This is the latest version of the custom FRENZEL  HB1 Hot Box Tube Preamp.  This  preamp  provides so many tones and overdrive that it will drive you crazy trying to choose the one you want. Perhaps a more detailed description would help.  I am sure all  you guitar guys know about the vintage Matchless Hot Box,and what a great tube effects pedal it was, so I won't go into a history of it...but I will tell you a little about the original Hot Box circuitry. The original  Hot Box  used two 12AX7's. They were wired so that, in the clean mode, you had one stage of gain, with a Gain control. The clean stage had a bright cap and some other audio filtering that made the tones  sparkle. For the boost stage you had three stages of gain, with circuitry very similar to the vintage Marshall preamps. The boost channel had Gain and Master level controls. The three stages of gain drove a cathode follower which fed a two band tone stack. All in all a really ace combination....but  despite it's excellence, it had a few problems and we have endeavored to correct them by listening to  suggestions made by our "rock on" guitar buds.
 

The first change was to replace two band tone stack in the Boost channel with a   3 band type tone stack similar to the one was used on the JTM 45.This stack  allows you to create a much wider range of fantastic overdrive tones. We also changed the CLEAN/BOOST channel switching circuit to use a sealed ultra low noise relay to eliminate switching noises and loud pops. Another problem with the original Hot Box was that they all had a lot of 60 cycle hum. We have corrected this by using DC on the filaments. In the CLEAN amp section  we installed a BRIGHT pull switch on the Clean Gain control. These two changes give you a much larger range of tones. Also, a second pushbutton was added to the footswitch to allow you to completely bypass the Hot Box. This gives the player three options.....Bypass, Clean, and Boost. Regarding the footswitch, we have added LED's so that you know which mode you are in. This was requested by several players.

Additional features include a 3 prong ground power cord and all point-to-point handwiring. The controls are Input, Clean Gain with Bright Switch,  Boost Gain with Boost Switch, Boost Bass, Boost Mid, Boost Treble, Boost Master, Power LED, and Power On/Off. The rear panel has a 1/4" footswitch jack,  1/4" Output jack, Output Level control, and power line fuse.  The tube line up is 2 -12AX7's. 

If you have never played through a Hot Box... you are in for a real treat. If you have, you are still in for a trip, because of the new features that have been added.  It makes any tube amp sound better......and for you guys with solid state amps who are craving that vintage tube sound, you can insert it in front of your solid state amp and get that classic Fender, Marshall, or Vox preamp tube overdrive distortion tones.

The preamp is built on a 10" x 6" x 2" chassis. It is constructed with all new top of the line parts....Switchcraft jacks, EH 12AX7's, ceramic tube sockets, polypropylene caps, metal film resistors... etc.  It comes with a two button Marshall style footswitch. 

Tubes:  The amp comes with 2 - 12AX7,  but you can substitute 12AT7's or 12AU7's in the preamp and driver for different tones and and less preamp overdrive

1. VINTAGE CAGE - A retro style metal cage   is available in  as an option. Please add $90.00 to the cost of the auction for this option. (See picture) 

2. RACK MOUNT CHASSIS - Studio pro grade rack mount ventilated chassis assembly. Removeable covers.Add $250.00 

3. 100 - 240 VOLT  POWER TRANSFORMER - for operation outside the USA. Please specify line voltage. Add $40.00