What’s on the Bench?

Always something cool at Rock It Science Audio

This is an exciting project that’s underway this year on the bench at Rock It Science Audio.  It’s called the Tube Top II, which is to be the successor to the original Curry Tube Top, the tube powered bass preamp designed by electronics guru Dave Curry.

The original Tube Top uses a 2-tube circuit with EQ that was patterned after the Ampeg B-15 “Flip-Top” bass amp from the 1960s, probably the most utilized studio bass amp in history. 

Dave was kind enough to lend us a Tube Top at Pearl Music where we could play around with it on some recordings.  Of course, I immediately fell in love with the warm and vibey sound it produced, along with the versatility of the sound variations made using the EQ and Drive function.  I just had one minor quibble in that all the front panel settings are made using potentiometers, that work just fine but make it difficult to recall precise settings for overdubbing.  

I told Dave how I prefer rotary switches over pots because in addition to precise repeatable settings, they also allow for multiple circuit functions to be operated at one time when using multilayer rotary switches.   Dave, the cool laidback guy that he is, responded with “well why don’t you design a Rock It Science Audio version and put anything on it you want”.

So, this was the start of the ensuing conversation about what would become the Tube Top II.   Eventually, as featured were considered, the circuit grew to 3 tubes to allow for more distortion control and selectable frequency points were added to the EQ.  As you can see, this is a work in progress and may occupy bench space at Rock It Science for some time to come.

The original Tube Top

Tube Top II prototype

Making use of a surplus Groove Tube amplifier enclosure, the new Tube Top II circuitry is being assembled and tested on the bench.