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Home Insiders Amp Insider with Brandon Montgomery: The Dumble Zone
December 3, 2020
Amp Insider with Brandon Montgomery: The Dumble Zone PDF Print E-mail
Tuesday, 02 June 2009 10:16
Part 1

GJD: There seems to be a lot of misnomers about Dumble amplifiers in terms of the models names, voicings, serial #s, etc.

BM:  I agree but I don’t think any one really knows all the exact details except the man himself.

GJD: In your opinion, why is there such a mystery and lack of clarity around a lot of the details about these amps.

BM: Well, I think there is a few factors that come into play.  First off, there is a lot of misinformation based on hearsay and just like anything else, inaccurate statements that get repeated over and over end up being what people believe. 

Second of all, there are less than 300 Dumble amplifiers in existence.  They are scattered throughout the globe and no two amps are exactly the same.  Also, there are variations upon variations which again can lead to inaccurate descriptions.

GJD: So, let’s talk about the difference between the silver chassis and the black chassis models in the Overdrive Special series.

BM: The amps with the silver chassis were from the early build-era in the 1970s.
They are simpler in design, have less gain, and usually do not have a lead master control.

The black chassis models have more features, a lead master control and ended up becoming the flagship model.

GJD: What was the first serial number of the black chassis era?

BM: I’d say around serial number 84 or a bit earlier.

GJD: Talk a bit more specifically about the black chassis Overdrive Special voicings.

BM: There are 4 basic voicings of the clean channel.  Classic, Skyliner, Bluesmaster, and the Ripper.  There are also a few different overdrive circuits. The Standard, HRM (Hot Rubber Monkey), and another more obscure circuit known as the MegaPlex.  I believe The MegaPlex circuit really only exists in the Ripper model.

GJD: A lot of people use the term non-HRM.  What exactly are they talking about?

BM: It’s kind of funny because what they are really referring to is the Standard voicing and the Standard voicing came out before the HRM was in existence.
Again, it’s just one of those terms that came about from people talking about the amps.  Come to think of it if you apply the same logic you could call the HRM, the Non-Standard. LOL

GJD: Can you be a bit more specific about the HRM?

BM: The HRM has internal tone controls including bass, mid and treble.  This is to help you further dial in your lead tone as opposed to being at the mercy of a fixed voicing amp.

The MegaPlex also has internal tone controls but is more closely voiced to a Marshall circuit.  Hence the term, MegaPlex as in a Plexi Marshall amp. By the way, The Standard and the HRM models are the most common.

GJD: Can you get into some details in terms of tones for Standard versus HRM?

BM: The Standard is very fat sounding and has greater harmonic content.  It has that classic smooth early Larry Carlton sound.  It has two gain stages with coupling caps and no internal EQ for the lead channel.  As I mentioned earlier, the HRM does have the internal EQ.  It is more dynamic to the touch of your pick attack.  I mean, you can go from pretty extreme clean by picking soft to dirty sounding by picking harder.  It is also more compressed.  I might also add that all of this that I am referring to is without the pre-amp boost engaged. Once the pre-amp boost is engaged, it is all together a different world.

GJD: If you are a legato-type player which amp would you prefer?

BM: I’d say most likely the Standard.


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