Looking for the best Preamp with a phono circuit built in

All the AI Modulus preamps that I have owned (2B, 3A and 3B) have had a dual mono configuration, which included 2 separate volumes pots—one for each channel. So channel balance was adjusted by the two separate channel volume pots being at different levels. The other two large knobs on the Modulus 3, 3A and 3B are input selector and source/tape controls. The Modulus 2 handles those input and tape selections by a set of push buttons rather than rotary knob controls.

The simplicity yet pain of a two knob master volume control is adjusting the overall levels of output voltage to the amp(s) will require one to also maintain proper signal balance by adjusting both volume pots to a given level and then making slight micro adjustments to correct the balance if needed for a given environment. As shown below, this is alleviated by having two channel level trim pots under the control of a third “master” level volume control that maintains the relative levels set by the 2 channel trim pots as the overall volume level is increased.

Now the Modulus L1 through L3A units are line stage preamps lacking a phono stage circuit (hence these units have 2 tubes instead of 4 tubes found in the full preamps). These line stage preamps devote 2 knobs to control voltage signal levels to each channel (designated “left” and “right”) that act as a balance control when used in combination. Another knob, labeled “volume” is the master volume control for the outputs to the mains (1 and 2) as well as the headphone amp section built into this unit. I have this setup on my Juicy Music Blueberry Extreme full function preamp (2 channel trim pots and a master volume control pot). The other (4th) large knob on the AI L1-L3A line stage preamps is the input selector. The source/tape switching is handled by a set of push buttons, akin the the AI Modulus 2 series preamps.

(Note added in edit: This is a popular circuit design set up, as Ralph explained above for his preamps.)

That's how our preamps are set up. The individual Gain Trim controls are used to set balance and overall gain. The Master control then makes adjusting the volume very easy.

The hearing in my right ear is ever so slightly better than my left ear and I usually notice that the sound stage favors the right side.  Can that be due to slightly better hearing in my right ear or might it be room acoustics?  Would a preamp with trim controls and a master volume be useful in this situation?  It seems like it would.

@ketchup

The one must be the source with its choices--the other 2 are left and right volume control. Should help your problem in hearing significantly as I’m sure your hearing varies on different days. This will enable you to get ’er done quickly and adjusted equally with some practice. Some recordings seem to be off on that too--so you can fix a poor mix. Plus, you get a little extra exercise without the remote.

@dobnbav--Well said. 24 years with AI preamps and I loved them.

Bob

@dorkwad

See below.  Volume, left, right, and source knobs.
https://positive-feedback.com/wp-content/uploads/2018/01/Photo-1.png

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