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Blues 20 Dumble Overdrive Special Clone 20 Watt Head | Guitar Amplifier


Blues 20 Dumble Special ODS Clone Hand Wired Classic Amp Head

There have been three amplifiers that I have plugged into that had very special qualities. The harmonics jumped out at me, with touch sensitivity and sustain beyond all others. One was a Dumble. One was an old blonde Fender Bandmaster head that had no business sounding as good as it did. The third is this Blues 20 Special. When Chuck first told me that he was thinking of incorporating it into the Bootlegger lineup, we were both a bit skeptical.  Having tried many products, both amplifiers and pedals, that claimed to achieve that famous D style sound and feel, I have been consistently disappointed. Until now.


Upon unboxing, I was immediately struck by the high quality brown Tolex application and perfectly straight grill cloth and piping, as well as the substantial look and feel of the cab. Nothing sloppy or careless here. This is a beautiful amp! The pictures don’t quite do it justice. It’s solidly built and not lightweight. Very old school.

Front Panel

On the front panel you have the preamp section, with input, three switches (Bright, Mid Boost, Rock/Jazz), Volume, Treble, Mid and Bass controls. Next, the overdrive section, with Level and Drive controls. Last is the poweramp section, featuring Master Volume and Presence controls and a Standby switch. The rear panel features the Power switch, speaker Main and Extension outputs with choice of 4, 8 or 16 ohms, Overdrive Trim control, Overdrive and Preamp Boost switches, with choice of manual or pedal control, FX loop, and the foot switch connector.


The tube compliment consists of two EHX EL84 power tubes and three Ruby 12AX7s. It has very large transformers for a 20 watt amp. It is completely hand-wired with chassis mounted tube sockets and (full size!) pots. Time to test it! I turned it on to warm it up and grabbed my 335. Set the master volume to half way up, bright and mid boost off, jazz/rock set on jazz. I plugged in the guitar, fiddled with the controls a bit and started playing. Those sweet harmonics and pure tone hit me. I picked my jaw up off the floor and switched on the overdrive. I was instantly in Larry Carlton land! It has that fat, sweet, thick, warm, singing sustain for days.

In His Head

It’s the sound I hear in my head. The sound I’ve been chasing for decades. That “clean” overdrive. It’s got it! Most of this was at levels you could talk over, but it also gets LOUD. Much louder than it’s 20 watt rating would indicate. I started playing with different switch combinations and settings and realized this thing is a swiss army knife! The bright switch and mid boost are very effective and perfectly voiced. I think if I could have just one amp (I’m down to eight now), this would be it! I’m really trying hard not to be too effusive here, probably unsuccessfully, but this has the tone and response of my dreams. You feel connected to it in a way that makes the guitar and the amp one instrument, responding to every nuance of your fingers.

More Testing

I then tested it with a Strat, a 52 reissue Tele, a 72 reissue Thin Line Tele (with Lollar Imperial pups) a couple of nice Gretsches, an SG, a gold top Les Paul with P90s and a Les Paul special with P90s. It’s instantly adaptable to any guitar or musical style. It has sweet sounding F style cleans with a bit of V style chime from the el84s (perhaps my favorite power tubes) and D style drive and harmonic content. It’s also very quiet as guitar amps go, not noisy at all. For me, this is my dream amp!


The only thing I can think of that may be a negative for some people is no reverb or tremolo. Most of us have pedals for those things these days, and it does have an FX loop.


In summation, I have not been this impressed with an amplifier in decades. I now have a bad case of G.A.S. (Gear Acquisition Syndrome, for those who may not know) and I blame you, Chuck Wilson! In fact, you may have to pry this amp from my cold dead hands! But seriously, if you’ve been chasing that perfect tone and versatility that I’ve been seeking for such a long time, here it is. The Bootlegger Blues 20 Special. Get it!

 Rex bailey bootlegger guitar

Rex Bailey Musician, Mastering Genius, Audio file nut & Guitarist.

Specifications of Blues 20

Blues 20 Controls Front

Pre Amp Controls

One 1/4 jack input Volume knob Treble knob Middle knob Bass knob Bright switch Mid boost switch Rock / Jazz switch

Overdrive Controls

Level knob Mix / Ratio knob

Power Amp Controls

Master knob Presence knob Standby switch

Back panel

Power in for cord Fuse Main speaker on switch Output for extension speaker cabinet Impedance selector Effect Loop input / output OD Trim knob (trims signal before it hits the OD) Pedal set up preferences 2 switches Foot Pedal in 


Foot-switch pedal metal body 2 switch with led lights EHX EL84 power tubes and three Ruby 12AX7s

Weigh in

41 pounds
20 x 17 x 10

Dumble clone refers to Mr Alexander (Howard) Dumble. Howard was considered as a master guitar amplifier builder. Dumble effect, pedal, circuit, copy, Over Drive Special. The amplifiers we sell are not original Dumble amplifiers. They are clones of the Dumble circuit as many other amps are clones of Vox, Marshal, Fender..

About Front Panel Controls

Front Panel Controls

1. INPUT – Plug your electric bass guitar in here.

2. BRIGHT – Provides a high-frequency boost.

3. VOLUME – Adjusts the loudness of clean, but note it will impact the overdrive mode as well.

4. MID BOOST – It is a midrange-frequency boost.

5.TREBLE – Adjusts the high-frequency tone.

6. ROCK / JAZZ – Adjusts the overall frequency response and voicing of the amplifier. ROCK has a fatter midrange and a deeper, spongier bottom end. You might find ROCK more familiar territory. JAZZ tightens up the bottom end and adjusts the contour of the mid range, giving the amplifier more of a hi-fi response.

7. MIDDLE – Adjusts the mid-frequency tone.

8. BASS – Adjusts the low-frequency tone.

9. DRIVE – Adjusts the gain level of the overdrive channel.

10. LEVEL – Adjusts the volume control for the overdrive channel.

11. MASTER – Adjusts the overall volume of your amplifier.

12. PRESENCE – Adjusts the high frequency response of the power amplifier using negative feedback. Use this control to add sparkle and clarity to your tone.

13. STANDBY – Use STANDBY instead of switching the power off during short breaks to eliminate the tube warm-up delay upon returning to play. Use STANDBY for 30 seconds when first switching the power on. Using these standby procedures will extend the lifespan of your amplifier tubes.

14. INDICATOR – Illuminates when the unit is on. If INDICATOR does not turn on, check your power cable connections, and then the fuse on the rear of the unit.

About Rear Panel Controls

Rear Panel Controls

1. MAINS IEC Cable Inlet – Plug a suitable IEC power cable into this inlet to power your amplifier.

2. FUSE – The fuse protects the unit from electrical faults. Replacement fuses must match the type and rating specified on the fuse holder.

3. H.T. FUSE – This is a proto type tube power fuse Replacement fuses must match the type and rating specified on the fuse holder.

4. POWER – Turn the unit on and off.

5. SPEAKER OUTPUT – ¼” speaker cable jacks. Use a ¼” speaker cable to connect your speaker cabinet to the amplifier using these jacks. If you use one speaker cabinet, use the jack labeled MAIN. If you want to run two cabinets in parallel. Connect the second cabinet to the amplifier using the jack labeled EXTENSION.

6. IMPEDANCE – Three-way rotary selector. Set this selector to the position that matches the impedance of your speaker cabinet.

7. EFFECTS LOOP – Connect PRE AMP OUT to input of an effects device and the output of the effects device to POWER AMP IN.

8. ODTRIM – Adjusts the gain level of the overdrive channel.

9. OVERDRIVE – Two-way toggle switch manually switches between clean and overdrive channels.

10. PREAMP BOOST – Two-way toggle switch manually switches between boosted and normal configurations. The accentuates midrange frequencies and attenuates low frequencies, making it great for cutting through during a solo. Engaged, you will also notice an increase in gain and distortion characteristics.

Note: The previous EQ bass adjustment does not work when this feature is turned on.

11. FOOT PEDAL – By connecting this jack it is possible to remotely swith channel and preamp boost switching capability. Red LED indicates OVERDRIVE, and Green LED indicates PREAMP BOOST.

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