I forgot to add that I put in a 12AY7 in the pro jr for V1. But with this little pro jr, it is a great match and I can make it sound like a marshall to a hot rodded marshall. But at the loud levels and in the band mix his amp fit perfectly.īack to the BK, in general I never use for gigging but for some strange reason have hung onto. I played his amp after the session and did not like it all. I did a live session were we were recorded. One of the other things I am always finding out is what sounds good at home may not cut in a band mix and vice versa. I think the dirt is still generated with diodes, but the tube warms up or tubifies the sound. Changing the tubes can make some difference I think my preference was low gain tubes like 12AY7. With my pro jr I can crank the mid and bass up to noon. On most amps I had to have all the tone knobs way down at around 9. Actual shipping cost to be determined at close of bidding.Īll gear as described.Mine has a separate treble, mid, bass. I will only charge you the exact shipping price no more and no less.
Shipping cost is an estimate based on past shipping. Thanks to Chris Mann for his YouTube video LOW CONTROL: Shelving control for frequencies from 100 Hz down. MID CONTROL: Adjusts mid-range frequencies. HI CONTROL: Shelving control for frequencies of 1500 Hz and up. Changes output volume without noticably altering the tone. MASTER CONTROL: Sets overall output level. Increasing this control beyond 5 gradually adds more harmonic distortion.ĬONTOUR CONTROL: Adjusts the amount of low frequencies driven into the tube.īIAS CONTROL: Quoting from two page owner’s manual, "The bias control actually adjusts the amount of cathode bias voltage of the tube stages, thereby regulating the amount of plate current" Setting the drive at 5 or below yields some tube warmth but with a clean output signal (no distortion). Again, this seems to be more useful for guitarists as well as bassists.ĭRIVE CONTROL: Can be thought of as a pre-amp volume control, it determines how much gain is provided by the pre-amp section. This can also be controlled using a footswitch plugged into the bypass jack on the unit back. Seems intended for guitarists as I simply boost my input level via theīYPASS SWITCH: Switches the Blue Tube in and out of the effects chain. The switch off after the solo to fade back into the mix. Using the boost switch for increased volume and distortion, then turn The idea is that you can drive the tube hard for a solo Overridden when a footswitch is connected to the boost jack on the back SWITCH: Increases the amount of gain to the tube by 10dB. The 12AX7 preamp tube makes an incredible tonal difference compared to non-tube effects. Rare and hard to find in this quality condition. Simply one of the most desired Overdrive Boost preamps ever made.
No manual, but online manual link below in the description. This Blue Tube RT-904 has been stored in a rack case, therefore it has no tiny rubber feet, I may find some around the work bench and add them. This is previously owned but well taken care off expect very light wear/scratches.Īwesome tones and classic blues & rock tube sounds. BK Butler RT-904, Blue Tube, Tube Works, Tube Instrument Preamp, Vintage RackĬondition: Near mint excellent cosmetic condition.