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Mini-Bassman 50

50 Watts Of Audio Dynamite!




  • Model No. FM-5F6MB

  • Push-Pull 6L6 Guitar & Bass Amp

  • 50 Watts

  • 4-8-16 Ohm Speaker Switch

  • Multi Power Level  1/4 - 1/2 - Full

  • Dual Channel Bassman & Plexi Preamps

  • Separate Gains With Bright Switches

  • Deep Bass Switch

  • 3 Band Tone Stack

  • Presence With Edge Boost

  • 6L6-EL34 Bias Switch

  • Solid-State Rectifier

  • Post OT Line Out With Level

  • Tubes: 3 -12AX7, 2-6L6

  • Custom Upgrade Options


MSRP: $1455.00


Guitarist Description: I received my Mini Bassman last week and I am thrilled with it!  It sounds wonderful with guitar and Rhodes through 2 JBL D120Fs.  Such a natural transition from clean to overdrive, rich, shimmery sparkly tone with great clarity, just what I've been dreaming of.  It sounds so pure with bass through a 15" cab....Kenny H. (California) 


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The FRENZEL  "Mini Bassman" was "INSPIRED" by one of the greatest Bass - Guitar amps ever built...the Fender 5F6A Bassman, but it is not a clone. The power has been increased to 50 watts and it is loaded with features not available in the original Bassman...including a Super Lead Plexi preamp for the bright channel. Smooth warm Fender blues and jazz tones out of the Normal channel or super soaring dynamic rock leads on the Bright channel.   All enclosed in a small lightweight rugged cage enclosure.  

Standard Features:

  • Normal (Type F) Bright (Type M) inputs with separate preamps and Gain controls for the unique smooth Fender Bassman/JTM45 warm tones or the Marshall JMP/Plexi great high mid-tones....or you can use an AB-Y switch and create your own distinct tones.

  • Classic Bassman 5F6A style 3-BAND TONE STACK for extended flexibility in shaping your tone.

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

  • Presence control  - used to adjust the high-frequency response and damping factor of the power amp section.

  • Bright Pull-Switch on F and M Gains

  • Deep Pull-Switch on Bass

  • Boost - Unique NNFB "Edge" boost pull switch on the PRESENCE control that transforms the power amp section into a No-Negative-FeedBack style amp for soaring dynamic leads. 

  • Line Out - post output transformer LINE OUT with LINE OUT LEVEL control for recording or driving a power amp, Auto switched internal load to simulate speaker if speaker is  not plugged in. Inject great tone directly into the PA system with the Speaker Simulated Direct Interface.

  • Custom heavy duty output transformer for extended low frequency performance with 4 - 8 - 16 ohm outputs selectable by a rotary switch.

  • Three Power Level Selector Switch - Provides three power levels. 1/4 -1/2  FULL.

  • Ultra-fast high voltage solid-state rectifier  for sharp pick attack and dynamic bass.

  • EL34/6L6 Bias Selector Switch - Allows you to use either 6L6 or EL34 power output tubes.

  • Standby Switch - Protects tubes from cathode stripping during warm-up. 

  • Tube Complement: comes standard with 3 - 12AX7,  2 - 6L6, but you can substitute 12AT7's or 12AU7's in the preamp  for  warmer clean  tones with just a small amount of overdrive. You can also substitute 5881's, KT66's or EL34's and KT77's when using the EL34/6L6 Bias Selector Switch  in the output stage for different sounds. 


Electrical Specifications: 

  • Input Power  120 VAC 50-60Hz - 155 Watts Standard IEC plug-in three prong grounded power cord. (230 - 240VAC available. See Upgrade Options) 

  • Output Tubes - Class AB Push-Pull 6L6's - Fixed Bias

  • Output Power  - 50 Watts

  • Output Transformer Frequency Range -  20-20,000 hz 

  • Speaker Output Impedance - selectable by switch 4-8-16 ohms.

  • Output Power Selector Switch - provides three power levels. 1/4 - 1/2 - FULL power.

  • Line Out Impedance - 10K ohms

  • Instrument Input Impedance - 1 Megohm

Physical Data: 

  • Retro Vintage Cage Mini Head  - heavy duty lightweight steel mesh cage provides protection and excellent ventilation for tubes. Comes with easy carry Fender style strap handle. Overall Dimensions - 12" Wide x 10" Deep x 10" High 

  • Chassis Dimensions - 12" Wide x 8" Deep x 2" High. (Add 6" clearance for tubes)

  • Weight - 15 lbs. 

  • Chassis - Heavy gauge aluminum with welded corners.

  • 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.

  • 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, Presence/Edge Boost Switch, Pilot Lamp, On-Standby-Off Power Switch

  • Rear Panel Controls -  Power Cord Connector, Fuse,  Line Out Level, Line Out Jack, Speaker Output Jack, Output Power Level Switch, Speaker 4-8-16 Impedance Selector Switch 

Upgrade Options:

These options allow you to  customize your amp to meet your special individual requirements. 

EFFECTS LOOP -  pure tube buffered serial effects loop designed to perfectly match the low impedance solid-state pedal levels with high impedance tube levels..  Add $75.00. 

5U4 DUAL RECTIFIER POWER SUPPLY - This upgrade comes with a 5U4GB tube rectifier which provides that classic smooth warm  tube compression on peaks  and a  solid-state rectifier  for  tight dynamic bass.  A switch on rear panel selects the mode of operation. Add $105.00 


Featured Artist - To Frenzel Team, I recently received my Frenzel Mini Bassman 540 and WOW!!!! I was absolutely blown away. Like many I’m sure I was a tad skeptical by the price tag, but that vanished as soon as I played the first note. This amp could easily compete with any boutique amp on the market. The quality is top notch and despite its size, this amp has a sound as big as Texas. (Hope you don’t mind but I took the liberty to make mine the “Don’t mess with Texas” edition.) Bottom line this amplifier makes whatever you plug in sound phenomenal. It’s clear and defined, plus the the two input options along with other tonal controls make this amp extremely versatile which any guitar player would appreciate. Again thank you, y’all knocked it out of the park. 
-Steven P. (Oregon)   

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Customer Reviews

FM-5F6MB - Jim and Team Frenzel, et al...Privileged to own three of your guitar amps. Started with a Deluxe Plus
Vibe...I picked up on ebay...using KT66's  du Tung Sol.  Best amp I've heard.  I've built amps, fixed amps and modded amps since the 60's.  Got pretty much THE amps. My vote is to award JIM the Western Electric Emeritus. I now have his Mini Bassman (which I dig in the Jim Marshall mode) and another Frenzel Deluxe Plus Vibe (which I dig in the F mode)...all with KT66's...Genalex and Tung Sol.  I play with a cord. A wood tele and two 12" Marshalls,  stacked.  Weber Alnico and Jensen Ceramic. JF, From one old radio guy to another...hey, good job.   yo ron  - Ron J. (Oklahoma) 

MB550 - Hi Jim, Got the amp now for one week. One word I think of is woow!! You know you've ruined me for other amps! It is the best tone and sound I've heard and plenty loud enough! Thanks a lot From one happy bass player.  Glen G. (Belgium)

Hi Jim, this email is long overdue, just wanted to thank you and the team very much for building me the awesome mini bassman a few months ago, it sounds incredible! The many features makes it super versatile and I can get pretty much any sound I want out of it. I'm really impressed with how articulate it is and how little noise it makes, even with lots of overdrive and gain. Its so responsive and clear I've had to work on my technique and clean up my sloppy playing. Playing my baritone guitars on my old amp wasn't getting enough clarity and definition in the low notes, but the Frenzel handles the lows great and the baritones' bottom-end sounds solid and well-defined. It also works well with a Boss Bass Overdrive pedal. Next step is to get a splitter and blender so I can really play with the F and M tones. 

I'm extremely satisfied and happy I went with this amp - I'd been playing on my old Randall for almost 20 years, so this is a major step forward! I really appreciate all the questions you took the time to answer, it really helped me make my purchase with confidence. And of course, thank you for the red knobs, that was extremely kind of you for making that request happen. I hope I have a need to buy more Frenzel equipment in the future. Best of luck and take care! Garen B. (California)


 FRENZEL MB540 "MINI-BASSMAN"  - Jim,just wanted to express how much I love my MB540. I had purchased a Super Deluxe of yours for a church I was at years ago and found myself missing that tone again. Got the MB540 just in time for a recording trip to Nashville, and a few weekends here at home. Cannot overstate how great this amp sounds. Mainly using the M Channel, but the F channel was a hit in Nashville. This is my #1 amp now, and will be for a long time. Garrett H. (Texas)

I received my Mini Bassman last week and I am thrilled with it!  It sounds wonderful with guitar and Rhodes through 2 JBL D120Fs.  Such a natural transition from clean to overdrive, rich, shimmery sparkly tone with great clarity, just what I've been dreaming of.  It sounds so pure with bass through a 15" cab.  Even with 6v6s in it I get a stout sound.  It's everything I hoped it would be and I can't wait to hear it in the mix on stage! Thanks, you guys did great work with this one. Kenny H. (California)  

Dear Frenzel Amplification, I received the Mini Bassman Very well packed and built like a tank. After trying different combinations of tubes I found the three 12AX7 tubes, two 6L6GC power tubes and a 5U4 rectifier tube for a little more sag. The 5F6A Bassman input sounds excellent, the Marshall Plexi input sounds excellent also. When I use an AB switch to combine the inputs I discovered Tube Amp Nirvana, absolutely stellar tone to my ear. I added the Attenuator switch which comes in very handy. At the full 40 watts, this little amp is really loud. I am playing the amp through a close 2X12 enclosure with 2 Celestion Vintage 30 (16 ohm) speakers in Parallel. The amp sound great with Semi-Hollow guitars, Fender Strats, Gibson SG, Fender Telecasters. Single coils, humbuckers, P90s, Seymour Duncan rails. The amp responds very well to all types of pedals. If you are looking for a compact head, with a lot of versatility, look no further. Thanks Frenzel - Joe V.  (Ohio)

Hey Frenzel Team - Purchased a FM-5F6MB Mini-Bassman about 4 months ago. Since then I've gigged indoors and outdoors - sounds great with my 1x12 cab, LesPaul, drive pedal and touch of delay. Clean on F-channel with bright-pull engaged was pure&smooth at the blues festival yesterday. An outdoor venue - set master at 3/4, gain at 10:00, bass down & presence up - exactly what I was looking for. Surprisingly loud, fit in the mix with full 'Fendr' tone + sparkle. My thanks to Jim and the Frenzel crew - this light-weight amp is affordable quality. Robert O. (Oregon)

FM-5F6MB  - Played my first gig with the 5F6MB last night, blues&rock - what an improvement over my last amp! Sent it thru a 112 Weber spkr, I use 2 pedals:  EH echo + overdrive. Using a single-coil guitar (strat), F input is the place - Using my Les Paul, it's a mix of F and M. The M circuit removes some of the bass frequencies that come with humbucker PU's + bassman circuit, reducing the 'boomy-factor.' Tone is still there, I like the balance by setting them half & half F&M - sounds great. - Regarding  tubes in V1 preamp position...12AU7/ECC82 delivers less clip at high gain/master settings, good for jazz or anything clean - 12AT7/ECC81 or 12AX7 delivers more clip, better for blues/rock. - Seems like the 12AT7 is just right for me, at this point.  Robert O. (Oregon)

FM-5F6MB This is a fantastic little amp, really special and incredibly versatile, just wanted to let you know.  I think I'm going to build a bracket for it to mount to the fliptop, by the way.  Thanks so much!  Best, Kevin B. (New Jersey) 

FM-5F6MB  - Man, this thing is AMAZING!   Does everything I want it to, and then some.  The low end response is amazing.  Completely Satisfied, and looking forward to taking it out on gigs.  Amazing work, folks!   Amazing!  Best, Brad R. (California)

Hi Jim, "Just a little plug for Jim and the fine folks at Frenzel. My experience with them and the Frenzel Mini Bassman has been great. Out of the box it was a little too hot for pedal steel, but all I had to do was some tube swapping (a 12AT7 in V1, and a Weber Copper Top solid state rectifier) to make a great clean tube machine for pedal steel. It's got a lot of tone-tweaking features, 2 channels with different voicings, and with the way the tone stack works I can even shift the curve to put the mid scoop where it needs to be. I could not justify one of the high-end boutique amps, but this will keep me smiling for a long time!" (Built the head cabinet myself, don't blame that on the Frenzel folks!) Tommy B. (Virginia)
You guys did good!! - The Mini-bassman arrived yesterday in excellent condition while I was at worship practice.  I built the cab for it over a month ago and was able to install the amp today and it sounds great!  This is my fourth Frenzel and never a disappointment with any of them. Many thanks, John W.(Indiana) 


Hi Jim and others, I have purchased a Mini Bassman  tube amp from you guys many years ago (2012)and it has been the most rock solid tube head. It has never failed or needed service, I still don't quite understand how it can use so many different power tube types. Everyone I talk to is confused when I try to explain how it will run off of different tube pairs, even mismatched sets. How does that even work? The line output is an amazing feature to have in the studio. I have enjoyed it best with a set of vintage rca 12ax7a pre tubes and 6l6 pair with solid state rectifier insert. Ryan A. (Oregon)

For more reviews please check our Customers Reviews page.  

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