Frenzel – FM-DP1 Open Chassis Custom Guitar Tube Preamp – Used

The FRENZEL FM – DP1 “Deluxe Plexi” dual channel guitar/bass tube preamp is part of our “INSPIRED” line of products and  will give you the classic vintage tones of our Type F(Fender Deluxe)  and Type M (Marshall Plexi)  tube amps…and much more. This is the same preamp we use in our FM-5E3DP-525 and other similar voiced amps.  As with all of our “INSPIRED” Line of products, this preamp was inspired by the vintage 50’s-60’s amps with the “TONES YOU KNOW”…but it’s far from simply a clone….this preamp incorporates features and mods developed over FRENZEL Tube Amps 65 plus years of building and fine tuning amps…plus it has many unique upgrade options.

The preamp uses two dual triodes with DC on the filaments for low noise. The first tube is a 12AX7 wired as a dual input preamp…one Type F input for the vintage smooth warm Fender Deluxe type tones and one Type M input for the classic vintage Marshall SLP high-mids rock tones. Each input has separate gain controls for each preamp section. The second tube is a 12AX7 wired as a common voltage amplifier to drive the tone stack with a  cathode follower to provide a common low impedance output. The three band tone stack was designed by the “tube amp God” Leo Fender, so no improvements there, but we did add a Master volume.  With the tone stack and Gain and Master control combination you can get just about any sound you want…..including great clean tones…or the classic tube preamp distortion that the vintage tube amps are famous for. Also, for you Bass and hollow-body guitar players a Deep Bass Boost pull-switch has been added on the Bass control  to give that Bassman 864 contour for those deep bass tones; and a Bright Pull-Switch has been added on the F and  M Gain controls for sparkling Treble tones. There is a Trim control on the rear panel to match the input drive level of the amp you are using it with. Also…an added extra…..you can use an “AB-Y” pedal on the input jacks and blend the Type F  and Type M preamp sections for your own custom sound. The inputs are high impedance and the output is low impedance. This allows the preamp to work as an effects amp between your guitar and the input jack of your amp….or in your amp’s  effects loop…or as  a Direct In for recording.  It will also drive studio mixers or PA amps. If  you have never played through a tube preamp.. you are in for a real treat. If you have, you are still in for a trip, because of the combination of Type F smooth warm tones and Type M high-mid overdrive tones and other extras that have been added.  It makes just about 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 vintage  custom sound of your own. It works great with guitar, bass, keyboard and harp. 

Standard Features:

• Input Jacks isolated from chassis to eliminate eddy currents and hum.

• DC on filaments to eliminate 60 hz hum.

• Star ground system to eliminate induced current chassis noise.

• Type F (Fender) and Type M (Marshall) inputs with separate preamps and Gain controls for the unique smooth Fender Deluxe rich warm blues tones or the Marshall Plexi SLP dynamic high-mids  tones….or you can use an AB-Y switch and create your own distinct tones.

• Classic  Plexi – Bassman style 3-BAND TONE STACK with mid-scoop for extended flexibility in shaping your tone.

• Deep Pull-Switch on Bass

• Bright Pull-Switch on F and M Gains

• MASTER level control so you can crank the GAIN’s up and overdrive the preamp without overdriving the output tubes.

• Preamp tubes are classic 12AX7’s known for low noise and linearity. You may also use 12AT7’s or 12AU7’s for different tones and less preamp overdrive.

• Classic Knobs and Toggle Power Switch

• Standard IEC plug-in three prong grounded power cord. 

• Rock solid point-to-point hand wiring using only the best of parts…low noise tubular polypropylenes caps, metal film resistors, Micalex sockets, Neutrik  jacks…etc.

• Sweet vintage clean to classic overdrive tones with three different types of  distortion depending on whether you are overdriving the preamp, output… or both! ​

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Electrical Specifications: 

• Input Impedance:  1 megohm

• Level:  Instrument Level (100 millivolts RMS)

• Output Impedance:  25K ohm

• Output Level:  Line Level (2.5 volts RMS) 

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Physical Data: ​

• Dimensions  –  Open Chassis 10″W x 6″D x 2″H; Pro Audio Cab 11″W X 7″D X 5″H; 2U Rack Mount Chassis 19″W x 10″D x 3.5″H

• Rock solid point-to-point hand wiring with military style tie-wrapped wiring harnesses for long life and reliability.

• DC on filaments to eliminate 60 hz hum.

• Star ground system to eliminate induced current chassis noise.

• Input and Output Jacks isolated from chassis for low noise, eddy currents, and hum.

• Classic Vintage Fender Control Knobs

• Components – Only the highest quality parts are used including heavy duty transformers, low noise tubular polypropylenes capacitors, metal film resistors, Micalex sockets, Neutrik jacks. All parts are rated for commercial high use conditions. Wherever possible we use parts made in the USA.

• Front Panel Controls – F Input Jack, M Input Jack, F Gain/Bright Pull Switch, M Gain/Bright Pull Switch, Bass/Deep Pull Switch, Middle, Treble, Output Level, Pilot Lamp, On-Off Power Switch

• Rear Panel Controls –  Power Cord Connector, Fuse, Output  Jack,