Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: macula56 on November 11, 2014, 11:04:23 am

Title: Dumble style amp
Post by: macula56 on November 11, 2014, 11:04:23 am
a friend wants me to build him a dumble clone and i know pretty much zero about them. whats the best place to start looking for schematics and layouts and such? he really likes Robben Ford's tone with the Blue Line so i am guessing an Overdrive Special as a starting point. anyone here have any experience building these types of amps? any help greatly appreciated.
Title: Re: Dumble style amp
Post by: shooter on November 11, 2014, 12:03:46 pm
I just typed "bumble" in the search feature and got lots - o hits, might be a good place to start.  use intire forum on the pull-down.
Title: Re: Dumble style amp
Post by: tubenit on November 11, 2014, 01:52:26 pm
TAG (the AmpGarage) has tons of info on Dumblish amps along with schematics and layouts.

http://ampgarage.com/forum/viewforum.php?f=4 (http://ampgarage.com/forum/viewforum.php?f=4)

With respect, Tubenit
Title: Re: Dumble style amp
Post by: MakerDP on November 11, 2014, 01:53:55 pm
A good place to start looking would be the D'Mars OD Special here:

http://el34world.com/Forum/index.php?topic=14302.0 (http://el34world.com/Forum/index.php?topic=14302.0)

I haven't built it but I plan to one of these days. I really like how it sounds.
Title: Re: Dumble style amp
Post by: macula56 on November 11, 2014, 05:29:44 pm
thanks gentlemen.
Title: Re: Dumble style amp
Post by: G._Hoffman on November 11, 2014, 07:25:54 pm
Doug's Tube Amp Library (link at the Bottom of this page) has some schematics, and if I remember right some of them were supposedly from one of Robin Ford's amps (though who knows, it being the internet - Doug is just hosting them, he didn't draw them!)  Ceria Tone makes a bunch of "Overtone Special" kits, and they have layouts (but no schematics) on their website.  And has been mentioned, The Amp Garage has a sub-forum dedicated to Dumble clones.  Also, there are several forum members here who build variations, and maybe kind enough to share some of their expertise with you.  I used a bit of all of those, when I was designing and building one for my shop.


Gabriel
Title: Re: Dumble style amp
Post by: DummyLoad on November 12, 2014, 11:00:49 am
a high quality dumble style chassis is available from the source in the link below.

http://www.cepedals.com/Dumble-Style-Chassis.html (http://www.cepedals.com/Dumble-Style-Chassis.html)

--pete
Title: Re: Dumble style amp
Post by: Mike_J on November 12, 2014, 04:58:31 pm
The advice to go to the Amp Garage site is very good.  Ford's amp is the Overdrive Special serial number 102.  As I recall there is a schematic for the amp on the forum.  Part of the sound is the way Dumble wired the amp.  The amp that is the most documented is #124.  There are pictures of the inside of the amp on the 124 site.  I made one and copied every wiring technique Dumble used on his build with very good results.  I also made a HRM amp which I prefer.  The HRM has EL34s and the 102 and 124 run 6L6s. 

The reason I probably prefer the HRM is I play a Strat and the 6L6 amps sound much better with humbuckers.  I got very lucky on ebay getting two fantastic ODS chassis for $45 each with free shipping.  Holes were drilled and the workmanship top notch.  I don't remember his name but he was from California and a real craftsman.

I use Inkscape to do my faceplates and back plates.  Have them printed on vinyl.  Has worked well for me.  If you need any help let me know.

Thanks
Mike
Title: Re: Dumble style amp
Post by: Willabe on November 12, 2014, 06:07:41 pm
I use Inkscape to do my faceplates and back plates.  Have them printed on vinyl.  Has worked well for me.  If you need any help let me know.

Not to hijack this thread but how do you get things to scale with Inkscape?

(I can split this part off to a new thread if it gets away.) 


             Brad    :dontknow:
Title: Re: Dumble style amp
Post by: Mike_J on November 13, 2014, 06:44:14 am
I use Inkscape to do my faceplates and back plates.  Have them printed on vinyl.  Has worked well for me.  If you need any help let me know.

Not to hijack this thread but how do you get things to scale with Inkscape?

(I can split this part off to a new thread if it gets away.) 


             Brad    :dontknow:

It has a scale built into the program.  If you want to start a new thread we can discuss it and I will try to help you get started in using it.  To me it is pretty intuitive so I haven't had a problem but tubenit says his sch program is easy to use and it drives me nuts.

Thanks
Mike
Title: Re: Dumble style amp
Post by: macula56 on November 13, 2014, 09:20:45 am
I use Inkscape to do my faceplates and back plates.  Have them printed on vinyl.  Has worked well for me.  If you need any help let me know.

Not to hijack this thread but how do you get things to scale with Inkscape?

(I can split this part off to a new thread if it gets away.) 


             Brad    :dontknow:

 
no worries. all this info is great. i have inkscape so this is of interest to me as well.
i'd love to see some of your work Mike_J. i meant the amp, but i'd like to learn more about Inkscape as well.
Title: Re: Dumble style amp
Post by: Willabe on November 13, 2014, 09:23:42 am
Ok, I'll start a new thread in 'Other Topics'.


                  Brad     :icon_biggrin: