Backert Labs Rhythm 1.4 preamplifier: New Stereo Times review on a great line-stage

Therefore, the difference between the two line-stages is which tubes they use. What do you like better, 6SN7s or 12AU7s? Both tubes are great, but present music somewhat differently. For example which do you like better 2A3s,300bs,211s? All great sounding power tubes but different. Which would give you more synergy in the context of your system and better fit your personal taste? Both preamps are superlative, but different because of the tubes they use.

@teajay  So for those of us who don’t know the differences between the rubes, what are the specific sonic differences between the Rhythm and the Motherload?  It’s not lost on me that the Rhythm costs more than twice the price of the Motherload. 

Hey soix,

Both preamps have none existent noise floors, offer excellent overall dynamics, have great control and extension on the top and bottom frequencies, and high-level transient speed.

Regardless, of the cost difference they are more similar in the above stated areas and then part ways because of the different tubes each one uses. 

In what ways do they part ways?  That’s really what I was asking. You seem hesitant to describe the critical differences. 

Hey soix,

I truly don't get what you don't get. Call it a draw between the two line-stages, in the ways I answered your question above. The "ways they part company" is totally dependent on the differences between the sonics of a 6SN7 vs 12AU7. 

When I use my all time favorite 6SN7 NOS TungSol black glass oval plates I experience a slightly rounded leading edge to the note, holographic imaging, sense of sound-space, where it was recorded, as much as the sound-stage of the music.

When I use one of my favorite NOS 12AU7, the Mazda Silver plate, the leading edge is more precise, there is more punch/dynamics, less warmth, but still great tonality.

The difference is in the tubes, not the preamps themselves. Both units disappear and let the signatures of the type of tube and different brands to be heard.

Don't know how to explain any better

Well, you finally described the sonic differences between the tubes.  That’s what I didn’t get and was looking for.