The Super Stack DI is a tube preamp for musical instruments, utilizing the popular passive tone stack found in vintage Fender amps. Like the P15, this full featured preamp is mains powered, and offers both a line output and a transformer-coupled balanced output.
 
Upgraded features found in the P15 are also used in the Super Stack DI, including:
Power transformer selected for high voltage, DC heaters, low noise, and choice of mains voltage
Double copper plating on the PCB for improved reliability and heat dissipation
New production JJ 12AX7 tested for low noise and microphonics
Neutrik audio jacks
Ground lift
 
Purchasing 
The Super Stack DI can only be purchased directly from this web page and is limited in stock. There are no waitlists, preorders, or reservations. Check this product page for updates on the status of the project. Please do not order more than one preamp, or combine your order with other pedals.
 
Overview
The Super Stack DI is a tube preamp based on classic Fender amplifiers that include a three band tone control. It is an exact recreation of the preamp section, using one 12AX7 tube. The audio path includes a tube gain stage that drives the tone stack, followed by another tube gain stage to adequately boost the signal to line level. A high voltage MOSFET cleanly drives both the line output and the transformer coupled balanced output.
 
Input 
The input is designed for mono instrument level signals via a 1/4" jack. You can use your input signal coming out of the Thru jack to feed another device, such as a tuner, or a bass amp. The Super Stack DI does not affect the signal of the Thru jack. The input is muted when neither jack is used.
 
Controls 
The Volume controls the amount of signal transferred from the first gain stage to the second gain stage. The Volume control can be set to reach a line level output when using instrument level signals. Tube overdrive can be introduced at higher volume levels. The Bass, Middle, and Treble controls are passive and interactive. The Bass and Treble controls boost and cut their respective bands in a shelving manner. The Middle control affects the amount of scoop at 500 Hz, and also adjusts the boost/cut range of the Bass and Treble controls. A suggested starting point would be to max the Middle control, set the Bass and Treble controls to noon, and adjust the Volume control as needed.
 
Output 
The balanced output is transformer coupled, and can drive long XLR cable lengths to feed a mixing console, or other equipment that accepts balanced signals. The output is stepped down from the line output. The ground lift button connects pin 1 of the XLR to the chassis of the Super Stack DI. Releasing the button disconnects pin 1. Choose the option that provides the least amount of noise. Phantom power should not be used on the Super Stack DI, but no damage will occur if connected.
 
The line output is an unbalanced mono signal coming from the 1/4" jack. This is capable of driving power amps, or other equipment that accepts line level signals. Both outputs may be used simultaneously. Due to the high level signal output, you may wish to use a pad (attenuator) on the receiving device. Set your volume and tone controls on the Super Stack DI as desired, and then add gain, if needed, at the receiving device.
 
Tube 
The Super Stack DI uses a new production JJ 12AX7 tube. We do not accept requests to use different tubes.
 
Mains Power 
When ordering, choose either the 115VAC model for North American voltage, or 230VAC model for European voltage.
 
Dimensions 
The Super Stack is 6" wide, 10" long, and 6" tall. It weighs 5 pounds.
 
Miscellaneous 
Shipping costs will update when you input your information upon checkout. International shipping is available. The package dimensions are 14" x 8" x 8". All shipments are insured and come with tracking.
 
The Super Stack DI does not come with a case. These cases will fit the Super Stack:
Gator GU-1309-06-WPDF
Gator G-MIXERBAG-1306
Apache 3800
 
The Super Stack DI comes with a power cable for North American orders only.