII and Atma-Sphere S-30.
What are the issues that the Electra-Print Magnetic Line Amplifier is trying to address that the Lightspeed Attenuator does not - under what circumstances would that design approach be preferable to the LSA and other "simple" resistor-based attenuators, as well as AVC and TVCs?