Dumble ODS Build pt. 1 - Schematic Review

I'm going to scratch build a Dumble ODS (Overdrive Special) style amplifier, and in this video I review some schematics to build my plan of attack with my build.
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[@KleyDeJong]

Here is a link to a build thread recording my journey - www.tdpri.com/threads/a-unicorn-with-haunting-mids-dumble-ods-analysis-build-adventure.1055918/ D'Lite schematic - live.staticflickr.com/65535/50747812541_fa8fe5e155_o.jpg My Schematic - live.staticflickr.com/65535/51159043663_9cb490bb93_o.png

[@SuperBatiskaf]

I think, the main feature of the Dumble ODS - is the tone stack. I thinking about to modify my DRRI to apply there the Dumble Tone Stack only, let's see how it sounds

[@shovington67]

It seems to me that Dumble just did his homework well. Studied the circuits of amplifiers already on the market, and quickly realized that the larger manufacturers were often using substituted parts and substituted values when they had supplier shortages, and never checked values of parts they were getting in the first place. Dumble followed schematics to a "T", checking all parts for proper values and rejecting more the 30%-40% of the parts suppliers sent him. He used only the best parts on the market, which he scrutinized relentlessly. Probably his greatest asset was his well trained ear, and the fact that he was a guitarist who could understand what other guitarists sought in an amplifier. He was especially good at building individualized tone stacks for players, spending excessive amounts of time with each buyer in person and over the phone, tinkering until he got it right. His note taking was especially important in duplicating products for players as they needed more gear. A very good electronics engineer, but his real talent was in communication, and his ability to listen. Ive played a copy of an overdrive special, which sounded nice to me, but I've always liked the gain structure of Mesa Boogie amps myself. That of course is personal preference. I'm sure if I had the time and money to have Dumble build me an amplifier, I would have been very happy.

[@Triple3hot]

Ive always wondered if the tolerance of the values of the components mattered snd results in batch of amps not sounding the same. If there is a range of 10% are production amps identical or does it not matter as the pots can be adjusted to compensate

[@PolaOpposite]

I understood that what made Alexander's amps special is that he selected every component he put into his amp with his ears; it wasn't a matter of just following the schematic. In other words, he kept swapping out parts until he got the exact sound he wanted.

[@ignacioibanez6138]

Electronics don’t work like that, Dunble will test and return 30% of components even before put them in the circuit, and the schematics are crucial on the study of his designs and this vid make a very nice analysis so go study electronics before make such none sense comment

[@ampman5863]

One last item: R28, the NFB resistor at 4k7 allows for a lot of NFB, so this tightens up the overall response. Yet another design idea that goes along with the high filter cap values and SS rectifier. Excellent vid; keep them coming. Some of us out here really understand amps and like to see others' take on circuit design.

[@robdovi4922]

Best description and analysis of the Dumble schematic I’ve heard in a long time. (FET = field effect transistor)

[@roelschouten8834]

Thanks for the schematic mate

[@michaelsutliffe5714]

Kley: Thanks so much for a superb explanation of the ODS circuit.

[@GiuBernardi]

Nice! This is going to be an interesting series.

[@billguitarvin]

What he said, +1. Love your looking at the schematic and your analysis of the philosophy behind what the amp is doing. Wish I could give it 1,000 thumbs up. Keep up the great work and looking forward to watching the videos as you make the amp.

[@srinip]

Thank you very much. I'm no amp builder (I can barely solder!), but I thoroughly enjoyed the video.

[@petercornell2002]

Great project, looking forward to the build. Thanks

[@johnbotman2181]

I ❤️ schematics! Can't wait to watch part 2!!

[@snakebite8925]

Hey Kley, good explanation for the Dumble architecture. I have build it and it sounds fantastic. The first section is 100% Blackface sound. But I did a mod. I made a switch for placing the tonestack before or after the second gain stage. This gives me a kind of tweed sound. very useful for cloning Neil Young. In the overdrive section I build for the 220k resistor in series, the parallel circuit of a Cap 1n2 and a pot 1MB for bass regulation. That means that the caps C11 and C16 could be 47n. That gives you in low overdrive the possibility to ad some low end. I skipped the C12 and C14. Placed after R15 and R19 caps of 270 pF. In mine opinion it is better to kill the fizzy high freq before the gain stage. I have build two of these Dlones and am very happy with them. I first build an ENGL E530 clone. Very high gain but not so controlled as the Dumble clone. Keep on rock'n.

[@Skman22]

Look forward to following this build. Love your work, cheers.

[@ElektroCuration]

Very cool! I just built a SSS for a friend, and the amp is a fascinating study in tube amp design. The tones from these amps are far from hype

[@FendCore]

Brilliant and inspiring! Really liked your explanation. Thank you.

[@cameronstolhand7149]

Thank you for your videos. You make learning this stuff so much easier. 👍

[@ashleykenyon7856]

Most informative video on circuit design for Tube Amps Guitar or Hifi. Excellent Video and your description really helped me understand what he was thinking and how to go about designing and amp.

[@bradt.3555]

Also the grid stopper shaves highs but doesn't really reduce signal. To have a voltage divider you need a resistor to grd AFTER the series resistor. Series then to ground = voltage divider. Resistor to ground then series resistor = no voltage divider. The 180k before the grid will have almost 0 effect on gain but substantial treble cut.

[@MrBeblis]

VHT makes their version of a Dumble and it sounds and plays beautifully. Under a 1000

[@blave549]

Thanks so much for this! Excellent analysis and explanation.

[@MacawAviculture]

From my experience Michael Soldano built amplifiers with similar quality. Marshall built amplifiers that also gave us the classic rock sound from Hendrix to SRV. Dumble took design and build quality of guitar amps to its ultimate end point as shovington67 mentioned below in his comment. But other manufacturers have also built and designed fantastic sounding amps. I currently use a Soldano Hot Rod 25 linked to a Marshall DSL 20H and run both in stereo. Whatever sound you like can be created if you have the skill and are willing to spend the time developing it by trial and error. Great video Kley De Jong!

[@andrewdenine1685]

Great stuff . And great explanation your connecting alot of the dots that didn't make much sense to me before . I will def. Be following your channel closely . Thank you for this

[@andreberger7847]

Hey Kley, I love your video's. Very inspiring! I started a D clone too. Its my third build. Ive learnt a lot from you. Thanks. Grz from Holland. Andre

[@DemonKingOFFICIAL]

I’ve seen a schematic or two of these. Couldn’t figure out why they’re so popular through looking at them.

[@majestikj5652]

Best intro to a video ✌️

[@jloewenheim]

Great video Kley!

[@auddoc99]

Right on bro!

[@coreymihailiuk5189]

That was an excellent overview of the schematic with many insights into Dumble's build approach and sound philosophy. Never having seen one of his schematics before, I was already able to guess at a few things that he put into play. I will be very curious to hear what your finished amp will sound like. It would be very interesting to know what he chose for his various components as they would also dictate a certain tone. I am sure he experimented endlessly over the years to determine what would provide the sound he heard in his head.

[@guitarpoetone1]

Hi I'm so glad I found this video I'm a guitarist really love the explanation u give on the Dumble amp Schematics cheers on yer amp build. I love u to make me a combo 1x12 type u are fantastic thanks again

[@andrewdenine1685]

Just going through this listing to you I'm like . Damn that ratio/o.d volume I need . Every amp should have it

[@sammyrothrock6981]

I built this back in 08 I still have it..

[@dyamariv3628]

Awesome Idea for an amp Kley, I'm subscribed!! Please show us lots of the actual build please :)

[@KleyDeJong]

More coming soon!

[@rievezahl]

Great vid, would like to see more of such! Just 2 remarks I learned from trying to make a jcm800 out of rod type tubes. Didn't actually work but I can now add my knowledge: I strongly doubt 25pF caps actually cut audible highs. I had 100 and 220pF in similar configurations, but they didn't do much to the tone compared to leaving them out. I guess they rather do add stability preventing high frequency oscillations. And I miss explanations for what does most prominently determine the gain and frequency spectrum of a tube amplification stage: the preamp tubes' cathode resistors and cathode bypass caps! I believe that's where the midforward nature of the tone is actually coming from

[@KleyDeJong]

Good points thanks

[@KleyDeJong]

Good points thanks

[@chokkan7]

Very nice overview; I've enjoyed the installments that I've seen. Not to appear argumentative, but from what I've read about Dumble's 'balance' control in the driver, his goal was to dial in some imbalance. Many people, especially fans of paraphase driver amps, believe that the amps sound best when they are about 3% out of balance. Needless to say, that's a matter of taste, but I thought I'd toss it out there for your consideration. Give it a try and see what you think...

[@KleyDeJong]

Yeah interesting stuff. I do find some PI imbalance to be quite nice. I also tend to not pay the upcharge to get balanced output tubes for a similar reason.

[@ampman5863]

I've found out over the years that as you said, a certain amount of imbalance in the PI sounds much like power amp distortion, so I like some imbalance in the LTP. The paraphase inverter has long since been done away with because it distorted simply because if its design. It was mostly imbalanced. It's very hard to get a clean signal through one of these. The cathodyne PI distorts only when power tubes are driven to distort and draw grid current. This acts because the hugely differing output impedance of the plate and cathode outputs. Plate is ~40k ohm and cathode is around 667R. This is why it is mostly used with 15-18 watt amps. LTP works best for over this wattage

[@russellesimonetta3835]

I like the dumbleized tweeds! You should do a tweedle dee!

[@KleyDeJong]

That sounds like fun! I will put it on the list!

[@Lordofthethings2]

Great video Kley. Will be following this series. Btw, any idea where we can find that D'lite schematic?

[@zjokka]

07:40 Merlin Blencowe, Designing Tube Preamps for Guitar and Bass, 2nd edition, p.162: "...it is interesting to note that if the tail resistance is increased to more than about 18k, the balance becomes *worse* with this 82k:100k combination than if both anode resistors are 100k" Interesting to see that Howard just follows Leo, as does Dr. Z, ... Just to say: you need this book. Great videos btw ;-)

[@KleyDeJong]

That book is my Bible for guitar amps!

[@GertjanRoossien]

I love what you do Kley!!! I am a Trainwreck builder and I love reading schematics. I will follow your build here. I am Curious????

[@KleyDeJong]

Nice! I built a train wreck and love it!

[@moodyga40]

Dumble magic

[@rcanderson4328]

Would you do a video on Marshall YJM 100? I’d be really curious.

[@dustinbeasley]

I've always wondered if the snubber caps were actually just trimming HF content in the OD stage...or were they allowing bypass signal from the cathode side of the tube, or functioning as some kind of local NFB?

[@bradt.3555]

I wonder about the 25pf plate to cathode cap. On early amps he used 500pf, on Ford's it was 250pf, another I saw was 270pf. 25pf does almost nothing. I've never seen any other brand use that small. Could that be a misprint? I've noticed in my experimenting more that cutting treble they have a large effect on upper mid resonant peak.

[@user-om6je6mt4y]

Hello good job it appears that there is a difference between the amp schematic and yours about the connection at the top of the bass pot . Amp shows the connexion with the 0.001 cap too and in yours the 0.001 goes directly into the Rock /jazz switch. Is there any dot missing in the schematic of the video? thanks to clarify which one works

[@auddoc99]

Thanks for the tour through the schematic. Much appreciated. Please see my comment regarding my experiences servicing D's amps on Rhett Schull's page.

[@jgordonbarnes]

Love your video, Kley! Can I get a copy of the schematic used in your video?

[@KleyDeJong]

Sure, I put one in the pinned comment.

[@jgordonbarnes]

I'm sorry but I don't see it. The schematic in your video is #183 but the schematic in the link is a D'Lite Brown Note.

[@roelschouten8834]

Awesome build, where can I get a copy of the schematic?

[@KleyDeJong]

live.staticflickr.com/65535/51159043663_9cb490bb93_o.png

[@lgs6692]

Hi Kley, i don't know if this was asked before, but you talked about using EL84's for less output. i agree, what do you think about 6V6 tubes instead of EL34's ? Then you don't have to change the sockets , if you rebuild an amp. grtz Ron

[@KleyDeJong]

See parts 2 and 3 for more on that.

[@angrybirds2472]

Im gonna quote howARD, the D man himself. " Tube amps are favored because those complex harmonics and mojo is able to live and thrive in a vacuum tube and those transistors are just crystal vases and those complex sounds and harmonics suffer and perish in a crystal case.....THATS THE DIFFERENCE! The man was also using the synergy between him and his hand picked customers and doing a great job building that into those amps...... Which are also pretty much evolved from the infamous 59 Bassmans that Marshall based their original designs on. Where do you put the synergy and mojo on the schematics? Is it next to the PI balance POT???? PROBABLY Not! But i believe in the transfer of energy into objects and there's no way to prove it or write it scientifically but capturing it on recordings.....well the reason the D sound became a thing is more because of that than the parts and the builder. Have a blessed day and tell me your thoughts!

[@heh2k]

Wait, long-tail phase inverter is cathode to cathode, but that shows connected grids. So maybe the phase inverter detail isn't shown, and those are 2 input channels.

[@PurposefulPorpoise]

Does anyone know which ODS circuit this is? Skyliner? Classic?

[@jonasgrunberger5382]

Great video 👍 I also want to build one, and i also found the schematics online, but the writing is very blurry... Would you send me a copy of your schematics?

[@Paulmccarthy6801]

How about a dumble SSS how much would it cost ?

[@DavidSchneiderIP]

I am selling a 1964/65 Fender Super Reverb modded by Dumble in Santa Cruz, CA in in the early 70s. Any suggestions or inquiries are welcome. Photos, serial numbers of amp etc.

[@blucheer8743]

What’s lost in the dumble arguments is the fact he built them like Mac trucks. You could take it on the road 300 days out of the year and depend on it. Those guys that owned them truly depended on their amps and sound for their lively hood. Rock went from clubs and small venues to stadiums over night but the equipment was slow to change. Getting a custom dumble amp, built like a truck, for a guy like SRV, was the only way to go.

[@WalterHolokai]

Did you get the schematics from Howard? Sadly, he's gone now. Hope you have success in your build. I hope Howard gave the plans to you.

[@KleyDeJong]

No, I created this schematic with heavy influence from the amp garage forum. It was a very fun build. I wish I could have met Mr. Dumble!

[@literallyshaking8019]

In the ultra-high boutique, mythical, unobtanium world of amps, I’ve always felt that Trainwreck amps sound better than Dumbles (not that I’ve ever been in the same room as one of either let alone played one). For one there’s less Trainwrecks by quite a large margin, making them much more rare. But most importantly, from all accounts, Ken Fischer (the builder of Trainwreck amps) was far less reclusive than Alexander Dumble, and was more than willing to share his knowledge with anyone willing to listen. There are many current day amp builders who got their start by simply sparking a correspondence with Ken, and he guided their builds for years with suggestions, critiques and parts. Contrast that with Dumble, who was essentially a hermit, building only for those whom he deemed worthy (even then taking years to deliver) and would then “goop” his boards to hide anything and everything from prying eyes (making it a nightmare for future maintenance/repairs). To me when you add the rarity, the overall tone and the ethos of the builder I’ve always gravitated towards Kens amps. Not to mention my favorite guitar player, Trey Anastasio from the band Phish, recently started playing an original Trainwreck from the 90s, and his tone is impeccable.

[@KleyDeJong]

The two are definitely different beasts. My Trainwreck clone is a wild stallion. It is responsive and can have a bit of a mind of its own. If the builder isn't careful it can degenerate into a mess. Obscenely loud. My Dumble is more of a Cadillac. More refined and elegant. Revealing and singing. Both are fantastic. As a player I would have some mild preference to the Dumble. I think it is interesting how the myth of Mr. Dumble himself as a person has grown. He was definitely adverse to all the celebrity status. I believe the 'myth' has probably well outpaced the reality. I've heard just as many stories from people that found him to be warm, personable, and very passionate about building them the very finest amp he could - as you hear about the prickly side of things. I never met him, so I won't comment on his character. Gooping is kinda interesting. I personally love sharing information openly. I love Ken Fischer's Trainwreck Pages and have learned a ton from them. I obviously have studied the second hand information on Dumble amps quite a lot. But I also acknowledge that these men spent their life's work developing these schematics and building techniques. I also am a big fan of Mr. Fischer. He is a fantastic builder and I really appreciated how he openly shared so much of his master of his craft.

[@PolaOpposite]

The Dodge Nitro, is much more rare than a Tesla S Model, but no one in their right mind would think a Nitro is better than a Tesla simply because the Nitro is more rare. And critiquing an amp based on the manufacturer's personality is also an odd metric on which to gage the quality of an amp... it's non sequitur. As far as Trainwrecks being _better_ than a Dumble, at the level of these fine amps, it's a matter of personal taste and not a matter of your strangely constructed opinion deciding for all people which amp is qualitatively superior.

[@markmcdonald5711]

I thought Trey was playing a 5 watt Swart amp, maybe that was his solo thing as opposed to playing with the band.

[@literallyshaking8019]

@@markmcdonald5711 nope, Trey plays an original Ken Fischer built Trainwreck Express named “Jan Marie” (Ken used women’s names instead of serial numbers).

[@j.justinzimmerman9836]

Once you got going with your explanation of the schematic flow, I really enjoyed listening. It’s obvious that you were quite well prepared. Nice, clear presentation! However, I think there was more than enough talk, at the beginning, about your plans, and intentions. It was 4 minutes before you finally started the wonderful lesson. I do - fully appreciate your work. Thank you very much for sharing your time, and your talents. I’m looking forward to your upcoming videos. This has been very enlightening! JJZ…(°¿.°`)

[@johnmiller9219]

0:46 coveted

[@roncarter2188]

I might be jumping the gun here but have you thought about what you're going to use for the Transformers power and output, it seems to really get these boutique amp builds like the "Dumble"you've got to use some very robust and beefy transformers as you already know.

[@KleyDeJong]

No jumping, good question! I used transformers from Hammond. I would say they were adequately spec'd, but wouldn't say they were meaningfully over spec. I was very happy with how they performed.

[@roncarter2188]

@@KleyDeJong I've been looking into this as well and I found this company called Pacific Transformer company out of Anaheim California they are supposedly making some really good Transformers and chokes, etc. Maybe check them out.

[@roncarter2188]

@@KleyDeJong Pacific Transformer Team Up With Guitar Amplifier Icon to Create a Direct-to-Consumer Product Line of Innovative Magnetics, they teamed up with George Alessandro to produce Transformers and chokes

[@KleyDeJong]

@@roncarter2188 I've seen their website, but don't really where they sell guitar transformers. Would you need to get something custom made?

[@roncarter2188]

@@KleyDeJong I saw some on Reverb listed, I think they do custom and have others made already to go.

[@flanneldaddy5220]

Dude you’re fucking funny as shit.

[@Renshen1957]

He prefers to be called Alexander…

[@scottcorden2481]

Notorious?? 😂

[@thevillageshaman]

Hellooo? I'm wondering if I can ask a question

[@KleyDeJong]

Sure

[@HomespunEffects]

Hey Kley, can you hook me up with a copy of that schematic?

[@KleyDeJong]

Sure, here is the one I used - live.staticflickr.com/65535/51159043663_9cb490bb93_o.png and the d'lite schematic - live.staticflickr.com/65535/50747812541_fa8fe5e155_o.jpg

[@HomespunEffects]

@@KleyDeJong thanks, friend!

[@KleyDeJong]

@@HomespunEffects 👍

[@HomespunEffects]

@@KleyDeJong that 1967 Bassman that’s put on my channel isn’t my favorite amp so I think I’m going to gut it and make it into a Dumble. 👍

[@LothyBluesCave]

EL84, really? Not a good idea. Go for 6V6 at least, if you want lower output. BTW, I built a 100 w 6L6 Dumble #124 and it sounds very good and equal on every volume level. It's because the power amp makes it only louder and has very low influence to the tone by changing the level. The whole concept of this amp is based on a strong power amp and the stiff filtering. It don't think it's gonna work, if you crank it up and the power amp starts to compress, like EL84s do. You don't want power amp distortion on this one. Cheers Gerhard

[@KleyDeJong]

I appreciate your input. I definitely acknowledge that EL84's and the power supply I am proposing breaks from traditional ODS circuit design. Keep an eye out for subsequent parts as this theory evolves throughout the build in interesting ways.

[@LothyBluesCave]

@@KleyDeJong For sure I will do! Cheers

[@moodyga40]

c12 is a cap

[@leasttrending]

Im tryin to build a fuzz pedal and i wanna burn all my shit ive been working for a month and havent built one fuckin pedal.

[@jamesprice6381]

TAG KNOWS TONE NO ONE HAS A BETTER SOUND, THE QUEEN OF ENGLAND USES ONE FOR A COFFEE TABLE, NO ONE DOES IT BETTER, U DONT KNOW TONE IF U DONT KNOW DUMBLE, THANK YOU ......HAD.................

[@sidewaysrain7609]

Then...... You are not building a Dumble!

[@Docante1]

More like totally over rated

[@JonDeth]

What I found from seasoned engineers and builders where they have said the Dumble's are far more myth than unique. Their claim to fame is filtering and adding signature switches outside the fold of standard design framework to give alternate voicings. In my experience as an amateur engineer with a good amount of college behind me, is filtering can achieve virtually anything you are after, outside of your clipping style and texture pursuits. Of course, I suppose clipping style and texture is 50-70% of what we're desiring, and filtering does the rest. *Remember kids, the true "magic" to tubes is primarily they are high voltage, low bandwidth cutoff compared to semiconductors, and the control grid offers a very natural compression so it sounds warm rather than compressed.* Once you understand that with a bit more depth, you should come to the realization that semiconductors can do it better, and majority of companies behind all the boutique brands aren't typically engineers by education, it is by trade meaning trial, error and very limited theory. *In fact, having gone to a technical college which makes theory a critical area of focus, I've found conventionally educated engineers have mediocre theory with huge voids.* They can pump numbers, produce excellent circuit analysis from a topological and mathematical perspective, but their grasp on quantum mechanics and solid-state physics is dog shit.