A Black Box to Solve Everything

For you DIYers, Ethan Winer provides directions on how to build his Mojo Maestro box, which he states is: "...a simple box that can add distortion ranging from very subtle—to add a little grit to a sterile sounding instrument track or to help “glue” a full mix together—through severe clipping to add “mojo” or “dirt” to any musical source that will benefit. The Mojo setting also switches in a capacitor to gently roll off the highest frequencies to counter the added buzziness. With gentler settings, the overall effect is similar to running music through a tube amplifier or an analog tape recorder but without the added tape hiss and flutter.": https://audioxpress.com/article/you-can-diy-build-the-mojo-maestro

Many of us have used tube preamps with SS amps to bring some desirable tube qualities to our systems, and others use SS preamps and tube amps. In 1973 as a college kid I ran a PAS3x with an H-K Citation 12.  Later a Motif FET pre with av MV55 amp.  All worthy experiences.  There is no single silver bullet, for this or any other system voicing conundrum.

@bdp24 Yes a preamp and a reasonably easy kit to build. Nelson is brilliant with solid state devices and while Ralph and Roger are/were known for their brilliance with tubes, Ralph has now demonstrated he can manufacture a solid state amp with similar distortion characteristics as tubes. Somewhat of a little known fact, Roger's first amp to be manufactured was the one he designed for the Beveridge 2SW speaker. It was a solid state amp designed specifically for the woofer section. This required him to develop the RM-3 active crossover to act as a frequency dividing network as the 2SW required biamping. The RM-3 also used sold state devices.

Getting back to the B1, Nelson's choice of the Korg Nutube is interesting and I'm sure was selected to support his circuit requirement to allow for the adjustable harmonics. However, it's probably the worst tube I have ever dealt with. Many examples of this tube are extremely microphonic. I went through 3 of them building that kit and none of them were quiet enough. So I never could really test out the adjustable distortion feature.

@knotscott 

Tubes for guitar and tubes for hi fi have very different objectives. Audible distortion for a guitar amp is a desirable feature, not so for a hi fi amp.

FYI, distortion ("overdrive") is not the sole goal or attribute of guitar amps/pedals that attempt to mimic tubes!  "Clean" tube tones are as prized as "dirty" tube tones as is the ability of some of them to mimic a variety of amps that are associated with different types of tubes. Some examples include but are not limited to: 6L6/6V6 for Fender, EL34 for Marshall, EL84 for Vox, etc. This seems quite in line with what the OP states:

My thinking is that of a black box with switches and knobs to adjust harmonic distortion to mimic different tube types. 

 

 

@koestner 

I have a BSG QOL Signal Completion processor in my system and I use it most of the time. It is not adjustable and I would not describe it as adding any sort of tube distortion. It affects the phase information in the signal and adds depth and focuses the imaging. I suppose one could describe these effects as tube virtues but I've never heard any piece of tube gear that has such a dramatic impact on the signal. I also have a Yaqin tube buffer which produces a very subtle difference - nothing close to what the QOL provides.

BTW, I've experimented with several signal processors and the QOL is the only one I use. It adds a very nice effect.