If I want to build a Dumble amp : which one ?

[tubelectron]

Hello All,

I read extensively the topics of The Amp Garage forum, and found one billion of informations to decipher about the Dumble models, variants, clones, modifications, tips, etc... And I certainly missed too many of them for the moment... So I am a bit puzzled .

Let's suppose that I want to built my own Dumble : which model should I choose to meet my requirements ? Let's list them :

1 - I dislike most of the hard-rock and heavy metal stuff.

2 - I like Carlos Santana (see my restored/improved 1980 MKIIA S/N° 4915 below) and most of the music styles which doesn't carry specifically hatred or agression, to sum up.

[img:600:800]http://img11.hostingpics.net/pics/397033IMG0341.jpg[/img]

3 - I like smooth overdriven tones, from light to heavily sustained, but expressive, not agressive.

4 - I like deep clean tones, of course.

5 - I always use reverb, and I like beautiful sounding well decayed reverb, as long as surf music reverb, and both spring or digital reverb.

The only Dumble that I saw (not heard nor played, unfortunately) was in 1989-90. It was a combo, black face plate, hardwood mahogany or teak cab, with a Vox-like grillcloth. Probably an Overdrive Special. I wonder if the lettering was not in the digital 7-segment style... There is probably not much Dumbles here in France, IMHO.

So according to you, which model of Dumble and/or variant should I consider for a release ?

Thanks for your advices,

A+!

[ayan]

It's a very subjective matter, needless to say. I played Boogies (IV, I, IIC+, in that order) before building my first D clone in 1999, so in a way is sounds like we have a bit in common from that perspective. That being the case, you will probably want to consider a classic build. You can try 100K plate load resistors with 1.5K cathode bypass resistors first and see how you like that. I would start with a 100K slope resistor as well... If that doesn't do it for you, you could go high plate classic, with 220K/150K plate load resistors and 3.3K/2.2K cathode resistors for V1/2 A and B respective, and you can try experiment with a 150K or 100K slope resistors -- 100K being significantly thicker sounding. In all cases above, the tone stack would be classic with a .047 uF mid range cap. To me, out of everything I ever tried, that was the closest thing to a Boogie type of sound, very smooth and uncluttered.

However, eventually I grew fond of the Skyliner preamp and ended up with my amps built around that (one is a 124 style, so 100K plate loads, the other a 102 with 220K/150K plate loads). Those amps are way fatter sounding, the 102 being the fatter one between the two, but, surprisingly enough, they can be dialed in for less cluttered sounds too.

I once played one of Brandon's 70s style amp and loved it, but not enough to go and build one for myself. I liked the Blues Master clean the best, but its lack of headroom (to me) and HRM lead channel would always leave me dissatisfied, so I sold that amp to a guy that swore by it. I never did like the Skyliner HRM amps myself.

Hope this helps,

Gil

Hello All,

I read extensively the topics of The Amp Garage forum, and found one billion of informations to decipher about the Dumble models, variants, clones, modifications, tips, etc... And I certainly missed too many of them for the moment... So I am a bit puzzled .

Let's suppose that I want to built my own Dumble : which model should I choose to meet my requirements ? Let's list them :

1 - I dislike most of the hard-rock and heavy metal stuff.

2 - I like Carlos Santana (see my restored/improved 1980 MKIIA S/N° 4915 below) and most of the music styles which doesn't carry specifically hatred or agression, to sum up.

[img:600:800]http://img11.hostingpics.net/pics/397033IMG0341.jpg[/img]

3 - I like smooth overdriven tones, from light to heavily sustained, but expressive, not agressive.

4 - I like deep clean tones, of course.

5 - I always use reverb, and I like beautiful sounding well decayed reverb, as long as surf music reverb, and both spring or digital reverb.

The only Dumble that I saw (not heard nor played, unfortunately) was in 1989-90. It was a combo, black face plate, hardwood mahogany or teak cab, with a Vox-like grillcloth. Probably an Overdrive Special. I wonder if the lettering was not in the digital 7-segment style... There is probably not much Dumbles here in France, IMHO.

So according to you, which model of Dumble and/or variant should I consider for a release ?

Thanks for your advices,

A+!

[tubelectron]

Thanks ayan for your description : I note it for further reference, when I will know more about the subject... I am still at the Dumble basics level of knowledge !

you will probably want to consider a classic build.

OK, but : ODS ? ODR ? SSS ? HRM ? BM ? I am searching / discovering step by step what are the differences between these models, in fact...

I did not found a topic explaining those differences on the forum, but I may missed it ?

A+!

[M Fowler]

From my notes Skyliner Amps -

Skyliner amps can either be with or without the post overdrive stack. The word skyliner refers to the clean tone stack. This stack has a bass knee of around 80 hertz and give a hard attack on the bass notes. The middle control is centered approximatelty at 400 hertz and this give the more pronounced upper mids that many folks talk about. The skyliner amps also used more negative feedback in the power amp stage which gave better control of the bass response (flattens over PA response). The skyliner also had a unique boost circuit that breaks the connections between the treble and the bass controls as well as the top of the bass control to the wiper of the bass. This gives about 10+dB of boost on the top end with a gradual rolloff in response starting at around 600 to 800 hertz. This helps the bottom end from getting "wolfy".

Later amps used the Bluesmaster setup. Once again Bluesmaster refers to the clean stack and changes in the power amp. The Bluesmaster stack as a little more gain due to its circuit layout. The Bass control is centered around 130 hZ. This gives the bass a softer / spongier feel/attack (to my ears, your ears my be diferent). The middle control centers at around 800 hertz and give a more scooped mid range sound. The power amp section is roughly the same as a Marshall Plexi (a few component changes). This has reduced negative feedback and gives more PA gain and a large bass response. The Bluemaster also used a completed different boost arrangement that simply lifts the entire tone stack off of ground. This give a HUGE amount of boost, especially in the lower registers. This boost system also tends to roll the high end off just a little bit (6 to 8 dB) as compared to the bottom end. In general it is accepted that the Tone stack boost must be used when running a post overdrive tone stack amp in Overdrive mode. This reason is that most of these amps (not all) had a large amount of padding on the input of the overdrive stage that makes it necessary to have a large signal on the input of the OD section to get any reasonable amount of gain. You can decrease the input padding, but it does not sound as good.

The early Dumbles used a tone stack that was similar to the Skyliner with different values and different plate loads. These amps were generally a little brighter and for some are the holy grail of Dumbles. They also have a little less bass response due to the 100k plates Tony

[ayan]

Correction: in my previous post I had written 183, should have been 102 -- I corrected that. The 102 and 124 amps are fully documented in the "Dumble Files" section . As for the Classic I mentioned, I think what I had built came to be called here the 4th Generation Classic, years after I had built my amp. I am pretty sure there is documentation here for that amp as well, but unfortunately you will either have to use the search function or wait to see if someone posts a direct link to the specifics of that particular amp.

I was referring to ODS amps in my post, I never built either an ODR or SSS. I briefly talked about the BM, and I believe that is fully documented in the files section as well. It does implement the HRM (Hot Rubber Monkey, Hot Rodded Marshall...or?) which amounts to a secondary tone stack, internal to the amp, located after the overdrive section and affecting it but not the clean channel. As per my experience, the HRM amps (BM, Skyliner HRM, etc.) are all difficult to dial if you implement the second tone stack internally, like Dumble did. Other people have moved those controls outside and ended up with a very versatile amp.

While there is a great deal of information here, I think you will be better off catching up by doing some reading so that you can familiarize yourself with terms commonly used, preamp voicing types (Classic VS Skyliner VS Blues Master), types of boost (Classic VS "Mega Boost"), phase inverter designs used over the years, etc., etc. If you want a very popular amp to build that does sound great, build the Robben Ford amp (S/N 102) which is fully documented, and be done with it without going down a rabbit hole -- which is a high risk for anyone entering this place. It's one of the two amps I've kept at the end of my quest, although it is my back up and not my main gigging amp. However, that amp is not the first one that would come to mind as a recommendation to you. The info for 102 can be found here:

https://tubeamparchive.com/viewtopic.php?t=12873

As for reverb or delay... to me the easiest thing would probably be to build an outboard, self standing Dumbleator and use it. That is what I did when I built my first amp, so I never worried about that kind of thing any more. Some people have successfully built Dumbleators inside their ODS chassis, but things get a bit crowded so you may end up pulling some hairs out if you go that route (to be clear, you will be pulling a lot of hairs out either way, but maybe moreso if you decide to do an internal Dumbleator). If you build an external unit, and you can find all of the information needed in the files section, you won't have to worry about real estate as much, but you will have to carry a rack to gigs if you want to use effects. Not a problem back when I built my first amps and was in my 30s... but now, however, maybe I wish I had built my loops internally!

At the end of the day, would I recommend someone build their own amp from scratch if they didn't have much experience? Not a chance, especially now that so many people have gone into business by building Dumble clones that sound good. When a couple of friends and I started back in the day, that was not an option. There are times when I think that if -- heaven forbid -- I were to lose the two amps I kept for personal use, I would probably buy something -- probably some kind of Fender or Marshall for around a grand or so -- and use pedals as needed for a good overdrive sound. Can't argue with so many people out there doing that and sounding great anyway. You will spend at least as much building your own amp, without taking into account the amount of time it will take to build it, debug it, make it sound good, then make it sound better, then make it sound better still, then try to make it sound like the real thing...getting close but never quite nailing it. On the flip side of the coin, it will be a unique experience and very rewarding.

Good luck,

Gil (happily retired form the amp building business for about 6 or 7years now!)

Thanks ayan for your description : I note it for further reference, when I will know more about the subject... I am still at the Dumble basics level of knowledge !

you will probably want to consider a classic build.

OK, but : ODS ? ODR ? SSS ? HRM ? BM ? I am searching / discovering step by step what are the differences between these models, in fact...

I did not found a topic explaining those differences on the forum, but I may missed it ?

A+!

[rogb]

It was posts like this that drew me into TAG in the first place, what a great place it has turned out to be. Thank you.

[tubelectron]

Thank you again guys for your sourceful informations about Dumbles.

It is not the 1st time that I built a tube amplifier (guitar or audio), fortunately : I started my 1st one in 1978. And I still and always repair, restore to its original condition or modify tube amps as a part-time job, for bands and local music shops.

So yes, ayan, I completely share your analysis about the pertinence of building or not that kind of amp, especially if convenient clones are available. For the moment, let's say that I am in an "investigation phase" about that project. But anyway, it is always rewarding in the end, indeed !

I started reading the schematics and something like a 100W ODS with an integrated digital reverb (Holy Grail Nano) is the possibilty that come to my mind now.

Anyway guys : your tips help me to see more clearly about these amps and where to seek for the suitable alternative. I note all of them for reference.

Any other advice or additional info is of course welcome, of course ...

A+!

[norburybrook]

If you use a modern reverb pedal like the TC hall of fame it will work perfectly well in the loop without a Dumbleator. As will their flashback delay unit.

#102,#124 and #183 are all very well documented and would make a good start.


I went form novice to building a great #102 with the help of everyone here this year and have been over the moon with the results.

Marcus

[jam-mill]

I purchased a kit (no transformers, tubes, or cabinets) for a first-time build because sourcing all of the (correct) parts seemed a bit daunting. I purchased Mercury Magnetics iron and Stagecraft cabinets here in the US. I also sourced my own parts for various modifications, which you will have to make no matter what route you choose.

Seemingly, the most difficult part of building a d-style amp is tuning it...

All-in-all, building one of these amps is both challenging and rewarding; very much worth the effort to me.

A+!

Regards,
-jack

[tubelectron]

Thanks Marcus and Jack,

So inserting a Holy Grail Nano in the FX loop of the ODS would give the result that I want, then ? That would be fine, Marcus... So the level of the FX loop is a guitar "-10db" level, if I understand well. Right ?

I will have a further look to the 102, 124 and 183 models.

Jack : would you let me know the name and references of the kit that you have purchased, just for my information ?

A+!

[jam-mill]

Thanks Marcus and Jack,

[...]

Jack : would you let me know the name and references of the kit that you have purchased, just for my information ?

A+!

Information sent via PM...

[tubelectron]

Thanks Jack for the information.

Here in Europe, tubetown.de has the chassis and the combo/head cabs to built a Dumble-style amplifier.

I will study the #102 and #114 schematics and infos, as recommended for a start.

A+!

[norburybrook]

I think the fx loop is line level but the new TC FX will handle it fine.

I built a dumbleator just to try it as it adds another level of tone and level control as well but to be honest the TC pedlas work just as well without it.

I found my #102 didn't need much tweaking , sounded great from the word go.



Marcus

[tubelectron]

Fine Marcus,

My goal is to integrate an Holy Grail Nano inside the amp itself (like on some of my other amps : Orient-Express, Val-King), and the HGN is guitar level, so an adaptation of the loop level is probably necessary (it may be the justification of the existence of the Dumbleator ?) and not a real problem.

I have the #124 and #183 schematic, and I will search for the #102 now. I already see some common points with MKII Boogies.

Thanks again,

A+!

[bluesfendermanblues]

Fine Marcus,

My goal is to integrate an Holy Grail Nano inside the amp itself (like on some of my other amps : Orient-Express, Val-King), and the HGN is guitar level, so an adaptation of the loop level is probably necessary (it may be the justification of the existence of the Dumbleator ?) and not a real problem.

I have the #124 and #183 schematic, and I will search for the #102 now. I already see some common points with MKII Boogies.

Thanks again,

A+!

Check out user "Aflynt" 's 102 in a box. It contains both builtin reverb and a Dumblelator loop:

https://tubeamparchive.com/viewtopic.ph ... hlight=box

The reverb is not a "holy grail", but a double accutronics brick. I have built the reverb myself and IMO it's on par with a TC or similar.