A 1978/9 Dumble Overdrive Special used by Joe Bonamassa

1978 Dumble Overdrive Special OD-50 WX

An exceptionally fine and all original 1978/79 Dumble Overdive Special Combo (serial number "038"). This 'Export Applied Acoustics' model 50 watt combo weighs 67 lbs and has a wooden cabinet with tan 'straw' speaker grill with "Dumble" metal logo. The exterior measurements are: 21 inches wide x 21 inches high x 10 1/2 inches deep. Original black plastic handle. One 12 inch Electro-Voice BRO/12 speaker. Five tubes: 2 x Fender 6L6 GC; 1 x Mullard 12 AT7; 1 x GE 12 AX7, and 1 x Mazda 12 AX7. The six rotary controls feature: 1 x 'Volume'; 1 x 'Treble'; 1 x 'Middle'; 1 x 'Bass'; 1 x 'Overdrive', and 1 x 'Level'. In addition there are five two-way slide switches: 'Bright'; 'Deep'; 'Rock'; 'Manual', and 'Accent'. Green pilot light. On the back of the amp are: Rotary voltage selector with pre-sets for 117/200/210/220/230/240 volts; Three-way 'Ground' switch; 2 Amp 'Slo Blo' fuse; 'Mains' on/off switch; 'Operate' and 'Standby' switch; Two jack inputs for 4 Ohm Speaker; One 'Pre-Amp Output'; One 'Foot Pedal' socket. Housed in a specially made aluminum flight-case with four wheels.

"Overdrive Special 038  This is another export model that was sent to Applied Acoustics in Germany. Some of them were only shipped as an amp chassis. The Cabinet for most of these, 20 - 25 amplifiers were not Dumble made.
Overdrive Special 034 is a 50 watt model. It has 6L6 power tubes and is fitted with a JBL K120 speaker. This amplifier has a beautifully clean and chimey tone and the unmistakable Dumble singing overdrive. This is a very clean Overdrive Special and except for the Applied Acoustics made cabinet, untouched." (Jesse Schwarz. A Dumble Book, pp. 113/114). Jesse Schwarz mistakenly confused the serial number which is in fact "038" and not "034" as shown in his book.

The Overdrive Special is a two channel amplifier, with a clean channel and a second "overdrive" channel. This overdrive channel is described as "cascading" from the first channel into at least one additional gain stage in the overdrive channel. This means that the clean channel tone stack and gain stages "cascade" into the gain stage of the overdrive channel, causing the clean channel to become "overdriven". In a sense, the overdrive channel sits "on top" of the clean channel. This is easily Dumble's most popular model, and subsequently is the most frequently seen. That said, the ODS (Overdrive Special) varies considerably from decade to decade, and serial number to serial number. For example, although most ODS amplifiers use 6L6 tubes in the power section (commonly associated with Fender amps), some have EL34 tubes (commonly associated with Marshall amps). On the other hand, even among the many 6L6 versions of the ODS, there are considerable variations. For example, some have a clean channel that stays clean "all the way up to 10" (referencing a gain potentiometer ranging from 1 - 10). Others have a clean channel that will start to "break up" around 3. Some overdrive channels can only reach a minimal amount of breakup, even when dialed up. However, most ODS overdrive channels have a large amount of tube distortion available if so desired. Along these same lines, many later versions of the ODS have "HRM" controls on the inside of the amplifier, which is a "Hot Rodded Marshall" tone stack that sits "on top" of the overdrive channel, or in other words comes after the Overdrive channel tube gain stage. There are certain commonalities across all ODS amplifiers. Firstly, the ODS amps are known for their harmonic richness in the overdrive channel breakup, and transparent "open-ness" in the clean channel. The overdrive channel is often described as "sustaining", "blooming", and "musical". The clean channel is often described as "fast", "huge", and "responsive".

The previous owner purchased this amp from a private client in Germany around 2004/2005. He told us "Some of the filter caps have been replaced and the speaker has been changed for a 12 inch Electro-Voice BRO/12. It is one of a run of 15 - 20 Dumble Amps where Howard Dumble shipped 15 - 20 chassis' to a German Dealer in Bochum - 'Applied Acoustics' who had the cabinets made."

Joe Bonamassa used this Dumble Overdrive several times including on his album “Driving Towards The Daylight”.
"Joe’s newest album titled “Driving Towards The Daylight” hits stores shelves on May 22nd. Joe’s lucky 13th album, was recorded with Kevin “Caveman” Shirley. This was their seventh collaboration over the past six years. Recorded at Studio At The Palms in Las Vegas, NV, The Village Recorder in Los Angeles, CA, and The Cave in Malibu, CA, Driving Towards The Daylight is a true blues rock album, that puts a rock twist on traditional blues songs."  http://bonamassalive.com/2012/05/10/driving-towards-the-daylight-review/#more-1037

The Overdrive Special is a two channel amplifier, with a clean channel and a second "overdrive" channel. This overdrive channel is described as "cascading" from the first channel into at least one additional gain stage in the overdrive channel. This means that the clean channel tone stack and gain stages "cascade" into the gain stage of the overdrive channel, causing the clean channel to become "overdriven". In a sense, the overdrive channel sits "on top" of the clean channel. This is easily Dumble's most popular model, and subsequently is the most frequently seen. That said, the ODS (Overdrive Special) varies considerably from decade to decade, and serial number to serial number. For example, although most ODS amplifiers use 6L6 tubes in the power section (commonly associated with Fender amps), some have EL34 tubes (commonly associated with Marshall amps). On the other hand, even among the many 6L6 versions of the ODS, there are considerable variations. For example, some have a clean channel that stays clean "all the way up to 10" (referencing a gain potentiometer ranging from 1 - 10). Others have a clean channel that will start to "break up" around 3. Some overdrive channels can only reach a minimal amount of breakup, even when dialed up. However, most ODS overdrive channels have a large amount of tube distortion available if so desired. Along these same lines, many later versions of the ODS have "HRM" controls on the inside of the amplifier, which is a "Hot Rodded Marshall" tone stack that sits "on top" of the overdrive channel, or in other words comes after the Overdrive channel tube gain stage. There are certain commonalities across all ODS amplifiers. Firstly, the ODS amps are known for their harmonic richness in the overdrive channel breakup, and transparent "open-ness" in the clean channel. The overdrive channel is often described as "sustaining", "blooming", and "musical". The clean channel is often described as "fast", "huge", and "responsive".

In an interview with Premier Guitar, Robben Ford shares that Dumble told Ford that the original inspiration for the Overdrive Special came while watching Ford play live in the 70s at a bar in Santa Cruz. Ford was using a mid-60s blackface Fender Bassman, and running a tube screamer in front of it to overdrive the tubes to breakup. Supposedly, Dumble thought Ford sounded so good, and while contemplating his sound had the revelations that led him down the path that eventually birthed the original Overdrive Special. Since buying his ODS, Ford has almost exclusively used his original Dumble or an exact clone of it live.

Dumble musical instrument amplifiers are custom manufactured in very limited numbers by Alexander "Howard" Dumble of Los Angeles, California. Dumble is a one-person operation; each amp is handcrafted by Dumble himself, and Dumble amplifiers are the most expensive boutique amplifiers on the used market. These costs are rising rapidly. In 2012 the Dumble Overdrive Special was described as the most valuable, with used amplifiers fetching on average between $70,000 and $150,000 apiece. Other examples have sold for more…